The 2001 revised criteria for diagnosis, classification, and staging of idiopathic osteonecrosis of the femoral head

Three-dimensional distribution of cystic lesions in osteonecrosis of the femoral head

Purpose

The aim of this study was to investigate the location characteristics of cystic lesions in a three-dimensional context and discuss the mechanism of formation.

Methods

A total of 155 femoral head computed tomography images from 94 patients diagnosed with stage II and III osteonecrosis of the femoral head were retrospectively reviewed. Three-dimensional structures of the femoral head including the cystic lesions and necrotic area were reconstructed. We divided each femoral head into eight regions to observe the positional relationship of the cystic lesions, normal areas, and necrotic areas.

Results

The regional distribution revealed 14 (13%), 35 (32%), 9 (8%), 25 (23%), 6 (6%), 15 (14%), 4 (4%), and 0 (0%) cystic lesions in regions Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ, Ⅵ, Ⅶ, and Ⅷ, respectively. The anteromedial zone, A (Ⅰ ​+ ​Ⅲ), contained 22% of the lesions, anterolateral zone, B (Ⅱ ​+ ​Ⅳ), contained 54%, posteromedial zone, C (Ⅴ +Ⅶ), contained 9% of the lesions, and posterolateral zone, D (Ⅵ ​+ ​Ⅷ), contained 15% of the lesions. Most of the cystic lesions (78%) were located between the normal and necrotic areas; 18% of cystic lesions were in the necrotic area ​and 4% were in the normal area.

Conclusions

Cystic lesions most often occur at the junction of the necrotic ​and normal areas and are most commonly located in the anterolateral femoral head, which is similar to the distribution of the stress concentration region.

The translational potential of this article

The study showed the location characteristics of cystic lesions in osteonecrosis of femoral head, which suggested that the formation of cystic lesions may be related to stress and could accelerate the collapse of femoral head. The results can support further research on cystic lesions and provide a reference for doctors' treatment strategies for patients with osteonecrosis of femoral head.

Classification of osteonecrosis of the femoral head: Who should have surgery?

Objectives

Using a simple classification method, we aimed to estimate the collapse rate due to osteonecrosis of the femoral head (ONFH) in order to develop treatment guidelines for joint-preserving surgeries.

Methods

We retrospectively analyzed 505 hips from 310 patients (141 men, 169 women; mean age 45.5 years (sd 14.9; 15 to 86)) diagnosed with ONFH and classified them using the Japanese Investigation Committee (JIC) classification. The JIC system includes four visualized types based on the location and size of osteonecrotic lesions on weightbearing surfaces (types A, B, C1, and C2) and the stage of ONFH. The collapse rate due to ONFH was calculated using Kaplan–Meier survival analysis, with radiological collapse/arthroplasty as endpoints.

Results

Bilateral cases accounted for 390 hips, while unilateral cases accounted for 115. According to the JIC types, 21 hips were type A, 34 were type B, 173 were type C1, and 277 were type C2. At initial diagnosis, 238/505 hips (47.0%) had already collapsed. Further, the cumulative survival rate was analyzed in 212 precollapsed hips, and the two-year and five-year collapse rates were found to be 0% and 0%, 7.9% and 7.9%, 23.2% and 36.6%, and 57.8% and 84.8% for types A, B, C1, and C2, respectively.

Conclusion

Type A ONFH needs no further treatment, but precollapse type C2 ONFH warrants immediate treatment with joint-preserving surgery. Considering the high collapse rate, our study results justify the importance of early diagnosis and intervention in asymptomatic patients with type C2 ONFH.

Cite this article: Y. Kuroda, T. Tanaka, T. Miyagawa, T. Kawai, K. Goto, S. Tanaka, S. Matsuda, H. Akiyama. Classification of osteonecrosis of the femoral head: Who should have surgery?. Bone Joint Res 2019;8:451–458. DOI: 10.1302/2046-3758.810.BJR-2019-0022.R1.

Osteocyte staining with rhodamine in osteonecrosis and osteoarthritis of the femoral head

Death of osteocytes is synonymous of bone death. Aseptic osteonecrosis of the femoral head is a lesion characterized by the death of osteocytes occurring after major vascular changes. The evolution may lead to hip osteoarthritis, which requires total hip arthroplasty in most cases. Evolution of aseptic osteonecrosis in four radiological stages is well known. We analyzed 24 femoral heads from patients with osteonecrosis or osteoarthritis, retrieved at the time of surgery for a hip arthroplasty. The aim of the study was to clearly identify the necrotic bone from the living bone in the histological samples. The femoral heads were sawed, and a large sample was harvested in the superior zone; it was stained en-bloc with rhodamine dissolved in formalin to make the osteocytes fluorescent under UV light microscopy. Undecalcified sections, 7 μm thick, were obtained on a heavy-duty microtome. A micrographic analysis using two UV excitation wavelengths visualized the living osteocytes (in green) and the bone matrix (in blue). A simple method to prepare combined images is described. In addition, the blocks can be analyzed by confocal microscopy to visualize more details. It is possible to identify at low magnification the osteocytes within the bone matrix and the osteonecrotic areas where osteocytes have disappeared. Identification of osteocytes showed that newly formed bone packets are laid on dead trabeculae in patients with aseptic osteonecrosis or with osteoarthritis. In the osteosclerotic areas, the enlarged trabeculae have a dead central core surrounded by recently apposed bone structure units.

Revascularization of the necrotic femoral head after traumatic open anterior hip dislocation in a child: a case report

INTRODUCTION

Avascular necrosis of the femoral capital epiphysis is the most serious complication after traumatic dislocation of the hip in children. This case report discusses the localization and revascularization of the necrotic femoral head following rarely experienced traumatic open anterior hip dislocation in children.

CASE PRESENTATION

Our patient was an 11-year-old Japanese boy who had open anterior hip dislocation sustained in a traffic accident. Reduction of the hip joint was performed in an emergency operation, and he was evaluated using serial gadolinium-enhanced magnetic resonance imaging. T1-weighted magnetic resonance images showed two bands with low signal intensity in the femoral capital epiphysis on coronal and oblique axial planes, indicating the existence of avascular osteonecrosis of the femoral head. We observed gadolinium enhancement in the central region of the epiphysis, where the area between the two bands with low signal intensity was located. Serial assessment with enhanced magnetic resonance images during a non-weight-bearing period of 1.5 years after injury showed revascularization starting from the central region and converging toward the peripheral region. Although the patient had leg-length discrepancy due to the early epiphyseal closure, non-weight-bearing treatment for the avascular osteonecrosis of the femoral head achieved a favorable outcome without any hip joint dysfunction, pain, or sign of secondary osteoarthritic change within 4.5 years after injury.

CONCLUSION

We confirmed the revascularization process of the necrotic lesion in the femoral capital epiphysis in an 11-year-old boy using serial gadolinium-enhanced magnetic resonance imaging. Conservative non-weight-bearing treatment achieved a favorable outcome.

Volume of hip synovitis detected on contrast-enhanced magnetic resonance imaging is associated with disease severity after collapse in osteonecrosis of the femoral head

OBJECTIVE

To evaluate the relationship between the volume of hip synovitis detected on contrast-enhanced magnetic resonance imaging (MRI) and the disease stage of osteonecrosis of the femoral head (ONFH).

MATERIALS AND METHODS

Sixty-three consecutive hips in 40 ONFH patients were reviewed using contrast-enhanced MRI. Ten unaffected hips in 10 patients with unilateral ONFH were used as controls. Based on the Japanese Investigation Committee system, these hips were classified according to stage and type. The volume and location of hip synovitis were semi-quantitatively measured on contrast-enhanced MRI. Clinicoradiological factors were statistically analyzed to determine the relationship with the volume of hip synovitis.

RESULTS

The mean synovial volume was significantly larger in ONFH hips (8,020 ± 6,900 mm³) than in controls (910 ± 1,320 mm³; p = 0.001). The area of synovitis in the anterior portion of the hip joint was double (mean: 2.17 ± 1.77) that in the posterior portion. The volume of synovitis was small in pre-collapse-stage hips (stage 1: 680 ± 690 mm³, stage 2: 1,460 ± 1,200 mm³), but significantly larger in post-collapse-stage hips (stage 3A: 7,820 ± 4,490 mm³, stage 3B: 13,850 ± 7,110 mm³; p < 0.001). Multiple regression analysis showed that disease stage was the only factor related to hip synovitis.

CONCLUSIONS

Our study suggests that hip synovitis in ONFH might occur after femoral head collapse and worsen with collapse progression, mainly in the anterior portion.

