Avascular necrosis of the femoral head after femoral neck fracture

Hyperbaric oxygen for stage I and II femoral head osteonecrosis

Hyperbaric oxygen therapy is a suggested joint-preserving treatment for symptomatic early-stage osteonecrosis of the femoral head. Limited studies of this treatment have been published. The goal of this study was to evaluate the effectiveness of this treatment in a relatively large patient cohort. The authors reviewed the files of 68 patients with 78 symptomatic joints with Steinberg stage I and II osteonecrosis of the femoral head. All patients were treated with hyperbaric oxygen at the authors' medical health center. Pretreatment and immediate posttreatment magnetic resonance imaging (MRI) findings were compared. On follow-up, a telephone interview was conducted to determine the survival of the joint. Modified Harris Hip Score and Short Form 12 health survey (SF-12) questionnaires of the start of treatment and at follow-up were obtained and evaluated for statistically significant differences. Half of the joints were stage 1 and half were stage II. Seventy-four joints underwent both pre- and posttreatment MRI. Eighty-eight percent of joints showed improvement posttreatment. On follow-up at a mean of 11.1±5.1 years, 54 patients (58 joints) were located and answered the questionnaires. At the time of follow-up, 93% of the joints survived. Mean Harris Hip Score improved from 21 to 81 (P<.0001), the mean physical component of the SF-12 improved from 24 to 46 (P<.0001), and the mean mental component of the SF-12 improved from 54 to 59 (P<.0001). The authors concluded that hyperbaric oxygen treatment is effective in preserving the hip joint in stage I and II osteonecrosis of the femoral head.

Bone impregnated hip screw in femoral neck fracture: Clinicoradiological results

BACKGROUND

Femoral neck fractures are treated either by internal fixation or arthroplasty. Usually, cannulated cancellous screws are used for osteosynthesis of fracture neck of femur. The bone impregnated hip screw (BIHS) is an alternative implant, where osteosyntehsis is required in femoral neck fracture.

MATERIALS AND METHODS

The BIHS is a hollow screw with thread diameter 8.3 mm, shank diameter 6.5 mm and wall thickness 2.2 mm and holes in the shaft of the screw with diameter 2 mm, placed in a staggered fashion. Biomechanical and animal experimental studies were done. Clinical study was done in two phases: Phase 1 in a group of volunteers, only with BIHS was used in a pilot study and phase 2 comparative study was done in a group with AO cannulated screws and the other group treated with BIHS.

RESULTS

In the phase 1 study, out of 15 patients, only one patient had delayed union. In phase 2, there were 78 patients, 44 patients in BIHS showed early union, compared to the rest 34 cases of AO cannulated screws Out of 44 patients with BIHS, 41 patients had an excellent outcome, 2 had nonunions and one implant breakage was noted.

CONCLUSIONS

Bone impregnated hip screw has shown to provide early solid union since it incorporates the biomechanical principles and also increases the osteogenic potential and hence, found superior to conventional cannulated cancellous screw.

Analysis of risk factors for femoral head necrosis after internal fixation in femoral neck fractures

Femoral head necrosis is a rare but devastating complication following femoral neck fracture. The reported incidence of avascular necrosis after femoral neck fracture fixation varies widely, and there is no consensus regarding its risk factors. The aim of this study was to analyze the risk factors for femoral head necrosis after internal fixation in femoral neck fracture. This retrospective study included 166 patients with femoral neck fractures treated with surgical reduction and internal fixation at the authors' institution from January 2004 to December 2008. Eight patients died for reasons unrelated to the surgery, and 12 patients were lost to follow-up. The remaining 146 patients (146 fractures) were followed until union or until conversion to total hip arthroplasty. The patients included 61 males and 85 females with an average age of 47.5 years (range, 18-68 years). The authors analyzed the following factors: age, sex, Garden classification, reduction quality, surgical methods, injury-to-surgery interval, preoperative traction, weight-bearing time, and implant removal. All patients were followed for a mean of 52 months (range, 6-90 months). The incidence of femoral head necrosis was 14.4% (21/146). Garden classification (P=.012), reduction quality (P=.008), implant removal (P=.020), and preoperative traction (P=.003) were significantly associated with femoral head necrosis. Patient age (P=.990), sex (P=.287), injury-to-surgery interval (P=.360), weight-bearing time (P=.868), and surgical methods (P=.987) were not significantly associated with femoral head necrosis. In multivariate logistic regression analysis, implant removal was not a significant risk factor for femoral head necrosis development (P=.498). Garden classification, reduction quality, and preoperative traction had a significant effect on femoral head necrosis development.

Subchondral insufficiency fracture of the femoral head after internal fixation for femoral neck fracture: histopathological investigation

Late segmental collapse after internal fixation for femoral neck fracture is the phenomenon observed in post-traumatic osteonecrosis of the femoral head (ON), which has generally been reported to occur over a year or more after internal fixation. Subchondral insufficiency fracture of the femoral head (SIF) has also been recognized to cause femoral head collapse, however, only two cases of SIF after internal fixation for femoral neck fracture have been reported. We report a case with femoral head collapse observed 5 months after internal fixation for femoral neck fracture, which was histopathologically diagnosed as SIF. Clinically, differentiating SIF from ON is important because some cases of SIF have been reported to heal without surgical treatments. The timing of femoral head collapse after femoral neck fracture may be different between SIF and post-traumatic ON.

Effect of depression on femoral head avascular necrosis from femoral neck fracture in patients younger than 60 years

The purpose of this study was to determine the effect of depression on femoral head avascular necrosis (AVN) from femoral neck fracture in patients younger than 60 years and the relationship between depression and postoperative quality of life. The Beck Depression Inventory-II (BDI-II) was completed by 641 patients (352 men and 289 women; average age, 41.7±10.2 years; range, 20-60 years) postoperatively. Patients were divided into groups according to BDI-II score: a depressed group (BDI-II score of 14 or higher) and a nondepressed group (BDI-II score lower than 14). They were followed for an average of 28 months (range, 24-37 months). The postoperative diagnosis was confirmed by typical radiographs and single photon-emission computed tomography. Quality of life among patients was assessed using the Short Form-36 (SF-36) questionnaire. The overall incidences of depression and AVN were 30.6% (196 of 641) and 20.9% (134 of 641), respectively. Ninety-four (48.0%) patients in the depressed group and 40 (9.0%) patients in the nondepressed group ultimately developed AVN. Symptoms of depression significantly affected AVN. In addition, depression predicted patients' quality of life, as did sex, partner status, employment status, living alone, frequency of exercise, severity of fractures, and length of hospital stay. In a multiple linear regression model analyzing all of these variables, depression was the best independent predictor of quality of life. Depression in patients younger than 60 years with femoral neck fractures may increase postoperative femoral head AVN risk and greatly affect patients' quality of life.

The association of eNOS gene polymorphism with avascular necrosis of femoral head

Objectives

Necrosis of femoral head is a severe pathological state with multiple etiologies. This study investigated the association of the 27-bp repeat polymorphism in intron 4 and G894T polymorphism in exon 7 of the endothelial nitric oxide synthase (eNOS) gene with the pathogenesis of avascular necrosis of femoral head (ANFH).

