Hip arthroplasty for the treatment of femoral neck fractures [302750]

Hip arthroplasty for the treatment of femoral neck fractures

Current concepts and a survival analysis based on the cases reported to the Romanian Arthroplasty Register

Stoica Ioan Cristian MD/PhD

Foreword

Femoral Neck Fracture represents a [anonimizat]. [anonimizat], [anonimizat], especially among elderly patients. Statistical data show that in 1990 there were 1.7 million new femoral neck fractures worldwide. It is estimated that the number of femoral fractures will reach 6.9 millions worldwide in 2050 (Cooper C., Campion G., Melton J III, Osteoporosis International, 1992, 2: 285-289). Only in Germany in 2016 the overall incidence of femoral neck fractures was 90 cases per 100,000 population. Taking into consideration only the population over 65 [anonimizat] 966 cases / 100,000 population, with wide variations depending on the regions (507/100,000 in Baden-Württemberg and 1404/100,000 in Hamburg) (Prokop A., Chmielnicki M., [anonimizat]. 29.06.2016).

From a [anonimizat]. Reduction and osteosynthesis (by various means), hemiarthroplasty (unipolar or bipolar) and total hip replacement (cemented or cementless) are the solutions that can be used. [anonimizat] 65 [anonimizat] a cause for contradictions.

Among recent research in the field (2016) it can be found out that: "[anonimizat]" (Prokop A., Chmielnicki M., [anonimizat]. 2016), or else: "[anonimizat] a primary treatment" (Kapil Nani et al., Orthopedic & Muscular System: Current Research, 18 December 2015 ).

[anonimizat] (the average cost per patient for 2 years of surgical care was $ 21,000 for osteosynthesis and $ 15,000 [anonimizat]. Acta Orthopaedica Scandinavica epub 16 Sept. 2009) justifies the need for publishing the monograph "[anonimizat] a survival analysis based on the cases reported to the Romanian Arthroplasty Register" by Dr. John Cristian Stoica.

[anonimizat], [anonimizat], illustrating both Garden and Pauwels classification. Clinical, radiological and differential diagnosis is then discussed regarding to the topic. [anonimizat]. [anonimizat], [anonimizat].

The principles and technical means of treatment by osteosynthesis are presented. [anonimizat], the immediate results, the probable complications and also the occuring incidences are reviewed. There are multiple meta-analyzes quoted that determine the value of each type of arthroplasty. The well-documented conclusion is that if osteosynthesis remains indicated for patients under the age of 65, at the time of reaching this age, in the presence of many comorbidities, a very low life expectancy and a very low activity threshold, hemiarthroplasty represents the indicated solution whereas for healthy patients over 65 years old, the indication of choice is total cemented arthroplasty, whose cost / benefit report results in finding it as the optimal solution.

I shall emphasize the importance of the chapter in which the data provided by the Romanian Arthroplasty Register between 2001 – 2015 was analyzed, in regard to the cases of femoral neck fractures treated through hip replacement. The statistical analysis highlights that the highest rate of revision in 10 years for all groups of the studied population (50-59, 60-69, 70-79) is linked to Moore type endoprosthesis (14.27%, 8.7% 4.36%). For the age group less than 49 years old at the time of intervention, 10-year revision rate indicates the highest values for Moore type endoprosthesis (7.35%) and bipolar/unipolar endoprosthesis (8.84%), whereas the lowest revision risks are indicated for total cementless (4.95%) and cemented endoprosthesis (0.00%). The pertinent conclusion of the study is that Moore type endoprosthesis, although with a low price level, easy implantation procedure and minimal blood loss, must be abandoned given its rapid deterioration, bone loss and major difficulties in achieving a total hip arthroplasty, similar to a Revision arthroplasties as exemplified by illustrative cases.

Prof. Dr. Dinu M. Antonescu

Introduction

Fractures of the femoral neck represent a common type of fracture with increased morbidity and mortality and with disabling and economically expensive consequences. They are frequently managed operatively by internal fixation or arthroplasty, with non-operative treatment generally reserved for non-ambulatory patients or for patients with high anesthetic risk.

Fractures of the hip are associated with a 30% mortality rate at one year after trauma and sometimes may be associated with an important temporary or permanent impairment of independence and quality of life [1]. It was estimated that in 1990, 1.3 million hip fractures occurred world-wide. There were 4.5 million hip fracture sufferers living and 0.7 million deaths as a result of a hip fracture [1]. Worldwide, 4.5 million persons suffer from disabilities generated by hip fractures each year, with an estimated increase to 21 million people living with a disability connected to a hip fracture by 2040 [2, 3]. About 9 million new osteoporotic fractures were estimated for the year 2000, of which 1.6 million were hip fractures, representing a 25% increase compared to 1990 when 1.3 million osteoporotic fractures were estimated worldwide [3]. Femoral neck fractures represent about 50 % of all hip fractures [4, 5].

The incidence of femoral neck in the Korean population was 29.3 per 100,000 persons. In a population older than 60 years, the incidences of femoral neck and intertrochanteric fractures men and women were 260 and 527 per 100,000 persons respectively. The incidences of femoral neck and intertrochanteric fractures exponentially increased with aging, being more common in women than in men of over 60-years-old [6].

The estimated annual cost of treating the fractures of the femoral neck is enormous and is becoming an increasingly important problem of the healthcare system. In a pilot study made in Netherlands in 14 hospitals, it was demonstrated that the mean total costs per patient after treatment with hemi- or total hip arthroplasty for femoral neck fracture were €23.869 at 1 year postoperatively and €26.399 at 2 years postoperatively. [7].

History

At the end of the 19th century, it was accepted that the displaced femoral neck fracture can not be made to heal. The widespread opinion was that the fate of the femoral head was decided at the time of the fracture since the epiphyseal arteries, which are essential for the perfusion of the femoral head, are affected and thus an avascular femoral head necrosis would inevitably arise [8].

Pauwels postulated that for biomechanical reasons, healing was not possible in displaced femoral neck fractures. According to his theory bending and shearing forces occured during load transfer of the body weight from the pelvis to the thighs preventing healing. [9]

The first successful internal fixation of a proximal femoral fracture was done in 1875 by Franz König. In 1897 and 1899, Professor Nicolaysen at the National Hospital in Oslo published his technique, and the results of closed nailing of fractures of the femoral neck in 21 patients. He performed his first operation in July 1894.

In 1925, Whitman introduced the "spica-cast" (leg-pelvis-chest) for the conservative treatment of femoral neck fractures. The results were considered acceptable with about 50% healing within 6 months [10].

The first modern osteosynthesis solution was reported by Smith-Peterson in 1930 [11]. In the 1930s the methods of osteosynthesis improved, but the results were still unsatisfactory.

The development of the endoprostheses at an acceptable level took place in the 1950s. Ultimately it went to a widespread use of endoprosthese in the treatment of the femoral neck fracture.

In 1971, in his retrospective work on 500 patients about the cause of avascular necrosis in subcapital fractures of the femur, Garden summarized that the fate of the femoral head depends on the quality of the reduction. He questioned whether the posttraumatic ischemia of the femoral head is really responsible for collapse [12].

In 1976 Barnes, Brown, Garden, and Nicoll, summarized the results of their study on 1503 patients in 19 main points. They found that the rate of deaths had significantly increased if the operation had been performed more than 3 days after the fracture and that a "delay of more than one week has no significant effect on the frequency of the development of a pseudoarthrosis or of late femoral head necrosis" [13].

In Hungary, Manninger was intensively concerned with the problem of femoral neck fractures and their operative care. Manninger followed the evolution of 740 patients, who were treated operatively from 1972-1977. He concluded that avascular necrosis of the femoral head can be significantly reduced by an early surgical intervention consisting of reduction and fixation of the fragments within the first 6 h after the onset of the fracture [14].

In the last 3-4 decades, the total endoprosthesis and the bipolar prosthesis have proved themselves useful for the treatment of the displaced fractures of the femoral head. The phase of over-therapy of the non-displaced femoral neck fractures with endoprostheses has declined, and because of the improved results of the osteosynthesis, displaced Garden III fractures are increasingly treated with osteosynthesis even in the elderly (Tabel 1).

Tabel 1. History of the treatment of femoral neck fractures

Epidemiology

Femoral neck fractures occur most frequently in female patients older than 60 years and in the white race populations from Europe and North America [15]. The high risk of femoral neck fractures in older patients is due to osteoporosis and due to increased risk of falling.

Osteoporosis is becoming an important burden for the public health in strong correlation with the aging population in the economically developed countries. The World Health Organization defines osteoporosis as a skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue with a consequent increase in bone fragility and susceptibility to fracture [16-18]. The spatial distribution of bone mass is another major determinant of load-bearing capacity of the bone. Recent studies demonstrated that femoral neck fractures may ocur in patients with normal bone mineral density, suggesting a strong correlation between femoral geometry and femoral neck fractures [18-21]. Although the bone mineral density decreases progresively with age, the risk of femoral neck fractures increases exponentially, supporting the idea that bone mineral density is the most important determinant of bone strengh, but not the only one to explain bone strength and differences in femoral geometry may have an important contribution.

The overall risk, a femoral neck fracture is between 11-23% for women and between 5-11% for men. However, the incidence is expected to quadruple in people more than 60 years old [22]. Young people are significantly less affected by a femoral neck fracture than the elderly. However young people have higher functional demands from their hip joints [23].

The main risk factors for developing a femoral neck fracture are represented by increasing age, female sex, family history of osteoporotic fractures, low body mass index, low sunlight exposure, chronic diseases, smoking and alcohol abuse.

Mechanism of injury

There are three main mechanisms of injury for femoral neck fractures. Most of these fractures occur in elderly female as a result of a low intensity trauma, generally due to a simple fall from the same level. Less frequently, a high intensity trauma is incriminated for the femoral neck fractures and this mechanism is characteristic for young male patients. Stress fractures represent one important type of femoral neck fractures and they are the result of repetitive loading, which may eventually lead to bone fractures (Tabel 2).

Tabel 2. Mechanism of injury

Classification

There are two major categories of classifications that should be considered when deciding the treatment for femoral neck fractures. The first category defines the type of fracture and includes the Garden classification, the Pauwels classification, the anatomical classification and the AO classification. The second category defines the strenght of the femoral bone and includes the Singh Index and the Dorr classification.

Garden Classification

The Garden classification (Tabel 3) was published in 1961 and it is currently the most commonly used, due to its simplicity and its role in predicting the development of the avascular necrosis of the femoral head [24].

Tabel 3. Garden classification

Figure 1. Garden I femoral neck fracture

Based on the degree of displacement, as determined by evaluating the relationship of the trabecular lines in the femoral head to those in the acetabulum on the antero-posterior x-ray, the Garden classification divides femoral neck fractures into four groups. Garden I fractures (Fig. 1) are undisplaced incomplete valgus impacted fractures. The trabecular lines in the femoral head form an angle with those in the acetabulum. Garden II fractures are undisplaced complete fractures of the femoral neck. The trabecular lines in the head are colinear with those in the acetabulum and the femoral neck distal to the fracture. Garden III fractures (Fig. 2) are complete femoral neck fractures, incompletely displaced. The trabecular lines in the femoral head form an angle with those in the acetabulum, in the opposite direction to that described for Garden I fractures. Garden IV fractures (Fig. 3) are complete fractures, completely displaced. The trabecular lines in the femoral neck are paralel, but not colinear with those in the head.

Figure 2. Garden III femoral neck fracture

Tipically, Garden I and II fractures are considered stable fractures and internal fixation will be the surgical option in the majority of patients, while Garden III and IV fractures are considered unstable fractures and they can be treated with hemiarthroplasty or total hip arthroplasty.

Figure 3. Garden IV femoral neck fractures

Pauwels Classification

The Pauwels classification (Tabel 4) takes into consideration the angle between the fracture line and the horizontal line on the antero-posterior x-ray of the hip [24]. It separates femoral neck fractures into three types. Type I (transverse type) is defined by the presence of a fracture angle of less than 30o (Figure 4). Type II (oblique type) is characterised by a fracture angle of 30-50o (Figure 5). Type III (vertical type) is a femoral neck fracture with a fracture angle of more than 50o (Figure 6). The higher this angle, the higher the shearing forces acting on the fracture gap and the risk of secondary fracture displacement, fixation failure or non-union. The reduction of conservative treatment methods for femoral neck fractures decreased the therapeutic importance of this classification.