Predictive value of magnetic resonance imaging for multifocal osteonecrosis screening associated with glucocorticoid therapy

Objectives: The goals of this study were to elucidate the distribution of multifocal osteonecrosis associated with glucocorticoid therapy using magnetic resonance imaging (MRI) and to establish a MRI screening method.Methods: Between 1986 and 2018, 107 patients underwent MRI screening of their hips, knees, shoulders and ankle joints (856 joints in total) after systemic glucocorticoid therapy.Results: Osteonecrosis was observed in hip (68%), knee (44%), ankle (17%) and shoulder (15%) joints. Patients with bilateral osteonecrosis in their hips were likely to have bilateral osteonecrosis in their knees, whereas patients without osteonecrosis in both hips were unlikely to have osteonecrosis in both knees (p = .0299). Osteonecrosis was never evident in the ankle or shoulder joints when a patient did not have osteonecrosis in both hip and knee joints.Conclusion: In this study, MRI - as a screening method for multifocal osteonecrosis associated with glucocorticoid therapy - showed the sites affected first are hips and knees followed by ankles and shoulders. If osteonecrosis is absent in hip and knee joints, further screening of the ankles and shoulders is unnecessary. Any osteonecrosis observed in the hip and/or the knee joints warrants a second MRI screening of the ankles and shoulders.

Which Osteotomy for Osteonecrosis of the Femoral Head and Which Patient for the Osteotomy?

Transtrochanteric curved varus osteotomy (TCVO) and transtrochanteric rotational osteotomy (TRO) are joint-preserving procedures for osteonecrosis of the femoral head. The purpose of this review is to provide up-to-date guidelines for the osteotomies. One retrospective comparison revealed that TCVO has shorter operation time, less bleeding, lower incidence of osteophyte formation, and lower rate of secondary collapse. To obtain successful results of the osteotomy, the patient should be younger than 40 years and should have a body mass index of less than 24 kg/m². The osteotomy should be performed in early stages of femoral head osteonecrosis before marked collapse of the femoral head. The patient should have a medium-size lesion and an enough viable bone to restore the intact articular surface and subchondral bone in the weight-bearing area.

Transtrochanteric rotational osteotomy for various hip disorders

BACKGROUND

Joint-preserving procedures should be considered as much as possible for hip disorders in pediatric and young patients. However, in patients with extensive osteonecrosis (ON) of the femoral head combined with severe collapse and advanced secondary osteoarthritis (OA), the optimal procedure has not been elucidated. This retrospective study aimed to investigate the postoperative outcomes of 11 patients who underwent transtrochanteric rotational osteotomy (TRO) alone or with a combination treatment for various hip disorders in young patients and to evaluate the usefulness of TRO.

METHODS

Eleven patients (11 hips) with a mean age at operation of 22 years were included. The mean follow-up duration was 9.4 years. Preoperative diagnosis was secondary OA in 6 patients (pigmented villonodular synovitis, 2; after rotational acetabular osteotomy, 1; pyogenic arthritis, 1; femoroacetabular impingement, 1; acetabular dysplasia, 1) and ON in 5 patients (slipped capital femoral epiphysis, 4; femoral neck fracture, 1). Combination treatment was performed in 2 patients with distraction arthroplasty and in 6 patients with intra-articular procedures (mosaicplasty, 1; drilling, 1; microfracture, 4; cam resection, 1). Clinical evaluation was performed by using the Merle d'Aubigne and Postel score (MDPS). Joint congruency and progression of osteoarthritic change in all cases, and progression of collapse in the ON patients were evaluated radiographically.

RESULTS

The mean MDPS improved from 10.3 to 14.2 in the OA patients and from 9.4 to 14.8 in the ON patients. The OA grade was maintained or improved in 10 hips (91%). Progressive collapse was prevented in all ON patients, and good remodeling was demonstrated.

CONCLUSION

Even in the highly degenerative cases, TRO enabled repair and prevention of the progression of OA. This procedure might be a useful salvage operation for treating secondary OA and ON of the hip even if the clinical condition is advanced, especially in young patients.

Is There a Role of Pharmacological Treatments in the Prevention or Treatment of Osteonecrosis of the Femoral Head?: A Systematic Review

Background

Various pharmacological treatments have been suggested to treat osteonecrosis of the femoral head. However, their practicability remains a controversial issue.

Methods

We systemically reviewed articles published during last 20 years to assess the efficacy and safety of the pharmacological treatments.

Results

To date, enoxaparin, statins, bisphosphonates, iloprost and acetylsalicylic acid have been practiced for the treatment of osteonecrosis. However, none of them were proven to be effective by high level studies, and most of them have adverse reactions.

Conclusions

No pharmacological prevention or treatment of osteonecrosis is recommendable at this moment.

Pericollapse Stage of Osteonecrosis of the Femoral Head: A Last Chance for Joint Preservation

Objective:

To propose a new definition of the pericollapse stage of osteonecrosis of the femoral head (ONFH) and review its significance in disease diagnosis and treatment selection.

Data Sources:

A search for eligible studies was conducted in three electronic databases including PubMed, Cochrane Library, and Embase up to August 10, 2018, using the following keywords: “osteonecrosis”, “prognosis”, and “treatment”.

Study Selection:

Investigations appraising the clinical signs, symptoms, and imaging manifestations in different stages of ONFH were included. Articles evaluating the prognosis of various joint-preserving procedures were also reviewed.

Results:

The pericollapse stage refers to a continuous period in the development of ONFH from the occurrence of subchondral fracture to early collapse (<2 mm), possessing specific imaging features that mainly consist of bone marrow edema and joint effusion on magnetic resonance imaging (MRI), crescent signs on X-ray films, and clinical manifestations such as the sudden worsening of hip pain. Accumulating evidence has indicated that these findings may be secondary to the changes after subchondral fractures. Of note, computed tomography provides more information for identifying possible subchondral fractures than does MRI and serves as the most sensitive tool for grading the pericollapse lesion stage. The pericollapse stage may indicate a high possibility of progressive disease but also demonstrates satisfactory long- and medium-term outcomes for joint-preserving techniques. In fact, if the articular surface subsides more than 2 mm, total hip arthroplasty is preferable.

Conclusions:

The pericollapse stage with distinct clinical and imaging characteristics provides a last good opportunity for the use of joint-preserving techniques. It is necessary to separate the pericollapse stage as an independent state in evaluating the natural progression of ONFH and selecting an appropriate treatment regimen.

Corticosteroid dose increase is a risk factor for nonalcoholic fatty liver disease and contralateral osteonecrosis of the femoral head: a case report

BACKGROUND

The incidence of bilateral corticosteroid-induced osteonecrosis of the femoral head (ONFH) is high. Although the precise mechanism of corticosteroid-induced ONFH development is unclear, hepatic enzyme abnormalities such as low activity of hepatic cytochrome P450 3A could be one cause. Herein, we report the case of a patient who developed ONFH in the contralateral hip after the dose of corticosteroids for idiopathic thrombocytopenic purpura was increased. Liver biopsy was done to rule out autoimmune hepatitis.

CASE PRESENTATION

A 32-year-old woman had been treated with continuous corticosteroids of up to 10 mg/day for Sjögren's syndrome for 25 years and corticosteroid-induced ONFH in the left side. At age 33, idiopathic thrombocytopenia developed, which was treated by increasing the corticosteroid dose (40 mg/day). Two months later, liver enzyme level began to increase slightly and continued to increase. A year after corticosteroid dose increase, contralateral ONFH developed, and a liver biopsy demonstrated nonalcoholic fatty liver disease (NAFLD).

CONCLUSIONS

The current case indicates that corticosteroid dose increase is a potential risk factor for NAFLD and contralateral ONFH. Therefore, it would be useful and important for to screen and monitor patients with hepatic enzyme abnormality for ONFH occurrence.

Long-term hip survival and factors influencing patient-reported outcomes after transtrochanteric anterior rotational osteotomy for osteonecrosis of the femoral head: A minimum 10-year follow-up case series

Objectives: This retrospective study aimed to assess long-term hip survival after transtrochanteric anterior rotational osteotomy (ARO) for osteonecrosis of the femoral head (ONFH) and identify factors influencing patient-reported outcome measures (PROMs) in patients with preserved joints.Methods: Altogether, 95 consecutive hips in 85 ONFH patients who underwent ARO during 2000-2007 (86.7% follow-up) were studied. Controls were 35 patients with 41 hips with ONFH managed conservatively for >1 year after collapse. We analyzed hip survival using the Kaplan-Meier method, with the endpoint defined as any therapeutic surgery related to ONFH. We also evaluated PROMs for both groups in patients with surviving hips and available radiographs at the final follow-up.Results: The 10-year hip survival rate after ARO was 85.4%, which was significantly higher than the 5-year rate in the control group (50.4%). Multiple regression analyses showed that the presence of osteoarthritic change after ARO was significantly associated with poor scores for both the Oxford Hip Score and the Short Form-12 Health Survey Physical Component Summary.Conclusions: ARO could effectively preserve hip joints with post-collapse ONFH, although the presence of osteoarthritic change could lead to lower satisfaction even among patients with long-term hip survival after ARO.

Osteonecrosis in pediatric cancer survivors: Epidemiology, risk factors, and treatment

Several treatment regimens for childhood malignancies have been associated with the development of osteonecrosis, including radiation therapy, glucocorticoid medications, immunotherapy (including anti-angiogenic agents), and several chemotherapeutic agents. Adolescents older than 10 years are at greatest risk of developing osteonecrosis within 1 year of initiating therapy. Screening with magnetic resonance imaging in this high-risk population may be a useful method for detecting osteonecrosis. Surgery may be required for lesions that have progressed substantially despite nonoperative interventions.