Methods

A total of 125 non-traumatic ANFH patients and 126 healthy controls were recruited for this study. The 27-bp repeat polymorphisms in intron 4 were analyzed by polymerase chain reaction (PCR) and sequencing. The G894T polymorphisms in exon 7 were analyzed by PCR– restriction fragment length polymorphism (PCR-RFLP) analysis.

Results

All alleles were observed in non-traumatic ANFH patients and control subjects. Both ANFH patients and idiopathic subgroup of ANFH patients showed higher frequency of the 4a/b genotype than controls (p  = 0.001 and p  = 0.020, respectively). Significantly higher frequency of G/T genotype was observed in ANFH patients and idiopathic subgroup of ANFH patients compared to controls (p  = 0.009 and p  = 0.035, respectively).

Conclusion

eNOS gene polymorphisms may be a risk factor for ANFH. The 27-bp repeat polymorphism in intron 4, G894T polymorphism in exon 7, and subsequently reduced eNOS activity may be involved in the etiology of idiopathic ANFH.

Surgical treatment of trochanteric and cervical hip fractures in the United States: 2000-2009

The objective of this study was to evaluate the most common treatments performed for hip fractures over the last decade in the United States. The leading treatment for trochanteric fractures was internal fixation, accounting for 96%-98% of surgical treatments each year. For cervical fractures, hemiarthroplasty (HA), total hip arthroplasty (THA), and internal fixation were performed nearly 61%, 5%, and 33% of the time, respectively, each year without any sign of change during the period assessed. The surgical choice for cervical fractures varied greatly by patient age. In 2009, two-thirds of patients younger than 60 years underwent internal fixation while two-thirds of patients 60 years or older underwent HA. Regardless of patient age, HA was performed more often than THA for cervical hip fractures.

Autologous uncultured bone marrow-derived mononuclear cells and modified cannulated screw in repair of femoral neck fracture

The purpose of this study was to assess whether autologous uncultured bone marrow-derived mononuclear cells (BMMNCs) combined with modified cannulated screw would accelerate the healing of canine femoral neck fracture. BMMNCs were encapsulated within fibrin glue (FG) and implanted into the fractured femoral neck via modified cannulated screw in experiment group, and the control group was treated by modified cannulated screw. Gross observation, radiological examination, histological analysis, and blood vessel microdensity counting were used to compare bone healing of each group at 1, 2, and 3 months. FG was confirmed as an ideal cell-delivery vehicle for BMMNCs proliferation and differentiation in vitro testing. In vivo animal testing, faster new bone formation and fracture healing were confirmed by gross observation, radiological examination, histological analysis in experimental group than in control group at all times points. The blood vessel microdensity counting increased gradually both in the experimental group and control group, but was more obviously in experimental group at 3 months (p < 0.01). These data suggest that autologous BMMNCs combined with modified cannulated screw treatment is an effective therapy for femoral neck fracture and thus, may be an option for clinical applications.

Logistic regression analysis of factors associated with avascular necrosis of the femoral head following femoral neck fractures in middle-aged and elderly patients

BACKGROUND

Risk factors for femoral neck fracture-induced avascular necrosis of the femoral head have not been elucidated clearly in middle-aged and elderly patients. Moreover, the high incidence of screw removal in China and its effect on the fate of the involved femoral head require statistical methods to reflect their intrinsic relationship.

METHODS

Ninety-nine patients older than 45 years with femoral neck fracture were treated by internal fixation between May 1999 and April 2004. Descriptive analysis, interaction analysis between associated factors, single factor logistic regression, multivariate logistic regression, and detailed interaction analysis were employed to explore potential relationships among associated factors.

RESULTS

Avascular necrosis of the femoral head was found in 15 cases (15.2 %). Age × the status of implants (removal vs. maintenance) and gender × the timing of reduction were interactive according to two-factor interactive analysis. Age, the displacement of fractures, the quality of reduction, and the status of implants were found to be significant factors in single factor logistic regression analysis. Age, age × the status of implants, and the quality of reduction were found to be significant factors in multivariate logistic regression analysis. In fine interaction analysis after multivariate logistic regression analysis, implant removal was the most important risk factor for avascular necrosis in 56-to-85-year-old patients, with a risk ratio of 26.00 (95 % CI = 3.076-219.747).

CONCLUSION

The middle-aged and elderly have less incidence of avascular necrosis of the femoral head following femoral neck fractures treated by cannulated screws. The removal of cannulated screws can induce a significantly high incidence of avascular necrosis of the femoral head in elderly patients, while a high-quality reduction is helpful to reduce avascular necrosis.

Neglected neck femur fractures in adolescents and young adults: factors predicting the surgical outcome

BACKGROUND

Neglected femoral neck fracture in young adults is an intriguing problem. This retrospective study tried to solve that challenge through open reduction, cannulated screw internal fixation, autogenous iliac bone and bone marrow grafting.

METHODS

Thirty-six cases were studied; they were classified according to Sandhu et al.'s classification. Twenty cases were type I and 16 cases were type II fractures; the mean age was 26.8 years; fracture neglect averaged 44.6 days. Twenty cases had posterior comminution and 16 cases had anterior comminution. All cases had open reduction, cannulated screw internal fixation, autogenous iliac bone and bone marrow grafting. The Harris hip score and Matta et al. grading system were applied for functional and radiological evaluation, respectively.

RESULTS

The average postoperative follow-up was 25.3 months; 94.4 % of the cases had solid union in a mean of 19.6 weeks. Functionally, the Harris hip score averaged 87.8 points. Nonunion, avascular necrosis and coxa vara complicated two, two and four cases, respectively. Fair and poor radiological results were related to coxa vara and avascular necrosis, respectively. Nonunion was significantly related to posterior comminution, type II neglected fracture, and a neglect of more than 45 days. Age groups more than 30 years old and postoperative neck-shaft angles <140° were significantly associated with late-onset radiological healing and nonunion.

CONCLUSIONS

Cannulated screw osteosynthesis augmented by autogenous bone and bone marrow grafting is a simple, easy-to-perform surgical procedure with encouraging clinical outcomes for selected patients complaining of that difficult problem.

Injury-to-surgery interval does not affect the occurrence of osteonecrosis of the femoral head: a prospective study in a canine model of femoral neck fractures

Background

It is controversial whether an early reduction and internal fixation can reduce the occurrence of femoral neck fracture-induced osteonecrosis of the femoral head (ONFH). This prospective study was designed to reflect the relationship between injury-to-surgery interval (ISI) and traumatic ONFH based on a canine model of femoral neck fractures.

Material/Methods

Twenty-four dogs were equally divided randomly into 3 groups. A lateral L-shape approach centered left great trochanter was used for exposure of the femoral neck. A low-speed drill was used for making displaced fractures in the narrow femoral neck, with the femoral head kept in situ with ligamentum teres intact. In Group A, the fracture was immediately reduced and fixed with 3 parallel pins; while the operation was done 3 days later in Group B, and 3 weeks later in Group C. Another 2 dogs had their fractures untreated. Postoperatively, all dogs were fed separately and received regular x-ray examination. Left femoral heads were harvested for histological examination with a postoperative follow-up of 3.5 months.

