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

Tissue-Engineered Bone Regeneration for Medium-to-Large Osteonecrosis of the Femoral Head in the Weight-Bearing Portion: An Observational Study

Background

Stem cell therapy for the treatment of osteonecrosis of the femoral head (ONFH) showed promising outcomes. However, ONFH with a large lesion in the weight-bearing portion is a poor prognostic factor and still challenging issue to be solved. We aimed to evaluate the effect of tissue-engineered bone regeneration for this challenging condition to preserve the femoral head.

Methods

A total of 7 patients (9 hips) with ONFH who received osteoblasts expanded ex vivo from bone marrow-derived mesenchymal stem cells (BMdMSCs) and calcium metaphosphate (CMP) as scaffolds from March 2002 to March 2004 were retrospectively reviewed. The median age was 27.0 years (interquartile range [IQR], 23.0-34.0 years), and the median follow-up period was 20.0 years (IQR, 11.0-20.0 years). After culture and expansion of stem cells, we performed core decompression with BMdMSC implantation at a median number of 10.1 ×107 (IQR, 9.9-10.9 ×107). To evaluate radiographic outcomes, the Association Research Circulation Osseous (ARCO) classifications, the Japanese Investigation Committee (JIC) classification, and modified Kerboul combined necrotic angle (mKCNA) were evaluated preoperatively and during follow-up. Clinical outcomes were evaluated by a visual analog scale (VAS) and Harris Hip Score (HHS).

Results

The preoperative stage of ONFH was ARCO 2 in 5 hips and ARCO 3a in 4 hips. The ARCO staging was maintained in 3 hips of ARCO 2 and 4 hips of ARCO 3a. Two hips of ARCO 2 with radiographic progression underwent total hip arthroplasty. According to mKCNA, 2 hips showed medium lesions, and 7 hips showed large lesions. The size of necrotic lesion was decreased in 4 hips (2 were ARCO 2 and 2 were ARCO 3a). There were no significant changes in JIC classification in all hips (type C1: 3 hips and type C2: 6 hips) (p = 0.655). Clinically, there were no significant changes in the VAS and HHS between preoperative and last follow-up (p = 0.072 and p = 0.635, respectively).

Conclusions

Tissue engineering technique using osteoblasts expanded ex vivo from BMdMSC and CMP showed promising outcomes for the treatment of pre-collapsed and early-collapsed stage ONFH with medium-to-large size, mainly located in weight-bearing areas.

Concerns with alumina bipolar hemiarthroplasties compared to metal bipolar hemiarthroplasties when performed for nontraumatic osteonecrosis of the femoral head

PURPOSE

A nationwide multicenter follow-up cohort study of hip replacement arthroplasties performed for nontraumatic osteonecrosis of the femoral head (ONFH) aimed to answer the following questions: What factors were associated with need for reoperation? Although many modifications were made in bipolar hemiarthroplasties (BPs) to improve their durability, could we find any evidence of their efficacy?

METHODS

Excluding 58 infected hips and 43 ABS THAs with very poor survivorship, we analyzed 7393 arthroplasties; 6284 total hip arthroplasties (THAs), 886 BPs, 188 total resurfacing arthroplasties, and 35 hemi-resurfacing arthroplasties (hRSs). In the 886 BPs, 440 hips had a smooth small-diameter prosthetic neck (nBPs), 667 hips had a smooth neck (sBPs), 116 hips had highly cross-linked polyethylene in the outer head (hBPs), and 238 hips had an outer head whose outer surface was alumina ceramic (aBPs) (648 hips had an outer head whose outer surface was metal [mBPs]). Multivariate analyses using a Cox proportional-hazard model analyzed risk factors.

RESULTS

Follow-up ranged from 0.1 to 27 (average, 6.9) years, during which 265 hips (3.6%) needed reoperation. Combined systemic steroid use and excessive alcohol consumption and lateral approach were associated with higher risks, aBPs were less durable than THAs or mBPs, and hRSs were inferior to the others. Regarding BPs, the following divisions did not influence their survivorship; nBP or not, sBP or not, and hBP or not.

CONCLUSIONS

Factors associated with reoperation risk were identified as described above. The modifications made in BPs did not improve their durability, but aBPs made it worse.

LEVEL OF CLINICAL EVIDENCE

Level III, therapeutic cohort study.

Risk assessment for femoral head collapse in osteonecrosis utilizing MRI-derived large lesion ratio: a retrospective cohort study

PURPOSE

This study aimed to developed a novel and practical method to quantify the involvement of lesion in osteonecrosis of the femoral head (ONFH). We hypothesized that the new metric large lesion ratio (LLR) had promising prognostic value.

METHODS

A total of 131 hips with non-traumatic ONFH were included in this retrospective study. Patient aged 18-60 with MRI-confirmed diagnosis, and a minimum of 2-year follow-up or radiographic collapse progression during follow-up were included. Patients with prior hip surgery, incomplete data or advanced ONFH at baseline (femoral head collapse > 2 mm or osteoarthritis) were excluded. Involvement of necrotic lesion was evaluated by calculating LLR. The differences of LLR between collapse progression and non-progression groups were investigated, and the differences among different scanning parameters groups were also examined. Prognostic value of LLR was examined by multivariate regression analysis. Receiver operating characteristic curves (ROC) were constructed and areas under the curve (AUC) were compared.

RESULTS

The median of LLR was 66.67% in the collapse progression group, which was significantly higher compared with 25.00% in the non-progression group (P < 0.001). Subgroups analysis showed that LLR were significantly higher in the collapse progression group of Japanese Investigation Committee type C1 (P < 0.001)and C2 (P = 0.002). Multivariate regression showed that LLR were independently correlated with collapse progression (OR, 1.46 [95% CI, 1.24-1.78]; P < 0.001). ROC analysis showed that the AUC for LLR was 0.84, outperforming the 0.74 AUC OF the JIC classification.

CONCLUSION

LLR could served as a efficient tool to assess the risk of collapse progression and guide the selection of treatment strategy.

Acetabular coverage exerts minimal influence on femoral head collapse and the necessity for surgical intervention in patients with osteonecrosis of femoral head

PURPOSE

The acetabular coverage in osteonecrosis of the femoral head (ONFH) affects the need for surgical intervention, and the collapse of the femoral head remains unclear. This study aimed to evaluate the relation between the acetabular coverage and the need for surgical treatment and femoral head collapse.

METHODS

The study included 158 patients with 252 hips with glucocorticoid administration and idiopathic ONHF without osteoarthritis changes. The mean age at the first visit was 45.2 years, and the mean follow-up period was 92.2 months. All ONFH hips were subsequently divided into two groups: those needing surgical intervention and those without surgery. Additionally, it divided 167 initially non-collapsed hips into those that either later collapsed or not. Radiographic parameters with the centre-edge angle, acetabular roof obliquity, sharp angle, and necrotic location, following the guidelines of the Japanese Investigation Committee, were evaluated.

RESULTS

There were no significant differences in radiographic parameters between the 106 hips that underwent surgery and the 146 hips without surgery. Among the 167 hips without initial collapse, 91 eventually collapsed while 76 did not; their radiographic findings have no significant differences. The necrotic locations were significantly larger in hips requiring surgical intervention or femoral head collapse. Furthermore, 21.8% (55 out of 252 hips) had acetabular dysplasia, which did not significantly correlate with the necessity for surgical treatment or the incidence of femoral head collapse.

CONCLUSIONS

Acetabular coverage has little effect on the necessity for surgical treatment and femoral head collapse in ONFH patients over a long-term follow-up.

Multi-sequence MRI-based radiomics: An objective method to diagnose early-stage osteonecrosis of the femoral head

OBJECTIVES

This study investigated the use of radiomics for diagnosing early-stage osteonecrosis of the femoral head (ONFH) by extracting features from multiple MRI sequences and constructing predictive models.

MATERIALS AND METHODS

We conducted a retrospective review, collected MR images of early-stage ONFH (102 from institution A and 20 from institution B) and healthy femoral heads (102 from institution A and 20 from institution B) from two institutions. We extracted radiomics features, handled batch effects using Combat, and normalized features using z-score. We employed the Least absolute shrinkage and selection operator (LASSO) algorithm, along with Max-Relevance and Min-Redundancy (mRMR), to select optimal features for constructing radiomics models based on single, double, and multi-sequence MRI data. We evaluated performance using receiver operating characteristic (ROC) and precision-recall (PR) curves, and compared area under curve of ROC (AUC-ROC) values with the DeLong test. Additionally, we studied the diagnostic performance of the multi-sequence radiomics model and radiologists, compared the diagnostic outcomes of the model and radiologists using the Fisher exact test.

RESULTS

We studied 122 early-stage ONFH and 122 normal femoral heads. The multi-sequence model exhibited the best diagnostic performance among all models (AUC-ROC, PR-AUC for training set: 0.96, 0.961; validation set: 0.96, 0.97; test set: 0.94, 0.94), and it outperformed three resident radiologists on the external testing group with an accuracy of 87.5 %, sensitivity of 85.00 %, and specificity of 90.00 % (p < 0.01), highlighting the robustness of our findings.

CONCLUSIONS

Our study underscored the novelty of the multi-sequence radiomics model in diagnosing early-stage ONFH. By leveraging features extracted from multiple imaging sequences, this approach demonstrated high efficacy, indicating its potential to advance early diagnosis for ONFH. These findings provided important guidance for enhancing early diagnosis of ONFH through radiomics methods, offering new avenues and possibilities for clinical practice and patient care.

Factors related to collapse progression in Japanese Investigation Committee classification type B osteonecrosis of the femoral head

PURPOSE

This study aimed to identify factors related to collapse progression in Japanese Investigation Committee classification type B osteonecrosis of the femoral head (ONFH) and to identify patients who would benefit from surgical treatment.

METHODS

This study included 41 patients (56 hips) with type B ONFH with a minimum follow-up of three years. Based on a ≥ 3 mm collapse progression in ONFH, we categorised patients into two groups: collapse progression and no collapse progression. Sagittal and coronal computed tomography images were used to measure the necrotic region relative to the intact femoral head diameter. The ratios of the necrotic regions of transverse and vertical diameter in coronal and sagittal images are defined as mediolateral transverse and mediolateral vertical, anteroposterior transverse and anteroposterior vertical, respectively. Demographic data and these imaging findings were compared between the two groups. We established a cut-off value for predicting collapse progression through receiver operating characteristic analysis and determined survival rates.