Huo Xue Tong Luo capsule, a vasoactive herbal formula prevents progression of asymptomatic osteonecrosis of femoral head: A prospective study

Background/objective

A prospective cohort study aimed to evaluate the clinical efficacy of a specific vasoactive herbal formula, Huo Xue Tong Luo capsule (HXTL capsule), for the treatment of patients with asymptomatic osteonecrosis of femoral head (ONFH).

Methods

We evaluated a clinical trial of 55 patients (59 hips) with asymptomatic ONFH (no joint collapse) evaluated by Steinberg staging system and necrosis range classification criteria. Then, they were given HXTL capsule under specific protocol. Among them, 39 males and 16 females with an average age of 36.4 ± 10.1 years were followed up for an average of 4.38 years during treatment. The aggravation of clinical and imaging results was assessed by initial pain and joint collapse. The clinical and imaging outcomes of these patients were compared with those of a historical control group from the literature under critical inclusion criteria.

Results

At the latest follow-up, initial pain occurred in five of 59 (8.5%) hips of patients taking HXTL capsule compared with 31 of 81 (38.3%) controls (p < 0.001), and joint collapse occurred in 13 of 59 (22.0%) hips of patients taking HXTL capsule compared with 26 of 81 (32.1%) controls (p < 0.001). There was no association between joint collapse and multiple key factors of ONFH. Only the location of type C2 necrotic lesions (hazard ratio, 4.12; 95% confidence interval, 2.64–18.91) and the extent of large necrotic lesions (hazard ratio, 3.39; 95% confidence interval, 1.43–16.21) predicted joint collapse.

Conclusion

As an agent formulated by vasoactive herbals, HXTL capsule with specific protocol is an effective medicine for relieving hip pain and preventing joint collapse in patients with asymptomatic ONFH.

The translational potential of this article

The translation potential of this prospective cohort study is that the initially officially approved clinical indication for HXTL capsule for treatment of ONFH is due to its possible effect of revascularization on angiogenesis of necrosis. It is has been now proven to be effective for a new clinical application.

A mathematical model for predicting postoperative leg shortening after curved intertrochanteric varus osteotomy for osteonecrosis of the femoral head

Despite good clinical outcomes associated with curved intertrochanteric varus osteotomy for the treatment of osteonecrosis of the femoral head, post-operative leg-length discrepancy is frequently reported and might reduce patient satisfaction. Although previous report showed that varus angulation affected post-operative leg-length discrepancy, sufficient varus angulation is the most important factor for obtaining a lateral intact portion. Therefore, to ensure better postoperative outcomes, detection of other parameters associated with leg shortening may prove useful. This study aimed to detect other factors influencing post-operative leg-length discrepancy and to develop a theory for pre-operative planning. The study included 42 hips of 36 patients with osteonecrosis of the femoral head [25 men and 11 women; mean age at the time of surgery, 33.8 years (range, 17 to 53 years)]. Patients were assessed their clinical and radiological results bofore and after surgery. Additionally, a mathematical model was developed to predict leg shortening after curved intertrochanteric varus osteotomy based on the degree of varus angulation and the distance between the femoral head and osteotomy arc centers. Predicted and actual leg shortening in patients were compared to verify the accuracy of our model. Post-operatively, mean varus angle was 21.7° (range, 15 to 38°) and mean leg shortening was 1.7 mm (range, -5.1 to 11.4 mm). Univariate analysis showed that varus angulation and lateral shift of the osteotomy arc might influence the degree of leg shortening. Furthermore, mathematically predicted leg shortening significantly correlated with actual leg shortening (r = 0.905, p < 0.001), suggesting the usefulness of our model for predicting complications of curved intertrochanteric varus osteotomy. This study indicates the importance of not positioning the center of the osteotomy arc lateral from the center of the femoral head to minimize leg shortening after curved intertrochanteric osteotomy.

Effects of sclerotic changes on stress concentration in early-stage osteonecrosis: A patient-specific, 3D finite element analysis

Stress distribution remains unclear in early-stage osteonecrosis of the femoral head (ONFH). To clarify this issue, we generated patient-specific finite element models (FEMs) from 51 patients with ONFH. Patients' hips were classified into three groups: ONFH without a sclerotic boundary (Stage 1, n = 6), ONFH with a sclerotic boundary (Stage 2, n = 10), and ONFH with both a sclerotic boundary and <2 mm collapse (Stage 3, n = 35). Four hips without ONFH were used as controls. Stress distribution in each FEM was compared with magnetic resonance imaging (MRI) and computed tomography (CT) results. Fifteen wholly resected femoral heads in Stage 3 hips were assessed by micro-CT. Furthermore, we histologically examined three Stage 2 femoral heads that subsequently developed subchondral fractures after FEM analyses. In all FEMs of both control and Stage 1 hip, stress was equally distributed on the femoral head surface. However, in all FEMs of both Stages 2 and 3 hips, stress was concentrated at the lateral boundary of the femoral head surface, corresponding to both a low-intensity band on T1-weighted MRI images and sclerotic changes on CT. On micro-CT, subchondral fractures consistently began at the lateral boundary with sclerotic changes, in which bone volume fraction was increased. Histology showed breakage of subchondral plates at the junction between necrotic and reparative zones. In early-stage ONFH, sclerotic changes caused stress concentration, which can trigger subchondral fractures at the lateral boundary. Clinical Significance: Our results will clarify the pathogenic mechanism of collapse in ONFH. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3169-3177, 2018.

Clinical results of hemiarthroplasty using new bipolar cups for stage 3 or lower osteonecrosis of the femoral head: a retrospective study

PURPOSE

The aim of this study was to evaluate clinical and radiographic findings of stage 3 or lower osteonecrosis of the femoral head (ONFH) with intact acetabular cartilage in patients treated with bipolar hemiarthroplasty (BHA).

METHODS

A total of 79 hips that underwent BHA for ONFH were included in this study. The average observation period was 7.6 years. Clinical results were evaluated using the Harris hip score. We performed radiographic analysis to assess the migration of the outer cup, the permanent image around the outer cup, and loosening of the stem.

RESULTS

The total Harris hip score improved from 50 points before surgery to 92 points at final follow-up, while pain improved from 14 points to 36 points. Flexion improved from 94° to 120° and abduction from 27° to 37°. One patient on dialysis showed progress in terms of inward migration, and revision surgery was performed on the patient 14 years after the original surgery.

CONCLUSIONS

Midterm performance of BHA for stage 3 or lower ONFH at our hospital was good.

Unexpected dislocation following accurate total hip arthroplasty caused by excessive hip joint laxity during myasthenic crisis: a case report

BACKGROUND

Dislocation following total hip arthroplasty is mainly caused by malposition. However, the coexistence of neuromuscular disorders is also considered a risk for dislocation due to excessive hip joint laxity. To minimize risk of dislocation, preoperative planning using combined anteversion has been widely used. The recommended combined anteversion angle (the total of cup and stem anteversion angles) is 50 ± 10°.

CASE PRESENTATION

A 33-year-old Japanese woman underwent elective total hip arthroplasty due to osteonecrosis of the femoral head associated with corticosteroid pulse therapy for myasthenia gravis. Intraoperatively, no tendency of dislocation was found when simulating an evoking position under general anesthesia. In postoperative X-ray and computed tomography scans, cup inclination, cup anteversion, and stem anteversion angles were 37°, 13°, and 35° respectively. The resulting combined anteversion was 48°, which was set as the target along with accurate placement. Her postoperative course was normal and she was discharged without adverse events. Three months postoperatively, due to worsening of myasthenic weakness in her lower extremities while resting, she tended to raise her left limb up using both hands for sitting up. An anterior dislocation occurred when her legs were in a figure-of-four position. She was brought to an emergency department, and reduction of dislocation was performed. It was inferred that myasthenic crisis in the affected limb enabled excessive passive motion due to joint hyperlaxity. At the end of 2016, elective total hip arthroplasty on the contralateral side was performed. Cup anteversion, stem anteversion, and the combined anteversion angles were 27°, 24°, and 51° respectively. We instructed her to exercise care during passive leg movement, which may worsen her myasthenic condition. She returned to a normal life and was able to walk long distances without a cane. No recurrence of dislocation was seen at final follow-up.

CONCLUSIONS

Even if accurate component orientation is attained in total hip arthroplasty, patients with neuromuscular disorders such as myasthenia gravis have a potential risk of muscle weakness in the affected limb. Therefore, physicians' instructions and patients' careful attention are required to prevent dislocation due to excessive hip joint laxity under conditions of motor weakness.