Figure 4. Pauwels I femoral neck fracture

Figure 5. Pauwels II femoral neck fracture

Figure 6. Pauwels III femoral neck fracture

Tabel 4. Pauwels classification

Anatomical Classification

The anatomical classification takes into consideration the position of the fracture at the level of the femoral neck and includes four main types: A – subcapital, B – mediocervical, C-bazicervical and D-high angle shear fracture.

AO/OTA Classification

The AO/OTA classification (Tabel 5) has rather an academic significance, due to its limited usefulness in the routine clinical practice. The femoral neck fracture is defined as 31B based on the affected bone (3-femur), the affected segment (1-proximal) and the morphology of the fracture (type B-extraarticular fracture, femoral neck). Type B includes 3 fracture groups and each group includes 3 subgroups. The B1 group describes subcapital femoral neck fractures, with slight displacement. The B2 group describes transcervical fractures. The B3 group describes subcapital displaced fractures. Subgroups further specify fracture geometry.

Tabel 5. AO/OTA classification

Singh index

It defines the degree of osteoporosis as determined on an antero-posterior X-ray view of an intact proximal femur (Fig. 7).

Tabel 6. Singh Index

There are 5 trabecular groups described in the proximal part of the femur: the principal compression group, the secondary compression group, the principal tensile group, the secondary tensile group and the greater trochanter group. The radiolucent area between principal compression, secondary compression and primary tensile trabecular groups of the proximal femur is called Ward’s triangle. With progressing osteoporosis these trabeculae get thinner and may even disappear completely.

Grade 6 is defined by the fact that all trabeculae are visible and of normal thickness. Grade 5 is characterised by the presence of readily visible principal tensile and compression trabeculae with proeminent Ward triangle. Grade 4 is associated with thinned principal tensile trabeculae without loss of continuity.

Figure 7. Singh Index

Grade 3 is associated with thinned principal tensile trabeculae with loss of continuity. Grade 2 is characterised by the presence of principal compression trabeculae, but with other trabecular groups nearly completely resorbed. Grade 1 is associated with the presence of thin, but visible compression trabeculae. Grade 3 and below indicate the presence of definite osteoporosis (Tabel 5).

Dorr Classification

It categorizes the bone stock type on an antero-posterior X-ray view of an intact proximal femur (Tabel 7). This classification is very useful for choosing the adequate prosthetic solution (cemented or uncemented, depending on the quality of the bone stock) for patients with displaced femoral neck fractures.

Type A is defined by the presence of a narrow canal with thick cortical walls, the so-called champagne flute canal. Type B is characterised by the presence moderate thickness cortical walls. Type C is defined by the presence of a wide canal with thin cortical walls, the so-called stove-pipe canal.

Tabel 7. Dorr classification

Diagnosis of femoral neck fractures

In the majority of cases, there is a history of a low energy trauma causing the femoral neck fracture. Rarely, the fracture may be the result of high energy trauma, generally in young active patients. In 2-3% of cases, there is no history of trauma (stress or pathologic fracture) [25].

History

The history of previous medical conditions is mandatory for the correct management of these patients. In addition, the nature and the timing of the injury must be also noted. The trauma may be the result of a deterioration of a previous medical condition. There are some risk factors or medical conditions that may predispose to osteoporosis including alcohol abuse, steroids, endocrine diseases, rheumatoid arthritis, and renal failure. Osteoporosis treatment should always be considered in the postoperative period. The ingestion of anticoagulants and pre-existing malignant diseases (pathological fracture) are very important from the surgical perspective.

Physical findings

In an undisplaced femoral neck fracture, physical findings may be limited to painful range of motion of the hip, without obvious deformity. In displaced femoral neck fractures, range of motion may be very painful and the affected leg has typical deformity for proximal femur fractures – shortening and externally rotated. Yet, shortening is rarely as important as in the extracapsular intertrochanteric fractures. The intraarticular location of femoral neck fractures is responsible for the limited blood loss. Hematoma in the region of the greater trochanter can occur as a result of femoral neck fratcures. The patients present with inability to bear weight on the affected leg and inability to move the affected leg. Pressure sores should also be identified and treated adequately as these will increase the risk of postoperative septic complications.

The planning of the postoperative course requires information about the family environment of the patients in order to initiate early measures for social reintegration.

Imaging studies

Standard antero-posterior and lateral x-ray views are generally adequate for clinical decision making (Fig. 8). Moreover, in the majority of cases the diagnosis is obvious on the antero-posterior radiograph. The lateral radiograph may be difficult to obtain when pain is very important, but in some cases it may be very useful in determining the presence or the displacement of the femoral neck fracture. For many patients, a chest radiograph will be indicated as for most patients there is a high incidence of associated cardiovascular and respiratory problems.

Figure 8. Standard antero-posterior (9A) and lateral (9B) x-ray views in a patient with a femoral neck fracture

In a minority of cases, it may be impossible to visualize the fracture on plain radiographs. Historically, a technetium bone scan was considered a useful tool for the diagnosis of occult fractures of the femoral neck [26]. Although it is usually positive in cases with a femoral neck fracture, there is a risk of a false-negative result in osteopenic bone if the it is carried out within 48 to72 hours after the trauma.

In rare cases, computed tomography (CT) may be necessary to safely diagnose fractures, but it exposes the patient to further radiation. Since intracranial trauma may be associated with femoral neck fractures, the acute onset of confusion in these patients is an indication for cranial CT scan.

In uncertain cases, a magnetic resonance imaging (MRI) scan is the most useful additional imaging modality of current practice. It has been shown to be more accurate than technetium bone scan for the diagnosis of occult femoral neck fractures in the early stages after injury [27] and there is no radiation as well. It is also able to demonstrate soft tissue injuries that may be responsible for hip pain in the absence of a fracture. In other cases, MRI may be useful to assess the vitality of the femoral head after a femoral neck fracture and can be helpful in distinguishing between an old and a recently produced femoral neck fracture.

Dual-energy x-ray absorptiometry (DEXA) scans represent the best method of identifying osteoporotic patients, in order to guide postoperative treatment.

Differential diagnosis of femoral neck fractures

The femoral fracture is to be distinguished from the intertrochanteric fracture, which is associated with similar clinical symptoms, but can be clearly differentiated radiologically. Anterior pelvic ring fractures and acetabulum fractures can also lead to typical pain in the region of the hip and groin, but the external rotation of the lower limb is absent. In case of doubt, the CT examination quickly establishes the diagnostic (Table 8).

Table 8. Differential diagnosis of femoral neck fractures

Treatment

The majority of femoral neck fractures are treated surgically. Conservative treatment may be used in exceptional cases only. The prolonged bed rest of conservative treatment has too many complications (pneumonia, urinary tract infection, pressure sores, thromboembolic disease) and this is why it should be avoided. In undisplaced femoral neck fractures, the risk of a secondary displacement is very high (20 to 60%) when conservative treatment is attempted [28-31]. A displaced femoral neck fracture treated conservatively will lead in case of patient survival with great probabibility to a painful and useles limb [4].

Conservative treatment

Nonoperative treatment is an option in non-ambulatory patients before the injury, in patients with severe soft tissue problems in the surgical area or in patients with associated medical co-morbidities that represent a contraindication for surgery (Table 9). Patients can be mobilized with touch-down weight-bearing with crutches. The expected time for fracture healing is around 4 to 6 weeks. The main advantage of this method is that it avoids surgery eliminating the surgical and anesthetic risk. The disadvantages are represented by the fact that it is associated with a an important activity limitation and a 30-50% risk of secondary displacement.

Tabel 9. Indications for conservative treatment

General considerations about internal fixation

The surgical results after internal fixation of undisplaced fractures are good with high union rates (95%) and surgical complication rates of 10-15%, and this treatment is recommended by most surgeons [4,28,30-33]. Fractures in young and healthy patients are equally treated with internal fixation [28,34-36]. In the context of femoral neck fractures, young is generally considered below 60–70 years. Many of the young patients will, however, be biologically old, having significant medical comorbidities and/or drug abuse and often short life expectancy, thus being most suited for a hemiarthroplasty procedure. In the presence of symptomatic arthritis or other diseases affecting the hip joint an arthroplasty would be preferred treatment, even in young patients or patients with undisplaced fractures, as the healing prognosis is poorer and a painful hip with reduced function is a likely result even with a healed fracture. Some orthopaedic surgeons recommend internal fixation for the very elderly with important comobidities due to fear of a higher mortality in this group [37]. Yet, there is limited evidence to support this point of view. More than 100 different types of internal fixations have been identified. In theory, a sliding screw/plate device may be more stable mechanically compared with screws, but it also requires more extensive surgery with a higher risk of infection and higher blood loss. Whether a screw/plate device, or two or three or even four screws or nails is better, remains uncertain.

General considerations about arthroplasty

Most of the recent publications conclude that most patients with displaced femoral neck fractures should be treated with a hip replacement [38-43]. There are several alternatives for arthroplasty, but the most important choice is between a hemiarthroplasty and a total hip arthroplasty. In a hemiarthroplasty the acetabulum is left intact, whereas in a total hip arthroplasty the acetabulum is replaced by a prosthetic cup. There is some evidence that the relatively younger and fitter benefit from a total hip arthroplasty. This is more extensive surgery, however, and more prone to complications, and in some studies the risk of a prosthetic dislocation is as high as around 20%. In some studies, however, the rate of complications is acceptably low, especially when selecting the relatively healthiest patients, with dislocation rates of 2–4% [39-41,43]. Another important choice in arthroplasty is between components that are cemented in place or components that require bony ingrowth. Existing evidence suggest that cemented prostheses perform better, but there are few studies where modern cementless implants that do well in osteoarthritis have been used for femoral neck fractures [44,45]. The last major division in arthroplasty is between a bipolar hemiarthroplasty and a unipolar hemiarthroplasty. The theory is that the range of motion will improve and especially that the wear of the acetabulum will be reduced in bipolar hemiarthroplasty. There is, however, little evidence that there is any advantage with a bipolar solution over a simpler unipolar hemiarthroplasty, and indeed the bipolar mechanism carries a risk of complications as the prosthesis may dislocate internally.

Preoperative planning of total hip arthroplasty for femoral neck fractures

Preoperative templating of total hip arthroplasty for femoral neck fractures should be performed in all cases before surgery. The standard x-ray examination protocol should include antero-posterior and lateral views of the pelvis. The antero-posterior views are taken with the patient positioned supine and the beam centered over the pubic symphysis. A 10-15° of internal rotation is recommended to balance physiologic anteversion, but this may be difficult to obtain in the injured hip. A 10 cm diameter calibration metal coin should be placed at the level of the greater trochanter.

The Cedara software can be used for digital tempating on the contralateral side. The first step is to make a horizontal reference line tangential to the inferior point of the ischium bilaterally. The aim is to preserve length and offset as determined by the uninjured limb. The superolateral acetabular margin, the teardrop and the centre of rotation are identified. The acetabular component template is positioned and sized to maintain the native centre of rotation (at 45° of inclination relative to the horizontal). The femoral component template is positioned and sized to obtain adequate fit in the canal and to maintain the native length and offset. The femoral neck tip should overlap the centre of rotation (Fig. 9).

Figure 9. Preoperative planning of total hip arthroplasty for femoral neck fractures

Treatment algorithm (Fig. 10)

Figure 10. Femoral neck fractures treatment algorithm

The primary aim of the treatment of the femoral neck fractures is the early mobilization of the patient in order to reduce the peri/postoperative complications.

For patients with Garden I or II femoral neck fractures osteosynthesis is the preferred treatement option. However, in cases of increased surgical risk due to associated medical co-morbidities, conservative treatment should be considered. Total hip arthroplasty or hemiarthroplasty are the therapeutic solutions in case of failure of the first line treatment options for patients with Garden I or II femoral neck fractures.

For patients older than 65 years with Garden III or IV femoral neck fractures, total hip arthroplasty or hemiarthroplasty is generally the treatment of choice. In patients with high-functional demands, the total hip arthroplasty is the main surgical option. For patients with lower functional demands, in general, a hemiarthroplasty is the preferred treatment [46].

However, a fixed age limit can not be defined. The treatment option depends on the patient's associated diseases and his level of activity, and also according to the "biological" age. For example, a healthy patient older than 65 years can benefit from osteosynthesis with an acceptable risk of avascular necrosis of the femoral neck and pseudarthrosis formation. Nevertheless, the older the patient, the higher the risk of failure of osteosynthesis [47,48].

In any situation, pre-existing hip arthritis is an indication for total hip arthroplasty in the treatment of femoral neck fractures.

The development of a decision making score for the implantation of a total hip arthroplasty or hemiarthroplasty is currently considered, taking into account the activity and functional levels, as well as medical comorbidities.