Results

The canine model of femoral neck fractures could be achieved successfully. Radiological signs of post-fracture ONFH could not be detected at intervals of 2 weeks, 4 weeks, 1 month and 2 months. Histologically, there were 2 cases with ONFH in Group A, 1 case in Group B, and 2 cases in Group C. The difference had no statistical significance. For untreated fractures, obvious ONFH could be found radiologically.

Conclusions

A shorter ISI may not reduce the incidence of fracture-induced ONFH, which suggests that intrinsic factors play an important role in the occurrence of ONFH.

Magnetic resonance imaging of the postoperative hip

Magnetic resonance imaging (MRI) is ideally suited to imaging the patient with painful hip arthroplasty due to its superior soft tissue contrast, multiplanar capabilities, and lack of ionizing radiation. MRI is the most accurate imaging modality in the assessment of periprosthetic osteolysis and wear-induced synovitis, and can also assess regional tendons and neurovascular structures. This article discusses the technical aspects of MRI around metallic implants as well as the appearance of potential complications following hip arthroplasty, including osteolysis, wear-induced synovitis, infection, hemarthrosis, fracture, loosening, component displacement, heterotopic ossification, tendinopathy, and neurovascular impingement. The specific complication of metal hypersensitivity following metal-on-metal prostheses is reviewed.

DSA observation of hemodynamic response of femoral head with femoral neck fracture during traction: a pilot study

OBJECTIVE

To investigate the early influence of traction on blood supply to the femur head after femoral neck fractures using digital subtraction angiography (DSA).

DESIGN

Prospective case series.

SETTING

University Level I trauma center.

PATIENTS

Nine patients who sustained a unilateral femoral neck fracture underwent selective femoral artery DSA within 2-23 days after their injury.

INTERVENTION

DSA of the medial and lateral circumflex femoral artery was performed for all 9 fractured hips before traction. Repeat DSA study of the femoral head circulation was performed after the addition of 3 kg of traction in 7 patients and 5 kg of traction in 6 patients. For comparison, DSA was also performed on the uninjured hip in 8 of the 9 patients.

MAIN OUTCOME MEASURE

Blood circulation of the femoral head was evaluated by observing morphology of the feeding arteries, perfusion volume, venous drainage, and the circulation time of the microvasculature.

RESULTS

Femoral neck fracture damaged the retinaculum artery and led to femoral head hemodynamic disorder in all 9 cases. Application of linear traction and repeat DSA decreased femoral head perfusion (faint arterial imaging and delayed venous display) in all patients' retinaculum arteries except the inferior branch compared with the pretraction imaging. These findings were more pronounced as the traction was increased from 3 to 5 kg. These findings were significant (P < 0.05).

CONCLUSIONS

Traction impairs blood perfusion to the femoral head. Blood flow in the retinacular arteries was reduced and venous drainage impeded. Traction may be one of the major causes of femoral head osteonecrosis after femoral neck fracture.

Caspase-3 may be employed as an early predictor for fracture‑induced osteonecrosis of the femoral head in a canine model

The aim of the current study was to investigate the local expression of caspase-3 following femoral neck fractures in a canine model and to investigate its effect on the occurrence of fracture-induced osteonecrosis of the femoral head (ONFH). Eight dogs had surgically-induced femoral neck fractures on the left side which remained untreated. Radiological and histological examinations were employed to detect morphological changes of the femoral head. Immunohistochemical staining of caspase-3 was used to evaluate cell apoptosis, which may play an important role in ONFH. The results were compared to the normal side for statistical analysis. As a result, all eight dogs had ONFH, with non-union in five and malunion in three on radiological examination. Histologically, the untreated femoral heads developed osteonecrosis with an accumulation of bone marrow cell debris, empty lacunae and/or ghost nuclei in the lacunae, and an increase in the number of fat cells. Immunohistochemical staining of caspase-3 indicated that it was upregulated in fracture-induced ONFH two weeks postoperatively, which showed a statistical difference when compared to the normal side. In conclusion, the local expression of caspase-3 was upregulated in fracture-induced ONFH, suggesting that cell apoptosis is crucial in traumatic ONFH. Caspase-3 may therefore be employed as an effective and early predictor for fracture-induced ONFH.

HGF-transgenic MSCs can improve the effects of tissue self-repair in a rabbit model of traumatic osteonecrosis of the femoral head

Background

Osteonecrosis of the femoral head (ONFH) is generally characterized as an irreversible disease and tends to cause permanent disability. Therefore, understanding the pathogenesis and molecular mechanisms of ONFH and developing effective therapeutic methods is critical for slowing the progress of the disease.

Methodology/Principal Findings

In this study, an experimental rabbit model of early stage traumatic ONFH was established, validated, and used for an evaluation of therapy. Computed tomography (CT) and magnetic resonance (MR) imaging confirmed that this model represents clinical Association Research Circulation Osseous (ARCO) phase I or II ONFH, which was also confirmed by the presence of significant tissue damage in osseous tissue and vasculature. Pathological examination detected obvious self-repair of bone tissue up to 2 weeks after trauma, as indicated by revascularization (marked by CD105) and expression of collagen type I (Col I), osteocalcin, and proliferating cell nuclear antigen. Transplantation of hepatocyte growth factor (HGF)-transgenic mesenchymal stem cells (MSCs) 1 week after trauma promoted recovery from ONFH, as evidenced by a reversed pattern of Col I expression compared with animals receiving no therapeutic treatment, as well as increased expression of vascular endothelial growth factor.

Conclusions/Significance

These results indicate that the transplantation of HGF-transgenic MSCs is a promising method for the treatment for ONFH and suggest that appropriate interference therapy during the tissue self-repair stage contributes to the positive outcomes. This study also provides a model for the further study of the ONFH etiology and therapeutic interventions.

Osteoscopy for assessment of blood supply to the femoral head: a preliminary study

OBJECTIVES

The aim of our study was to develop a minimally invasive endoscopic procedure (osteoscopy), which is capable of visualizing blood supply and quantitatively assessing circulation to the femoral head at the time of definitive surgery.

METHODS

The new diagnostic technique was developed in animal experiments (four piglets) and was subsequently tested in nine consecutive patients requiring surgery for a femoral neck fracture. The direct visualization of the femoral head circulation was performed in the mortise prepared for the implant. The osteoscope optic fiber was placed at the orifice of the cavity created by the custom-made drill bit. The "mortise-sleeve-optic" system was connected to a manometer and a saline reservoir. The bleeding from the wall of bony cavity was observed, meanwhile the inner pressure of the "mortise-sleeve-optic" system was changed gradually. The pressure measurement at the first appearance of bleeding and the intraosseal pressure was recorded.

RESULTS

The animal investigations demonstrated that the osteoscopy readily distinguished among diffuse bleeding, pulsatile bleeding, and the absence of bleeding in the femoral head. The human experiments proved that a different quality of the femoral head circulation can be observed during osteoscopy.