Mid- to long-term results of resurfacing hip arthroplasty in Japanese patients: a comparison of osteoarthritic vs non-osteoarthritic patients

Past reports showed good mid-term results of RHA for Japanese patients. However, few reports have compared the mid- to long-term results for RHA in Japanese patients with and without osteoarthritis. Therefore, this study investigated the mid- to long-term results of RHA in Japanese patients with osteoarthritis compared to those without. We conducted a retrospective review of a consecutive series of 92 hips in 80 patients (59 men and 21 women). The minimum follow-up period was 5 years. The JOA hip scoring system was used to clinically evaluate hip function. In the radiological assessment, stem-shaft angle, inclination of the acetabular component, postoperative complications, and adverse reactions around RHA were evaluated. The 10-year survival rate using the Kaplan-Meier method was investigated to compare patients with and without osteoarthritis. A significant difference was observed between the preoperative and postoperative JOA hip scores of either group. Also, the radiological assessment revealed no significant changes in either group. All three revision THAs were performed on patients in the only non-osteoarthritis group. In the osteoarthritis group, the 10-year survival rate was 94% (95% CI 81.8-100) in males and 100% (95% CI 100) for females; in the non-osteoarthritis group, the rate was 80% (95% CI 55.1-100) in males and 66.7% (95% CI 13.3-100) for females. In conclusion, this study showed good mid- to long-term clinical results for young Japanese osteoarthritis patients, with less satisfactory mid- to long-term results in patients without osteoarthritis.

[Radiological characteristics of the cyst-like lesion of condyle in temporomandibular joint by cone beam computed tomography]

OBJECTIVE

To analyze the radiological characteristics and classifications of the cyst-like lesion of condyle in temporomandibular joint (TMJ) by cone beam computed tomography (CBCT).

METHODS

The study was conducted retrospectively on TMJ images from 194 patients who underwent CBCT examinations. Location, size, amount, surrounding bone trabecula, cortical bone white line of cyst-like lesion, and the overall condition of the condylar bone were evaluated. According to the overall condition of the condylar bone, the cyst-like lesion of condyle were divided into typesⅠand Ⅱ. The location, size, amount, surrounding bone trabecula, and cortical bone white line of the two types of cyst-like lesions were compared.

RESULTS

In 198 condylars of 194 patients, cyst-like lesions were detected in the left side of 94 patients, in the right of 96 patients, and in both sides of 4 patients. The size of lesions ranged from 1.2 mm to 13.5 mm, with an average size of (3.4±1.5) mm. Half of the cyst-like lesions were located underneath the anterior lateral cortical bony layer (99 condylars, 50.0%). Most cyst-like lesions were solitary (149 condylars, 75.3%), while 62.6% (124 condylars) were surrounded by continuous bony white lines. Bone sclerosis could be observed in 160 condylars (80.8%). A total of 132 condyles (66.7%) were accompanied by changes in late-stage osteoarthrosis, while the others were only accompanied by early-stage osteoarthrosis (10 osteoarthrosis, 5.1%) or showed no evidence of osteoarthrosis (56 osteoarthrosis, 28.3%). Statistical difference were observed in the location, amount, and surrounding bone trabecula of the two types of cyst-like lesions. TypeⅠcyst-like lesions had more frequent and bone sclerosis than type Ⅱ, whereas type Ⅱ cyst-like lesions occurred more on condylar internal or condyle neck than typeⅠ.

CONCLUSIONS

The pathogenesis and mechanism of the two types of cyst-like lesions may be different from each other.

The depth of the low-intensity band on the T1-weighted MR image is useful for distinguishing subchondral insufficiency fracture from osteonecrosis of the collapsed femoral head

PURPOSE

To verify the hypothesis that depth of the low-intensity band on T1-weighted MR image is useful for distinguishing subchondral insufficiency fracture (SIF) from osteonecrosis of the collapsed femoral head (ON).

PATIENTS AND METHODS

We reviewed 35 consecutive hips in 35 patients with radiological evidence of subchondral collapse of the femoral head and available MR images and histology between May 2013 and January 2016. Both clinical and radiological appearances were investigated. The ratios of distance from articular surface of the femoral head to the T1 low-intensity band to femoral head diameter (band depth ratio: BDR) on (1) mid-coronal slice of MR images and that on (2) coronal slice of MR images in which the highest BDR was observed, were calculated.

RESULTS

The mean age in SIF group was significantly higher than that in ON group (SIF: 68 years, ON: 49 years, P = 0.0017). The rates of history of steroid intake or alcohol consumption in SIF group were significantly lower than those in ON group (P = 0.0022 and P = 0.0408, respectively). The mean BDRs in SIF group were (1) 0.16 and (2) 0.23, which were significantly lower than those in ON group [(1) 0.42 and (2) 0.59] (P < 0.0001 for both). The cut-off BDR values to differentiate SIF from ON were (1) 0.22 and (2) 0.38, respectively.

CONCLUSION

The results of the study suggest that depth of the low-intensity band on T1-weighted MR image is useful for distinguishing SIF from ON in cases with collapsed femoral heads.

Classification systems of hip osteonecrosis: an updated review

PURPOSE

Osteonecrosis of the femoral head (ONFH) typically impacts middle-aged patients who are typically more active and in whom many surgeons would try to delay performing a total hip arthroplasty (THA). This poses a clinical decision-making challenge. Therefore, several options for joint preservation have been advocated, but varying indications and success rates have led to debate on when to use the various procedures. This is due in part to the lack of a generalized system for assessing ONFH, as well as the absence of a standardized method of data collection for patient stratification. Due to the paucity of studies, in this review, we aimed to provide an up-to-date review of the most widely utilized classification systems and discuss the characteristics of each system.

METHODS

A comprehensive literature review was conducted. Studies published between January 1st, 1975 and March 1st, 2018 were reviewed. The following key words were used in combination with Boolean operators AND or OR for the literature search: "osteonecrosis," "avascular necrosis," "hip," "femoral head," "classification," "reliability," and "validity." We defined the inclusion criteria for qualifying studies for this review as follows: (1) studies that reported on the classification systems for hip osteonecrosis, (2) studies that reported on the inter-observer reliability of the classification systems, and (3) studies that reported on the intra-observer reliability of any ONFH classification systems. In addition, we employed the following exclusion criteria: (1) studies that assessed classification systems for traumatic osteonecrosis, (2) Legg-Calvé-Perthes disease, or (3) Developmental Dysplasia of the Hip. Additionally, we excluded case reports and duplicate studies among searched databases.

RESULTS

The following classification systems were the most commonly utilized: The Ficat and Arlet, Steinberg, the Association Research Circulation Osseous (ARCO), and the Japanese Investigation Committee (JIC) classification systems. The details of each system have been discussed and their inter- and intra-observer reliability has been compared.

CONCLUSION

To this date, there is a lack of consensus on a universal and comprehensive system, and the use of any of the previous classification systems is a matter of dealer's choice. The Ficat and Arlet system was the earliest yet remains the most widely utilized system. Newer classification systems have been developed and some such as the JIC shows promising prognostic value while maintaining simplicity. However, larger validating studies are needed. While all of these systems have their strengths, the lack of a unified classification and staging system is still a problem in the diagnosis and prognosis ONFH. Further multi-center collaborative efforts among osteonecrosis experts are needed to adopt a universal classification system that may positively reflect on patient's outcomes.

Which Classification System Is Most Useful for Classifying Osteonecrosis of the Femoral Head?

BACKGROUND

Many studies have confirmed that the size and location of necrotic lesions are major factors that affect the prevalence of collapse and prognosis in patients with osteonecrosis of the femoral head (ONFH). Although several classification systems categorize and quantify ONFH, there is no agreement on which one is most useful for the purpose.

QUESTIONS/PURPOSES

We compared the Steinberg, modified Kerboul, and Japanese Investigation Committee (JIC) classifications of ONFH in terms of (1) the correlation among the three different classification systems. We further examined (2) the inter- and intraobserver reliability of the three classification systems and (3) the association of higher grades within each classification and the risk of subsequent collapse.

METHODS

Between January 2000 and December 2014, we treated 101 hips in 74 patients for precollapse ONFH, diagnosed either on plain radiographs or MRI. Of those, one patient (1%) died, six patients (8%) were lost to followup, and two patients (3%) underwent osteotomy before 2 years, leaving 86 hips in 65 patients (88%) for analysis here. Three-dimensional spoiled gradient-echo sequence (3D-SPGR) MRI was performed for all hips, and the presence of ONFH was determined by finding the area surrounded by the outer margin of the low-signal-intensity band on 3D-SPGR MRI. Patients with ONFH were categorized using the Steinberg, modified Kerboul, and JIC classification systems, and correlations among these three classification systems were investigated. Inter- and intraobserver reliability was assessed by 10 orthopaedic surgeons using 40 sets of 3D-SPGR MR images. The reliability of each system was evaluated using the kappa coefficient. The cumulative survival rate with collapse and undergoing hip arthroplasty as the endpoints was evaluated for each of the three classification systems (mean followup, 9 years; range, 2-16 years), and the association of higher grades within each classification and the risk of subsequent collapse were also evaluated.