Principles and surgical options for internal fixation in femoral neck fractures

The hip joint is a synovial joint providing an important range of movement due to its articulation with the acetabulum. Meanwhile, it is a joint with great strength through the thick capsule, the well-developed ligaments and muscular attachments. The normal neck-shaft angle is 131o±5o in men and 129o±5o in women [49]. There is a wide variation when speaking about the anteversion of the hip, with an average of 8o in men and 14o in women [50].

Figure 11. Blood supply to the femoral neck

Figure 12. Internal fixation for femoral neck fractures with 2 parallel screws. A – preoperative view, B – postoperative view

The blood supply to the femoral neck is very vulnerable as it relies on an extracapsular arterial ring formed around the femoral neck, derived mainly from the medial femoral circumflex artery, with some smaller branches of the lateral femoral circumflex artery anteriorly (Fig. 11). The blood supply to the femoral head is enhanced by branches from the superior and inferior gluteal arteries and the artery of ligamentum teres. The branches of the extracapsular ring penetrate beneath the capsule to form the retinacular vessels that will form the intracapsular ring in the proximal neck which supplies branches for the vascularization of the femoral head. As a result of this configuration, any fracture within the capsule will potentially damage the blood supply to the femoral head. The greater the displacement, the more important the risk for vascular compromise and increased risk of avascular necrosis of the femoral head. Therefore, prompt reduction and stable fixation is of critical importance for recovery of the blood supply to the femoral head and should be achieved as soon as possible [34].

Figure 13. Internal fixation for femoral neck fractures with 3 parallel screws

The Dutch Guideline for the treatment of femoral neck fractures describes a series of criteria for acceptable reduction and positioning of the implant for internal fixation implant [51] (Fig. 12, 13). Acceptable reduction of femoral neck fractures is defined by the following criteria: varus-valgus dislocation to a maximum Garden index of 160–180°, femoral neck shortening neutralised and dorsoventral dislocation to a maximum of 10° retroversion and 5° of anteversion. Acceptable position of cancellous screws is characterised by the following criteria: one screw placed caudally over the calcar femoris, one screw placed over the dorsal cortex and the screws positioned into the subchondral bone with the maximum distance between screw tip and femoral head lining of 5–10 mm. Acceptable position of the sliding hip screw is defined by the following criteria: the screw is positioned in the central or caudal 1/3 part of femoral head in the frontal plane, the screw is positioned in the central or dorsal part of femoral head in the sagital plane and the screw is positioned into the subchondral bone with a maximum distance between screw tip and femoral head lining of 5–10 mm.

Tabel 11. Internal fixation options for femoral neck fractures

Several implants (intramedullary or extramedullary) are available for the fixation of femoral neck fractures, each one with its advantages and disadvantages (Table 11). The main goal of the fixation is to provide the optimal conditions in which bony union can occur. The implants should be able to provide enough strength to prevent fatigue failure until the fracture healing, by resisting the normal forces acting on the hip joint [52]. In some specific situations the stability of the fixation depends mainly on the stability of the implant, as for example in comminuted fractures where stable anatomical reduction is generally not possible. In a study evaluating the strength of the commonly used implants for femoral neck fractures, Cheng et al. has demonstrated that the strength of the internally fixed femoral fractures was limited to only 71% of that of the normal femur [53]. All efforts should be made to obtain fracture reduction under closed means with image intensifier guidance, regardless of the implant of choice. An angle of reduction within the range of 160o–180o is considered satisfactory [51].

When considering the femoral neck fractures, the intramedullary devices mainly include of the various types of hip arthroplasty and cephalomedullary nails. For the treatment of younger patients with femoral neck fractures, the cephalomedullary nails respresent the main type of intramedullary implant used for fixation. Cephalomedullary nail for the treatment of femoral neck fractures, is mainly indicated in the presence of associated ipsilateral fractures of the femoral diaphysis. From the biomechanical point of view the main advantage of fixation device is that it stabilizes the fracture, allowing at the same time the distribution of the load along the femoral shaft, thus allowing patients to weight bear immediately after surgery.

Although extensive research exists concerning the use of cephalomedullary nails for diaphyseal fractures of the femur, there is a limited literature concerning the biomechanics of these devices in femoral neck fractures. Rupprecht et al., in his cadaveric study on Pauwels type III fractures, made a comparison between cephalomedullary nails with two cephalocervical screws and Dynamic Hip Screw or cannulated screw fixation [54]. Following axial loading to determine the number of cycles to failure, load to failure and femoral head displacement, he reported that cephalomedullary nails survived more cycles of loading, resisted higher loads until failure and had less displacement of the femoral head. These findings were confirmed in another cadaveric study developed by Roderer et al., who demonstrated that the cephalomedullary nails allowed for less rotational and valgus/varus displacement compared to Dynamic Hip Screw. However, this study failed to show any significant differences in the overall load failure between the two implants [55].

Fracture configuration is another important element for a succesful treatment using this type of device, in addition to the already mentioned implant strength and stiffness. In a study using artificial femora, Eberle et al. tested a cephalomedullary nail fixation in both a stable and an unstable model. He demonstrated that implants used in an unstable model fail at 28% lower loads than those with a stable model of the femoral neck fracture [56].

Vidyadhara et al., in a clinical study concerning femoral neck fractures associated with ipsilateral diaphyseal fractures, evaluated the role of the number of neck-screws for the efficiency of fixation in femoral neck fractures [57]. They suggested that one-neck screw cephalomedullary nail fixation was inferior to fixation with two-neck screws cephalomedullary nail, allowing for more displacement and a less stiffer fixation overall. Wu et al., published a biomechanical study in transcervical or subcapital fractures with ipsilateral femoral shaft fractures, suggesting that the use of a reconstruction interlocking nail combined with an additional cannulated screw eliminates complications associated with stabilization [58].

Extramedullary devices are generally indicated in the non-elderly for the treatment of both undisplaced and displaced femoral neck fractures. The application of these devices is more invasive and the surgical aggresion to the surrounding soft tissues is greater compared to intramedullary devices. Yet, the intramedullary blood supply is not further compromised [59]. The main goal of their use is to restore the anatomy of the hip joint, thus reducing the disruption of the blood flow to the femoral neck as soon as possible following the injury and increasing the potential of the femoral head to maintain its vitality. The most commonly used implants in this category in current orthopaedic practice include either cannulated screws or a Sliding Hip Screw devices.

Cannulated screws are frequently indicated in young patients with good bone stock for the treatment of both displaced and undisplaced femoral neck fractures. Biomechanically, the screws resist axial, bending and torsional forces passing through the hip. Partially threaded screws can be utilized to compress the fracture fragments during fixation, reducing the risk for a potential fracture gap and improving fracture healing [60]. However, a mojor disadvantage of their use is that during the post-operative period the patient is not allowed full weight bearing for a six to twelve weeks interval. Thus, the healing process advances adequately to sustain the normal forces at the level of the hip joint.

The effect of the orientation and number of the screws used on the fracture stability was studied by numerous authors. A convergent configuration has been demonstrated to be inferior to a divergent or parallel configuration [61]. Additionally, Holmes et al. suggested that a parallel configuration of the cannulated screwa allowed for a better reduction of fracture gap in femoral head fractures and demonstrated its superiority over non-parallel screw configurations [62]. The number of screws used for the fixation is still a mater of debate and controversy. In their study, Holmes et al. suggested that there was no difference between outcomes after using three or four cannulated screws [62]. In his biomechanical studies comparing the use of three or four screws for femoral neck fractures with or without posterior comminution, Kauffman et al. demonstrated that the three-screw fixation was stronger than the four-screw fixation in both transverse and oblique fractures, while in fractures with posterior comminution the four-screw fixation was significantly stronger, resulting in less displacement of the femoral head [63]. On the contrary, in Pauwels III fractures, Walker et al. suggested that a third screw is not necessary and that two-screw fixation is strong enough [63].

Chosing the configuration of the screws in the femoral neck is the next step after deciding upon the number of screws to be used. In transverse fractures of the femoral neck, Zdero et al. compared the inverted traingle configuration abutting the inferior, anterior and posterior cortices with that of three adjacent screws positioned parallel. He suggested that the inverted triangle construct had better mechanical stability, sustaining higher axial loads before failure and having greater torsional and axial stiffness [64]. Bishop et al. proved that the use of additional washers can further improve the fixation by distributing the force on the lateral cortex, especially in patients with osteoporosis, allowing for improved compression of the fracture site [65]. The use of washers prevents the screw head from penetrating the lateral cortex providing an improved purchase of the screws, thus reducing the risk of implant failure. Basso et al. evaluated the effect of locking plates on generating angular stability to the three screws in an inverted triangle configuration, by reducing micromotion around the fracture site. He demonstrated that an additional lateral locking plate in an inverted triangle configuration improved fracture stability and increased the resistance to shear forces [66].

The Sliding Hip Screw is composed of a lag screw that when introduced parallel to the femoral neck is able to slide within a barrel, thus allowing for a controlled collapse of the fracture site and creating an increased potential for healing. However, full weight bearing is not permitted for a period of six to twelve weeks for patients with femoral neck fractures. Kyle et al. supported that the higher the screw-plate angle, the better the bone impaction and the fracture stability [67]. Booth et al. evaluated the effect of the position of the lag screw in relation to the femoral neck and suggested that when the screw was positioned in the calcar region there was significantly improved stability, load, stiffness, and displacement compared to the central position [68]. Nonetheless, Brandt et al. showed that compression through a plate provides a much stronger fixation, allowing a better contact between the fracture ends, together with improved rotational and axial stiffness [69].

The choice of the implant for femoral neck fracture fixation depends on patient and surgeon related factors and sometimes may be difficult. Although a great number of studies have attempted to compare the biomechanical properties of different fixation techniques according to fracture characteristics, there is still no consensus about the most advantageous method.

Saglam et al. reported that three parallel cannulated screws were inferior to minimally invasive Sliding–Antirotator–Compressive Hip Screw, having lower axial, rotational stiffness and inferior compression properties [70]. Similarly, Deneka et al. suggested that a Sliding Hip Screw with an additional derotation screw offers a superior configuration with a lower failure risk in unstable fractures, compared to cannulated screws in a triangle configuration [71]. On the contrary, Holmes et al. and Clark et al. reported no difference in fixation strength between cannulated screws in an inverted triangle configuration and the Sliding Hip Screw [71, 72]. Roderer et al. compared the Dynamic Hip Screw with an antirotation centromedullary nail and advocated that the overall load to failure was similar, but fractures fixed with Dynamic Hip Screw showed more varus/valgus and rotational displacement [55].

Rupprecht et al. compared all three fixation methods (cannulated screws, dynamic hip screw and centromedullary nail) and demonstrated that centromedullary nail was superior to the other devises, whereas dynamic hip screw performed significantly better than the cannulated screws. However, none of the implants was able to restore the native mechanical strength of the hip joint [54].

Principles and surgical options for arthroplasty in femoral neck fractures

Primary replacement after a femoral head fracture may be performed with a total hip arthroplasty or a hemiarthroplasty (Fig. 14-17) (Tabel 12).

The advantages of monopolar and bipolar hemiarthroplasty compared to total hip arthroplasty include shorter surgical time and quicker postoperative mobilization of the patient, with good clinical and radiological results. In the 1950’s Moore and Thompson pioneered the first monoblock devices, which since then, have continuously developed and have gained increasing popularity for the treatment of displaced femoral neck fractures [73, 74]. In addition, the Bateman prosthesis, designed by Bateman in the early 1970s to reduce the acetabular wear associated with the Moore and Thompson prostheses, provided an important progress with improved functional outcomes [75].

Figure 14. Austin-Moore hemiartroplasty for left femoral neck fracture – A, B preoperative view, C, D postoperative view

Monopolar hemiarthroplasty may produce significant acetabular wear and subsequent complications. These problems can be reduced by choosing bipolar hemiarthroplasty or total hip arthroplasty for the treatment of displaced femoral neck fractures in the elderly. Pain relief and function are better in patients with bipolar hemiarthroplasty compared to unipolar arthroplasty. Bipolar hemiprostheses consists of a metal cup that serves as an outer head, a metal femoral component, a metal femoral head and a polyethylene insert in between. The range of motion occurs mainly at the inner bearing, thus reducing the damaging effect of metal against the acetabulum. In this way, the bipolar hemiprosthesis provides a low-friction layer at the metal head-polyethylene interface, with less frictional forces than at the outer shell-acetabulum interface [75].