RESULTS

Type B ONFH had a 17.8% collapse progression rate. The mediolateral transverse, mediolateral vertical, anteroposterior transverse, and anteroposterior vertical were significantly higher in the collapse progression group (P < 0.01). Mediolateral transverse was an independent risk factor of collapse progression (hazard ratio, 1.27; 95% confidence interval, 1.03-1.57; P = 0.03), with an optimal cut-off of 45.6%. The 5-year survival rates with collapse progression as the endpoints were 57.0 and 94.9% in the mediolateral transverse of ≥ 45.6 and < 45.6%, respectively.

CONCLUSION

A mediolateral transverse of ≥ 45.6% predicts collapse progression in patients with type B ONFH.

Implantation of Culture-Expanded Bone Marrow Derived Mesenchymal Stromal Cells for Treatment of Osteonecrosis of the Femoral Head

BACKGROUND

Although core decompression (CD) with stem cell for the treatment of osteonecrosis of the femoral head (ONFH) showed promising results in many reports, the efficacy remains uncertain. We aimed to evaluate the efficacy of CD with culture-expanded autologous bone marrow-derived mesenchymal stem cell (BM-MSC) implantation in early stage ONFH.

METHODS

A total of 18 patients (22 hips) with ONFH who underwent CD with culture-expanded BM-MSC implantation from September 2013 to July 2020 were retrospectively reviewed. The median age was 35.0 years [interquartile range (IQR), 28.5-42.0], and the median follow-up period was 4.0 years (IQR, 2.0-5.3). The median number of MSCs was 1.06 × 108. To evaluate radiographic and clinical outcomes, Association Research Circulation Osseous (ARCO) classifications, Japanese Investigation Committee classification, combined necrotic angle (CNA) visual analogue scale (VAS) and Harris Hip Score (HHS) were checked at each follow-up.

RESULTS

The preoperative stage of ONFH was ARCO 2 in 14 hips and ARCO 3a in 8 hips. The ARCO staging was maintained in 7 hips in ARCO 2 and 4 hips in ARCO 3a. The radiographic failure rate of ARCO 2 and 3a was 14.3 and 50%, respectively. Furthermore, CNA decreased to more than 20° in 6 hips (four were ARCO 2 and two were ARCO 3a).There was no significant difference in the VAS and HHS (P = 0.052 and P = 0.535, respectively). Total hip arthroplasty was performed in 4 hips.

CONCLUSION

CD with culture-expanded autologous BM-MSCs showed promising results for the treatment of early stage ONFH.

Spherical varus rotational osteotomy of the femur using a navigation system as extra-articular surgery for extensive osteonecrosis of femoral head: a case control study

BACKGROUND

Curved varus osteotomy (CVO) is an effective femoral head-preserving surgical procedure for osteonecrosis of the femoral head (ONFH) classified as type B or C1 according to the Japanese Investigation Committee (JIC) classification; it reportedly provides better postoperative outcomes than transtrochanteric rotational osteotomy (TRO). We have developed a new procedure called spherical varus rotational osteotomy (SVRO) in which osteotomy of the femur into a spherical shape is followed by varus and anterior rotation using navigation to increase indications and improve postoperative outcomes.

METHODS

Nine joints of eight patients who underwent SVRO and could be followed up for > 1 year were included in the study. Disease types determined preoperatively according to the JIC classification were type C1 for four joints and type C2 for five joints. Preoperative disease JIC classification stages were 3a for eight joints and 1 for one joint. SVRO was performed using OrthoMap® 3D Navigation software, and the following variables were measured: surgery time, intraoperative blood loss, difference between preoperative and postoperative angles of anteversion, postoperative lower limb length discrepancy, and postoperative intact area occupancy. The Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ) was used for clinical evaluation. Visual Analog Scale and JHEQ scores were evaluated preoperatively and at the final follow-up.

RESULTS

The measurement results were as follows: surgery time, 130 min; blood loss, 200 ml; angle of varus, 20°; angle of anterior rotation, 30°; preoperative angle of anteversion, 15°; postoperative angle of anteversion, 22°; lower limb shortening, 11 mm; preoperative intact area occupancy, 0%; and postoperative intact area occupancy, 74.2%. There were no cases of progression in the postoperative stages or re-collapse.

CONCLUSION

SVRO allows for the repositioning of the exterior and posterior intact areas, providing a broader intact region postoperatively. This technique is particularly beneficial for young patients with ONFH and extensive necrosis and is a less invasive alternative to TRO. This procedure has been shown to be effective in achieving favorable outcomes in patients with extensive necrosis who would have otherwise required rotational osteotomy, depending on the necrosis location. Further longitudinal studies are necessary to validate these findings and establish long-term benefits.

Can necrotic depth be a substitute of necrotic volume to predict collapse progression in osteonecrosis of the femoral head?

OBJECTIVE

Although some patients may experience collapse progression while others may not in post-collapse osteonecrosis of the femoral head (ONFH) with a necrotic lesion located within the weight-bearing part of the acetabulum (Type B/C1), few studies have focused on the natural course after collapse. This study aimed to clarify the correlation between necrotic volume (NV) and necrotic depth (ND) in predicting collapse progression in patients with post-collapse ONFH Type B/C1.

MATERIALS AND METHODS

We retrospectively reviewed 54 hips with post-collapse ONFH Type B/C1 from 52 consecutive patients who were conservatively followed up for more than 1 year. We measured the amount of femoral head collapse using biplane radiographs at each follow-up period, and produced Kaplan-Meier survival curves with collapse progression (≥ 1 mm) as the endpoint. We compared NV and ND, which were calculated as the ratio of the distance from the articular surface of the femoral head to the deepest point of a necrotic lesion to the femoral head diameter in the mid-coronal slice of T1-weighted magnetic resonance imaging (MRI).

RESULTS

We observed collapse progression in 31 hips (57.4%). The NV and ND were significantly greater in hips with collapse progression than in those without collapse progression (p = 0.0127 and 0.0047, respectively). Necrotic volume was significantly correlated with ND　(rs = 0.56, p < 0.0001).

CONCLUSION

This study suggests that necrotic depth on the mid-coronal slice of T1-weighted MRI can be a substitute for necrotic volume to predict collapse progression in ONFH Type B/C1.

Panoramic heat map for spatial distribution of necrotic lesions

Aims

In this study, we aimed to visualize the spatial distribution characteristics of femoral head necrosis using a novel measurement method.

Methods

We retrospectively collected CT imaging data of 108 hips with non-traumatic osteonecrosis of the femoral head from 76 consecutive patients (mean age 34.3 years (SD 8.1), 56.58% male (n = 43)) in two clinical centres. The femoral head was divided into 288 standard units (based on the orientation of units within the femoral head, designated as N[Superior], S[Inferior], E[Anterior], and W[Posterior]) using a new measurement system called the longitude and latitude division system (LLDS). A computer-aided design (CAD) measurement tool was also developed to visualize the measurement of the spatial location of necrotic lesions in CT images. Two orthopaedic surgeons independently performed measurements, and the results were used to draw 2D and 3D heat maps of spatial distribution of necrotic lesions in the femoral head, and for statistical analysis.

Results

The results showed that the LLDS has high inter-rater reliability. As illustrated by the heat map, the distribution of Japanese Investigation Committee (JIC) classification type C necrotic lesions exhibited clustering characteristics, with the lesions being concentrated in the northern and eastern regions, forming a hot zone (90% probability) centred on the N4-N6E2, N3-N6E units of outer ring blocks. Statistical results showed that the distribution difference between type C2 and type C1 was most significant in the E1 and E2 units and, combined with the heat map, indicated that the spatial distribution differences at N3-N6E1 and N1-N3E2 units are crucial in understanding type C1 and C2 necrotic lesions.

Conclusion

The LLDS can be used to accurately measure the spatial location of necrotic lesions and display their distribution characteristics.

A nomogram for predicting the probability of femoral head collapse in convalescent SARS patients with glucocorticoid-induced osteonecrosis of the femoral head: an 18-year population-based retrospective cohort study

Background

This study aimed to develop a nomogram capable of predicting the probability of femoral head collapse based on an 18-year follow-up cohort of convalescent severe acute respiratory syndrome (SARS) patients with glucocorticoid-induced osteonecrosis of the femoral head (ONFH).

Methods

Data on the natural history of 120 patients (205 hips) who underwent glucocorticoid-induced ONFH at China-Japan Friendship Hospital (CJFH) in 2003 were retrospectively collected. Follow-up was conducted from June 2003 to October 2021. A nomogram was developed in a training cohort and validated in another cohort.

Results

A total of 205 hips were included for analysis, with 143 hips in the training cohorts and 62 hips in the validation cohorts. After 18 years of follow-up, 53 femoral heads collapsed, while 152 femoral heads spontaneously repaired to some extent (necrotic areas reduced or vanished). Following multivariate regression analysis, the Association Research Circulation Osseous (ARCO) staging, necrosis index (NI), and CJFH Classification were entered into the nomogram. The nomogram showed robust discrimination, with an AUC of 0.907 (95% CI: 0.85-0.96). The calibration curves showed an agreement between the probability as predicted by the nomogram and the actual probability. Application of the nomogram in the validation cohort also yielded good discrimination (AUC, 0.876, 95% CI: 0.7751-0.9761) and calibration.

Conclusion

The nomogram successfully predicted femoral head collapse in glucocorticoid-induced ONFH. With the nomogram, the prognosis for an individual patient with glucocorticoid-induced ONFH can be determined, which can lead to a rational therapeutic choice.

Autologous concentrated bone marrow injection for precollapse osteonecrosis of the femoral head concurrent with contralateral total hip arthroplasty: protocol for a clinical trial

INTRODUCTION

The femoral head contralateral to the collapsed femoral head requiring total hip arthroplasty (THA) often manifests in the precollapse stage of osteonecrosis of the femoral head (ONFH). It is not yet demonstrated how autologous concentrated bone marrow injection may prevent collapse of the femoral head concurrent with contralateral THA. The primary objective is to evaluate the efficacy of autologous concentrated bone marrow injection for the contralateral, non-collapsed, femoral head in patients with bilateral ONFH, with the ipsilateral collapsed femoral head undergoing THA.