RESULTS

We found strong correlations between the Steinberg and modified Kerboul classifications (ρ = 0.83, p < 0.001), the Steinberg and JIC classifications (ρ = 0.77, p < 0.001), and the modified Kerboul and JIC classifications (ρ = 0.80, p < 0.001). Interobserver reliability in the JIC classification (0.72; range, 0.30-0.90) was higher than that in the Steinberg classification (0.56; range, 0.24-0.84; p < 0.001) and the modified Kerboul classification (0.57; range, 0.35-0.80; p < 0.001). The cumulative survival rate with collapse as the endpoint after a minimum of 2 years of followup in the Steinberg classification differed between Grades A (82%; 95% confidence interval [CI], 66%-97%) and B (43%; 95% CI, 21.9%-64.8%; p = 0.007), Grades A and C (20%; 95% CI, 4.3%-35.7%; p < 0.001), and Grades B and C (p = 0.029). Survival was lower for modified Kerboul Grade 4 hips (12%; 95% CI, 0%-27.1%) than for Steinberg Grade C hips (20%; 95% CI, 4.3%-35.7%) and JIC Type C2 hips (18%; 95% CI, 2.8%-34.0%). The JIC classification was best able to identify hips at low risk of collapse because no JIC Type A hips collapsed.

CONCLUSIONS

The JIC classification was more reliable and effective, at least for early-stage ONFH, than the Steinberg or modified Kerboul classifications. Further investigation might be useful to identify whether each classification system emphasizes specific risk factors for collapse.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Nationwide multicenter follow-up cohort study of hip arthroplasties performed for osteonecrosis of the femoral head

PURPOSE

To identify modifiable factors related to post-operative dislocation and reoperation in patients with osteonecrosis of the femoral head (ONFH) in a large cohort.

METHODS

We studied 4995 hip arthroplasties: total hip arthroplasty (THA) was performed in 79% of patients; bipolar hemiarthroplasty (BP), 17%; total resurfacing arthroplasty (tRS), 3%; and hemi-resurfacing arthroplasty (hRS), 1%. A new type of BP (accounting for 49% of BPs) comprised a femoral component with a polished or smooth, small-diameter (approximately 10 mm) neck with a round or oval axial cut surface and no sharp corners.

RESULTS

The infection rate was relatively low (0.56%) even though 58% of cases of ONFH were associated with systemic steroid use, a known risk factor for infection. Post-operative dislocation occurred in 4.3% of cases, with re-operation needed in 3.9%. The dislocation rate was related to surgery type: 5.2% in THA, 0.9% in BP, and 0% in tRS and hRS. Among total arthroplasties with six month or longer follow-up (3670 THAs and 159 tRSs), the risk factors for post-operative dislocation were younger (≤ 40 years) or older (≥ 62 years) age, higher body weight, posterolateral approach, and smaller prosthetic head diameter. Regarding the need for re-operation, higher body weight and surgery type were identified as risk factors.

CONCLUSIONS

The relatively high dislocation rate of 5.2% in THA is a cause for concern. The identified risk factors for dislocation should be considered when selecting THA for treatment. Prosthesis survivorship in hRSs was inferior to that in BPs or THAs. Body weight also affected the survivorship of hip arthroplasties.

Transitional changes in the incidence of osteonecrosis in systemic lupus erythematosus patients: focus on immunosuppressant agents and glucocorticoids

Objective

The purpose of this study was to investigate transitional changes in the incidence of glucocorticoid-associated osteonecrosis in SLE patients, with a focus on immunosuppressive agent and glucocorticoid consumption.

Methods

We retrospectively registered 185 SLE patients with 740 joints, who were newly diagnosed and hospitalized for initial high-dose glucocorticoid therapy from 1986 to 2015. Immunosuppressive agent, glucocorticoid dose, age, sex, organ lesion at hospitalization, complement (C3, C4, CH50) and anti-DNA antibody before initial glucocorticoid therapy, the frequency of use of anticoagulant and antilipidemic drugs, and incidence of osteonecrosis were documented.

Results

Based on trends in immunosuppressive agent use, 116 patients treated from 1986 to 1999, before calcineurin inhibitors were introduced, comprised the past group, and 69 patients treated from 2000 to 2015 comprised the recent group. Patient characteristics (age, sex and organ lesion at hospitalization, complement, anti-DNA antibody, the frequency of use of anticoagulant and antilipidemic drugs) were similar between groups. Glucocorticoid doses were significantly lower in the recent group than in the past group (highest daily glucocorticoid dose, 45.7 vs 59.0 mg/day, respectively; dose per weight, 0.88 vs 1.16 mg/day/kg, respectively; and cumulative dose at 3 months, 3118 vs 3985 mg). The incidence of osteonecrosis was significantly lower in the recent group than in the past group (26.4 vs 41.0%, respectively), particularly in the knee (25.4 vs 46.6%, respectively).

Conclusion

The incidence of glucocorticoid-associated osteonecrosis in SLE patients decreased in association with a decrease in glucocorticoid administration after introduction of immunosuppressant agents.

Mid-term results of concentrated autologous bone marrow aspirate transplantation for corticosteroid-associated osteonecrosis of the femoral head in systemic lupus erythematosus

PURPOSE

We had previously established concentrated autologous bone marrow aspirate transplantation (CABMAT), a one-step, low-invasive, joint-preserving surgical technique for treating osteonecrosis of the femoral head (ONFH). This study aimed to evaluate the effects of CABMAT as a hip-preserving surgical approach, preventing conversion to total hip arthroplasty (THA) and femoral head collapse in patients with systemic lupus erythematosus (SLE).

METHODS

Since 2003, 52 SLE patients (8 male, 44 female, 92 hips, mean age 35.3 (16-77) (years) were treated with CABMAT. The mean follow-up period was 5.5 (0.7-14) years. Conversion rate to THA and its predicting factors were analyzed.

RESULTS

The overall conversion rate to THA was 29% (27/92). Conversion rate to THA was 0% (0/3), 0% (0/4), 22% (9/41), and 41% (18/44) in types A, B, C1, and C2, respectively. Conversion rate to THA was 26% (5/19), 26% (6/23), 28% (11/39), 44% (4/9), and 50% (1/2) in stages 1, 2, 3A, 3B, and 4, respectively. In multivariate logistic regression analysis, sex, body mass index (BMI), pre-operative type, and pre-operative stage were significantly correlated with conversion to THA.

CONCLUSION

The conversion rate to THA was lower than that in the natural course and core decompression, but was higher than that seen in other bone marrow transplantation and osteotomy. Since sex, pre-operative type, and pre-operative stage were significantly correlated with conversion to THA, it is suggested that the higher proportion of women, advanced stage (stage 3A or above), and advanced type (type C or above) in this study affected the THA conversion rate.

Raman spectroscopy reveals differences in molecular structure between human femoral heads affected by steroid-associated and alcohol-associated osteonecrosis

PURPOSE

The purposes of this study were to document novel Raman spectroscopic findings in femoral heads affected by osteonecrosis and to identify molecular structure differences based on aetiology.

METHODS

We obtained 13 femoral heads with osteonecrosis from 13 different patients who underwent total hip arthroplasty. Comparisons were made between the viable zones of each femoral head examined. The samples were scanned with X-ray micro-CT for structural mapping and a central coronal section slab was prepared for Raman spectroscopy and histological analyses. Raman spectra were collected at different locations, including the viable and necrotic zones of the femoral head, using a highly spectrally resolved Raman microprobe.

RESULTS

Significant alterations in the spectral morphology in the high wavenumber region were found, with a pronounced inhibition of peculiar lipid signals in the frequency interval 2851 ~ 2890 cm^-1 and at ~ 1750 cm^-1. The necrotic zone in steroid-associated osteonecrosis showed an increase in the ratio of lipid-related bands to protein-related bands, while alcohol-associated osteonecrosis exhibited a decrease in this ratio.

CONCLUSIONS

We systematically found a decrease in Raman intensity for sphingomyelin and phenylalanine fingerprint bands in the necrotic zones, and these differences may be related to the etiology of osteonecrosis.

Quality of life of patients with osteonecrosis of the femoral head: a multicentre study

PURPOSE

Quality-of-life (QOL) assessments in patients with osteonecrosis of the femoral head (ONFH) have rarely been reported. This multicentre study aimed to elucidate the relationship between disease severity, including necrotic lesion type and radiological staging, and QOL, as well as between patients' characteristics and QOL.

METHODS

Two hundred seventy-four patients with ONFH (108 females, 166 males; median age, 46 years) were asked to complete self-assessment QOL questionnaires including the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire, Oxford Hip Score, and SF-12v2.

RESULTS

Patients with large necrotic lesion type or collapsed ONFH had low QOL scores. Among patients with non-collapsed lesions, patients with alcohol-associated ONFH had lower QOL scores than those with steroid-associated ONFH, those with bilateral ONFH had lower mental scores, and male patients had worse social condition scores. Among patients with collapsed lesions, middle-aged patients exhibited lower mental QOL, and a strong correlation was observed between social activity and mental health.

CONCLUSION

Collapsed ONFH was associated with low QOL scores. Among patients with non-collapsed lesions, alcohol-associated ONFH, bilateral disease, and male sex were linked to low QOL scores.

Subchondral fracture begins from the bone resorption area in osteonecrosis of the femoral head: a micro-computerised tomography study

PURPOSE

For successful joint preservation in osteonecrosis of the femoral head (ONFH), it is important to understand the mechanism of collapse. The purpose of this study was to investigate the initiation of subchondral fracture in ONFH by using micro-CT imaging of the whole femoral head, focusing on the three-dimensional relationship between the subchondral fracture and the bone resorption area.