These prosthetic devices are usually implanted using a lateral Hardinge approach or an anterolateral Watson-Jones approach. Both approaches provide good visualization of the acetabulum and of the proximal femur with decreased risk of postoperative prosthetic dislocation compared to a posterior approach. The major disadvantage of the transgluteal approaches is represented by the compromise of the abductor mechanism which may create difficulties concerning the early postoperative weight bearing [76,77].

One disadvantage of the bipolar hemiarthroplasty is represented by the fact that after approximately one year it will act as an unipolar hemiarthroplasty, since movements are transferred to the inner metal-polyethylene bearing in arthritic patients. Consequently, the bipolar cup tends to horizontalize and it will remain in this position. However, the exact clinical consequences of this positioning remain unclear [78-83].

Figure 15. Bipolar hemarthroplasty for left femoral neck fracture

There is a considerable complication rate in both unipolar and bipolar hemiarthroplasty, independent of the experience of the surgeon who performed the procedure. One of the most important complications of hemiarthroplasty is represented by the potential need of reoperation, sometimes conversion to total hip arthroplasty being necesssary. This may be explained by the fact that restoring the individual femoral offset is often impossible using unipolar and bipolar hemiarthroplasty.

Treatment of pre-existing arthritic conditions of the hip joint with a fracture of the femoral neck cannot be adequately performed using bipolar hemiarthroplasty. Further complications of bipolar hemiarthroplasty include intra-operative metaphyseal fractures, postoperative dislocation with a rate of 1,5-4% [84, 85], heterotopic ossification which is more frequent in cemented than in uncemented bipolar hemiarthroplasty [86], migration of the bipolar head, stem migration, failure of the polyethylene inlay or component disassembly.

Figure 16. Cemented total hip arthroplasty for left femoral neck fracture – A, B preoperative view, C, D postoperative view

Both, unipolar and bipolar hemiarthroplasty increase biomechanical stresses on the acetabulum, thus causing migration of the head with consecutive destruction. Although some reports describe little acetabular erosion [87-89], other studies demonstrated significant acetabular wear in up to 67% of cases, with an average time to failure of 38 months [90, 91]. These prostheses are therefore only recommended in old patients with limited life expectancy and low functional demands.

Figure 17. Uncemented total hip arthroplasty for right femoral neck fracture – A preoperative view, B postoperative view

In most Western European countries and in the United States, total hip arthroplasty is the main surgical option for displaced femoral neck fractures in patients older than 65 years. Total hip arthroplasty is associated with good clinical results, with significantly less pain and better outcomes compared to hemiarthroplasty [92,93]. To adequately restore physical activities after surgery, intensive rehabilitation schemes are of paramount importance.

Tabel 12. Arthroplasty options for the treatment of femoral neck fractures

With improvement of the implants, total hip arthroplasty has gained increasing attention for the treatment of displaced femoral neck fractures even in the countries traditionally treating this group of patients with internal fixation or with hemiarthroplasty devices.

Smektala et al. showed no effect of the time to surgery on mortality in a series of patients with femoral neck fractures treated with total hip arthroplasty [94]. In contrast, in a smaller study including 265 consecutive patients, Vertelis et al. suggested that delayed hospitalization of more than 6 hours after trauma was related to higher mortality [95].

Figure 18. Monoblock uncemented hemiarthroplasty – Moore prosthesis

Total hip arthroplasty is usually performed using a lateral Hardinge approach or an anterolateral Watson-Jones approach. The posterior approach can also be used, but it increases the risk of dislocation after total hip arthroplasty. The minimally invasive anterior approach is increasingly used for total hip arthroplasty and allows for immediate full weight-bearing, as only the pars reflecta of the rectus femoris is partially detached while the external rotators of the hip are protected. However, the lateral cutaneous femoral nerve may be at risk using this approach.

Figure 19. Monoblock cemented hemiarthroplasty – Thompson prosthesis

Studies comparing bipolar hemiarthroplasty and total hip arthroplasty showed that total hip arthroplasty yields improved functional results at the same complication rate one year postoperatively [96, 97]. Bipolar hemiarthroplasty showed inferior function, worse long-term results, and higher revision rates [98]. Therefore, conversion of hemiarthroplasty to total hip arthroplasty is sometimes necessary.

Figure 20. Modular unipolar hemiarthroplasty

The need for revision sugery after total hip arthroplasty for femoral neck fractures was lower at 2 years of follow-up compared to those treated with cannulated screws [79]. Conversion to total hip arthroplasty can effectively restore function and relieve pain after failed internal fixation. Moreover, due to incresed costs of revision surgery, physically fit patients may beneficially be treated with primary total hip arthroplasty [100, 101].

Figure 21. Modular bipolar hemiarthroplasty

Figure 22. Cemented total hip arthroplasty

Total hip arthroplasty is not suitable for all the patients, especially for patients with multiple co-morbidities or those with limited life expectancy. Disadvantages of total hip arthroplasty include higher blood loss and primary costs compared to bipolar or unipolar hemiarthroplasty. However, because of increased long-term survival, better outcomes and less frequent reoperations after total hip arthroplasty, the overall costs are lower, although the initial costs of total hip arthroplasty are greater compared to unipolar or bipolar devices. Iorio et al., in a study evaluating the cost effectiveness of different treatment options used for femoral neck fractures, demonstrated that total hip arthroplasty was the most cost effective treatment [99].

Figure 23. Uncemented total hip arthroplasty

The rate of revision after total hip arthroplasty is higher in patients treated for fractures than in those treated for other reasons, with dislocation and periprosthetic fracture being the most frequent causes of revision [102,103]. However, with better prosthetic designs, the 10-year survivorship of total hip arthroplasty for femoral neck fractures is constantly improving.

Hemiarthroplasty versus total hip arthroplasty

In recent studies of modular hemiarthroplasty with a minimum of four to five years follow-up, the rate of major hip complications ranged from 2% to 10% [104-107]. The most important major complications after fracture-related hip arthroplasty are dislocation, infection and periprosthetic fracture. Hemiarthroplasty carries the additional risk of acetabular erosion. In many cases, acetabular erosion has a subclinical evolution, only with radiological evidence of the condition. Treating active patients, aged over 65 years and who can walk independently before injury, with a bipolar hemiarthroplasty will lead to radiological erosion in up to two thirds of the patients. However, only one fifth will undergo revision surgery [108].

For a correct comparison between hemiarthroplasty and total hip arthroplasty, studies including the outdated monoblock hemiarthroplasty should be eliminated. Considering this, only seven randomised trials comparing total hip arthroplasty and modular hemiarthroplasty in healthy and active patients, could be identified. Four of them demonstrate better quality of life and function after total hip arthroplasty [40,93,104,108], while three showed similar functional results [109-111]. Yet, Avery and al. proved that the rate of revision after total hip arthroplasty was 2.5%, compared with 20% after hemiarthroplasty [112]. The fact that only active and healthy individuals were included in this, may have influenced to the poor outcomes following hemiarthroplasty.

Patients treated with total hip arthroplasty for femoral neck fractures had a lower level of pain and a higher level of satisfaction in comparison with patients treated with hemiarthroplasty or internal fixation, as demonstrated in a large cohort study [113]. However, hemiarthroplasty has a lower risk of dislocation than total hip arthroplasty.

The choice of total hip arthroplasty or hemiarthroplasty should take into consideration the following factors: the biological age, the activity level, health status and life expectancy. For active individuals, total hip arthroplasty is considered the best option, since hemiarthroplasty has an important risk of acetabular erosion. For those with reduced activity levels and life expectancy, hemiarthroplasty is the treatment of choice, due to a shorter operative time, less bleeding and a lower risk of dislocation.

Cemented versus uncemented fixation

The role of bone cement in fracture-related arthroplasty surgery is currently still controversial. There is an increased risk of periprosthetic fracture when using uncemented implants with metaphyseal fixation, whereas the use of bone cement for implant fixation is associated with a higher risk of fat embolisation and intra-operative death [114-116]. The rate of intra-operative death due to fat embolisation is quite rare, about 0.18%.

Five more recent randomised studies compare modern uncemented and cemented hemiarthroplasties. There were only small differences regarding the quality of life and functional outcomes between the two fixation methods. When comparing the general complications three studies showed more complications in the uncemented fixation cases, mainly due to periprosthetic fractures [106,117-118], while two studies failed to demonstrate any difference [119, 120]. The uncemented groups had a shorter surgical time and reduced blood loss. There was no difference in mortality between cemented and uncemented stems.

A study published by the Australian register demonstrated a lower risk of death for patients with uncemented implants on the first post-operative day. Yet, the mortality risk proved to be higher in the uncemented group in the interval between one week and one year after injury [122]. The Norwegian Hip Fracture Register also found that although patients with cemented hemiarthroplasty had a higher risk of death on the day of surgery and the first post-operative day, thereafter the mortality rate was equal for the two groups [123]. The risk of bone cement implantation syndrome can be reduced by thorough lavage of the femoral canal and avoidance of excessive pressurization during cementation.

The decision for choosing one type of fixation or the other should take into consideration the increased risk of perioperative mortality with cemented implants and the higher risk of periprosthetic fracture for uncemented fixation. The reports and studies of the national registers demonstrate an increased risk of periprosthetic fracture with cementless hemiarthroplasty and consequently more frequent re-operations with this type of fixation. A second fracture may be an important problem for the elderly and this may explain the increased long time mortality present in some of the registry reports.

Surgical approach

The surgical approach for fracture related arthroplasty in femoral neck fracture will influence the type and the frequency of complications. The current knowledge supports the idea that a direct lateral approach reduces the risk of dislocation compared to the posterior approach.

There is only one modern randomized controlled trial comparing the direct lateral and posterior approach in hemiarthroplasty, which failed to show any difference concerning function and pain or the incidence of complications between the two types of approaches [124]. Dislocation is a common and devastating complication after hemiarthroplasty, present in 2-3% with the direct lateral approach compared to 9-13% of patients with the posterior approach, compromising the quality of life and the functional outcomes [125].

Taking into consideration the devastating effect of recurrent dislocations and their early occurrence, the direct lateral approach is prefered for fracture related arthroplasty.

Unipolar or bipolar hemiarthroplasty

There is an increased risk of acetabular erosion following hemiarthroplasty for femoral neck fractures. The development of the bipolar hemiprosthesis was meant to reduce this risk.

Current publications offer contradictory information, being unable to support the superiority of any of these treatment options [125,126]. When active patients are treated with unipolar hemiarthroplasty, acetabular erosion may be more pronounced. Yet, it may remain undetected in the elderly patients due to their more sedentary lifestyle.

There is no convincing evidence that bipolar hemiarthroplasty decreases the risk of acetabular erosion. Thus for patients with reduced functional demands and low life expectancy, unipolar implants may preferred taking into consideration the reduced expences.

Unipolar hemiarthroplasty – modular or monoblock

The poor clinical results of the uncemented monoblock Austin-Moore or the cemented monoblock Thompson implants are demonstrated. They are rarely used nowadays, generally in low mobility patients with reduced life expectancy.

Complications

The main complications after femoral neck fractures are represented by the fixation failure and nonunion, avascular necrosis of the femoral head, reoperation (due toimplant failure, infection, dislocation or aspetic losening) and mortality (Table 13).

Tabel 13. Main complications after femoral neck fractures

Nonunion and fixation failure

Fixation failure and nonunion represent the main cause of treatment failure after fixation of femoral neck fractures. Nonunion (Fig. 24) is a rare complication in undisplaced fractures, with a reported failure rate of up to 7% of the cases. In displaced femoral neck fractures requiring reduction and fixation the incidence of nonunion is 30-50%. Slobogean et al., in a study on patients less than 60 years old showed that the incidence of nonunion after fixation of undisplaced femoral neck fractures is 5.2%, while after fixation of displaced fractures is 10% [127].

The diagnosis is usually simple with the presence of hip pain, loss of reduction and shortening of the leg, and radiological proof of fixation failure.

Figure 24. Non-union after conservatively treated right femoral neck fracture

Conversion to total hip arthroplasty is in the majority of cases the best option. In patients with low functional demands and reduced life expectancy hemiarthroplasty may be considered. Although arthroplasty after fixation failure is a straightforward procedure, the rates of dislocation and infection are increased compared to primary arthroplasty for femoral neck fractures, the functional outcomes are inferior and the survivorship of these prostheses may be shorter [129].

Avascular necrosis of the femoral head

Slobogean et al. showed, in his study group of young patients with femoral neck fractures, that the total incidence of avascular necrosis of the femoral head after internal fixation was 14.3%, with an incidence of 14,7% for displaced fractures and 6,4% for undisplaced fractures [128] (Fig. 25).