CONCLUSIONS

Preliminary findings indicate that clinical osteoscopy may be a useful tool in the assessment of blood circulation to the femoral head.

Displaced femoral neck fractures in the young: significance of posterior comminution and raised intracapsular pressure

BACKGROUND

Osteosynthesis in fracture neck of femur (NOF) in young is a universally acceptable procedure. Various factors affect the outcome; with AVN (avascular necrosis) and non-union primarily contributing to adverse results in such patients. To identify factors affecting outcome of displaced fracture NOF, a prospective cohort study was carried out in the setting of a tertiary care centre in developing country.

METHODS

27 consecutive patients with displaced fracture NOF suitable for osteosynthesis underwent closed reduction and fixation with three 6.5 mm cancellous cannulated screws. A record of posterior comminution and its extent (as seen on CT scan) and the intracapsular pressure difference between the fractured and the opposite side was kept in all the patients. The patients were followed-up for 1 year. The main outcomes measured at 1 year were non-union (as identified by CT scan) and AVN (as identified by bone scan).

RESULTS

Cases with pressure difference >30 mm were found to have a higher rate of AVN and this result was found to be statistically significant (p value 0.034). The patients with significant posterior comminution were found to have higher non-union rates and this result was also found to be statistically significant (p value 0.04).

CONCLUSIONS

Prognosis of displaced fracture NOF is significantly associated significant with posterior comminution and intracapsular pressure difference between fractured and normal side.

Can injection CT scan assess the residual femoral head vascularity after acute neck fracture?

INTRODUCTION

Femoral neck fracture jeopardizes the vital prognosis of the elderly subject and the functional prognosis of the young subject. The vascular consequence is important, with the risk of osteonecrosis of the femoral head. In young patients, predicting the risk of necrosis at the acute stage seems warranted so as to optimize the choice of therapy. CT with injection could be useful to study the residual bone vascularity after an acute fracture of the femoral neck.

HYPOTHESIS

The CT scan with injection can diagnose ischemia of the femoral head after neck fracture by demonstrating hypoperfusion and thus estimating the risk for osteonecrosis.

PATIENTS AND METHOD

A CT scan with injection was performed prospectively in 20 adult patients who had given informed consent after verification of the inclusion and exclusion criteria. Ten presented femoral neck fracture and 10 a pertrochanteric fracture, the latter making up the control group. The second control group was the healthy side of patients presenting a femoral neck fracture. The images were analyzed after delineating a region of interest as a volume at the center of the femoral head. The results were analyzed after modeling based on the physical principle of diffusion.

RESULTS

No differences were found between the "healthy hip," "fractured hip," "femoral neck fracture," and "trochanteric region fracture" groups. The only statistically significant correlation was found between the "fractured hip" and "healthy hip" of the same patient independently of the type of fracture.

DISCUSSION

The results do not confirm the working hypothesis. This study was mainly limited by the small number of patients included, but this did not substantially effect the study's conclusions. According to the results, it seems that this study provided a CT evaluation of bone mineral density. At the end of the study, it seems that CT with injection is not well adapted in assessing residual femoral head vascularity or estimating the risk of progression towards avascular necrosis. According to the literature, only dynamic MRI with injection seems to be effective in this assessment and estimation.

LEVEL OF EVIDENCE

Level III prospective comparative diagnostic.

Avascular necrosis of the femoral head after osteosynthesis of femoral neck fracture

The reported incidence of avascular necrosis after femoral neck fracture fixation varies widely, and there is no consensus regarding its risk factors. We evaluated the incidence of avascular necrosis of the femoral head with the use of contemporary techniques for femoral neck fracture fixation. We then sought to determine what potential risk factors influenced the development of avascular necrosis.Between 1990 and 2005, one hundred sixty-three intracapsular femoral neck fractures in 163 patients were treated with internal fixation at our level-I trauma center. All patients were monitored until conversion to total hip arthroplasty or for a minimum of 2 years postoperatively. Ten patients (10 hips) died and 7 patients (7 hips) were lost to follow-up. The remaining 146 patients (146 hips) had a mean 5.2 years of follow-up (range, 3 months to 17 years). The incidence of avascular necrosis was 25.3% (37 hips). The average time to diagnosis of avascular necrosis was 18.8 months (range, 3-47 months). Patient sex, age, interval from injury to surgery, and mechanism of injury were statistically not associated with the development of avascular necrosis. The quality of fracture reduction, adequacy of fixation, degree of displacement, and comminution of the posterior cortex were significantly associated. After we controlled for patient and radiographic characteristics, multivariate analyses indicated that the important predictors for avascular necrosis are poor reduction (odds ratio=13.889) and initial displacement of the fracture (odds ratio=4.693).

Review of a single contemporary femoral neck fracture fixation method in young patients

An intracapsular femoral neck fracture in a young patient is a rare and difficult injury to manage. The occurrence of complications following fixation is multifactorial. Initial displacement and timing and accuracy of reduction are the key factors affecting outcome. The severities of the trauma to the hip and the impact of the intracapsular hematoma also play a role, the importance of which remains poorly understood. The purpose of this study was to evaluate the high incidence of femoral neck fractures treated in our institution over a 7-month period, to record the long-term outcome of these patients, all of whom were treated with contemporary methods of internal fixation, and to highlight the reasons for this injury being termed an "orthopedic emergency" and its differences from the same injury in the elderly population. We performed a retrospective analysis of 12 cases of intracapsular femur neck fracture in patients younger than 50 years treated over 7 months in a regional trauma center. All patients underwent satisfactory reduction and fixation. Nine of the 12 patients had a good outcome at a mean follow-up of 29 months. One patient developed a nonunion of the femoral head requiring total hip arthroplasty, one developed avascular necrosis of the femoral head, and one developed partial avascular necrosis. This compares favorably with other studies.

An irreducible variant of femoral neck fracture: a minimally traumatic reduction technique

We present 25 cases of irreducible variant femoral neck fractures that require surgical management after routine manipulative manoeuvre attempts have failed. In our study, an irreducible variant of femoral neck fractures is defined as a reduction that cannot be achieved after multiple attempts at closed reduction. This was evident radiographically, as seen in displaced–impacted femoral neck fractures when the proximal femur compacts and rotates along with the distal part, and anatomical reduction cannot be achieved with manipulative manoeuvres. Another rare situation also included is when the proximal fragment disconnects from the femur and dislocates as a ‘floating’ component, consequently resulting in failure of alignment of the distal fragment to the proximal femur.Here, we describe a technique, applied as a minimally traumatic procedure to achieve anatomic reduction in such cases. With the patient placed in supine position on the fracture table under general anaesthesia, the injury site is exposed and the procedure performed under intra-operative radiographic control. Location of the femoral artery is done first by palpation. The insertion site of the K-wires or Steinman pins on the proximal thigh is 1.5–3 cm lateral to the femoral artery. The K-wires or Steinmanpins are inserted vertically into the middle 1/2–2/3 of the femoral head and more than 1 cm inferior to the sub-chondral bone of the femoral head to a depth of approximately, 1/2 diameter of the femoral head. The pins are then used as a joystick to control the movement of the proximal femur. With the help of the K-wires, surgeons can manually control the movement of the proximal femur and ensure anatomic reduction with the distal fragment using routine-closed reduction. Three cannulated screws are used to stabilise the fracture after anatomic reduction is achieved and maintained in a stable position. All cases were treated with this minimally invasive procedure and internal fixation, 25 fractures united,uneventfully, whilst two of them developed femoral head necrosis at 10 months and 4.5 years postoperatively, respectively.