METHODS

A total of 40 femoral heads from 37 patients retrieved during total hip arthroplasty for stage 3A or 3B ONFH by Japanese Investigation Committee criteria were scanned using micro-CT with a 0.146-mm thickness cuts. We divided the cohort into early and late collapsed stages according to a threshold of 3 mm of collapse as measured by micro-CT.

RESULTS

According to the analysis on multiple radial plane views in the whole femoral head, there were two interesting findings. First, the initial fracture cracks ran between separated bone resorption areas at the anterosuperior portions of all 18 femoral heads in the early collapsed stage. Second, fractures of the necrotic bone at the sclerotic boundary and a fibrous, granulation-like, low-density tissue along the necrotic side of the sclerotic boundary were seen in 19 of the 22 in the late collapsed stage. After bone resorption around the retinaculum and teres insertion initiates the subchondral fracture, bone resorption expanding at the anterosuperior portion of the femoral head may result in the spread of fracture and the potential for massive collapse.

CONCLUSIONS

Three-dimensional micro-CT showed bone resorption around the reparative zone initiates the subchondral fracture in ONFH.

Do femoral head collapse and the contralateral condition affect patient-reported quality of life and referral pain in patients with osteonecrosis of the femoral head?

PURPOSES

The objectives of this study were to investigate patient-reported outcomes and referral pain at the first visit in patients with osteonecrosis of the femoral head (ONFH) and to clarify the influence of collapse of the femoral head and the contralateral condition.

METHODS

The study included 105 patients (130 hips) with ONFH at the first visit, who were divided into two groups based on the presence of bilateral walking hip pain (bilateral group 25 patients, 50 hips) and unilateral hip pain (unilateral group 80 patients, 80 hips). We compared the Short Form-36 (SF-36), Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), and visual analog scale (VAS) responses for hip, knee, and low back pain between the groups to investigate the influence of the contralateral condition. Regarding the influence of femoral head collapse, we investigated these subjects based on the stage classification in the unilateral group.

RESULTS

The physical component summary (PCS) of the SF-36 and all domains of the JHEQ were poorer in the bilateral group than in the unilateral group. In addition, the VAS score for low back pain was significantly poorer in the bilateral group than in the unilateral group. Regarding the collapse of the femoral head, the SF-36 for the PCS and JHEQ for pain had a significant relationship in the ONFH stage. The VAS scores for hip and knee pain had a significant relationship in the ONFH stage.

CONCLUSION

Collapse of the femoral head and the contralateral condition of ONFH strongly affect patients' activities of daily life.

Chronological Changes in Axial Alignment of the Ipsilateral Hip and Knee After Total Hip Arthroplasty

BACKGROUND

Internal rotation of the hip and lateral patellar tilt increases after total hip arthroplasty (THA). However, it remains unknown whether these parameters change with time after the index THA.

METHODS

A total of 91 patients undergoing 2-stage bilateral primary THAs between January 2008 and May 2014 were included to assess the association of chronological changes in internal rotation of the hip or lateral patellar tilt with anthropometric and perioperative parameter and changes in alignment after the index THA. Chronological changes were assessed as changes between postoperative computed tomography on the index surgery and the preoperative computed tomography on the contralateral THA. Internal rotation of the hip was defined as the angle between the posterior intercondylar line and a line passing through the posterior inferior iliac spines. Lateral patellar tilt was defined as the angle between the posterior intercondylar line and a line joining the medial and lateral edges of the patella.

RESULTS

Internal rotation of the hip and lateral patellar tilt changed until 2 years after the index surgery by a mean of -2° (range -17.3° to 17.7°) and -2° (range -18.2° to 5.3°), respectively. Adductor tenotomy was associated with increasing internal rotation of the hip with time (adjusted R² 0.076); leg lengthening and larger preoperative femorotibial angle were associated with decreasing lateral patellar tilt with time (adjusted R² 0.159).

CONCLUSION

Both internal rotation of the hip at rest and lateral patellar tilt decreased by approximately 2° until 2 years after surgery and there was a large variation in chronological change.

Interobserver and Intraobserver Reliability of Three-Dimensional Preoperative Planning Software in Total Hip Arthroplasty

BACKGROUND

The purpose of this study is to clarify interobserver and intraobserver reliabilities of the three-dimensional (3D) templating of total hip arthroplasty (THA).

METHODS

We selected preoperative computed tomography from 60 hips in 46 patients (14 men and 32 women) who underwent primary THA. To evaluate interobserver and intraobserver reliability, 6 orthopedic surgeons performed 3D templating twice over a 4-week interval. We investigated intraclass correlation coefficients (ICCs) and percent agreement of component size and alignment, comparing morphological differences in the hip. Reproducibility was also compared between groups with osteoarthritis (OA) and those with osteonecrosis (ON).

RESULTS

The interobserver reliabilities for mean cup size and stem size were excellent, with ICC = 0.907 and 0.944, respectively. The value was significantly higher in the ON group than in the OA group. In the OA group, the reliability of cup size and alignment decreased in hips with severe subluxation. Percent agreement of stem size was significantly different between the shapes of femoral canal. For intraobserver reliability, the mean ICC of cup size was 0.965 overall, while the value in the ON group was significantly higher than in the OA group. The mean ICC of stem size was 0.972 overall.

CONCLUSION

Computed tomography-based 3D templating showed excellent reliability for component size and alignment in THA. Deformity of the affected joint influenced the reliability of preoperative planning.

Risk factor analysis for postoperative complications requiring revision surgery after transtrochanteric rotational osteotomy for osteonecrosis of the femoral head

BACKGROUND

This study investigated the risk factors for postoperative complications requiring revision surgery within 3 years after transtrochanteric rotational osteotomy (TRO) for osteonecrosis of the femoral head (ONFH).

METHODS

We reviewed 127 patients (147 hips) who underwent TRO (anterior or posterior rotational osteotomy) for ONFH between January 2002 and December 2014. Two patients were lost to follow-up, and five patients with progression of femoral head collapse requiring a salvage procedure such as total hip arthroplasty within 3 years after TRO were excluded. The better hip in patients treated bilaterally was also excluded (n = 20) to avoid duplication of patient demographics, leaving 120 hips (120 patients) for the analysis. We reviewed the medical records of each patient to screen for postoperative complications that required revision surgery within 3 years after surgery, recording the patient's age, sex, body mass index, surgical side, condition of the contralateral hip, previous alcohol intake, previous alcohol abuse, previous corticosteroid use, perioperative corticosteroid use, smoking status, preoperative stage and type of ONFH, preoperative activity level, and preoperative and final follow-up Japanese Orthopaedic Association scores. Differences between cases with and without complications were analyzed.

RESULTS

Eleven (9.2%) cases showed postoperative complications that required revision surgery. The most common complication was deep infection (n = 5), followed by nonunion of the greater trochanter (n = 3), nonunion of the intertrochanteric osteotomy site (n = 2), and femoral head fracture (n = 1). The multivariate analysis showed an independent association between previous alcohol abuse and postoperative complications (odds ratio, 13.5).

CONCLUSION

A correlation might exist between alcohol abuse and complications following a TRO procedure.

Clinical analysis of 23 cases of steroid-associated osteonecrosis of the femoral head with normal initial magnetic resonance imaging presentation

To explore the clinical characteristics of steroid-associated osteonecrosis of the femoral head (ONFH) presenting initially normal magnetic resonance imaging (MRI) results.This retrospective study examined data from 23 cases that suffered from ONFH but presented a normal image at the first MRI examination after corticosteroid therapy from June 2005 to December 2013. Data on protopathy, age, sex, time of pain onset, MRI examination, and initial diagnosis were collected and analyzed.Average time from steroid therapy to first MRI examination was 45.7 ± 25.5 days (range, 10-94 days). Average time to final diagnosis was 199.9 ± 165.8 days (range, 32-762 days). Of the 23 cases, 21 cases complained of discomfort and were misdiagnosed because of a normal initial MRI scan. Twelve hips progressed to collapse and 1 hip received lumbar discectomy when got the final diagnosis. Cases with continuous pain (9/21) presented with pain at a later time than those with intermittent pain (12/21), although the continuous pain cases were diagnosed earlier.MRI performed 2 to 3 months after steroid therapy may present normal images. Another MRI examination is necessary to make a definite diagnosis.

Prognostic analysis of different morphology of the necrotic-viable interface in osteonecrosis of the femoral head

PURPOSE

The purpose of this study was to investigate the collapse progression in different morphologies of the necrotic-viable interface in osteonecrosis of the femoral head (ONFH).

METHODS

A total of 168 patients (202 hips) with Association Research Circulation Osseous (ARCO) stage II ONFH were included. Ending with the collapse of the femoral head, all patients received conservative treatment but without surgical intervention and were followed for three to 91 months. Bilateral hip-joint radiographs and magnetic resonance imaging (MRI) were examined, and the largest layer of necrosis within the coronal section of MRI images was selected together with its anteroposterior radiograph to observe the morphology of the necrotic-viable interface. The morphology was divided into four types: I, type transverse; II, type "V"; III, type zigzag; IV, type closed. The collapse rate and the time to collapse in different morphologies were assessed.