Avascular necrosis of the femoral head is a well-known complication of femoral neck fractures, but with increasing use of arthroplasty in the detriment of internal fixation and better patien selection, it is becoming less frequent in the current clinical practice [129]. Age less than 60 years and female sex are associated with a higher risk of complication [130].

The diagnosis can be made based on the clinical and standard x-ray exams (increased femoral head density or collapse), but these may be normal for a long period. However, MRI scan will diagnose the problem before standard x-rays, but it is not an accurate predictor of avascular necrosis of the femoral in the early weeks after injury [131]. The occurrence of avascular necrosis of the femoral head does not always require surgical intervention. In symptomatic cases, conversion to total hip arthroplasty is the usual treatment option. Hemiarthroplasty is a reasonable alternative if the acetabular surface is well preserved in elderly patients with reduced functional demands or associeated comorbidities.

Figure 25. Avascular necrosis of the femoral head after conservatively treated right femoral neck fracture

Reoperation

Slobogean et al. showed, in his study group of young patients with femoral neck fractures, that the overall reoperation incidence for isolated femoral neck fractures was 18.0%. The reoperation estimates were calculated for displaced fractures at 17.8% and were much lower for undisplaced fractures – 6.9% [128].

Infection

The incidence of surgical site infection was 5.1% in the study of Slobogean et al [128]. In a meta-analysis published by Bhandari et al., infection rates following internal fixation ranged up to 10% in comparison with arthroplasty infection rates which ranged up to 18%.

The risk of infection is higher with arthroplasty than with internal fixation, due to the fact that with internal fixation the operating time is shorter, the surgical exposure is minimally invasive and the implants are smaller. Moreover, the consequences are less serious following internal fixation.

The age of the patient, the functional demands, the medical comorbidities, and the infecting organism should be considered for the management of deep infection after hemiarthroplasty or total hip arthroplasty. In patients with multiple comorbidities and with an identified microorganism sensitive to common antibotics, one option would be to try to suppress the infection with low-dose antibiotic therapy. However, the presence of microorganisms such as methicillin-resistant Staphylococcus aureus in this group of patients may suggest the possibility of less radical surgical options including debridement of the hip, with partial replacement of the implant. In healthy patients, the recommended treatment option is to carry out an excision arthroplasty with reimplantation when infection is well controlled [129].

Prosthetic Dislocation in Femoral Neck Fractures

Dislocation is the most common reason for revision surgery after arthroplasty for femoral neck fractures. After unipolar hemiarthroplasty the dislocation rates with are 2%, rising to 3% following a bipolar hemiarthroplasty and to 6-8% after total hip arthroplasty.

The causes for dislocations in patients undergoing arthroplasty for femoral neck fractures are similar to those in arthroplasty for osteoarthritis: technical errors at the time of surgery, the use of the posterior approach, older prosthetic designs that may loosen easier and patient noncompliance with the usual arthroplasty precautions. Closed reduction is usually easier in unipolar and total hip implants, but the bipolar hemiarthroplasty is much more difficult to reduce closed. In cases of recurrent dislocation or irreducible dislocation, an open reduction is required, together with careful preoperative planning in order to be able to preview a potential revision of a previously malpositioned prosthetic implant [129].

Prosthetic Loosening in Femoral Neck Fractures

Prosthetic loosening tends to be a later complication of arthroplasty surgery even in patients with femoral neck fractures. The rate of loosening following bipolar hemiarthroplasty has been lower than following unipolar hemiarthroplasty [132]. The necessity for revision due to aseptic loosening is very low, considering the high mortality rate and the low functional demands in the majority of these patients. Most revision will be necessary within the first 2 years for dislocation or infection.

Mortality in Femoral Neck Fractures

Mortality in patients with femoral neck fractures is significant, with estimates of a 15% hospital mortality and a 30% mortality at 1 year. The mortality rates are similar for pertrochanteric and femoral neck fractures [133] and they are four to five times higher than in the population of the same age without a hip fracture [134]. The risk is increased in patients with significant cognitive impairment to a 1-year mortality rate of 50% and in pacients with associated medical comorbidities such as cardiorespiratory conditions or renal insuficiency. Mortality rate at 1 year following hemiarthroplasty was 38% compared with 11% after fixation for undisplaced fractures as repoted by Sikand et al. [135].

Outcomes for femoral neck fractures

Pain and function outcomes for femoral neck fractures

Multiple studies demonstrated the superiority of total hip arthroplasty over hemiarthroplasty or internal fixation in terms of pain control, improved functional outcomes and lower reoperation rate. Liao et al. showed that total hip arthroplasty is associated with better functional outcomes and lower reoperation rate when compared to hemiarthroplasty in the treatment of displaced femoral neck fractures in the elderly patients [136]. Similarly, He et al. demonstrated that in the long-term total hip arthroplasty patients exhibited significantly less pain and better function and were less likely to require a revision hip surgery [137]. In a meta-analisys Goh et al. emphasized in the long-term total hip arthroplasty patients were able to ambulate better, reported less pain compared with hemiarthroplasty, and were less likely to undergo a repeated hip surgery [138]. Burgers et al. and Yu et al. showed that total hip arthroplasty for displaced femoral neck fractures in active elderly leads to higher patient based outcomes but has higher dislocation rates compared with hemiarthroplasty [43,139]. Moreover, in their studies Jiang et al., Rogmark et al., Gao et al. and Gjertsen et al. demonstrated better functional outcomes and quality of life, less pain, less complications and lower reoperation rates for total hip arthroplasty compared to internal fixation in patients with femoral neck fractures [43,141-143].

Liu et al. demonstrated that unipolar and bipolar hemiarthroplasty achieved similar clinical outcomes in patients with displaced femoral-neck fractures concerning functional score, dislocation rates, acetabular erosion, operating time, blood loss and length of hospital [144]. Luo et al. suggested that compared with uncemented hemiarthroplasty, cemented hemiarthroplasty for treating the elderly with displaced femoral neck fractures was not associated with a higher risk of mortality, reoperation or complications. However, cemented hemiarthroplasty demonstrated a reduced the risk of residual pain and provided better functional results [145].

Economic outcomes for femoral neck fractures

Rogmark et al., in a study evaluating the costs of internal fixation and arthroplasty for displaced femoral neck fractures, concluded that primary arthroplasty is a cost efficient treatment [146]. Thakar et al., in his study evaluating the cost and consequences of proximal femoral fractures which required further surgery following initial fixation, showed that the mean cost of treatment in patients with complications was 18709£ compared with 8610£ for uncomplicated cases [147]. Zielinski et al. evaluated the societal costs of femoral neck fracture patients treated with internal fixation showing that the mean total costs per patient at 2-years follow-up were 19425€. In the non-revision surgery patients total costs were 17405€, in the implant removal patients 10066€, and in the revision arthroplasty patients 26,733€. The main contributing costs were related to the primary surgery, admission days, physical therapy, and revision surgeries [148].

Conclusions

The current evidence recommends that for active and healthy patients with a fracture of the femoral neck, the treatment of choice should be a cemented total hip arthroplasty. In patients younger than 65 years, internal fixation is the preferred alternative, considering that a secondary total hip arthroplasty may be required in case of failure of primary fixation. A patient with low functional demands and severe comorbidities will do well with a cemented, modular, unipolar hemiarthroplasty. The direct lateral approach is preferable to the posterior approach, due to reduced rates of postoperative dislocation.

Case Study: Survival analysis based on the cases reported to the Romanian Arthroplasty Register

Rationale

In Romania, femoral neck fracture represents the second pre-operative indication for primary hip replacement, after primary osteoarthritis. Based on the data extracted from the Romanian Arthroplasty Register, between 2001 – 2015, femoral neck fracture represents 31.5% of all reported diagnoses.

Taking into consideration the significant percentage, the focus of this study is to analyze all the cases reported to the Romanian Arthroplasty Register between 2001 – 2015, which underwent a hip replacement procedure, having the diagnosis of femoral neck fracture for the primary intervention.

The objective of study is to determine the survival analysis of the cases diagnosed with femoral neck fracture, treated with hip replacement, taking into consideration subgroup analysis that include demographic aspects such as gender, age group and the endoprosthesis type used.

The study is based on a population of 36.857 patients with femoral neck fracture as indication for the primary hip replacement, cases reported in 15 years (between 2001-2015) to the Romanian Arthroplasty Register.

The analysis was performed starting with the date of the first hip replacement intervention and ending with the date associated with death, revision (intervention for the removal/exchange of one part or the whole implant) or the last day of the year 2015.

The implemented statistical methods refer to Kaplan–Meier estimates of survival probabilities, Nelson-Aalen cumulative hazard estimates of the revision rates and Cox regression for the risk analysis outcomes.

Femoral neck fracture diagnosis is predominant in elderly patients due to increasing osteoporosis and an increased risk of falling with increasing age. Consequences of aging on the hip joint (osteoporosis, varisation of the femoral neck), as well as reduction of psycho-physical abilities of a patient (neuromuscular incoordination, fear from activities) and comorbidities predispose elderly to hip joint fracture.

This remark can be extended when analyzing the Romanian patients which suffered a femoral neck fracture, and have been treated with a hip replacement procedure.

With a mean age at the time of intervention of 74.02 (73.92 – 74.13), 71.84% of the patients are aged over 70 years old. Gender distribution indicates an important predominance of 69.8% (n = 25.727) of the cases for female patients, meanwhile the male patients represent only 1/3rd of the total population (n = 11.130).

Figure 26 – Patients gender distribution, arthroplasty for femoral neck fracture, 2001-2015

Figure 27 – Age distribution at time of surgery, femoral neck fracture patients, 2001-2015

Types of endoprosthesis used for hip replacement in femoral neck fractures

There is a multitude of publications in the current literature that focus on comparing the evolution and survival of different types of endoprosthesis used for the treatment of patients diagnosed with femoral neck fractures. In the case of the Romanian patients diagnosed with femoral neck fracture, the hip replacement procedure has been performed using different type of endoprosthesis with a remarkable uniform distribution (Table 15). Hemiarthrolasties including bipolar/unipolar and Moore endoprosthesis were preferred for the treatment of 84.31% of the total number of patients, while total hip replacement was used in only 15.69% of the total number of cases.

Table 15 – Implant type distribution for primary hip replacement endoprosthesis, femoral neck fracture, 2001 – 2015

The heterogenous distribution led to the extended analysis of the survivorship comparison of each endoprosthesis type, first including an overall comparison of the survival rate at 10 years from the time of the intervention and also performing a risk analysis adjusted by two of the most important covariates of the focus: the age of the patients at time of intervention and the gender.

10-years Survival Perspective

In terms of general survival perspective, Kaplan Meyer estimates of survival analysis offers a clear perspective of the overall phenomenon, when comparing the different types of endoprosthesis. Because of the use under 1.5% of hybrid total hip replacement and reversed hybrid total hip replacement, the two groups were excluded from the analysis.

Table 16 – 10 years cumulative survival rate for primary hip replacement endoprosthesis, femoral neck fracture, 2001 – 2015

The analysis of all age groups indicates minor differences in terms of 10 years cumulative survival rates. The lowest rate corresponds to Moore hemiarthropasty, while the highest survival is associated to bipolar or unipolar hemiarthroplasty, each endoprosthesis type aiming around a 95% survival rate at 10 years (Table 16).

It must be taken into consideration that, as we stated previously, the revision rates are unadjusted by important covariates, reason to extend the survival analysis by studying endoprosthesis evolution by specific age groups and gender – as the population studied clearly lacks distribution homogeneity.

10-years Revision Hazard Rate. Age group <49 years old at time of intervention

Despite the overall survival analysis, the survival studied on particular age groups indicates visible differences between different types of endoprosthesis. For young patients, with less than 49 years at the time of surgery, Nelson-Aalen cumulative hazard indicates that the lowest estimates for revision of the primary implant in 10 years belongs to cemented total hip replacement, none of the cases suffering a revision intervention during a 10 years follow-up period. Remaining in the zone of the least revised endoprosthesis, uncemented total hip replacement returns a cumulative hazard rate for revision of 4.95% in 10 years (Table 17, Figure 28).

Table 17 – 10-years Revision Hazard Rate by type of endoprosthesis – Age group <49 years

Figure 28. Nelson-Aalen cumulative hazards – patients < 49 years treated by hip replacement

On the contrary, hemiarthroplasties have almost double risk for 10-years revision rates: Moore hemiarthroplasty – 7.35% and bipolar and unipolar hemiarthropasty – 8.84%. For young patients, less than 49 years old, total hip replacement represents without doubt the treatment with the lowest revision rates in the case of femoral neck fractures.