Early prediction of femoral head avascular necrosis following neck fracture

Femoral neck fracture puts at risk functional prognosis in young patients and can be life-threatening in the elderly. The present study reviews methods of femoral head vascularity assessment following neck fracture, to address the following issues: what is the risk of osteonecrosis? And what, in the light of this risk, is the best-adapted treatment to avoid iterative surgery? Femoral head vascularity depends on retinacular vessels and especially the lateral epiphyseal artery, which contributes from 70 to 80% of the femoral head vascular supply. Fracture causes vascular lesions, which are in turn the prime cause of necrosis. Other factors combine with this: hematoma tamponade effect, reduced joint space and increased pressure due to lower extremity positioning in extension/internal rotation/abduction during surgery. Head deformity is not due to direct cell death but to the repair process originating from the surrounding living bone. In post-traumatic necrosis, proliferation rapidly invades the head, with significant osteogenesis. Pathologic fractures occur at the boundary between the new and dead bone. Many techniques have been reported to help assess residual hemodynamics and risk of necrosis. Some are invasive: superselective angiography, intra-osseous oxygen pressure measurement, or Doppler-laser hemodynamic measurement; others involve imaging: scintigraphy, conventionnal or dynamic MRI. The future seems to lie with dynamic MRI, which allows a new classification of femoral neck fractures, based on a non-invasive assessment of femoral head vascularity.

Is liver cirrhosis a risk factor for osteonecrosis of the femoral head in adults? A population-based 3-year follow-up study

BACKGROUND

The relationship between osteonecrosis of the femoral head (OFH) and liver cirrhosis is controversial. The aim of this study was to determine whether liver cirrhosis is associated with the occurrence of OFH.

METHODS

We used the National Health Insurance Database, derived from the Taiwan National Health Insurance program. The study cohort comprised 40,769 adult patients with liver cirrhosis. The comparison cohort consisted of 40,769 randomly selected age- and sex-matched subjects.

RESULTS

During the 3-year follow-up period, there were 321 (0.8%) cirrhotic patients with OFH, and 126 (0.3%) non-cirrhotic patients with OFH (p<0.001). Cox's regression analysis, adjusted by the patients' age, sex, and other confounding factors, showed that the cirrhotic patients had a higher risk for occurrence of OFH than non-cirrhotic patients during the 3-year period (hazard ratio=2.38, p<0.001). In this 3-year study, the incidence density of cirrhotic patients hospitalized for OFH was 3 episodes/1,000 person-year.

CONCLUSION

We conclude that cirrhotic patients have a higher risk for occurrence of OFH than non-cirrhotic patients.

Biphasic threat to femoral head perfusion in abduction: arterial hypoperfusion and venous congestion

BACKGROUND

Hip abduction can cause avascular necrosis (AVN) of the femoral head in infants.

OBJECTIVE

To compare the US perfusion pattern of femoral head cartilage in neutral position with that in different degrees and duration of abduction, testing the venous congestion theory of post-abduction ischemia.

MATERIALS AND METHODS

In 20 neonates, the Doppler flow characteristics of the posterosuperior (PS) branch of the femoral head cartilage feeding vessels were evaluated in neutral and at 30 degrees, 45 degrees, and 60 degrees abduction. In three neonates the leg was held in 45-degree abduction and flow was assessed at 5, 10, and 15 min.

RESULTS

Male/female ratio was 11/9 with a mean age of 1.86 +/- 0.7 weeks. The peak systolic velocities (PSV) declined in all three degrees of abduction. After 15 min of 45-degree abduction, the mean PSV declined and showed an absent or reversed diastolic component and undetectable venous return. No perfusion was detected at 60-degree abduction.

CONCLUSION

Abduction-induced femoral head ischemia is biphasic and degree- and duration-dependent. In phase I there is arterial hypoperfusion and in phase II there is venous congestion. A new pathogeneses for femoral head ischemia is offered.

Biomechanical comparison of 3 possible fixation strategies to resist femoral neck shortening after fracture

In light of recent reports that patients with femoral neck shortening following fracture fixation are dissatisfied with their outcomes, the objective of this study was to compare the compressive strength, or resistance to shortening, of 3 possible strategies for stabilization of the femoral neck that should resist shortening. The proximal portion of 21 synthetic composite femurs were prepared to isolate the femoral neck for study. A 4-mm segment of the femoral neck was removed to simulate a transcervical comminuted fracture that would be expected to shorten under standard treatment conditions. These simulated fractures were fixed by 1 of 3 methods: a 3-screw configuration using parallel partially threaded screws augmented with an injectable hydroxyapatite bone substitute in the fracture site; a 3-screw configuration using parallel fully threaded screws; or a nonparallel 3-screw configuration using partially threaded screws. The specimens were tested in compression along the axis of the femoral neck, and the mean stiffness and load to failure values were calculated.The hydroxyapatite bone substitute-augmented partially threaded screw fixation construct resulted in the highest stiffness (1928+/-135 N/mm) and load to failure (6529+/-674 N), followed by the fully threaded screw construct (1210+/-166 N/mm and 3987+/-419 N, respectively), and finally the nonparallel construct (518+/-176 N/mm and 592+/-295 N, respectively) (P<.001 for all groups). This study supports further evaluation of hydroxyapatite bone substitute augmentation at the fracture site to prevent femoral neck shortening in femoral neck fractures receiving internal fixation.

Challenges in the treatment of femoral neck fractures in the nonelderly adult

Femoral neck fractures in young patients are a relatively rare event and are often the consequence of a high-energy injury. Concomitant injuries are present more than 50% of the time. Previous reports have found the rate of nonunion and avascular necrosis in this population to be as high as 35% and 45%, respectively. The salvage options, which tend to yield more acceptable results in elderly patients with femoral neck fractures, yield disproportionately poor results in young, active patients who are often productive members of the labor force. Many reports exist in the literature evaluating the various treatment options of these injuries. This review will address the epidemiology and diagnosis of the injury. In addition, the various treatment options in the acute presentation, as well as options available for treating the sequelae of femoral neck fractures in the young, will be discussed. Although longer life expectancy and the sustained activity level of many people previously considered elderly has blurred the definition of "young," this review will use the available literature dealing with skeletally mature patients up to the age of 60 years.