METHODS AND ANALYSIS

This is a multicentre, prospective, non-randomised, historical-data controlled study. We will recruit patients with ONFH who are scheduled for THA and possess a non-collapsed contralateral femoral head. Autologous bone marrow will be collected using a point-of-care device. After concentration, the bone marrow will be injected into the non-collapsed femoral head following the completion of THA in the contralateral hip. The primary outcome is the percentage of femoral head collapse evaluated by an independent data monitoring committee using plain X-rays in two directions 2 years after autologous concentrated bone marrow injection. Postinjection safety, adverse events, pain and hip function will also be assessed. The patients will be evaluated preoperatively, and at 6 months, 1 year and 2 years postoperatively.

ETHICS AND DISSEMINATION

This protocol has been approved by the Certified Committee for Regenerative Medicine of Tokyo Medical and Dental University and Japan's Ministry of Healthy, Labour and Welfare and will be performed as a class III regenerative medicine protocol, in accordance with Japan's Act on the Safety of Regenerative Medicine. The results of this study will be submitted to a peer-review journal for publication. The results of this study are expected to provide evidence to support the inclusion of autologous concentrated bone marrow injections in the non-collapsed femoral head in Japan's national insurance coverage.

TRIAL REGISTRATION NUMBER

jRCTc032200229.

What are the differences in the recovery of physical function and clinical score between patients with steroid-related osteonecrosis of the femoral head and hip osteoarthritis undergoing total hip arthroplasty? A propensity score-matched study

PURPOSE

Steroid-related osteonecrosis of the femoral head (ONFH), arising from steroid administration for underlying diseases, represents a unique pathology for total hip arthroplasty (THA) and typically affects a younger demographic compared to osteoarthritis (OA). Given the significant age-related differences, this study aims to employ propensity score matching to align patient backgrounds between these two diseases and compare physical function. Additionally, our objective is to scrutinize the patterns of clinical score recovery over the course of one year following THA.

METHODS

Using propensity score matching, 29 patients each with steroid-related ONFH and OA were selected. Muscle strength (hip abductor and knee extensor) were assessed before and after THA. Additionally, recovery of the Harris Hip Score (HHS) and Oxford Hip Score (OHS) up to one year postoperatively was analyzed.

RESULTS

The steroid-related ONFH group exhibited gender bias and significantly younger age compared to the OA group. Propensity score matching achieved balanced patient backgrounds. Physical function showed trends of lower hip abduction and knee extensor strength on the operative side in the steroid-related ONFH group. Notably, nonoperative knee extensor strength decreased significantly after matching. HHS and OHS were poor in steroid-related ONFH up to three months postoperatively but recovered after six months.

CONCLUSIONS

Patients with steroid-related ONFH experience positive outcomes in clinical score following THA. Propensity score matching effectively identified muscle weakness on both operative and nonoperative sides, highlighting its utility in comparative analyses.

Evaluation of the long-term patient-reported outcomes after hip arthroplasty or joint preserving with Sugioka femoral osteotomy in patients with femoral head osteonecrosis

PURPOSE

This study retrospectively evaluated long-term clinical outcomes and patient-reported outcome measures (PROMs) in patients with osteonecrosis of the femoral head (ONFH) who underwent transtrochanteric rotational osteotomy (TRO), curved varus osteotomy (CVO), and total hip arthroplasty (THA).

METHODS

We retrospectively reviewed the 109 hips in 96 patients (46 men, 50 women) who underwent CVO, TRO, or THA for ONFH treatment. The mean follow-up period for the TRO, CVO, and THA groups was 14.8, 11.5, and 13.3 years, respectively.

RESULTS

The THA conversion rate of the TRO patients was significantly higher than that of the patients with CVO, and the final clinical scores in the patients with TRO did not improve compared with preoperative scores. Postoperative PROMs showed that the total and pain scores of the patients with THA were significantly higher than those of patients with TRO and CVO, while the PROM score did not change between patients with TRO and CVO. The analysis further showed that the preoperative type C2, stage 3A, or postoperative type C1 and C2 were significant predictors of decreased final PROM scores.

CONCLUSION

This study found that CVO and THA are clinically effective treatments for ONFH, with significant improvements compared with preoperative scores. However, THA was associated with significantly higher PROMs and pain scores than those of CVO and TRO in long-term follow-up. Furthermore, our results suggest that postoperative PROMs depend mainly on the preoperative level of collapse and postoperative transposed intact ratio of the articular surface of the femoral head.

Corticosteroid-associated osteonecrosis of the femoral head in an 87-year-old patient following treatment for COVID-19-associated pneumonia: A case report

Coronavirus disease 2019 is known to cause severe acute respiratory syndrome, and serious cases need to be treated with corticosteroids. Herein, we report an 87-year-old woman who developed bilateral osteonecrosis of the femoral head after corticosteroid treatment for coronavirus disease 2019-related pneumonia. Sixteen months after treatment, she developed right hip pain without any evidence of trauma. A diagnosis of bilateral osteonecrosis of the femoral head was made based on sclerotic bands on plain radiographs and low-signal bands on T1-weighted magnetic resonance images. The patient underwent right total hip arthroplasty 4 months after symptom onset. Histological examination of the resected femoral head revealed pathological evidence of osteonecrosis. The postoperative course was good, and the patient can now walk unassisted. To the best of our knowledge, this is the first report of histologically proven osteonecrosis after corticosteroid therapy for coronavirus disease 2019-related disease.

Long-Term Outcomes of Cementless Bipolar Hemiarthroplasty in Young Patients With Osteonecrosis of the Femoral Head: The Impact of Implant Improvements and Preoperative Stage

Introduction Advancements in bipolar hemiarthroplasty (BHA) implants in the mid-1990s contributed to favorable short-term outcomes for osteonecrosis of the femoral head (ONFH), particularly in cases without acetabular cartilage lesions. Nevertheless, long-term results remain unclear. In this study, we investigated (i) the impact of new-generation BHA implants and (ii) the effect of the preoperative stage on long-term outcomes in young patients with ONFH. Methods The records of consecutive patients with ONFH who underwent cementless BHA were retrospectively reviewed. Patients aged ≥60 years, with <10 years of follow-up, or who underwent acetabular reaming during surgery were excluded. Radiographical and clinical outcomes of patients who received first-generation BHAs and new-generation BHAs (developed after 1998) were compared by stratifying based on preoperative stage 2/3A and 3B/4, according to the Japanese Investigation Committee classification. Results Overall, 50 hips from 39 patients (mean age: 44.6 years; 64% male) with an average follow-up of 18.6 years were included. The frequency of advanced-stage patients was significantly higher in the first-generation BHA group than in the new-generation group. Regarding postoperative outcomes, the first-generation BHA group had higher acetabular erosion grades (p<0.001) and more femoral component loosening than those in the new-generation group (p<0.001). Revisions were performed in eight hips (seven in the first-generation and one in the new-generation BHA groups, p<0.001). In the new-generation BHA group, there were no significant differences in patient background between stage 2/3A and 3B/4 groups, and only one case in the stage 3B/4 group required revision. In the new-generation group, the grade of acetabular erosion was significantly higher for stage 3B/4 than stage 2/3A (p<0.001); other radiographical and clinical outcomes did not differ significantly between stages. Conclusion New-generation BHAs have significantly better implant survival rates for early-stage ONFH than those of first-generation BHAs. These findings indicate that BHA is an acceptable treatment option for early-stage ONFH in young patients.

Time elapsed from definitive diagnosis to surgery for osteonecrosis of the femoral head: a nationwide observational study in Japan

OBJECTIVES

This study documents the time elapsed from the diagnosis of osteonecrosis of the femoral head (ONFH) to surgery, exploring the factors that influence ONFH severity.

DESIGN

Retrospective observational study of a nationwide database.

SETTING

The Kaplan-Meier method with log-rank tests was applied to examine the period from definitive diagnosis of ONFH to surgery using any surgery as the end point. For bilateral cases, the date of the first surgery was the endpoint.

PARTICIPANTS

This study included 2074 ONFH cases registered in 34 university hospitals and highly specialised hospitals of the multicentre sentinel monitoring system of the Japanese Investigation Committee between 1997 and 2018.

MAIN OUTCOME MEASURE

The primary outcome was the time from diagnosis to surgery. The secondary outcome was the proportion of subjects remaining without surgery at 3, 6 and 9 months, and at 1, 2 and 5 years after diagnosis.

RESULTS

The median time to surgery was 9 months (IQR 4-22 months) after diagnosis of ONFH. The time to surgery was significantly shorter in the alcohol alone group and the combined corticosteroid and alcohol group than in the corticosteroid alone group (p=0.018 and p<0.001, respectively), in early stage ONFH with no or mild joint destruction (stages II and III, p<0.001), and with joint preserving surgery (p<0.001). The proportion without surgery was 75.8% at 3 months, 59.6% at 6 months, 48.2% at 9 months, 40.5% at 1 year, 22.2% at 2 years and 8.3% at 5 years.

CONCLUSION

ONFH has been considered to be an intractable disease that often requires surgical treatment, but the fact that surgery was performed in more than half of the patients within 9 months from diagnosis suggests severe disease with a significant clinical impact.

TRIAL REGISTRATION NUMBER

Chiba University ID1049.

Effects of the location of both anterior and lateral boundaries of the necrotic lesion on collapse progression in osteonecrosis of the femoral head

BACKGROUND

The location of the lateral boundary of the necrotic lesion to the weight-bearing portion of the acetabulum (Type classification) is an important factor for collapse in osteonecrosis of the femoral head (ONFH). Recent studies also reported the significance of the location of the anterior boundary of the necrotic lesion on the occurrence of collapse. We aimed to assess the effects of the location of both anterior and lateral boundaries of the necrotic lesion on collapse progression in ONFH.

METHODS

We recruited 55 hips with post-collapse ONFH from 48 consecutive patients, who were conservatively followed for more than one year. Using a plain lateral radiograph (Sugioka's lateral view), the location of the anterior boundary of the necrotic lesion to the weight-bearing portion of the acetabulum was classified as follows: Anterior-area I (two hips) occupying the medial one-third or less; Anterior-area II (17 hips) occupying the medial two-thirds or less; and Anterior-area III (36 hips) occupying greater than the medial two-thirds. The amount of femoral head collapse was measured by biplane radiographs at the onset of hip pain and each follow-up period, and Kaplan-Meier survival curves with collapse progression (≥1 mm) as the endpoint were produced. The probability of collapse progression was also assessed by the combination of Anterior-area and Type classifications.