RESULTS

A total of 120 hips collapsed in two years or less, 61 were type-I, 51 were type-II, and 8 were type-III. Non-collapse occurred in all 17 hips with type-IV ONFH during long-term follow-up. In 202 hips with ARCO stage-II ONFH, the collapse rate in type-I ONFH was significantly higher than that of type-II and type-III ONFH (P < 0.01 for both). The time to collapse was markedly shortened.

CONCLUSIONS

The risk of ONFH-induced collapse is influenced by the morphology of the necrotic-viable interface. Effective mechanical support for preventing the collapse of the femoral head is necessary when the morphology of the necrotic-viable interface is type transverse.

Genome-wide Association Study of Idiopathic Osteonecrosis of the Femoral Head

Idiopathic osteonecrosis of the femoral head (IONFH) is an ischemic disorder that causes bone necrosis of the femoral head, resulting in hip joint dysfunction. IONFH is a polygenic disease and steroid and alcohol have already known to increase its risk; however, the mechanism of IONFH remains to be elucidated. We performed a genome-wide association study using ~60,000 subjects and found two novel loci on chromosome 20q12 and 12q24. Big data analyses identified LINC01370 as a candidate susceptibility gene in the 20q12 locus. Stratified analysis by IONFH risk factors suggested that the 12q24 locus was associated with IONFH through drinking capacity. Our findings would shed new light on pathophysiology of IONFH.

Percutaneously drilling through femoral head and neck fenestration combining with compacted autograft for early femoral head necrosis: A retrospective study

BACKGROUND

The purpose of this study was to evaluate the clinical results, survivorship and quick rehabilitation effects of modified surgery of percutaneously drilling and decompression through femoral head and neck fenestration combined with compacted autograft for early femoral head necrosis.

METHODS

We conducted a retrospective cohort study with 83 hips performed percutaneous decompression through femoral head and neck fenestration (Modified group) combined with autogenous bone grafting for early ONFH. For comparison, another 90 hips treated with conventional core decompression with bone grafting (Control group).

RESULTS

Median follow-up was 36 months (32-44 months). The length of incision, blood loss in operation, incision drainage, operation time and hospital stays in Modified group had better results than those in control group (P < 0.001). There were four cases in Modified group and five cases in control group had complications (P = 0.9). The VAS score and range of hip motion were better in Modified group during hospital stays summarily (P < 0.05). The average Harris score in modified group was higher than the control group at the first month (P = 0.005), while at other time of follow-up the two groups were with similar Harris scores (P > 0.05). There were 22 hips progressed to stage III in Modified group, while 23 hips progressed to stage III in control group (P = 0.89). The clinical success rate in Modified group were 86.7%, compared with that in control group (87.8%) ( P= 0.84).

CONCLUSION

Percutaneous drilling and decompression through femoral head and neck fenestration combined with compacted autograft we reported showed an good surgical effect with a quick rehabilitation and had similar short-term effects compared with the conventional core decompression in treatment of early ONFH.

Effects of intertrochanteric osteotomy plane and preoperative femoral anteversion on the postoperative morphology of the proximal femur in transtrochanteric anterior rotational osteotomy: 3D CT-based simulation study

BACKGROUND

Transtrochanteric anterior rotational osteotomy (ARO) is joint-preserving surgery for patients with osteonecrosis of the femoral head (ONFH). During ARO, femoral neck-shaft varus angulation by changing intertrochanteric osteotomy plane is often designed to obtain a sufficient postoperative intact ratio. However, the effect of intertrochanteric osteotomy plane on postoperative femoral anteversion has not been well examined. Therefore, we performed a simulation study of ARO to determine how intertrochanteric osteotomy plane and preoperative femoral anteversion affect both femoral neck-shaft varus angle and postoperative femoral anteversion.

HYPOTHESIS

Both femoral neck-shaft varus angle and postoperative femoral anteversion are predicted by intertrochanteric osteotomy plane and preoperative femoral anteversion in ARO.

MATERIALS AND METHODS

Using CT-data obtained from 10 hips in 10 patients with ONFH, ARO was simulated. On anteroposterior view, basic intertrochanteric osteotomy line (AP-view line) was defined as the perpendicular line to the femoral neck axis. On lateral view, basic intertrochanteric osteotomy line (lateral-view line) made through the cut surface of greater trochanter was defined as the perpendicular line to the lateral axis of the femur. By changing either AP-view or lateral-view line, 49 ARO models/hip were produced, in which femoral neck-shaft varus angle and postoperative femoral anteversion were assessed.

RESULTS

With increase in the vertically-inclined degree of AP-view line, both neck-shaft varus angle and postoperative femoral anteversion increased. With increase in the posteriorly-tilted degree of lateral-view line, neck-shaft varus angle increased, whereas postoperative femoral anteversion decreased. The approximation equations based on the multiple regression analyses were as follows: neck-shaft varus angle≈vertically-inclined degree of AP-view line×0.9+posteriorly-tilted degree of lateral-view line×0.8+preoperative femoral anteversion×0.7; postoperative femoral anteversion≈vertically-inclined degree of AP-view line×1.1-posteriorly-tilted degree of lateral-view line×0.8.

DISCUSSION

The postoperative morphology of proximal femur was nearly defined by intertrochanteric osteotomy plane with preoperative femoral anteversion, which is useful for preoperative planning in terms of both achieving a sufficient postoperative intact ratio and maintaining femoral anteversion.

LEVEL OF EVIDENCE

Level IV case series without control group.

A 12-year follow-up study of combined treatment of post-severe acute respiratory syndrome patients with femoral head necrosis

OBJECTIVE

To investigate the long-term efficacy of a combination treatment of alendronate, extracorporeal shock and hyperbaric oxygen for osteonecrosis of the femoral head (ONFH) of post-severe acute respiratory syndrome (SARS) patients.

PATIENTS AND METHODS

The retrospective study was performed including a total of 37 post-SARS ONFH patients (66 hip joints) in the Department of Orthopedics of the General Hospital of Tianjin Medical University between November 2003 and November 2015, consisting of 6 males (11 hip joints) and 31 females (55 hip joints), with age between 19 and 47 years (average 29.9 years). Visual analog scale (VAS) score, Harris score and Association Research Circulation Osseous (ARCO) stage of imaging examination were compared among those before treatment, and at 1, 3, 6, 9 and 12 years after treatment. Paired t-test was used for statistical analysis of VAS and Harris score before and after treatment. Difference of effective rate on all stages was analyzed with Chi-square test.

RESULTS

With 12-year follow-up, significant improvements on VAS (6.81 of pre-treatment vs 3.94 of 12-year post-treatment) and Harris score (74.54 of pre-treatment vs 80.14 of 12-year post-treatment) were observed (all p<0.05). Effective rate showed statistical significance among three stages of ARCO (p<0.05). The combined treatment showed different efficacies on different ARCO stages; the best was on ARCO Phase I.

CONCLUSION

The combined treatment may delay or discontinue the development of ONFH in post-SARS patients.

Influence of cigarette smoking on osteonecrosis of the femoral head (ONFH): a systematic review and meta-analysis

BACKGROUND

Current studies demonstrate controversy regarding the relationship between cigarette smoking and osteonecrosis of the femoral head (ONFH).

METHODS

We conducted a meta-analysis to evaluate the association between smoking and ONFH. Relevant articles published before September 2016 were identified by a systematic search of EMBASE and MEDLINE via Ovid. Summary odds ratios (OR) were calculated using random effects models, and study quality was assessed using a modified Newcastle-Ottawa scale.

RESULTS

102 citations were screened and 7 case-control studies were identified and included in the review. When compared with nonsmokers, current smokers had a higher risk of developing ONFH (OR 2.53; 95% confidence interval [CI] 1.68-3.79), as did former smokers (OR 1.82; 95% CI, 1.10-3.00). Within the group of current smokers, those classified as heavy smokers (with a daily number >20 cigarettes/day) demonstrated higher risks of ONFH (OR 2.03; 95% CI, 1.29-3.19), and light smokers classified as smoking <20 cigarettes/day, also demonstrated a higher risk of ONFH when compared with nonsmokers (OR 1.73; 95% CI, 1.06-2.83). When smoking was classified by pack-years, heavy smokers (>20 pack-years) were at a higher risk of ONFH (OR 2.26; 95% CI, 1.24-4.13), but no significant difference in risk was identified in light smokers (<20 pack-years) (OR 1.81; 95% CI, 0.88-3.71) when compared with nonsmokers.

CONCLUSIONS

Our meta-analysis showed that current smokers were at a higher risk of ONFH, this high risk can also be found in former smokers. And heavy cigarette smoking showed a higher risk of ONFH than light smoking.