To study the role of dynamic magnetic resonance imaging in assessing the femoral head vascularity in intracapsular femoral neck fractures

Intracapsular femoral neck fractures remain unsolved fractures even after improvement in techniques of diagnosis and internal fixation. Individuals who sustain displaced femoral neck fractures are at high risk of developing avascular necrosis and non-union. Although several methods for predicting the viability of femoral head have been reported, they are not effective or widely used because of unreliability, potential complications and technical difficulties. Dynamic MRI was introduced in the recent past as a simple, non-invasive technique to predict the femoral head viability after the femoral neck fractures. In this study role of dynamic MRI was studied in 30 patients with 31 intracapsular femoral neck fractures. Fractures were divided in to three types according to dynamic curve patterns on MRI evaluation and were followed up for 6 months to 2 years to observe the final outcome. Sensitivity, Specificity and the Accuracy of dynamic MRI in predicting vascularity after femoral neck fracture are 87%, 88% and 87%, respectively. Type A or Type B curve pattern is a positive factor to successful osteosynthesis with p value <0.0001 (Chi-square test). This is a statistically significant value. From this finding it can be suggested that the reliability of dynamic curves A and B in predicting maintained vascularity of femoral head is high. This investigation can be used to predict the vascularity of femoral head after intracapsular femoral neck fractures. There was a good correlation between the outcomes of fractures and dynamic MRI curves done within 48 h of injury. This signifies the role of dynamic MRI in predicting the vascularity of femoral head as early as 48 h. A treatment algorithm can be suggested on the basis of dynamic MRI curves. The fractures with Type C dynamic curve should be considered as fractures with poor vascularity of femoral head and measures to enhance the vascularity of femoral head along with rigid internal fixation should be undertaken to promote revascularization process and better healing of fractures. Patients with these fractures should be on longer non-weight bearing ambulation than other patients. To conclude, the dynamic MRI seems to be reliable, non-invasive, sensitive, specific and accurate method of assessing the femoral head vascularity after intracapsular femoral neck fractures as early as 48 h of injury and to predict the outcome of fractures and may be used as a guideline for management of intracapsular femoral neck fractures.

Internal fixation versus arthroplasty for displaced femoral neck fractures: what is the evidence?

A review of the current evidence for internal fixation versus hemiarthroplasty versus primary total hip arthroplasty for displaced femoral neck fractures was undertaken. At the meta-analysis level no difference in postoperative pain, function, or quality of life can yet be demonstrated. A significant difference in mortality has also not been found, but a trend towards higher mortality after primary arthroplasty is possible. Internal fixation (IF) has less morbidity, but a higher risk of revision and less cost-effectiveness. Independent adjudication for IF technique is rare in studies and bias towards higher revision rates due to technical failure is an issue. Randomized trials comparing IF with arthroplasty remain underpowered in specific subgroups of patients, in which IF revision rates could be acceptable. In hemiarthroplasty the data suggest minimal differences in outcome between the prosthesis types. The cementless Austin-Moore prosthesis is out-dated. Currently a cemented unipolar or bipolar, depending on costs, hemi-arthroplasty is the treatment of choice for an elderly patient with functional limitations before the fracture. The role of modern, uncemented hemiarthroplasty designs are uncertain until more data are published. Total hip arthroplasty (THA) should be considered in any active older patient with a displaced femoral neck fracture. Patients with concomitant osteoarthritis, rheumatoid arthritis, or renal failure do poorly with other treatment options and should be treated with THA. Randomized trials have shown THA to be a cost-effective treatment with lower revision rates than IF. THA may also appear to be superior to hemiarthroplasty in specific subgroups, but larger trials are needed to confirm this observation.

Prognostic value of dynamic MRI in assessing post-traumatic femoral head vascularity

OBJECTIVE

The vascular status of femoral heads in the post-traumatic period of intracapsular femoral neck fracture (ICFNF) remains uncertain until the patient actually develops avascular necrosis (AVN). Several methods for predicting the viability of femoral head have been reported, that are not effective or widely used because of unreliability, potential complications, and technical difficulties. The present study involved the use of Dynamic MRI (DMRI) in assessing femoral head vascularity to predict AVN.

MATERIALS AND METHODS

The role of DMRI was studied prospectively in 30 patients with 31 ICFNF. Fractures were divided in to three types (Type A, B, or C) based on the femoral head vascularity shown by dynamic curve patterns on MRI evaluation. Type A was preserved vascularity, Type B was some decrease in vascularity but still viable while Type C was significantly reduced vascularity. These were followed-up for 6 months to 2 years to observe the final outcome in terms of union, non-union, or AVN.

RESULTS

We found that Type A curves correlate well with vascular status and Type C curves correlate well with poor vascularity of the femoral heads. No AVN was seen in any of Type A (13/31) or Type B (eight out of 31). Five cases showed AVN and all of them were of Type C dynamic curves.

CONCLUSION

Dynamic MRI is a reliable tool to evaluate vascularity of femoral heads and thus reduces the uncertainty of outcome of treatment of ICFNFs. DMRI can be a useful tool to formulate a treatment algorithm in management of ICFNF.

Bone density comparisons in male competitive road cyclists and untrained controls

Low bone mineral density (BMD) has been documented in endurance-trained runners; however, the bone status of cyclists is unclear.

PURPOSE

The purpose of this study was to compare total body, lumbar spine, and dual proximal femur BMD in male competitive road cyclists (n = 32) and in age- and body mass-matched controls (n = 30).

METHODS

The cyclists had an average of 9.4 yr of racing experience and trained 7-22 h wk(-1). BMD was measured using dual energy x-ray absorptiometry (DXA; GE Lunar Prodigy, v. 6.70.021). Calcium intake was estimated from a food frequency questionnaire. Resting serum total and free testosterone levels were measured by RIA (Diagnostic Systems Laboratory).

RESULTS

There were no significant differences (P > 0.050) between the cyclists (CYC) and the controls (CON) for age, height, body mass, or testosterone levels. CYC had significantly (P < 0.050) lower percent body fat and higher bone-free lean body mass than the CON. Calcium intake for CYC was significantly higher (P < 0.050) than for the CON group (1557 +/- 132 vs 1098 +/- 69 mg d(-1)). Anterior-posterior spine (L2-L4) and lateral spine (LS) BMD (g cm(-2)) were significantly lower (P < 0.050) for CYC (L2-L4 = 1.165 +/- 0.023 g cm(-2); LS = 0.781 +/- 0.025 g cm(-2)) than for CON (L2-L4 = 1.246 +/- 0.028 g cm(-2); LS = 0.911 +/- 0.027 g cm(-2)). Based on t-scores (SD from the young adult reference population mean), 9% of CYC and 3% of CON were classified as osteoporotic, whereas 25% and 10% of CYC and CON, respectively, were osteopenic.

CONCLUSIONS

Our findings indicated that male cyclists had lower spine BMD than controls, which was not associated with group differences in testosterone. Future studies are needed to elucidate the underlying mechanisms for low bone mass in cyclists.

Rotational acetabular osteotomy for osteonecrosis of the femoral head after intracapsular fracture of the neck of the femur

The treatment of osteonecrosis of the femoral head in younger patients varies among orthopaedic surgeons. In particular, the optimal treatment of extensive osteonecrosis associated with femoral head collapse remains controversial. Since 1995, we have performed rotational acetabular osteotomy on 70 hips, including those of 3 patients with extensive osteonecrosis of the femoral head after intracapsular fracture of the neck of the femur. In all 3 patients, adequate coverage of the femoral head by the osteotomized acetabulum was obtained, and their symptoms (especially pain) showed marked improvement at latest follow-up.