RESULTS

Collapse progression was observed in 38 of the 55 hips (69.0%). The survival rate of hips with Anterior-area III/Type C2 was significantly lower. Among hips with Type B/C1, collapse progression occurred more frequently in hips with Anterior-area III (21 of 24 hips) than in hips with Anterior-area I/II (3 of 17 hips, P < 0.0001).

CONCLUSIONS

Adding the location of the anterior boundary of the necrotic lesion to Type classification was useful to predict collapse progression especially in hips with Type B/C1.

Hip-sacroiliac joint-spine syndrome in total hip arthroplasty patients

This study is designed to compare the extent of sacroiliac joint (SIJ) degeneration at total hip arthroplasty (THA) for two pathologies: osteoarthritis of the hip (OA) and osteonecrosis of the femoral head (ON). We also assessed the prevalence of SIJ degeneration in patients with lumbar spondylolisthesis or degenerative scoliosis. A total of 138 hips from 138 patients (69 OA and 69 ON) were assessed in this study, including 66 hips affected by OA secondary to developmental dysplasia of the hip. The degenerative changes in the SIJ and lumbar spine were evaluated prior to THA using radiographs and computed tomography (CT) scans, showing 9 instances of spondylolisthesis and 38 of degenerative scoliosis. The OA group exhibited longer duration from onset to surgery than the ON group. The OA group also included more cases with significant pelvic obliquity (3 degrees or more) and with significant increases in SIJ sclerosis and irregularities. Patients with lumbar spondylolisthesis or degenerative scoliosis were significantly more likely to have SIJ irregularities. The prevalence of SIJ degeneration was higher in cases of THA for OA than for ON. This study also suggests the possibility of Hip-SIJ-Spine syndrome in THA patients with OA.

The association of an elevated Th/Ts ratio and lupus anticoagulant with symptomatic osteonecrosis in systemic lupus erythematosus patients

Objective

This study aimed to assess the risk factors for symptomatic osteonecrosis (ON) in systemic lupus erythematosus (SLE) and identify clinical characteristics and laboratory markers for predicting symptomatic ON occurrence in SLE patients.

Methods

Seventy (6.0%) of 1175 SLE patients diagnosed with symptomatic ON were included in this study. An equal number of SLE patients without symptomatic ON, matched in terms of age and gender, were enrolled in the control group. Clinical symptoms, routine laboratory examinations, lymphocyte subsets, and treatments of these patients were retrospectively reviewed and compared between the two groups. Logistic regression analysis was employed to identify risk factors associated with symptomatic ON in SLE.

Results

Among the 70 cases in the symptomatic ON group, 62 (88.6%) patients experienced femoral head necrosis, with bilateral involvement observed in 58 patients. Bone pain was reported in 32 cases (51.6%), and 19 cases (30.6%) presented with multiple symptoms. Univariate analysis revealed significant differences between the two groups in various factors, including disease duration (months), cumulative steroid exposure time, history of thrombosis, neurological involvement, the number of affected organs, myalgia/myasthenia, and the use of medications such as glucocorticoids, immunosuppressants, aspirin, and statins (P<0.05). Moreover, lupus anticoagulant (LA) levels were significantly higher in the symptomatic ON group than in the control group (P<0.05). Furthermore, notable distinctions were observed in peripheral blood immune cells, including an elevated white blood cell count (WBC), a decreased percentage of Ts cells (CD3+CD8+), and an elevated Th/Ts ratio. Logistic regression analysis revealed that a history of thrombosis, LA positivity, and an elevated Th/Ts ratio remained positive factors associated with symptomatic ON (P<0.05).

Conclusion

Decreased Ts cells and changes in the T lymphocyte subset play an important regulatory role in the development of symptomatic ON. A history of thrombosis and LA are associated with an increased probability of symptomatic ON in SLE and may serve as potential predictors.

Extension of the Antero-Posterior Necrotic Regions Associated With Collapse Cessation in Osteonecrosis of the Femoral Head

BACKGROUND

Collapse cessation is of utmost importance following a long period of collapse due to osteonecrosis of the femoral head (ONFH). This study investigated the relationship between collapse cessation and the extent of the necrotic regions of ONFH.

METHODS

Overall, 74 patients who had symptomatic ONFH (collapse < 3 mm) at the first visit with a minimum follow-up of 3 years were included in this study. Patients were categorized based on collapse progression or cessation into the progression and stable groups. The extent of the antero-posterior (AP) and medio-lateral necrotic regions between the groups was assessed using sagittal and coronal sections of T1-magnetic resonance imaging. Additionally, the most effective cutoff value was determined from the receiving operating characteristic curve where collapse cessation could be obtained, while the survival rates were determined with collapse progression as the endpoints were evaluated.

RESULTS

Overall, 45 and 29 patients were in the progression and stable groups, respectively. The AP and medio-lateral necrotic regions were significantly different (P < .01 and P < .01, respectively) between the progression and stable groups. A cutoff value of 62.1% of the AP necrotic regions was determined from the receiving operating characteristic curve analysis. The 5-year survival rates with collapse progression as the endpoints were 5.4 and 77.8% in the AP necrotic regions of ≥62.1 and <62.1%, respectively (P < .01).

CONCLUSIONS

Cases with AP necrotic regions of ≤62.1% can be expected to have collapse cessation, which could be a useful index for ONFH treatment strategies.

LEVEL OF EVIDENCE

Level IV.

Effects of bone mineral density at the lateral sclerotic boundary on the femoral head collapse onset in osteonecrosis of the femoral head: A preliminary study

BACKGROUND

In the natural course of osteonecrosis of the femoral head, sclerotic changes at the boundary of necrotic lesion gradually occur until femoral head collapse. This study aims to examine the effects of bone mineral density at the lateral boundary of necrotic lesion on a subsequent femoral head collapse.

METHODS

We developed patient-specific finite element models of 9 hips with subsequent collapse and 10 hips without subsequent collapse. Cubic regions of interest were selected at both subchondral areas of the lateral boundary and the adjacent necrotic lesion. Bone mineral density values of the regions of interest were quantitatively measured, and a ratio of bone mineral density values (lateral boundary/necrotic lesion) was calculated. Stress values at the lateral boundary were also evaluated.

FINDINGS

The ratio of bone mineral density values was significantly higher in hips with subsequent collapse than that without subsequent collapse (p = 0.0016). The median equivalent stress and shear stress were significantly higher in hips with subsequent collapse than that without subsequent collapse (p = 0.0071, and p = 0.0143, respectively). The ratio of bone mineral density values showed a promising value in predicting the occurrence of subsequent femoral head collapse (AUC = 0.97).

INTERPRETATION

Our results indicated that bone mineral density value at the lateral boundary of necrotic lesion may be associated with the occurrence of subsequent femoral head collapse in pre-collapse stage osteonecrosis of the femoral head.

Sclerosis rim volume ratio and Japanese Investigation Committee classification as predictive factors for femoral head collapse progression after non-vascularized fibular grafting in osteonecrosis patients

OBJECTIVE

The purpose of this retrospective cohort study was to determine the relationship between sclerosis rim volume ratio (SVR) and the progression of femoral head collapse after non-vascularized fibular grafting (NVFG) surgery in patients with osteonecrosis of the femoral head (ONFH), investigating risk factors associated with femoral head collapse progression and establishing a predictive model to enhance clinical decision-making.

METHODS

ONFH patients who underwent NVFG between January 2008 and December 2021 were analyzed retrospectively to assess the risk of post-operative collapse progression (collapse >2 mm). A logistic regression model was used to evaluate the independent risk factors associated with collapse progression, including age, sex, etiology, affected side, Japanese Investigation Committee classification (JIC), and the sclerosis rim volume ratio (SVR). SVR values was collected from three weight-bearing columns, namely SVR1, SVR2, and SVR3, respectively.

RESULTS

57 patients with 64 hips who had undergone NVFG and were followed up for at least one year were included. During the follow-up, collapse＞2 mm occurred in 30 hips (46.88%). Multivariable analysis revealed that JIC (p =0.037) and SVR1 (p = 0.04) were independent risk factors for collapse progression after NVFG. The results of the receiver operating characteristic (ROC) analysis indicated that the aforementioned indices provided a satisfactory prediction of early femoral head collapse progression in ONFH patients after NVFG. The regression model using the above two indicators as a composite index showed satisfactory performance in predicting early postoperative femoral head collapse progression, with an area under the curve (AUC) of 84.6%.

CONCLUSIONS

SVR is significant predictor of post-operative collapse progression following NVFG, and the composite index provides an optimal predictive value for femoral head collapse progression after surgery.

Serum glutathione peroxidase 4 as a novel biomarker for nontraumatic osteonecrosis of the femoral head: A retrospective case-control study

There are no serum biomarkers available in nontraumatic osteonecrosis of the femoral head in clinical practice. This study aimed to evaluate the clinical value of serum glutathione peroxidase 4 in nontraumatic osteonecrosis of the femoral head. This retrospective study analyzed serum glutathione peroxidase 4 levels and clinical data of 80 patients with nontraumatic osteonecrosis of the femoral head and 80 healthy controls between August 2021 and May 2022. Serum glutathione peroxidase 4 levels were analyzed using an enzyme-linked immunosorbent assay. The Association Research Circulation Osseous classification system determined disease progression. Clinical severity was assessed by Harris hip score and visual analogue scale. Correlations between serum glutathione peroxidase 4 and disease progression as well as clinical severity were evaluated statistically. The diagnostic accuracy of serum glutathione peroxidase 4 in nontraumatic osteonecrosis of the femoral head was determined using receiver operating characteristic analysis. The baseline characteristics of participants between 2 groups were comparable. Patients with nontraumatic osteonecrosis of the femoral head displayed a decreased glutathione peroxidase 4 level compared with healthy controls (11.87 ± 2.76 μU/mL vs 16.54 ± 4.89 μU/mL, P < .01). The levels of glutathione peroxidase 4 were inversely correlated with Association Research Circulation Osseous stage (P < .01) and visual analogue scale scores (P < .01), and positively correlated with Harris score (P < .01). Receiver operating characteristic analyses showed that area under curves of glutathione peroxidase 4 was 0.808 (95% CI 0.721-0.858) and 0.847 (95% CI 0.743-0.951) with regard to diagnosis and collapse prediction in nontraumatic osteonecrosis of the femoral head, respectively. Serum glutathione peroxidase 4 could serve as a novel biomarker for diagnosing nontraumatic osteonecrosis of the femoral head and predicting collapse of the femoral head.