10-years Revision Hazard Rate. Age group 50 – 59 years old at time of intervention

Table 18 – 10-years Revision Hazard Rate by type of endoprosthesis – Age group 50-59

For patients aged between 50–59 years old at time of intervention, Moore hemiarthroplasty presents a concerning cumulative revision rate of 14.27% in 10 years from the primary procedure. In the same category, bipolar and unipolar hemiarthroplasty is at the opposite pole compared to Moore hemiartrhoplasty, with 4.35% cumulative revision rate in 10 years (Table 18, Figure 29).

Figure 29. Nelson-Aalen cumulative hazards – patients 50-59 years treated by hip replacement

10-years Revision Hazard Rate. Age group 60 – 69 years old at time of intervention

For patients aged between 60–69 years old at time of intervention, Moore hemiarthroplasty presents a cumulative revision rate of 8.7% in 10 years from the primary procedure. In the same category, uncemented total hip replacement is at the opposite pole compared to Moore hemiartrhoplasty, with 3.37% cumulative revision rate in 10 years (Table 19, Figure 30).

Table 19 – 10-years Revision Hazard Rate by type of endoprosthesis – Age group 60-69

Figure 30. Nelson-Aalen cumulative hazards – patients 60-69 years treated by hip replacement

10-years Revision Hazard Rate. Age group 70 – 79 years old at time of intervention

For patients aged between 70–79 years old at time of intervention, Moore hemiarthroplasty presents a cumulative revision rate of 4.36% in 10 years from the primary procedure. In the same category, cemented total hip arthroplasty is at the opposite pole compared to Moore hemiarthroplasty, with 0,02% cumulative revision rate in 10 years (Table 20, Figure 31).

Moore hemiarthroplasty presents a higher cumulative revision rate in 10 years from the primary procedure compared to other types of endoprosthesis used for the treatment of femoral neck fractures no matter the age group studied.

Table 20 – 10-years Revision Hazard Rate by type of endoprosthesis – Age group 70-79

Figure 31. Nelson-Aalen cumulative hazards for patients 70-79 years treated by hip replacement

For patients aged between 70–79 years old at time of intervention, Moore hemiarthroplasty presents a cumulative revision rate of 4.36% in 10 years from the primary procedure. In the same category, cemented total hip arthroplasty is at the opposite pole compared to Moore hemiarthroplasty, with 0,02% cumulative revision rate in 10 years (Table 20, Figure 31).

Moore hemiarthroplasty presents a higher cumulative revision rate in 10 years from the primary procedure compared to other types of endoprosthesis used for the treatment of femoral neck fractures no matter the age group studied.

Monopolar hemiarthroplasty – Is it time to eliminate this surgical option?

Femoral neck fracture is a common indication for hemiarthroplasty in the elderly. The Austin Moore hemiarthroplasty was introduced in the 1950s. It is a press-fit non-porous coated perforated and collared femoral stem, included in the category of monobloc cementless hemiarthroplasty systems. Although modern modular hemiarthroplasty and total hip arthroplasty systems have been introduced for many years, the Austin-Moore hemiarthroplasty continues to be an important surgical option for the treatment of femoral neck fracture in the less economically developed countries.

This is supported by the findings of our research, which shows that 70,15% of the femoral neck fractures reported to the Romanian Artrhroplasty Register between 2001-2015 requiring an endoprosthetic solution, were treated by Austin-Moore hemiarthroplasty. Although early reports about the results of monoblock hemiarthroplasty demonstrate poor outcomes in terms rapid mechanical loosening and thigh pain, they continue to be used on a regular basis in our country. The main argument explaining this may be represented by the initial low costs of Austin-Moore hemiarthroplasty. However, the total costs related to early revision after this type of surgery may be much higher, supporting the oppinion of some leading arthroplasty surgeons that monoblock hemiarthroplasty should be eliminated from the therapeutic arsenal. Secondly,

orthopaedic surgeons are concerned about the embolic complications and mortality related to cementing techniques in the elderly with associated important co-morbidities.

Implantation of a total hip arthroplasty system in patients with previous Austin-Moore hemiarthroplasty is technically demanding due to the presence in many cases of associated large bony defects both on the acetabular and femoral side. The surgical procedure itself should be considered a real revision arthroplasty due to the increased surgical difficulties and to the fact that the initial arthroplasty system should be completely eliminated. Thus, we recommend not using the term conversion arthroplasty for this type of surgery, a term frequently used by a large number of surgeons in the past years.

A change in the healthcare policy should be considered during the future period. This will allow improvement of subjective and objective outcomes after endoprosthetic treatment for femoral neck fractures as well as reduction of the total social medical and social costs after this type of surgery.

In order to better support our „pleading”, we will present a series of clinical cases of revision of an Austin-Moore hemiarthroplasty to total hip arthroplasty. This is meant to present the technical difficulties the orthopaedic surgeon encounters when performing this surgical procedure.

Studied Case 1

Preoperatively – painful Moore hemiarthroplasty with proximal migration of the center of rotation of the right hip

Postoperatively – hybrid total hip arthroplasty with acetabular reconstruction with a tantalum augment

Studied Case 2

Preoperatively – painful right hip after Moore hemiarthroplasty, with supero-medial migration of the prosthesis

Postoperatively – revision surgery using an uncemented total hip arthroplasty, with reconstruction of the acetabular defect with morselized allograft

Studied Case 3

Preoperatively – early postoperative pain after Moore hemiarthroplasty, due to defixation of the prosthesis

Postoperatively – revision cemented total hip arthroplasty

Studied Case 4

Preoperatively – implant failure after Thompson cemented hemiarthoplasty for a femoral neck fracture

Postoperatively – after revision uncemented total hip arthroplasty

References

1. Johnell O, Kanis JA (2004) An estimate of the worldwide prevalence, mortality and disability associated with hip fracture. Osteoporos Int 15(11):897–902

2. Cooper C, Campion G, Melton LJ 3rd (1992) Hip fractures in the elderly: a world-wide projection. Osteoporos Int 2(6):285–289

3. Johnell O, Kanis JA (2006) An estimate of the worldwide prevalence and disability associated with osteoporotic fractures. Osteoporos Int 17(12):1726–1733

4. Handoll HH, Parker MJ (2008) Conservative versus operative treatment for hip fractures in adults. Cochrane Database Syst Rev 3:CD000337

5. Zielinski SM, Meeuwis MA, Heetveld MJ, Verhofstad MH, Roukema GR, Patka P, Van Lieshout EM (2013) Adherence to a femoral neck fracture treatment guideline. Int Orthop. 2013 Jul;37(7):1327-34

6. Yoon BH, Lee YK, Kim SC, Kim SH, Ha YC, Koo KH (2013) Epidemiology of proximal femoral fractures in South Korea. Arch Osteoporos. 2013;8:157

7. Burgers PT, Hoogendoorn M, Van Woensel EA, Poolman RW, Bhandari M, Patka P, Van Lieshout EM (2016) Total medical costs of treating femoral neck fracture patients with hemi- or total hip arthroplasty: a cost analysis of a multicenter prospective study. Osteoporos Int. 2016 Jun;27(6):1999-2008

8. Cooper A (1822) Dislocations and fractures. 1 edn. John Churchill, London

9. Pauwels F (1935) Der Schenkelhalsbruch ein mechanisches Problem. Ferdinand Enke, Stuttgart, S 75

10. Whitman R (1925) The abduction treatment of fractures of the neck of the femur. Ann Surg 81: 374

11. Smith-Petersen MD, Cavé EF, Gorder GW van (1931) Intracapsular fracture of the femur. Treatment by internal fixation. Arch Surg 23: 715

12. Garden RS (1971) Malreduction and avascular necrosis in subcapital fractures of the femur. J Bone Joint Surg Br 53: 183–189

13. Barnes R, Brown JT, Garden RS, Nicoll EA (1976) Subcapital fractures of the femur. A prospective review. J Bone Joint Surg Br 58: 2–24

14. Manninger J, Kazar G, Fekete G et al. (1989) Significance of urgent (within 6 h) internal fixation in the management of fractures of the neck of the femur. Injury 20: 101–105

15. Kannus P, Parkkari J, Sievanen H, et al. Epidemiology of hip fractures. Bone. 1996;18(suppl 1):57S–63S

16. European Foundation for Osteoporosis Bone Disease, National Osteoporosis Foundation, National Institute of Arthritis and Musculoskeletal and Skin Diseases (1993) Consensus development conference: diagnosis, prophylaxis, and treatment of osteoporosis. Am J Med 94:646–650

17. Kanis JA (1994) Assessment of fracture risk and its application to screening for postmenopausal osteoporosis: synopsis of a WHO report. WHO Study Group. Osteoporos Int 4:368–381

18. Kim KM, Brown JK, Kim KJ, Choi HS, Kim HN, Rhee Y, Lim SK (2011) Differences in femoral neck geometry associated with age and ethnicity. Osteoporos Int. 2011 Jul;22(7):2165-74

19. El-Kaissi S, Pasco JA, Henry MJ et al (2005) Femoral neck geometry and hip fracture risk: the Geelong osteoporosis study. Osteoporos Int 16:1299–1303

20. Szulc P, Duboeuf F, Schott AM, Dargent-Molina P, Meunier PJ, Delmas PD (2006) Structural determinants of hip fracture in elderly women: re-analysis of the data from the EPIDOS study. Osteoporos Int 17:231–236

21. Kaptoge S, Beck TJ, Reeve J et al (2008) Prediction of incident hip fracture risk by femur geometry variables measured by hip structural analysis in the study of osteoporotic fractures. J Bone Miner Res 23:1892–1904

22. Fitschen-Oestern, Lippross, Klüter, Behrend, Weuster, Seekamp A (2016) Femoral neck fractures in young patients. Unfallchirurg. 2016 Sep;119(9):763-80

23. Malchau H, Herberts H, Eisler T, Garellick G, Soderman P (2002) The Swedish total hip replacement register. J Bone Joint Surg Am 84–A(2):2–20

24. Pauwels F (1935) Der Schenkelhalsbruch, ein mechanisches Problem. Z Orthop Ihre Grenzgeb 63:1–135

25. Hodgkinson JP, Meadows TH, Davies DR, et al. A radiological assessment of interprosthetic movement in the Charnley-Hastings hemiarthroplasty. Injury. 1988;19(1):18–20

26. Fairclough J, Colhoun E, Johnston D, et al. Bone scanning for suspected hip fractures. A prospective study in elderly patients. J Bone Joint Surg. 1987;69B:251–253

27. Rizzo PF, Gould ES, Lyden JP, et al. Diagnosis of occult fractures about the hip. Magnetic resonance imaging compared with bone scanning. J Bone Joint Surg. 1993;75A:395–401

28. Parker MJ, White A, Boyle A. Fixation versus hemiarthroplasty for undisplaced intracapsular hip fractures. Injury 2008; 39(7): 791-795

29. Jensen J, Hogh J. Fractures of the femoral neck. A follow-up study after non-operative treatment of Garden’s stage 1 and 2 fractures. Injury 1983; 14(4):

339-342

30. Parker MJ, Pryor GA. Treatment of undisplaced subcapital fractures. J R Coll Surg Edinb 1992; 37(4): 263-264

31. Cserhati P, Kazar G, Manninger J, Fekete K, Frenyo S. Non-operative or operative treatment for undisplaced femoral neck fractures: a comparative study of 122 non-operative and 125 operatively treated cases. Injury 1996; 27(8): 583-588

32. Chen WC, Yu SW, Tseng IC, Su JY, Tu YK, Chen WJ. Treatment of undisplaced femoral neck fractures in the elderly. J Trauma 2005; 58(5): 1035-1098

33. Conn KS, Parker MJ. Undisplaced intracapsular hip fractures: results of internal fixation in 375 patients. Clin Orthop 2004; (421): 249-254

34. Damany DS, Parker MJ, Chojnowski A. Complications after intracapsular hip fractures in young adults. A meta-analysis of 18 published studies involving 564 fractures. Injury 2005; 36(1): 131-141

35. Zetterberg CH, Irstam L, Andersson GB. Femoral neck fractures in young adults. Acta Orthop Scand 1982; 53(3): 427-435

36. Gray AJ, Parker MJ. Intracapsular fractures of the femoral neck in young patients. Injury 1994; 25(10): 667-669

37. Parker MJ, Khan RJ, Crawford J, Pryor GA. Hemiarthroplasty versus internal fixation for displaced intracapsular hip fractures in the elderly. A randomised trial of 455 patients. J Bone Joint Surg Br 2002; 84(8): 1150-1155