Vascularized fibular grafting for osteonecrosis of the femoral head with unusual indications

We retrospectively reviewed the charts of 154 patients of various subgroups treated with the free vascularized fibular graft procedure for osteonecrosis of the femoral head (ONFH), evaluating pre- and postoperative Harris hip scores, hip range of motion, radiographs, and number of conversions to total hip arthroplasty (THA). Patients were followed a minimum of 1 year (mean, 6.8 years, range, 1 to 19 years). Athletes and patients with pyarthrosis-related osteonecrosis had high Harris hip scores at final review with scores of 94 and 97, respectively. Patients with ONFH after a slipped capital femoral epiphysis or following pregnancy had a low conversion rate to THA at 6% and 8%, respectively. Twenty-five percent of patients with transplant-related osteonecrosis of the femoral head were converted to THA at an average of 2.7 years. However, with select subsets of patients (athletes, pregnancy, organ transplant, femoral neck non-union, slipped capital femoral epiphysis, infection) the FVFG can result in a high rate of success.

Management of femoral neck fractures in young adults

Femoral neck fractures in young adults are uncommon and often the result of high-energy trauma. They are associated with higher incidences of femoral head osteonecrosis and nonunion. Multiple factors can play a significant role in preventing these devastating complications and contribute to a good outcome. While achieving an anatomic reduction and stable internal fixation are imperative, other treatment variables, such as time to surgery, the role of capsulotomy and the fixation methods remain debatable. Open reduction and internal fixation through a Watson-Jones exposure is the recommended approach. Definitive fixation can be accomplished with three cannulated or noncannulated cancellous screws. Capsulotomy in femoral neck fractures remains a controversial issue and the practice varies by trauma program, region and country. Until there is conclusive data (i.e. prospective and controlled) we recommend performing a capsulotomy. The data available is inconclusive on whether this fracture should be operated emergently, urgently or can wait until the next day. Until there is conclusive data available, we recommend that surgery should be done on an urgent basis. The key factors in treating femoral neck fractures should include early diagnosis, early surgery, anatomic reduction, capsular decompression and stable internal fixation.

The effectiveness of capsular decompression for internal fixation of intracapsular hip fractures

PURPOSE

To compare the results of screw fixation plus capsular decompression versus screw fixation alone for managing intracapsular hip fractures.

METHODS

Of 201 patients with intracapsular hip fractures, 99 underwent screw fixation with capsular decompression (capsular decompression group) and 102 underwent screw fixation alone (control group). The incidence and time to development of avascular necrosis of the femoral head, union rate, time to union, and other clinical parameters were compared.

RESULTS

In patients with displaced fractures, the incidence of avascular necrosis was significantly higher in the control than capsular decompression group, whereas the time to development of this complication was significantly shorter.

CONCLUSION

Capsular decompression did not improve the union rate and time to union in undisplaced intracapsular hip fractures, but in displaced fractures it appeared to reduce the incidence and delay the onset of avascular necrosis.

Influence of surgeon's experience and supervision on re-operation rate after hip fracture surgery

OBJECTIVE

To investigate the influence of the performing surgeon's experience and degree of supervision on re-operation rate among patients admitted with a proximal femoral fracture (PFF).

METHODS

Prospective study of 600 consecutive patients with proximal femoral fracture in our multimodal rehabilitation programme, between 2002 and 2004. Re-operation rate was assessed 6 months postoperatively. Surgeons were grouped as unsupervised junior registrars versus experienced surgeons operating or supervising. Fractures were stratified as technically undemanding or demanding.

RESULTS

Unsupervised junior registrars operated on 23% (137/600) of all and 15% (56/365) of technically demanding proximal femoral fractures. The latter had a higher re-operation rate within 6 months, compared with the rate when more experienced surgeons were present. In logistic regression analysis combining age, gender, American Society of Anaesthesiologists score, New Mobility Score, time to surgery and type of implant, surgery by unsupervised junior registrars was still a significant independent risk factor for re-operation in technically demanding proximal femoral fractures.

CONCLUSION

Unsupervised junior registrars should not operate on technically demanding proximal femoral fractures.

A predictive method for subsequent avascular necrosis of the femoral head (AVNFH) by observation of bleeding from the cannulated screw used for fixation of intracapsular femoral neck fractures

OBJECTIVES

To examine the validity of bleeding from the drill holes used for cannulated screw placement as a method for predicting any subsequent avascular necrosis of the femoral head (AVNFH) after the fixation of intracapsular femoral neck fractures.

DESIGN

Retrospective study.

SETTING

University hospital.

PARTICIPANTS

Forty-four patients (mean age, 51 years; range, 18-76 years) whose femoral neck fractures had been fixed with cannulated screws from March 1999 to January 2001 were enrolled in this study. The fractures were classified according to Garden and included 11 type I, 5 type II, 17 type III, and 11 type IV. The average delay between injury and surgery was 52 hours (< or =24 hours, 26; > or =24 hours, 18; range 7 to 504 hours). The follow-up period was more than 25 months (range, 25-57 months).

INTERVENTION

7.0 mm cannulated screws were used for fracture fixation. Three and 4 screws were used for fixation in 35 and 9 cases, respectively.

MAIN OUTCOME MEASUREMENTS

The presence or absence of blood drainage from the holes of the proximal cannulated screws was determined by an independent observer and defined as bleeding or no bleeding throughout a 5 minute observation period. According to those findings, patients were classified into 2 groups: the bleeding group (38 cases), and the nonbleeding group (6 cases). The validity of the relationship between the 2 groups and the development of AVNFH was evaluated according to the sensitivity, specificity, positive predictive value, and negative predictive value. A chi test was used for univariate analysis of the relationship between the related factors with the development of AVNFH.

RESULTS

The mean follow-up was 39 months (range, 25-57 months). AVNFH developed in 7 cases (16%). One patient of 38 in the bleeding group (2.6%) and all 6 patients in the nonbleeding group (100%) developed AVNFH. The sensitivity was 86%, specificity 100%, positive predictive value 100%, and negative predictive value 97%. Age (P < 0.734), sex (P < 0.587), the type of the fracture (P < 0.356), procedure interval (P < 0.398), the reduction status of the fracture site (P < 0.3849), the positions of the fixed screws (P < 0.2137), and the existence of osteoporosis (P < 0.4347) were not related to the development of AVNFH.

CONCLUSION

It seems that bleeding from the holes of proximal cannulated screws is a simple and accurate perfusion assessment technique for predicting the development of AVNFH after a femoral neck fracture. Given that assumption, primary arthroplasty might be an appropriate choice as a treatment method in a nonbleeding-group patient whose treatment choice is ambivalent or who might not be able to undergo additional surgery should he or she develop a subsequent AVNFH after internal fixation of femoral neck fracture.