Investigating the subchondral trabecular bone microstructure in patients with osteonecrosis of the femoral head using multi-detector row computed tomography

OBJECTIVES

To analyse the microstructural changes of subchondral trabecular bone in patients with osteonecrosis of the femoral head (ONFH) using multi-detector row computed tomography (MDCT).

METHODS

We retrospectively investigated 76 hips in 50 patients diagnosed with ONFH between 2017 and 2021. Groups 1, 2, 3, and 4 comprised hips without ONFH, ONFH without femoral head collapse (FHC), ONFH with mild collapse (<2 mm), and ONFH with severe collapse (>2 mm), respectively. All patients underwent MDCT, and the subchondral trabecular bone microstructure was assessed. Regions of interests were set at the lateral boundary of the femoral head necrotic lesion and centre of the acetabular weight-bearing portion.

RESULTS

In both the femoral head and the acetabular regions, there were significant differences in Groups 2 and 3 compared to Group 1, with increased volumetric bone mineral density and apparent bone volume fraction, and more plate-like with increased connectivity, indicating that osteosclerotic changes were occurring.

CONCLUSIONS

In both the femoral head and the acetabular regions, osteosclerotic changes of subchondral trabecular bone microstructure were present before FHC.

Lateral classification system predicts the collapse of JIC type C1 nontraumatic osteonecrosis of the femoral head: a retrospective study

PURPOSES

The aim of this study was to construct a lateral classification system for nontraumatic osteonecrosis of femoral head (NONFH) through three-dimensional reconstruction of the necrotic area to assist in evaluating the prognosis of patients with JIC type C1.

METHODS

Retrospective analysis of patients with JIC type C1 NONFH from January 2018 to December 2020. All patients were followed up for more than 3.5 years. The patients were divided into collapse group and non-collapse group according to whether the femoral head collapsed during the follow-up.Lateral classification system for femoral head necrosis is constructed through three-dimensional reconstruction of the necrotic area.Comparison of lateral classification system,midsagittal necrosis angle(MNA)and general data between the two groups.Furthermore, ROC curve analysis and survival analysis were performed.

RESULTS

318 patients were included in this study.There was a significant difference between the two groups in the lateral classification system (P < 0.05). In addition, the MNA in the collapsed group was significantly greater than that in the non-collapse group(P < 0.05). As revealed by the results of ROC analysis, the cutoff point of MNA was 104.5° (P < 0.05).According to the survivorship analysis, the mean survival time of the hips of patients with MNA less than 104.5°was greater than that of patients with MNA over 104.5° (P < 0.05). The survival rates of 3.5 years femoral head were 45.8%, 33.7%, 14.8%, 93.0%, and 100% for lateral classification system 1, 2, 3, 4, and 5, respectively.

CONCLUSION

Necrosis involving the anterior aspect of the femoral head is an important risk factor for collapse. The Lateral classification system can effectively predict the femoral head collapse in JIC C1 type NONFH patients, supplementing the deficiency of JIC classification in evaluating the front of the femoral head.

Subchondral Bone Plate Classification: A New and More Sensitive Approach for Predicting the Prognosis of Osteonecrosis of the Femoral Head

BACKGROUND

This study explores the impact of subchondral bone plate necrosis on the development of the osteonecrosis of femoral head (ONFH) and its joint collapse.

METHODS

This retrospective study included 76 ONFH patients (89 consecutive hips) with Association for Research on Osseous Circulation stage II who received conservative treatment without surgical intervention. The mean follow-up time was 15.60 ± 12.29 months. ONFH was divided into 2 types (I and II): Type I with a necrotic lesion involving subchondral bone plate and Type II with a necrotic lesion not involving subchondral bone plate. The radiological evaluations were based on plain x-rays. The data were analyzed using SPSS 26.0 statistical software.

RESULTS

The collapse rate in Type I ONFH was significantly higher than that in Type II ONFH (P < 0.001). The survival time of hips with Type I ONFH was significantly shorter than those with Type II ONFH and with the endpoint of the femoral head collapse (P < 0.001). The collapse rate of Type I in the new classification (80.95%) was higher compared with that of the China-Japan Friendship Hospital (CJFH) classification (63.64%), and the difference was statistically significant (χ2 = 1.776, P = 0.024).

CONCLUSION

Subchondral bone plate necrosis is an important factor that affects ONFH collapse and prognosis. Current classification using subchondral bone plate necrosis is more sensitive for predicting collapse compared with the CJFH classification. Effective treatments should be taken to prevent collapse if ONFH necrotic lesions involve the subchondral bone plate.

Updating Osteonecrosis of the Femoral Head

Osteonecrosis of the femoral head (ONFH), a condition characterized by the presence of a necrotic bone lesion in the femoral head, is caused by a disruption in the blood supply. Its occurrence is more common in young and middle-aged adults and it is the main reason for performance of total hip arthroplasty in this age group. Its incidence is increasing along with increased use of glucocorticoids for management of adjuvant therapy for treatment of leukemia as well as organ transplantation and other myelogenous diseases. Current information on etiology and pathogenesis, as well as natural history, stage system, and treatments is provided in this review. A description of the Association Research Circulation Osseous (ARCO) criteria for classification of glucocorticoids- and alcohol-associated ONFH, 2019 ARCO staging system, and 2021 ARCO classification using computed tomography for the early stages of ONFH is also provided.

Clinical outcomes of autologous platelet-rich plasma and bone marrow mononuclear cells grafting combined with core decompression for Association Research Circulation Osseous II-IIIA stage non-traumatic osteonecrosis of the femoral head

PURPOSE

This study aimed to investigate the efficacy and safety of autologous platelet-rich plasma (PRP) and bone marrow mononuclear cells (BMMCs) grafting combined with core decompression (CD) in the treatment of Association Research Circulation Osseous (ARCO) II-IIIA stage non-traumatic osteonecrosis of the femoral head (ONFH).

METHODS

The clinical data of 44 patients (44 hips) with non-traumatic ONFH from December 2018 to December 2019 were retrospectively reviewed. Twenty-four patients underwent CD combined with autologous PRP and BMMCs grafting (PRP+BMMCs group), and 20 patients underwent core decompression alone (CD group). During a minimum follow-up of 36 months, radiographic outcomes were evaluated using X-ray, radiographic failure rates were compared, and Harris hip score (HHS) and visual analog scale (VAS) were selected to evaluate clinical outcomes. The percentage of patients with minimal clinically important difference (MCID) in both groups was analyzed. Clinical failure was defined as further total hip arthroplasty (THA) with Kaplan-Meier survival analysis. Surgical complications were recorded.

RESULTS

All patients had well healed wounds, and no complications such as infection and thrombosis occurred. HHS and VAS scores in both the PRP+BMMCs and CD groups were better than those preoperatively (P<0.05). At the last follow-up, the HHS and VAS scores of the PRP+BMMCs group were significantly better than those of the CD group (P<0.05). In ARCO II-IIIA stage, 66.7% of the PRP+BMMCs group and 30.0% of the CD group achieved the MCID (P<0.05). The clinical and imaging failure rates in the PRP+BMMCs group were 12.5% and 20.8%, respectively, compared with 40.0% and 50.0% in the CD group (P<0.05). In ARCO II stage, the MCID, clinical and imaging failure rates of PRP+BMMCs group and CD group were 66.7% and 33.3% (P<0.05), 4.8% and 33.3% (P<0.05), 14.3% and 44.4% (P<0.05), respectively. The PRP+BMMCs group had better hip survival rate compared with CD group (P<0.05).

CONCLUSION

CD combined with autologous PRP and BMMCs grafting is a safe and effective method for the treatment of ARCO II-IIIA stage non-traumatic ONFH, especially for ARCO II stage, effectively reducing the collapse rate of the femoral head and delaying or even avoiding THA.

Reductions in Bone Mineral Density Are Apparent Early in Children With Prevalent Osteonecrosis Lesions Following Leukemia Therapy

Osteonecrosis (ON) is a serious complication of childhood acute lymphoblastic leukemia. We determined the prevalence of osteonecrotic lesions in our patient population by a one-time multisite magnetic resonance imaging (MRI) more than 1 year following leukemia therapy. MRI findings were evaluated in relationship to clinical factors (including longitudinal changes in bone mineral density [BMD]). Eighty-six children enrolled in the Steroid Associated Osteoporosis in the Pediatric Population (STOPP) study were evaluated for ON at 3.1 ± 1.3 years following therapy. Thirty children had a total of 150 confirmed ON lesions (35%). Lumbar spine (LS) BMD Z-scores (mean ± SD) were low at diagnosis and similar between patients with and without ON (-1.09 ± 1.53 versus -1.27 ± 1.25, p = 0.549). LS BMD Z-scores declined from baseline to 12 months in children with ON (-0.31 ± 1.02) but not in those without (0.13 ± 0.82, p = 0.035); the hip BMD Z-scores from baseline to 24 months declined in both groups, but to a greater extent in those with ON (-1.77 ± 1.22) compared to those without (-1.03 ± 1.07, p = 0.045). At the time of the MRI, mean total hip and total body (TB) BMD Z-scores were lower in children with ON (hip -0.98 ± 0.95 versus -0.28 ± 1.06, p = 0.010; TB -1.36 ± 1.10 versus -0.48 ± 1.50, p = 0.018). Pain occurred in 11/30 (37%) with ON versus 20/56 (36%) without, p = 0.841. In multivariable models, older age at diagnosis (odds ratio [OR] 1.57; 95% confidence interval [CI], 1.15-2.13; p = 0.004), and hip BMD Z-score at MRI (OR 2.23; 95% CI, 1.02-4.87; p = 0.046) were independently associated with ON. Overall, one-third of children demonstrated ON after leukemia therapy. Those with ON had greater reductions in spine and hip BMD Z-scores in the first 1 and 2 years of therapy, respectively. Older age and lower hip BMD Z-scores at MRI were significantly associated with prevalent, off-therapy ON. These data assist in identifying children at risk of ON. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Reliability and repeatability of 2021 ARCO classification and its guiding significance in treatment of nontraumatic osteonecrosis of the femoral head

BACKGROUND

The study was designed to evaluate the interobserver reliability and intraobserver repeatability of the 2021 Association Research Circulation Osseous (ARCO) classification and explore its guiding significance in the treatment of nontraumatic osteonecrosis of the femoral head (ONFH).