Analysis of damage in relation to different classifications of pre-collapse osteonecrosis of the femoral head

Objective This study aimed to investigate the damage pattern of the stress transfer path (STP) for the Japanese Investigation Committee (JIC) classification of pre-collapse osteonecrosis of the femoral head. We aimed to provide a specific biomechanical basis for treatment decisions of each subtype. Methods Five computational models were used in the experiment. Different necrotic classifications were simulated based on the JIC classification system. Damage patterns of the STP were used for qualitative assessment and average stresses were used for quantitative analysis. Results The STP of type A showed a strong similarity to the healthy level, which was consistent with the bone density distribution in X-rays and previous simulations results. The damaged area of principal stress of type B was approximately 25% of the healthy level. The STPs of types C1 and C2 were broken and the damaged areas of principal stress were more than 50% of the healthy level. The efficiency of stress transfer was reduced. Conclusions These results indicate that the damage patterns and stress transfer efficiency of the femoral head are associated with necrotic classifications.

Hip preserving surgery with concentrated autologous bone marrow aspirate transplantation for the treatment of asymptomatic osteonecrosis of the femoral head: retrospective review of clinical and radiological outcomes at 6 years postoperatively

Background

We had previously established concentrated autologous bone marrow aspirate transplantation (CABMAT), a one-step, low-invasive, joint-preserving surgical technique for treating osteonecrosis of the femoral head (ONFH). The present study aimed to evaluate the effects of CABMAT as a hip preserving surgical approach, preventing femoral head collapse in asymptomatic ONFH.

Methods

In total, 222 patients (341 hips) with ONFH were treated with CABMAT between April 2003 and March 2013. Based on magnetic resonance imaging, we determined that 119 of these patients had bilateral asymptomatic ONFH (238 hips), and 38 further patients had unilateral asymptomatic ONFH (38 hips). In this series, we retrospectively examined 31 hips in 31 patients with unilateral asymptomatic ONFH treated surgically between 2003 and 2012 and followed up for more than 2 years. Clinical and radiological evaluation were performed immediately before the procedure and at the final follow-up. The two-year follow-up rate among patients with unilateral ONFH was 82% (31/38). Therefore, the present study included 31 patients (19 males and 12 females), with a mean age and follow-up period of 40 and 5.8 years, respectively. Of the 31 asymptomatic hips, 5, 6, 10, and 10 had osteonecrosis of types A, B, C1, and C2, respectively. The diagnosis, classification, and staging of ONFH were based on the 2001 Japanese Orthopaedic Association (JOA) classification.

Results

Secondary collapse of the femoral head was observed in 6/10 hips and 5/10 hips with osteonecrosis of types C1 and C2, respectively. Total hip arthroplasty was performed in 9.6% of patients (3/31 hips), at an average of 33 months after surgery. Clinical symptoms improved after surgery, and the secondary collapse rate at a mean of 5.8 years after CABMAT was lower than that reported in several previous studies on the natural course of asymptomatic ONFH.

Conclusions

Early diagnosis of ONFH (i.e., before femoral head collapse) and early intervention with CABMAT could improve the clinical outcome of corticosteroid and alcohol-induced ONFH.

Effect of collapse on the deformity of the femoral head-neck junction in osteonecrosis of the femoral head

INTRODUCTION

The purpose of this study was to morphologically assess the effect of collapse on the deformity of the femoral head-neck junction in patients with nontraumatic osteonecrosis of the femoral head (ONFH).

MATERIALS AND METHODS

From January 2005 through March 2016, magnetic resonance (MR) imaging including the oblique view was repeatedly performed before and after collapse in 24 hips of patients with ONFH (16 men, 8 women; mean age 43 years; range 23-68 years), that were the subjects of this study. The interval of MR imaging before and after collapse was 8.0 months (range 1-32 months). In addition, 82 asymptomatic hips in patients without ONFH as identified by MR imaging taken at the same duration were used as controls. The oblique MR image was used to measure the radiological parameters of the femoral head-neck junction, including the α-angle and head-neck offset ratio (HNOR).

RESULTS

The α-angle and HNOR after collapse (58.3° ± 10.0° and 0.138 ± 0.033, respectively) indicated significantly decreased anterior femoral head-neck offset compared with those before collapse (46.2° ± 5.7° and 0.178 ± 0.018, respectively; p < 0.0001). These parameters had a positive association with the depth of femoral head collapse (p < 0.0001 and p < 0.01, respectively). However, there were no significant differences in either the α-angle or HNOR between hips with ONFH before collapse and hips without ONFH.

CONCLUSIONS

This study demonstrated that the decreased femoral head-neck offset observed in patients with ONFH was a consequence of collapse.

Heterotopic ossification related to the use of recombinant human BMP-2 in osteonecrosis of femoral head

Despite the wide use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in bone defect, its application in treating osteonecrosis of femoral head (ONFH) is yet to be elucidated. The heterotopic ossification (HO) after rhBMP-2 usage in some orthopedic surgeries has been reported previously; however, only a few studies describe this complication in the treatment of ONFH.The present study investigated whether the rhBMP-2 application would increase the risk of HO formation in selected ONFH patients with nonvascularized bone grafting surgery and enhance the surgical results of nonvascularized bone grafting as compared to patients who did not receive intraoperative rhBMP-2.A retrospective analysis was performed on 94 patients (141 hips) who, with Association Research Circulation Osseous (ARCO) stages IIb, IIc, and IIIa ONFH, underwent nonvascularized bone grafting surgery. The first 46 patients (66 hips) received intraoperative rhBMP-2. The postoperative radiographic results (X-ray and CT scan) and Harris hip score (HHS) were reviewed in each patient to record the incidence of HO formation and evaluate the clinical efficacy of rhBMP-2, respectively.HO formation frequently occurred in patients receiving intraoperative rhBMP-2 (8/66 hips) than those not receiving the protein (1/75 hips) (P = .02). HHS improved from preoperatively at the final follow-up (P < .01) in the BMP-positive group, with a survival rate of 83.3%. In the BMP-negative group, the HHS improved from preoperatively at the end of the follow-up (P < .01), and the survival rate was 72.0%.rhBMP-2 has osteoinductive property and might serve as an adjuvant therapy in the surgical treatment of ONFH. However, the incidence of HO formation might increase when used in high doses.

Screening of the COL2A1 mutation in idiopathic osteonecrosis of the femoral head

Idiopathic osteonecrosis of the femoral head (idiopathic ONFH) is an ischemic disorder resulting in necrosis of the subchondral bone of the femoral head. COL2A1 mutations, including c.3508G>A, have been reported to be involved in its etiology. However, the etiological role of COL2A1 mutations in idiopathic ONFH remains controversial, because the pathology of idiopathic ONFH is ischemic necrosis, not epiphyseal dysplasia usually seen in the diseases caused by COL2A1 mutations. The purpose of this study is to examine whether COL2A1 mutations have causal relation with idiopathic ONFH or not. We recruited 1,451 Japanese patients with idiopathic ONFH, including steroid-, alcohol-, and neither steroid nor alcohol-associated (neither-associated) ONFH. The diagnosis was based on the criteria of the Japanese Research Committee on idiopathic ONFH of the Ministry of Health, Labour and Welfare. By whole-exome sequencing, entire COL2A1 coding regions and flanking introns were analyzed in 49 neither-associated ONFH patients. In addition, the c.3508G>A mutation of COL2A1 was checked in all idiopathic ONFH patients using the invader assay. Whole-exome sequencing did not detect any COL2A1 mutations in the 49 patients. The c.3508G>A mutation was not found in any of the 1,451 patients. In conclusion, COL2A1 is unlikely to cause idiopathic ONFH. Epiphyseal dysplasia of the femoral head caused by COL2A1 mutations may radiographically mimic idiopathic ONFH. COL2A1 mutations should prompt clinical re-evaluation of the patient's phenotype. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:768-774, 2017.

Error range in proximal femoral osteotomy using computer tomography-based navigation

PURPOSE  : The purpose of this preliminary study was to determine the error range compared with preoperative plans in proximal femoral osteotomy conducted using a computed tomography (CT)-based navigation system. METHODS  : Four patients (four hips) underwent transtrochanteric rotational osteotomy (TRO), and three patients (four hips) underwent curved varus osteotomy (CVO) using CT-based navigation. Volume registration of pre- and postoperative CT was performed for error assessment. RESULTS  : In TRO, the mean osteotomy angle error was [Formula: see text] (range [Formula: see text]) in the valgus direction and [Formula: see text] (range [Formula: see text]) in the retroversion direction. The mean osteotomy position error, with the femoral head side as positive, was -0.4 mm (range -1.4 to 0 mm). The bone fragment rotational movement error was [Formula: see text] (range [Formula: see text]). In CVO, the mean osteotomy position error, with the femoral head side as positive, was -0.2 mm (range -2.0 to 1.7 mm) at the level of the lesser trochanter and 0.8 mm (range 0-3.2 mm) at the level of the greater trochanter. Bone fragment varus accuracy was [Formula: see text] (range [Formula: see text]). CONCLUSIONS  : In proximal femoral osteotomy using CT-based navigation, the angle error of osteotomy was within [Formula: see text] and the positional error was within 4 mm. The rotational movement error of the proximal fragment was within [Formula: see text]. These margins of error should be considered in preoperative planning. To improve surgical accuracy, it would be necessary to develop a computer-assisted device which can track the osteotomized fragment.