Long-term outcome of undisplaced fatigue fractures of the femoral neck in young male adults

The incidence and long-term outcome of undisplaced fatigue fractures of the femoral neck treated conservatively were examined in Finnish military conscripts between 1970 and 1990. From 106 cases identified, 66 patients with 70 fractures were followed for a mean of 18.3 years (11 to 32). The original medical records and radiographs were studied and physical and radiological follow-up data analysed for evidence of risk factors for this injury. The development of avascular necrosis and osteoarthritis was determined from the follow-up radiographs and MR scans. The impact of new military instructions on the management of hip-related pain was assessed following their introduction in 1986. The preventive regimen (1986) improved awareness and increased the detected incidence from 13.2 per 100,000 service-years (1970 to 1986) to 53.2 per 100,000 (1987 to 1990). No patient developed displacement of the fracture or avascular necrosis of the femoral head, or suffered from adverse complications. No differences were found in MRI-measured hip joint spaces at final follow-up. The mean Harris Hip Score was 97 (70 to 100) and the Visual Analogue Scale 5.85 mm (0 to 44). Non-operative treatment, including avoidance of or reduced weight-bearing, gave favourable short- and long-term outcomes. Undisplaced fatigue fractures of the femoral neck neither predispose to avascular necrosis nor the subsequent development of osteoarthritis of the hip.

Postoperative imaging of the hip

The number and type of operative procedures involving the hip continue to increase, placing a greater emphasis on characterizing patient postoperative condition accurately. Optimal postoperative imaging evaluation may involve multiple modalities, including conventional radiography, radionuclide scintigraphy, and cross-sectional imaging. Many of the surgical procedures involve the placement of metallic joint replacements or fixation that can make the imaging evaluation of the postoperative anatomy challenging. Clinical examination of patients combined with the type of procedure performed direct the appropriate imaging evaluation; adequate clinical knowledge of these procedures and how to optimally image them provide an opportunity to attain the most accurate evaluation possible.

Resurfacing hip prostheses revisited: failure analysis during a 16-year follow-up

We conducted a prospective study of the clinical and radiographic variables related to the survival of 114 cementless resurfacing double-cup hip replacements (RHR) with a mean follow-up of 9 (range: 1--16) years. Three patients died, and 22 were unavailable for the final review in 2003. Sixty-one RHRs had to be revised to a total hip replacement. Failure analysis of these revised RHRs showed femoral head and neck resorption under the prosthesis in 33, acetabular protrusion in seven, both femoral and acetabular resorption in 14 and a femoral-neck fracture in three. One hip had dislocated, and there were three hips with unexplained pain. The Kaplan-Meier 5-year mean survival was 92%, the 10-year survival was 47% (95% CI 37--57%) and the 15-year survival was 30% (95% CI 20--40%). Pre-operative joint destruction (grade 1), a high degree of radiological osteoporosis, a body mass index >25 and prosthesis mismatch were significantly related to failure of the RHR. We believe that in young, non-obese patients with pre-operative radiological central destruction but without severe proximal femoral osteoporosis, a resurfacing arthroplasty may have some value. Our failures were mainly due to femoral resorption under the prosthetic femoral component.

Observer assessment of femoral neck radiographs after reduction and dynamic hip screw fixation

INTRODUCTION

It is not known how the described methods of reduction and dynamic hip screw (DHS) fixation of displaced intracapsular femoral neck fractures translate into proper assessment of the postoperative radiographs. At teaching or evaluation sessions in daily practice, frequent discussion arises about postoperative technical assessment. The assessment of correct reduction and DHS fixation using the described methods in the literature may be subject to differences between observers. The aim of this study was to assess the extent of inter- and intraobserver agreement on technique, based on the methods in the literature, in a simulated daily practice setting.

MATERIALS AND METHODS

The postoperative anteroposterior (AP) and lateral radiographs of 35 randomly selected patients aged 60-90 years were rated twice, 2 months apart, by six surgical observers from three institutions with similar views on reduction and DHS fixation for this fracture type. The radiographs were of sufficient quality for proper assessment. Criteria for reduction and fixation could be rated as either adequate or inadequate. An adequate rating was assigned if in the observer's opinion, regardless of likely outcome, technical perfection according to the described methods had been achieved. The kappa statistic was calculated as a measure of agreement.

RESULTS

Fracture reduction on the AP view approached a good kappa value (0.54). Poor to moderate interobserver agreement was found for fracture reduction on the lateral view and aspects of DHS fixation (kappa 0.10-0.36). Intraobserver agreement was good for five out of six observers for reduction and DHS fixation aspects (kappa 0.51-0.81).

CONCLUSION

During routine practice six surgical observers can nearly agree on adequate fracture reduction on the AP view, but do not agree on adequate reduction on the lateral view and adequate DHS fixation on the postoperative radiographs of displaced intracapsular femoral neck fractures.

Reversible and Irreversible Peri-implant Lesions: Report and Etiopathogenic Analysis of 7 Cases

The purpose of this report is to review the aberrations in the integration process of cylindrical endosseous implants, though such aberrations are seldom observed. These issues are treated according to the following scheme: (1) infectious lesions, which consist of peri-implantitis, intraosseous infectious foci, and septic voids; (2) transitory lesions; (3) lesions related to occlusal overload; and (4) healing defects. In this report, we illustrate these categories with patient histories and discuss the clinical findings and etiopathogenies.

Autosomal dominant avascular necrosis of femoral head in two Taiwanese pedigrees and linkage to chromosome 12q13

Avascular necrosis of the femoral head (ANFH) is a debilitating disease that commonly leads to destruction of the hip joint in adults. The etiology of ANFH is unknown, but previous studies have indicated that heritable thrombophilia (increased tendency to form thrombi) and hypofibrinolysis (reduced ability to lyse thrombi), alcohol intake, and steroid use are risk factors for ANFH. We recently identified two families with ANFH showing autosomal dominant inheritance. By applying linkage analysis to a four-generation pedigree, we excluded linkage between the family and three genes related to thrombophilia and hypofibrinolysis: protein C, protein S, and plasminogen activator inhibitor. Furthermore, by a genomewide scan, a significant two-point LOD score of 3.45 (recombination fraction [theta] = 0) was obtained between the family with ANFH and marker D12S85 on chromosome 12. High-resolution mapping was conducted in a second family with ANFH and replicated the linkage to D12S368 (pedigree I: LOD score 2.47, theta = 0.05; pedigree II: LOD score 2.81, theta = 0.10). When an age-dependent-penetrance model was applied, the combined multipoint LOD score was 6.43 between D12S1663 and D12S85. Thus, we mapped the candidate gene for autosomal dominant ANFH to a 15-cM region between D12S1663 and D12S1632 on chromosome 12q13.

Non-union of femoral neck fractures with osteonecrosis of the femoral head: treatment with combined free vascularized fibular grafting and subtrochanteric valgus osteotomy

Femoral neck fractures, frequently complicated by non-union and femoral head osteonecrosis,present a difficult clinical situation, especially when young patients are concerned. Existing treatment options are valgus osteotomy to address the biomechanical factors or bone grafting to address the biologic factor. The authors describe the operative technique and results of combined subtrochanteric valgus osteotomy and free vascularized fibular grafting in management of five young patients with both non-union and avascular necrosis.