METHODS

In this retrospective study, we randomly selected and investigated 50 sets of preoperative computed tomography or magnetic resonance imaging scans from 96 patients (139 hips) to validate the reliability and repeatability of the 2021 ARCO classification. Patients with a nano-hydroxyapatite/polyamide-66 support rod were included in the clinical efficacy study. The Harris hip score (HHS) was used to assess hip function. Femoral head collapse of > 2 mm was considered radiological failure. Total hip arthroplasty (THA) was performed for clinical failure, and follow-up was discontinued.

RESULTS

The average kappa value of interobserver consistency was 0.652. The average rate of consistency was 90.25%, and the average kappa value of intraobserver consistency was 0.836. Eighty-two patients (122 hips) were enrolled and followed up for a mean of 43.57 ± 9.64 months. There was no significant difference in the HHS among the three groups before surgery, but the difference was statistically significant at the last follow-up. Among them, types 1 and 2 had significantly higher scores at the last follow-up than preoperatively (P < 0.05), whereas type 3 had a lower score at the last follow-up than preoperatively, although the difference was not statistically significant (P > 0.05).According to the imaging evaluation, the failure rate of type 1, 2, and 3 at the last follow-up was 0%, 19%, and 87%, respectively. Univariate analysis showed that the femoral head survival rate of radiography was significantly affected by the new classification system (P = 0.00). At the last follow-up, the incidence rate of THA in type 1, 2, and 3 was 5%, 7%, and 31%, respectively. Univariate analysis showed that the femoral head survival rate was significantly affected by the new classification system (P = 0.001).

CONCLUSIONS

The 2021 ARCO classification for early-stage ONFH shows substantial consistency and repeatability. We do not recommend femoral head-preserving surgery for patients with type 3 ONFH.

Application of Biomaterials in Treating Early Osteonecrosis of the Femoral Head: Research Progress and Future Perspectives

Osteonecrosis of the femoral head (ONFH), a progressive pathological process of femoral head ischemia and osteocyte necrosis, is a refractory orthopedic disease caused by multiple etiologies and there is no complete cure at present. With the extension of ONFH duration, osteocyte apoptosis and trabecular bone loss can decrease the load-bearing capacity of the femoral head, which leads to the collapse of the articular cartilage and subchondral bone. Therefore, an urgent clinical need exists to develop effective treatment strategies of early-stage ONFH for maintaining the hip joint function and preventing femoral head collapse. In recent years, extensive attention has been paid to the application of diverse biomaterials in treating early ONFH for sustaining the normal morphology and function of the autologous femoral head, and slowing disease progression. Herein, we review the research progress of bone grafts, metallic materials, bioceramics, bioglasses and polymer materials for early ONFH treatment, and discuss the biological mechanisms of bone repair and regeneration in the femoral-head necrotic area. We propose suggestions for future research directions, from a special perspective of improving the local microenvironment in femoral head by facilitating vessel-associated osteoclasts (VAOs) generation and coupling of bone-specific angiogenesis and osteogenesis, as well as inhibiting bone-associated osteoclasts (BAOs) and BAO-mediated bone resorption. This review can provide ideas for the research, development, and clinical application of biomaterials for treating early ONFH. STATEMENT OF SIGNIFICANCE: We believe that at least three aspects of this manuscript make it interesting to readers of the Acta Biomaterialia. First, we briefly summarize the incidence, pathogenesis, risk factors, classification criteria and treatment of early osteonecrosis of the femoral head (ONFH). Second, we review the research progress in biomaterials for early ONFH treatment and the biological mechanisms of bone repair and regeneration in femoral-head necrotic area. Third, we propose future research progress on improving the local microenvironment in femoral head by facilitating vessel-associated osteoclasts generation and coupling of bone-specific angiogenesis and osteogenesis, as well as inhibiting bone-associated osteoclasts and bone resorption. We hope this review can provide ideas for the research, development, and clinical application of biomaterials for treating early ONFH.

Bone tissue engineering for treating osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) is a devastating and complicated disease with an unclear etiology. Femoral head-preserving surgeries have been devoted to delaying and hindering the collapse of the femoral head since their introduction in the last century. However, the isolated femoral head-preserving surgeries cannot prevent the natural progression of ONFH, and the combination of autogenous or allogeneic bone grafting often leads to many undesired complications. To tackle this dilemma, bone tissue engineering has been widely developed to compensate for the deficiencies of these surgeries. During the last decades, great progress has been made in ingenious bone tissue engineering for ONFH treatment. Herein, we comprehensively summarize the state-of-the-art progress made in bone tissue engineering for ONFH treatment. The definition, classification, etiology, diagnosis, and current treatments of ONFH are first described. Then, the recent progress in the development of various bone-repairing biomaterials, including bioceramics, natural polymers, synthetic polymers, and metals, for treating ONFH is presented. Thereafter, regenerative therapies for ONFH treatment are also discussed. Finally, we give some personal insights on the current challenges of these therapeutic strategies in the clinic and the future development of bone tissue engineering for ONFH treatment.

Association between magnitude of femoral head collapse and quality of life in patients with osteonecrosis of the femoral head

OBJECTIVES

The magnitude of femoral head collapse (MFHC) is one of the criteria for staging osteonecrosis of the femoral head (ONFH). The present study aimed to clarify the relationship between MFHC and hip pain or functional quality of life (QOL) scores in patients with ONFH.

METHODS

Seventy patients with ONFH who had femoral head collapse without osteoarthritic changes were divided into four groups based on MFHC by 1 mm. Pain was assessed using the visual analogue scale (VAS). QOL was evaluated using patient-reported outcome measures such as the Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire (JHEQ), Oxford Hip Score (OHS), and Short Form-12 Health Survey, version 2 (SF-12v2). We also explored the relationship between MFHC and QOL.

RESULTS

Pain score and satisfaction score in the VAS, JHEQ pain subscale, JHEQ movement subscale, and JHEQ total score were significantly associated with MFHC, and no significant differences were found between groups in any subscale or total score for OHS and SF-12v2.

CONCLUSION

In patients with ONFH, differences in MFHC by 1 mm were associated with deterioration of some pain VAS and QOL outcomes.

The Many Faces of Marrow Necrosis

Depending on the age and location within the skeleton, bone marrow can be mostly fatty or hematopoietic, and both types can be affected by marrow necrosis. This review article highlights the magnetic resonance imaging findings of disorders in which marrow necrosis is the dominant feature.Fatty marrow necrosis is detected on T1-weighted images that show an early and specific finding: the reactive interface. Collapse is a frequent complication of epiphyseal necrosis and detected on fat-suppressed fluid-sensitive sequences or using conventional radiographs. Nonfatty marrow necrosis is less frequently diagnosed. It is poorly visible on T1-weighted images, and it is detected on fat-suppressed fluid-sensitive images or by the lack of enhancement after contrast injection.Pathologies historically "misnamed" as osteonecrosis but do not share the same histologic or imaging features of marrow necrosis are also highlighted.

Collapse-related bone changes at multidetector CT in ARCO 1-2 osteonecrotic femoral heads: correlation with clinical and MRI data

OBJECTIVE

To assess the frequency of collapse-related bone changes at multi-detector CT (MDCT) in osteonecrotic femoral heads (ONFH) and to compare clinical parameters and MRI findings in Association Research Circulation Osseous (ARCO) 1-2 ONFH with or without collapse-related bone changes (CRBC) at MDCT.

MATERIALS AND METHODS

This is a secondary analysis of radiographic, MRI, and MDCT examinations of ONFH of patients eligible for a prospective clinical trial. Radiographs and MRI were analyzed to perform ARCO staging. Frequency of CRBC at MDCT including cortical interruption, trabecular interruption, impaction, and resorption was determined by two readers (R1, R2) blinded to radiographic, MRI, and clinical data. Baseline clinical and imaging data of ARCO 1-2 ONFH were compared between hips with or without CRBC at MDCT.

RESULTS

One hundred thirty-two hips of 77 participants were analyzed. There were 78 non-collapsed and 54 collapsed ONFH. For R1 and R2, 31/78 (40%) and 20/78 (26%) ARCO 1-2 ONFH and 54/54 (100%) and 53/54 (98%) ARCO 3-4 ONFH showed at least one CRBC at MDCT. For both readers, there was no significant difference in pain, functional impairment, size of lesion, and the presence of BME on MRI between ARCO 1-2 hips with or without CRBC at MDCT.

CONCLUSION

Twenty-six to forty percent of ARCO 1-2 ONFH demonstrate at least one collapse-related bone change at CT. Their clinical and MRI findings do not differ from those without collapse-related bone changes.

KEY POINTS

• Ninety-eight to one hundred percent of collapsed and 26-40% of non-collapsed osteonecrotic femoral heads presented at least one collapse-related bone change at CT (cortical or trabecular bone interruption, trabecular bone impaction, or resorption). • There was no significant difference in age, sex, pain, functional impairment, size of lesion, or frequency of marrow edema on MRI between non-collapsed hips with or without collapse-related bone changes at CT. • The significance of collapse-related bone changes at CT should be further assessed.

Less sclerotic microarchitecture pattern with increased bone resorption in glucocorticoid-associated osteonecrosis of femoral head as compared to alcohol-associated osteonecrosis of femoral head

BACKGROUND

Glucocorticoid usage and alcohol abuse are the most widely accepted risk factors for nontraumatic osteonecrosis of femoral head (ONFH). Despite distinct etiologies between glucocorticoid-associated ONFH (GONFH) and alcohol-associated ONFH (AONFH), little is known about the differences of the microarchitectural and histomorphologic characteristics between these subtypes of ONFH.

PURPOSES

To investigate bone microarchitecture, bone remodeling activity and histomorphology characteristics of different regions in femoral heads between GONFH and AONFH.

METHODS

From September 2015 to October 2020, 85 patients diagnosed with GONFH and AONFH were recruited. Femoral heads were obtained after total hip replacement. Femoral head specimens were obtained from 42 patients (50 hips) with GONFH and 43 patients (50 hips) with AONFH. Micro-CT was utilized to assess the microstructure of 9 regions of interest (ROIs) in the femoral head. Along the supero-inferior orientation, the femoral head was divided into necrotic region, reactive interface, and normal region; along the medio-lateral orientation, the femoral head was divided into medial region, central region and lateral region. Decalcified and undecalcified bone histology was subsequently performed to evaluate histopathological alterations and bone remodeling levels.