38. Frihagen F, Nordsletten L, Madsen JE. Hemiarthroplasty or internal fixation for intracapsular displaced femoral neck fractures: randomised controlled trial. BMJ 2007; 335(7632): 1251-1254

39. Bhandari M, Devereaux PJ, Swiontkowski MF, Tornetta P, III, Obremskey W, Koval KJ et al. Internal fixation compared with arthroplasty for displaced fractures of the femoral neck. A meta-analysis. J Bone Joint Surg Am 2003; 85-A(9): 1673-1681

40. Keating JF, Grant A, Masson M, Scott NW, Forbes JF. Randomized comparison of reduction and fixation, bipolar hemiarthroplasty, and total hip arthroplasty. Treatment of displaced intracapsular hip fractures in healthy older patients. J Bone Joint Surg Am 2006; 88(2): 249-260

41. Blomfeldt R, Tornkvist H, Ponzer S, Soderqvist A, Tidermark J. Comparison of internal fixation with total hip replacement for displaced femoral neck fractures. Randomized, controlled trial performed at four years. J Bone Joint Surg Am 2005; 87(8): 1680-1688

42. Rogmark C, Carlsson A, Johnell O, Sernbo I. A prospective randomised trial of internal fixation versus arthroplasty for displaced fractures of the neck of the femur. Functional outcome for 450 patients at two years. J Bone Joint Surg Br 2002; 84(2): 183-188

43. Rogmark C, Johnell O. Primary arthroplasty is better than internal fixation of displaced femoral neck fractures: a meta-analysis of 14 randomized studies with 2,289 patients. Acta Orthop 2006; 77(3): 359-367

44. Khan RJ, MacDowell A, Crossman P, Datta A, Jallali N, Arch BN et al. Cemented or uncemented hemiarthroplasty for displaced intracapsular femoral neck fractures. Int Orthop 2002; 26(4): 229-232

45. Khan RJ, MacDowell A, Crossman P, Keene GS. Cemented or uncemented hemiarthroplasty for displaced intracapsular fractures of the hip – a systematic review. Injury 2002; 33(1): 13-17

46. Braun KF, Hanschen M, Biberthaler P. Fracture arthroplasty of femoral neck fractures. Unfallchirurg. 2016 Apr;119(4):331-4

47. Strohm PC, Raschke M, Hoffmann R, Josten C Hip fracture prosthetics in German trauma surgery. State of the art. Unfallchirurg (2015) 118(2):173–176

48. Miyamoto RG, Kaplan KM, Levine BR, Egol KA, Zuckerman JD. Surgical management of hip fractures: an evidence-based review of the literature. I: femoral neck fractures (2008). J Am Acad Orthop Surg 16(10):596–607

49. Nissen N, Hauge EM, Abrahamsen B, Jensen JE, Mosekilde L, Brixen K. Geometry of the proximal femur in relation to age and sex: a cross-sectional study in healthy adult Danes. Acta Radiol 2005;46:514–8

50. Yoshioka Y, Siu D, Cooke TD. The anatomy and functional axes of the femur. J Bone Joint Surg Am 1987;69:873–80

51. NVvH (Definitief concept 5-11-2007 (Final draft 5-11-2007) Guideline: Treatment of proximal femur fracturesin the elderly patient

52. Panteli M, Rodham P, Giannoudis PV. Biomechanical rationale for implant choices in femoral neck fracture fixation in the non-elderly. Injury. 2015 Mar;46(3):445-52

53. Cheng XG, Lowet G, Boonen S, Nicholson PH, Brys P, Nijs J, et al. Assessment of the strength of proximal femur in vitro: relationship to femoral bone mineral density and femoral geometry. Bone 1997;20:213–8

54. Rupprecht M, Grossterlinden L, Ruecker AH, de Oliveira AN, Sellenschloh K, Nuchtern J, et al. A comparative biomechanical analysis of fixation devices for unstable femoral neck fractures: the intertan versus cannulated screws or a dynamic hip screw. J Trauma 2011;71:625–34

55. Roderer G, Moll S, Gebhard F, Claes L, Krischak G. Side plate fixation vs. intramedullary nailing in an unstable medial femoral neck fracture model: a comparative biomechanical study. Clin Biomech (Bristol Avon) 2011;26: 141–6

56. Eberle S, Bauer C, Gerber C, von Oldenburg G, Augat P. The stability of a hip fracture determines the fatigue of an intramedullary nail. Proc Inst Mech Eng H J Eng Med 2010;224:577–84

57. Vidyadhara S, Rao SK. Cephalomedullary nails in the management of ipsilateral neck and shaft fractures of the femur – one or two femoral neck screws? Injury 2009;40:296–303

58. Wu CC, Tai CL. Reconstruction interlocking nails for ipsilateral femoral neck and shaft fractures: biomechanical analysis of effect of supplementary cannulated screw on intracapsular femoral neck fracture. Clin Biomech (Bristol Avon) 2009;24:642–7

59. Liu M, Yang Z, Pei F, Huang F, Chen S, Xiang Z. A meta-analysis of the Gamma nail and dynamic hip screw in treating peritrochanteric fractures. Int Orthop 2010;34:323–8

60. Wu CC. Using biomechanics to improve the surgical technique for internal fixation of intracapsular femoral neck fractures. Chang Gung Med J 2010;33: 241–51

61. Christie J, Howie CR, Armour PC. Fixation of displaced subcapital femoral fractures. Compression screw fixation versus double divergent pins. J Bone Joint Surg Br 1988;70:199–201

62. Holmes CA, Edwards WT, Myers ER, Lewallen DG, White 3rd AA, Hayes WC. Biomechanics of pin and screw fixation of femoral neck fractures. J Orthop Trauma 1993;7:242–7

63. Kauffman JI, Simon JA, Kummer FJ, Pearlman CJ, Zuckerman JD, Koval KJ. Internal fixation of femoral neck fractures with posterior comminution: a biomechanical study. J Orthop Trauma 1999;13:155–9

64. Zdero R, Keast-Butler O, Schemitsch EH. A biomechanical comparison of two triple-screw methods for femoral neck fracture fixation in a synthetic bone model. J Trauma 2010;69:1537–44

65. Bishop JA, Behn AW, Castillo TN. The biomechanical significance of washer use with screw fixation. J Orthop Trauma 2014;28:114–7

66. Basso T, Klaksvik J, Foss OA. The effect of interlocking parallel screws in subcapital femoral-neck fracture fixation: a cadaver study. Clin Biomech (Bristol Avon) 2014;29:213–67. Kyle RF, Wright TM, Burstein AH. Biomechanical analysis of the sliding characteristics of compression hip screws. J Bone Joint Surg Am 1980;62: 1308–14

68. Booth KC, Donaldson TK, Dai QG. Femoral neck fracture fixation: a biomechanical study of two cannulated screw placement techniques. Orthopedics 1998;21:1173–6

69. Brandt E, Verdonschot N, van Vugt A, van Kampen A. Biomechanical analysis of the percutaneous compression plate and sliding hip screw in intracapsular hip fractures: experimental assessment using synthetic and cadaver bones. Injury 2006;37:979–83

70. Saglam N, Kucukdurmaz F, Kivilcim H, Kurtulmus T, Sen C, Akpinar F. Biomechanical comparison of antirotator compression hip screw and cannulated screw fixations in the femoral neck fractures. Acta Orthop Traumatol Turc 2014;48:196–201

71. Deneka DA, Simonian PT, Stankewich CJ, Eckert D, Chapman JR, Tencer AF. Biomechanical comparison of internal fixation techniques for the treatment of unstable basicervical femoral neck fractures. J Orthop Trauma 1997;11:337–43

72. Clark DI, Crofts CE, Saleh M. Femoral neck fracture fixation. Comparison of a sliding screw with lag screws. J Bone Joint Surg Br 1990;72:797–800

73. Moore AT: The self-locking metal hip prosthesis. J Bone Joint Surg Am1957, 39:811-827.

74. Thompson FR: Vitallium intramedullary hip prosthesis, preliminary report. N Y State J Med 1952, 52:3011-3020

75. Bateman JE: Single-assembly total hip prosthesis–preliminary report. Clin Orthop Relat Res 1990, 251:3-6, 1974

76. Bauer R, Kerschbaumer F, Poisel S, Oberthaler W: The transgluteal approach to the hip joint. Arch Orthop Trauma Surg 1979, 95:47-49

77. Heimkes B, Posel P, Bolkart M: The transgluteal approaches to the hip. Arch Orthop Trauma Surg 1992, 111:220-223

78. Parvizi J, Pour AE, Peak EL, Sharkey PF, Hozack WJ, Rothman RH: One-stage bilateral total hip arthroplasty compared with unilateral total hip arthroplasty: a prospective study. J Arthroplasty 2006, 21(Suppl 2):26-31

79. Tidermark J, Ponzer S, Svensson O, Soderqvist A, Tornkvist H: Internal fixation compared with total hip replacement for displaced femoral neck fractures in the elderly. A randomised, controlled trial. J Bone Joint Surg Br 2003, 85:380-308

80. Bhattacharyya T, Koval KJ: Unipolar versus bipolar hemiarthroplasty for femoral neck fractures: is there a difference? J Orthop Trauma 2009, 3:426-427

81. Cornell CN, Levine D, O’Doherty J, Lyden J: Unipolar versus bipolar hemiarthroplasty for the treatment of femoral neck fractures in the elderly. Clin Orthop Relat Res 1998, 348:67-71

82. Ong BC, Maurer SG, Aharonoff GB, Zuckerman JD, Koval KJ: Unipolar versus bipolar hemiarthroplasty: functional outcome after femoral neck fracture at a minimum of thirty-six months of follow-up. J Orthop Trauma 2002, 16:317-322.

83. Raia FJ, Chapman CB, Herrera MF, Schweppe MW, Michelsen CB, Rosenwasser MP: Unipolar or bipolar hemiarthroplasty for femoral neck fractures in the elderly? Clin Orthop Relat Res 2003, 414:259-265

84. Barnes CL, Berry DJ, Sledge CB: Dislocation after bipolar hemiarthroplasty of the hip. J Arthroplasty 1995, 10:667-669

85. Figved W, Norum OJ, Frihagen F, Madsen JE, Nordsletten L: Interprosthetic dislocations of the Charnley/Hastings hemiarthroplasty–report of 11 cases in 350 consecutive patients. Injury 2006, 37:157-161

86. Chen TH, Huang CK, Chen WM, Chiang CC, Lo WH: Heterotopic ossification after cemented or uncemented bateman bipolar hemiarthroplasty. Zhonghua Yi Xue Za Zhi (Taipei) 1998, 61:520-523

87. Devas M, Hinves B: Prevention of acetabular erosion after hemiarthroplasty for fractured neck of femur. J Bone Joint Surg Br 1983, 65:548-551

88. Langan P: The Giliberty bipolar prosthesis: a clinical and radiographical review. Clin Orthop Relat Res 1979, 141:169-175

89. Long JW, Knight W: Bateman UPF prosthesis in fractures of the femoral neck. Clin Orthop Relat Res 1980, 152:198-201

90. Coleman SH, Bansal M, Cornell CN, Sculco TP: Failure of bipolar hemiarthroplasty: a retrospective review of 31 consecutive bipolar prostheses converted to total hip arthroplasty. Am J Orthop 2001, 30:313-319

91. Moon KH, Kang JS, Lee TJ, Lee SH, Choi SW, Won MH: Degeneration of acetabular articular cartilage to bipolar hemiarthroplasty. Yonsei Med J 2008, 49:719-724

92. Mainard D, Guillemin F, Cuny C, Mejat-Adler E, Galois L, Delagoutte J: Quality of life assessment one year after total hip or knee arthroplasty. Rev Chir Orthop Reparatrice Appar Mot 2000, 86:464-473

93. Macaulay W, Nellans KW, Garvin KL, Iorio R, Healy WL, Rosenwasser MP: Prospective randomized clinical trial comparing hemiarthroplasty to total hip arthroplasty in the treatment of displaced femoral neck fractures: winner of the Dorr Award. J Arthroplasty 2008, 23(Suppl 1):2-8

94. Smektala R, Endres HG, Dasch B, Maier C, Trampisch HJ, Bonnaire F, Pientka L: The effect of time-to-surgery on outcome in elderly patients with proximal femoral fractures. BMC Musculoskelet Disord 2008, 9:171

95. Vertelis A, Robertsson O, Tarasevicius S, Wingstrand H: Delayed hospitalization increases mortality in displaced femoral neck fracture patients. Acta Orthop 2009, 80:683-686

96. Blomfeldt R, Tornkvist H, Eriksson K, Soderqvist A, Ponzer S, Tidermark J: A randomised controlled trial comparing bipolar hemiarthroplasty with total hip replacement for displaced intracapsular fractures of the femoral neck in elderly patients. J Bone Joint Surg Br 2007, 89:160-165

97. Blomfeldt R, Tornkvist H, Ponzer S, Soderqvist A, Tidermark J: Displaced femoral neck fracture: comparison of primary total hip replacement with secondary replacement after failed internal fixation: a 2-year follow-up of 84 patients. Acta Orthop 2006, 77:638-643

98. Schleicher I, Kordelle J, Jurgensen I, Haas H, Melzer C: Femoral neck fractures in the elderly – bipolar hemiarthroplasty in total hip replacement. Unfallchirurg 2003, 106:467-471

99. Iorio R, Healy WL, Lemos DW, Appleby D, Lucchesi CA, Saleh KJ: Displaced femoral neck fractures in the elderly: outcomes and cost effectiveness. Clin Orthop Relat Res 2001, 383:229-42

100. Angelini M, McKee MD, Waddell JP, Haidukewych G, Schemitsch EH: Salvage of failed hip fracture fixation. J Orthop Trauma 2009, 23:471-478.