RESULTS

In the necrotic region, most of the microarchitectural parameters did not differ significantly between GONFH and AONFH, whereas both the reactive interface and normal region revealed a less sclerotic microarchitecture but a higher bone remodeling level in GONFH than AONFH. Despite similar necrotic pathological manifestations, subchondral trabecular microfracture in the necrotic region was more severe and vasculature of the reactive interface was more abundant in GONFH.

CONCLUSIONS

GONFH and AONFH shared similar microarchitecture and histopathological features in the necrotic region, while GONFH exhibited a less sclerotic microarchitecture and a more active bone metabolic status in both the reactive interface and normal region. These differences between GONFH and AONFH in bone microarchitectural and histopathological characteristics might contribute to the development of disease-modifying prevention strategies and treatments for ONFH, taking into etiologies.

Hip function in patients undergoing conservative treatment for osteonecrosis of the femoral head

PURPOSE

Once collapsed, osteonecrosis of the femoral head (ONFH) generally obtains collapse cessation naturally and surgical intervention can be avoided in the long term. This study aimed to investigate the process of hip function and secondary osteoarthritis changes in ONFH patients undergoing conservative treatment.

METHODS

We included 54 patients with symptomatic ONFH at the first visit with a minimum follow-up of three years with conservative treatment. Patients were divided into two groups based on collapse cessation < 3 mm (stable group) or progression to > 3 mm (progression group). Additionally, we investigated age, sex, body mass index (BMI), etiology, contralateral side hip joint, the Japanese Investigation Committee (JIC) type classification, Harris hip score (HHS), Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire (JHEQ), and survival rate with secondary osteoarthritis as the endpoint.

RESULTS

The stable and progression groups had 31 and 23 patients, respectively. No significant differences in age, sex, BMI, and aetiology were observed between the two groups, except for the contralateral side hip joint and JIC type classification. The HHS and JHEQ were significantly improved at the final follow-up than at the first visit in the stable group. However, there were no significant differences in HHS and JHEQ at the final follow-up than at the first visit in the progression group. The five year survival rates with secondary osteoarthritis as the endpoint were significantly higher in the stable group (100%) than in the progression group (32.5%).

CONCLUSION

Hip joint function improved by continuing conservative treatment in ONFH patients with collapse cessation < 3 mm.

Is There an Association Between Femoral Head Collapse and Acetabular Coverage in Patients With Osteonecrosis?

BACKGROUND

Osteonecrosis of the femoral head (ONFH) classification systems are based on the size, volume, and location of necrotic lesions. Often-but not always-ONFH results in femoral head collapse. Because acetabular coverage is associated with mechanical stress on the femoral head, it might also be associated with femoral head collapse in patients with ONFH. However, the association between acetabular coverage and femoral head collapse in these patients has not been established.

QUESTIONS/PURPOSES

(1) Is femoral head collapse associated with acetabular coverage or pelvic incidence (PI) in patients with ONFH? (2) Are established predictors of femoral head collapse in ONFH classification systems associated with acetabular coverage?

METHODS

Between 2008 and 2018, we evaluated 343 hips in 218 patients with ONFH. We considered all patients with ONFH except for those with a traumatic etiology, a history of surgical treatment before collapse, or those with collapse at initial presentation as potentially eligible for this study. Of those, 101 hips with ONFH (50% [50] were in males with a mean age of 44 ± 15 years) met our inclusion criteria. These patients were subsequently divided into two groups: those with femoral head collapse within 12 months (collapse group, 35 hips) and those without femoral head collapse (noncollapse group, 66 hips). No differences in patient demographics were observed between the two groups. CT images were used to measure the PI and acetabular coverage in three planes: the lateral center-edge angle (LCEA) in the coronal plane, the anterior and posterior center-edge angle in the sagittal plane, and the anterior and posterior acetabular sector angle in the axial plane; in addition, the difference between these parameters was investigated between the groups. The thresholds for femoral head collapse in the parameters that showed differences were investigated. Necrotic location and size were evaluated using the Japanese Investigation Committee (JIC) classification and the Steinberg grade classification, respectively. We examined the relationship between these parameters and classifications.

RESULTS

The mean LCEA was slightly greater in the noncollapse group than in the collapse group (32° ± 6° versus 28° ± 7°; mean difference 4° [95% CI 1.15° to 6.46°]; p = 0.005); the clinical importance of this small difference is uncertain. There were no differences in PI between the two groups. After accounting for sex, age, BMI, and etiology as confounding factors, as well as acetabular coverage parameters and PI, we found a lower LCEA to be independently associated with increased odds of collapse, although the effect size is small and of questionable importance (OR 1.18 [95% CI 1.06 to 1.33]; p = 0.001). The threshold of LCEA for femoral head collapse was 28° (sensitivity = 0.79, specificity = 0.60, area under the curve = 0.73). The percentage of patients with an LCEA less than 28° was larger in JIC Type C1 (OR 6.52 [95% CI 1.64 to 43.83]; p = 0.006) and C2 (OR 9.84 [95% CI 2.34 to 68.38]; p = 0.001) than in patients with both Type A and Type B. The acetabular coverage data for the excluded patients did not differ from those of the patients included in the analysis.

CONCLUSION

Our findings suggest that acetabular coverage appears to have little, if any, association with the likelihood of collapse in patients with ONFH. We found a small association between a lower LCEA and a higher odds of collapse, but the effect size may not be clinically important. Factors other than acetabular coverage need to be considered, and if our findings are verified by other investigators, osteotomy is unlikely to have a protective role. As the patients in our study were fairly homogeneous in terms of ethnicity and BMI, these factors need to be further investigated to determine whether they are associated with femoral head collapse in ONFH.

LEVEL OF EVIDENCE

Level III, prognostic study.

Volume and location of bone regeneration after autologous expanded mesenchymal stromal cells in hip osteonecrosis : a pilot study

AIMS

Successful cell therapy in hip osteonecrosis (ON) may help to avoid ON progression or total hip arthroplasty (THA), but the achieved bone regeneration is unclear. The aim of this study was to evaluate amount and location of bone regeneration obtained after surgical injection of expanded autologous mesenchymal stromal cells from the bone marrow (BM-hMSCs).

METHODS

A total of 20 patients with small and medium-size symptomatic stage II femoral head ON treated with 140 million BM-hMSCs through percutaneous forage in the EudraCT 2012-002010-39 clinical trial were retrospectively evaluated through preoperative and postoperative (three and 12 months) MRI. Then, 3D reconstruction of the original lesion and the observed postoperative residual damage after bone regeneration were analyzed and compared per group based on treatment efficacy.

RESULTS

The mean preoperative lesion volume was 18.7% (SD 10.2%) of the femoral head. This reduced to 11.6% (SD 7.5%) after three months (p = 0.015) and 3.7% (SD 3%) after one year (p < 0.001). Bone regeneration in healed cases represented a mean 81.2% (SD 13.8%) of the initial lesion volume at one year. Non-healed cases (n = 1 stage progression; n = 3 THAs) still showed bone regeneration but this did not effectively decrease the ON volume. A lesion size under mean 10% (SD 6%) of the femoral head at three months predicted no ON stage progression at one year. Regeneration in the lateral femoral head (C2 under Japanese Investigation Committee (JCI) classification) and in the central and posterior regions of the head was predominant in cases without ON progression.

CONCLUSION

Bone regeneration was observed in osteonecrotic femoral heads three months after expanded autologous BM-hMSC injection, and the volume and location of regeneration indicated the success of the therapy.Cite this article: Bone Joint Res 2022;11(12):881-889.

The impact of increasing femoral offset and stem anteversion on postoperative dislocation in bipolar hemiarthroplasty

BACKGROUND

Femoral offset and anteversion have been reported to affect the incidence of dislocation following bipolar hemiarthroplasty, although the magnitudes of contributions of the femoral offset and stem anteversion on dislocation, both singly and in combination is not fully understood.

METHODS

Using the CT data of 61 patients (61 hips), including 30 male and 31 female who underwent bipolar hemiarthroplasty, three-dimensional dynamic motion analysis was performed using a modular implant that enabled adjustment of femoral offset and stem anteversion independently. The pattern of impingement and relationship between femoral offset/stem anteversion and range of motion were evaluated using the software.

FINDINGS

We found that a higher femoral offset and stem anteversion correlate with a greater range of motion of flexion and internal rotation. Furthermore, an increased femoral offset has a great effect on increasing range of motion of flexion than stem anteversion, and increased both femoral offset and stem anteversion have fewer effect on the flexion, whereas increasing stem anteversion has a great impact on internal rotation than offset, especially in the case with lower femoral anteversion. However, a higher stem anteversion decrease the range of motion of external rotation, whereas a higher femoral offset leads to an increased range of motion of external rotation.

INTERPRETATION

We demonstrated that both a higher femoral offset and stem anteversion substantially affected the range of motion in flexion, internal rotation and external rotation. However, these are not independent, but rather mutually confounding, the surgeons should consider retaining femoral/anterior offset in bipolar hemiarthroplasty.

[Expert consensus on clinical diagnosis and treatment technique of osteonecrosis of the femoral head (2022 version)]

Osteonecrosis of the femoral head (ONFH) is a common and refractory disease in the clinic. Although the exact pathophysiological mechanism is not fully understood, it is believed to be closely related to the interruption of intra-bone circulation and eventual bone tissue death. The prevention and treatment of ONFH is always a great challenge for orthopedists. The diagnostic level of ONFH has been continuously improved with the development of imaging techniques such as MRI and the in-depth understanding of the disease in recent years.There are many treatment methods for ONFH, which are generally considered individually and comprehensively according to factors such as the patient's age, osteonecrosis stage, classification, and compliance with joint-sparing treatment. There is currently no unified standard. ONFH staging and classification play an important reference value for doctors to choose treatment options. In recent years, based on the characteristics of ONFH in Chinese people, the academic community has proposed Chinese staging and China-Japan Friendship Hospital (CJFH) classification. The consensus also introduces them together with the international Association Research Circulation Osseous (ARCO) staging to provide guidance for individualized treatment of ONFH. In order to further standardize the diagnosis of ONFH and expand the treatment of ONFH, the Association Related to Circulation Osseous, Chinese Microcirculation Society (CSM-ARCO) organized domestic experts in the field of ONFH to jointly formulate the expert consensus, in order to provide reference for the standardized diagnosis of ONFH and the selection of individualized diagnosis and treatment techniques.

The influence of bone marrow edema for the assessment of the boundaries of necrotic lesions in patients with osteonecrosis of the femoral head

This study aimed to investigate the influence of bone marrow edema (BME) for the assessment of the boundaries of necrotic lesions using unenhanced and contrast-enhanced (CE) magnetic resonance (MR) images in patients with osteonecrosis of the femoral head (ONFH). We retrospectively reviewed 72 consecutive hips in 55 patients of ONFH that were Association Research Circulation Osseous (ARCO) stage III or higher and underwent both unenhanced and contrast-enhanced MR imaging between January 2005 and February 2016. The degree of extension of BMEs, and the boundaries of the necrotic lesions were compared using unenhanced and CE MR images on both mid coronal and mid oblique-axial slices. Forty-two percent of the coronal T1 images, 40% of the coronal fat-saturated T2 images, and 48% of the oblique-axial T1 images showed differences in the boundaries of necrotic lesion, by comparison with those of CET1-weighted MR images. The boundaries of necrotic lesions were clearly detected in all hips on CE coronal slices and 97% of all hips on CE oblique-axial slices. The BME grade in the difference group was significantly higher than in the non-difference group on the coronal plane (P = 0.0058). There were significant differences between the BME grade and duration from the onset of hip pain to MR imaging examination. Multivariate analyses revealed that the duration from the onset to MR imaging examination in both coronal (P = 0.0008) and oblique-axial slices (P = 0.0143) were independently associated with differences in the boundary of necrotic lesion between T1 and CET1-weighted MR images. Our findings suggest that unenhanced MR image may be insufficient for a precise assessment of the boundaries of the necrotic lesions for ONFH cases in the early phase of subchondral collapse due to the diffuse BME.

Posterior Pelvic Tilt in the Standing Position Might Be Associated with Collapse Progression in Post-Collapse Stage Osteonecrosis of the Femoral Head

OBJECTIVE

Excessive pelvic tilt has been reported to impair the biomechanical loading of the hip joint. However, the influence of pelvic tilt in osteonecrosis of the femoral head (ONFH) remains unclear. This study aims to assess whether sagittal pelvic posture in the standing position correlates with progression of femoral head collapse in post-collapse stage ONFH.

METHODS

This is a single-center retrospective study. We investigated 107 patients (107 hips; 73 males and 34 females; mean age, 48 years) diagnosed with Association of Research Circulation Osseous (ARCO) stage III ONFH at the first visit and who subsequently underwent surgical treatment in our institution from July 2016 to December 2020. The sagittal pelvic posture in the standing position before surgery was quantified as the angle formed by the anterior pelvic plane and the vertical z-axis in the sagittal view (APP angle). An APP angle <0° indicated posterior pelvic tilt. Progression of femoral head collapse was calculated as collapse speed. The following factors potentially associated with collapse speed were evaluated by exploratory data analysis followed with multiple linear regression analysis: sex, age, BMI, etiology, pelvic incidence, contralateral hip condition, time interval between the first visit and surgery, size of necrotic lesion, location of necrotic lesion, and APP angle.

RESULTS

As ONFH progressed from ARCO stage IIIA to stage IV, APP angle decreased significantly and continuously (stage IIIA, -0.2° ± 5.5°; stage IIIB, -3.7° ± 5.8°; stage IV, -7.1° ± 6.4°). The factors significantly associated with collapse speed were size of necrotic lesion (p = 0.0079), location of necrotic lesion (p = 0.0190), and APP angle (p < 0.0001). APP angle showed a negative correlation with collapse speed (r = -0.40, p < 0.0001). After stratifying by size of necrotic lesion (<50% and ≥50% involvement) and location of necrotic lesion (JIC type C1 and C2), a significant negative correlation was observed between APP angle and collapse speed in each group (JIC type C1 with <50% involvement, r = -0.69, p < 0.0001; JIC type C1 with ≥50% involvement, r = -0.58, p = 0.0475; JIC type C2 with <50% involvement, r = -0.51, p = 0.0124; JIC type C2 with ≥50% involvement, r = -0.39, p = 0.0286).

CONCLUSIONS

Our results suggest that posterior pelvic tilt in the standing position occurred as ONFH progressed from ARCO stage IIIA to stage IV, which might be associated with progression of femoral head collapse in ONFH.

Biomechanical research of medial femoral circumflex vascularized bone-grafting in the treatment of early-to-mid osteonecrosis of the femoral head: a finite element analysis

Purpose

Hip preservation therapy of early ONFH (Osteonecrosis of the femoral head) has emerged as one of the hot areas of research. We have optimized the procedure of traditional MFCVBG (medial femoral circumflex vascularized bone grafting) by using specialized surgical tools and used the finite element analysis to guide the implantation position of the bone flap during surgery and validate the biological mechanical stability of the modified MFCVBG.

Methods

This study was based on the data of a male patient with left hip (ARCO stage IIB, JIC type C) hormonal ONFH. Harris score (HHS), anteroposterior and lateral hip radiographs, frog position hip radiographs and SPECT/CT of femoral head flow imaging were performed postoperatively to evaluate clinical efficacy. The patient’s CT data were used to establish upper femur finite element model of the normal group, osteonecrosis group and postoperative group, respectively. The force on the femoral structure of each group was analyzed under four different loads in the gait cycle of 0.5 times the body weight (0.5 G, standing on two feet), 2.75 G (standing on one foot), 4 G (walking with the middle foot on the ground) and 7 G (walking with the toe off the ground) to validate the biological mechanical stability of the modified MFCVBG, predict femoral head collapse risk, simulate of the different healing conditions of postoperative bone flap, and analyze the postoperative effect of non-ideal surgical model.

Results

According to the follow-up results, the bone flap and the inner wall of decompression channel healed well, no osteonecrosis progression, no local collapse or micro-fracture occurred in the femoral head, and the articular surface was intact and the necrosis was well repaired. According to the result of the finite element analysis, compared with the osteonecrosis group, the overall stress and displacement peak of the upper femur and the cortical bone stress peak of the femoral head in the postoperative group and normal group were significantly reducing; modified MFCVBG can significantly improve the biomechanical stability of necrotic femoral head and reduce the risk of femoral head collapse; there was no obvious abnormal stress distribution in the greater trochanter and intertrochanter region after the flap was removed; the bone flap of the complete removal of necrotic focus + long bone flap group was directly placed at the bottom of the decompression passage, and the bone flap cortical bone can provide substantial mechanical support; in theory, patients can try to reduce the load with crutches or walking aids and carry out appropriate flat activities to effectively promote the early postoperative recovery.

Conclusions

The modified MFCVBG resulted in good efficacy, safety and feasibility. The necrotic focus should be completely removed during the operation, and the long bone flap should be placed directly under the subchondral bone. For patients with better bone healing ability, a more positive attitude can be taken to promote early postoperative weight-bearing.

Effect of trochanter displacement on impingement and bone contact in total hip arthroplasty performed after curved intertrochanteric varus osteotomy for osteonecrosis of the femoral head: a simulation study

Background

Curved intertrochanteric varus osteotomy (CVO) is a useful treatment option for osteonecrosis of the femoral head (ONFH). However, the effect of proximal femoral deformity in cases of CVO converted to total hip arthroplasty (THA) remains unclear. The aim of this study was to evaluate the effect of trochanter displacement on impingement and the contact state of the implant and femur in THA.

Methods

Thirty-eight hips that had undergone CVO for ONFH were reviewed and compared with a control group of 30 contralateral hips that had not undergone surgery. The range of motion (ROM) and impingement patterns and the percentage of cortical bone in the stem placement within the femur were measured by simulation using CT-based three-dimensional template software. We also measured the ROM and the number of joints that achieved the ROM required for activities of daily living when the upward displaced apex of the greater trochanter with osteotomy was resected and compared the findings with those obtained when the apex was not resected.

Results

The CVO group showed a significantly greater bony impingement in external rotation (68.4% vs. 43.3%, p = 0.033) and abduction (78.9% vs. 33.3%, p < 0.001) than in the control group. The CVO group showed a significantly smaller range of external rotation (19.0° [interquartile range; 4.0–28.8] vs. 38.0° [interquartile range; 36.0–41.8], p < 0.001) and abduction (23.0° [interquartile range; 8.5–38.8] vs. 56.0° [interquartile range; 50.3–60.0], p < 0.001) than in the control group. Significantly more joints achieved the ROM necessary for activities of daily living when the apex was resected than when it was not (10.5% vs. 63.2%, p < 0.001). The percentage of cortical bone in the stem placement position was significantly higher in the CVO group than in the control group in the proximal portion of the stem (25.5% vs. 0.0%, p < 0.001).

Conclusion

In cases requiring conversion to THA, we recommend resecting the upward displaced apex to achieve a sufficient ROM and carefully resecting the bone to avoid malignment of the stem.

The intraoperative hip range of motion in total hip arthroplasty predicts postoperative patient's satisfaction for cutting toenails and putting on sock

BACKGROUND

Restricted hip range of motion (ROM) has been proposed as a useful diagnostic tool for osteoarthritis. The relations between the intraoperative hip ROM under anesthesia in total hip arthroplasty (THA) and recovery of clinical mobility outcomes were unclear. This study evaluated the association between the intraoperative hip ROM under anesthesia in THA and the postoperative recovery of clinical mobility, including cutting toenails and putting on socks after THA.

METHODS

The study was performed as a prospective cohort study and included 93 hips in 85 patients who underwent primary anterior-based muscle-sparing THA in the supine position. The hip ROM was evaluated under anesthesia before skin incision and intraoperative stability test. The Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire (JHEQ) was evaluated. A questionnaire on whether and how patients could cut toenails and putting on socks was assessed. The relationship between hip ROM at intraoperative stability tests and JHEQ moving score, cutting toenails, and putting on socks scores were evaluated statistically.

RESULTS

We observed a week positive correlation between intraoperative hip ROM and the total of JHEQ mobility score. A moderate positive correlation was observed between external rotation angle with flexion 90°and cutting toenails and putting on socks score oh JHEQ. 94.6% and 96.8% of the patients could cut their toenails and putting on socks by themselves after surgery. The optimum cutoff range for high patient satisfaction for putting on socks and cutting toenails was 110° for flexion and 35°-40° for the external rotation angle in the intraoperative stability test.

CONCLUSION

Hip ROM during intraoperative stability testing, especially the external rotation angle can predict postoperative outcomes and patient satisfaction for cutting toenails and putting on socks. We suggested that the capsule or capsular ligament release around the hip was increased to provide sufficient ROM without compromising stability.