101. Aleem IS, Karanicolas PJ, Bhandari M: Arthroplasty versus internal fixation of femoral neck fractures: a clinical decision analysis. Ortop Traumatol Rehabil 2009, 11:233-241

102. Leonardsson O, Sernbo I, Carlsson A, Akesson K, Rogmark C: Long-term follow-up of replacement compared with internal fixation for displaced femoral neck fractures: results at ten years in a randomised study of 450 patients. J Bone Joint Surg Br 2010, 92:406-412.

103. Eyssel M, Schwenk W, Badke A, Krebs S, Stock W: Total endoprosthesis or dual head prosthesis in endoprosthetic management of femoral neck fractures? Unfallchirurg 1994, 97:347-352

104. Hedbeck CJ, Enocson A, Lapidus G, et al. Comparison of bipolar hemiarthroplasty with total hip arthroplasty for displaced femoral neck fractures: a concise four-year follow-up of a randomized trial. J Bone Joint Surg [Am] 2011;93-A:445–450.

105. Inngul C, Hedbeck CJ, Blomfeldt R, et al. Unipolar hemiarthroplasty versus bipolar hemiarthroplasty in patients with displaced femoral neck fractures: a four-year follow- up of a randomised controlled trial. Int Orthop 2013;37:2457–2464.

106. Langslet E, Frihagen F, Opland V, et al. Cemented versus uncemented hemiarthroplasty for displaced femoral neck fractures: 5-year followup of a randomized trial. Clin Orthop Relat Res 2014;472:1291–1299.

107. Enocson A, Hedbeck CJ, Törnkvist H, Tidermark J, Lapidus LJ. Unipolar versus bipolar Exeter hip hemiarthroplasty: a prospective cohort study on 830 consecutive hips in patients with femoral neck fractures. Int Orthop 2012;36:711–717

108. Baker RP, Squires B, Gargan MF, Bannister GC. Total hip arthroplasty and hemiarthroplasty in mobile, independent patients with a displaced intracapsular fracture of the femoral neck. A randomized, controlled trial. J Bone Joint Surg [Am] 2006;88-A:2583–2589

109. Dorr LD, Glousman R, Hoy AL, Vanis R, Chandler R. Treatment of femoral neck fractures with total hip replacement versus cemented and noncemented hemiarthroplasty. J Arthroplasty 1986;1:21–28

110. van den Bekerom MP, Hilverdink EF, Sierevelt IN, et al. A comparison of hemiarthroplasty with total hip replacement for displaced intracapsular fracture of the femoral neck: a randomised controlled multicentre trial in patients aged 70 years and over. J Bone Joint Surg [Br] 2010;92-B:1422–1428

111. Mouzopoulos G, Stamatakos M, Arabatzi H, et al. The four-year functional result after a displaced subcapital hip fracture treated with three different surgical options. Int Orthop 2008;32:367–373

112. Avery PP, Baker RP, Walton MJ, et al. Total hip replacement and hemiarthroplasty in mobile, independent patients with a displaced intracapsular fracture of the femoral neck: a seven- to ten-year follow-up report of a prospective randomised controlled trial. J Bone Joint Surg [Br] 2011;93-B:1045–1048

113. Leonardsson O, Rolfson O, Hommel A, et al. Patient-reported outcome after displaced femoral neck fracture: a national survey of 4467 patients. J Bone Joint Surg [Am] 2013;95-A:1693–1699

114. Christie J, Burnett R, Potts HR, Pell AC. Echocardiography of transatrial embolism during cemented and uncemented hemiarthroplasty of the hip. J Bone Joint Surg [Br] 1994;76-B:409–412.

115. Donaldson AJ, Thomson HE, Harper NJ, Kenny NW. Bone cement implantation syndrome. Br J Anaesth 2009;102:12–22

116. Olsen F, Kotyra M, Houltz E, Ricksten SE. Bone cement implantation syndrome in cemented hemiarthroplasty for femoral neck fracture: incidence, risk factors, and effect on outcome. Br J Anaesth 2014;113:800–806

117. Talsnes O, Hjelmstedt F, Pripp AH, Reikerås O, Dahl OE. No difference in mortality between cemented and uncemented hemiprosthesis for elderly patients with cervical hip fracture. A prospective randomized study on 334 patients over 75 years. Arch Orthop Trauma Surg 2013;133:805–809

118. Inngul C, Blomfeldt R, Ponzer S, Enocson A. Cemented versus uncemented arthroplasty in patients with a displaced fracture of the femoral neck. Bone Joint J 2015;97-B:1475–1480

119. Deangelis JP, Ademi A, Staff I, Lewis CG. Cemented versus uncemented hemiarthroplasty for displaced femoral neck fractures: a prospective randomized trial with early follow-up. J Orthop Trauma 2012;26:135–140

120. Taylor F, Wright M, Zhu M. Hemiarthroplasty of the hip with and without cement: a randomized clinical trial. J Bone Joint Surg [Am] 2012;94-A:577–583

121. Figved W, Opland V, Frihagen F, et al. Cemented versus uncemented hemiarthroplasty for displaced femoral neck fractures. Clin Orthop Relat Res 2009;467:2426–2435

122. Costain DJ, Whitehouse SL, Pratt NL, et al. Perioperative mortality after hemiarthroplasty related to fixation method. Acta Orthop 2011;82:275–281

123. Talsnes O, Vinje T, Gjertsen JE, et al. Perioperative mortality in hip fracture patients treated with cemented and uncemented hemiprosthesis: a register study of 11,210 patients. Int Orthop 2013;37:1135–1140

124. Parker MJ. Lateral versus posterior approach for insertion of hemiarthroplasties for hip fractures: A randomised trial of 216 patients. Injury 2015;46:1023–1027

125. Enocson A, Tidermark J, Tornkvist H, Lapidus LJ. Dislocation of hemiarthroplasty after femoral neck fracture: better outcome after the anterolateral approach in a prospective cohort study on 739 consecutive hips. Acta Orthop 2008;79:211–217

126. Leonardsson O, Kärrholm J, Åkesson K, Garellick G, Rogmark C. Higher risk of reoperation for bipolar and uncemented hemiarthroplasty. Acta Orthop 2012;83:459–466

127. Graves S, Davidson D, de Steiger R, Tomkins A. Australian Orthopaedic Association National Joint Replacement Registry. Annual Report. Adelaide: AOA; 2012 https://aoanjrr.sahmri.com/ (date last accessed March 2017)

128. Slobogean GP, Sprague SA, Scott T, Bhandari M. Complications following young femoral neck fractures. Injury. 2015 Mar;46(3):484-91

129. Court-Brown CM, Heckman D, McQueen MM, Ricci WM, Tornetta P. (2015) Rockwood and Green’s Fractures in Adults

130. Loizou CL, Parker MJ. Avascular necrosis after internal fixation of intracapsular hip fractures: a study of the outcome for 1023 patients. Injury. 2009;40(11):1143–1146

131. Speer KP, Spritzer CE, Harrelson JM, et al. Magnetic resonance imaging of the femoral head after acute intracapsular fracture of the femoral neck. J Bone Joint Surg Am. 1990;72:98–103

132. Yamagata M, Chao EY, Ilstrup DM, et al. Fixed-head and bipolar hip endoprostheses. A retrospective clinical and roentgenographic study. J Arthroplasty. 1987;2:327–341

133. Giversen IM. Time trends of mortality after first hip fractures. Osteoporos Int. 2007;18(6):721–732

134. Young W, Seigne R, Bright S, et al. Audit of morbidity and mortality following neck of femur fracture using the POSSUM scoring system. N Z Med J. 2006;119(1234): U1986.

135. Sikand M, Wenn R, Moran CG. Mortality following surgery for undisplaced intracapsular hip fractures. Injury. 2004;35(10):1015–1019

136. Liao L, Zhao Jm, Su W, Ding Xf, Chen Lj, Luo Sx. A meta-analysis of total hip arthroplasty and hemiarthroplasty outcomes for displaced femoral neck fractures. Arch Orthop Trauma Surg. 2012 Jul;132(7):1021-9

137. Jiang J, Yang CH, Lin Q, Yun XD, Xia YY. Does Arthroplasty Provide Better Outcomes Than Internal Fixation At Mid- and Long-term Followup? A Meta-analysis. Clin Orthop Relat Res. 2015 Aug;473(8):2672-9

138. He JH, Zhou CP, Zhou ZK, Shen B, Yang J, Kang PD, Pei FX. Meta-analysis comparing total hip arthroplasty with hemiarthroplasty in the treatment of displaced femoral neck fractures in patients over 70 years old. Chin J Traumatol. 2012;15(4):195-200

139. Goh SK, Samuel M, Su DH, Chan ES, Yeo SJ. Meta-analysis comparing total hip arthroplasty with hemiarthroplasty in the treatment of displaced neck of femur fracture. J Arthroplasty. 2009 Apr;24(3):400-6

140. Liu Y, Tao X, Wang P, Zhang Z, Zhang W, Qi Q. Meta-analysis of randomised controlled trials comparing unipolar with bipolar hemiarthroplasty for displaced femoral-neck fractures. Int Orthop. 2014 Aug;38(8):1691-6

141. Luo X, He S, Li Z, Huang D. Systematic review of cemented versus uncemented hemiarthroplasty for displaced femoral neck fractures in older patients. Arch Orthop Trauma Surg. 2012 Apr;132(4):455-63

142. Burgers PT, Van Geene AR, Van den Bekerom MP, Van Lieshout EM, Blom B, Aleem IS, Bhandari M, Poolman RW. Total hip arthroplasty versus hemiarthroplasty for displaced femoral neck fractures in the healthy elderly: a meta-analysis and systematic review of randomized trials. Int Orthop. 2012 Aug;36(8):1549-60

143. Yu L, Wang Y, Chen J. Total hip arthroplasty versus hemiarthroplasty for displaced femoral neck fractures: meta-analysis of randomized trials. Clin Orthop Relat Res. 2012 Aug;470(8):2235-43

144. Gao H, Liu Z, Xing D, Gong M. Which is the best alternative for displaced femoral neck fractures in the elderly?: A meta-analysis. Clin Orthop Relat Res. 2012 Jun;470(6):1782-91

145. Gjertsen JE, Vinje T, Lie SA, Engesaeter LB, Havelin LI, Furnes O, Fevang JM. Patient satisfaction, pain, and quality of life 4 months after displaced femoral neck fractures: a comparison of 663 fractures treated with internal fixation and 906 with bipolar hemiarthroplasty reported to the Norwegian Hip Fracture Register. Acta Orthop. 2008 Oct;79(5):594-601

146. Rogmark C, Carlsson A, Johnell O, Sembo I. Costs of internal fixation and arthroplasty for displaced femoral neck fractures: a randomized study of 68 patients. Acta Orthop Scand. 2003 Jun;74(3):293-8

147. Thakar C, Alsousou J, Hamilton TW, Willett K. The cost and consequences of proximal femoral fractures which require further surgery following initial fixation. J Bone Joint Surg Br. 2010 Dec;92(12):1669-77

148. Zielinski SM, Bouwmans CA, Heetveld MJ, Bhandari M, Patka P, Van Lieshout EM. The societal costs of femoral neck fracture patients treated with internal fixation. Osteoporos Int. 2014 Mar;25(3):875-85