Determining lesion size in osteonecrosis of the femoral head

Mesenchymal Stem Cell Therapy for Bone Repair of Human Hip Osteonecrosis with Bilateral Match-Control Evaluation: Impact of Tissue Source, Cell Count, Disease Stage, and Volume Size on 908 Hips

We investigated the impact of mesenchymal stem cell (MSC) therapy on treating bilateral human hip osteonecrosis, analyzing 908 cases. This study assesses factors such as tissue source and cell count, comparing core decompression with various cell therapies. This research emphasizes bone repair according to pre-treatment conditions and the specificities of cell therapy in osteonecrosis repair, indicating a potential for improved bone repair strategies in hips without femoral head collapse. This study utilized a single-center retrospective analysis to investigate the efficacy of cellular approaches in the bone repair of osteonecrosis. It examined the impact on bone repair of tissue source (autologous bone marrow concentrate, allogeneic expanded, autologous expanded), cell quantity (from none in core decompression alone to millions in cell therapy), and osteonecrosis stage and volume. Excluding hips with femoral head collapse, it focused on patients who had bilateral hip osteonecrosis, both pre-operative and post-operative MRIs, and a follow-up of over five years. The analysis divided these patients into seven groups based on match control treatment variations in bilateral hip osteonecrosis, primarily investigating the outcomes between core decompression, washing effect, and different tissue sources of MSCs. Younger patients (<30 years) demonstrated significantly better repair volumes, particularly in stage II lesions, than older counterparts. Additionally, bone repair volume increased with the number of implanted MSCs up to 1,000,000, beyond which no additional benefits were observed. No significant difference was observed in repair outcomes between different sources of MSCs (BMAC, allogenic, or expanded cells). The study also highlighted that a 'washing effect' was beneficial, particularly for larger-volume osteonecrosis when combined with core decompression. Partial bone repair was the more frequent event observed, while total bone repair of osteonecrosis was rare. The volume and stage of osteonecrosis, alongside the number of injected cells, significantly affected treatment outcomes. In summary, this study provides comprehensive insights into the effectiveness and variables influencing the use of mesenchymal stem cells in treating human hip osteonecrosis. It emphasizes the potential of cell therapy while acknowledging the complexity and variability of results based on factors such as age, cell count, and disease stage.

Prognosis of hip osteonecrosis after cell therapy with a calculator and artificial intelligence: ten year collapse-free survival prediction on three thousand and twenty one hips

PURPOSE

Several reports have identified prognostic factors for hip osteonecrosis treated with cell therapy, but no study investigated the accuracy of artificial intelligence method such as machine learning and artificial neural network (ANN) to predict the efficiency of the treatment. We determined the benefit of cell therapy compared with core decompression or natural evolution, and developed machine-learning algorithms for predicting ten year collapse-free survival in hip osteonecrosis treated with cell therapy. Using the best algorithm, we propose a calculator for "prognosis hip osteonecrosis cell therapy (PHOCT)" accessible for clinical use.

METHODS

A total of 3145 patients with 5261 osteonecroses without collapses were included in this study, comprising 1321 (42%) men and 1824 (58%) women, with a median age of 34 (12-62) years. Cell therapy was the treatment for 3021 hips, core decompression alone for 1374 hips, while absence of treatment was the control group of 764 hips. First, logistic regression and binary logistic regression analysis were performed to compare results of the three groups at ten years. Then an artificial neural network model was developed for ten year collapse-free survival after cell therapy. The models' performances were compared. The algorithms were assessed by calibration, and performance, and with c-statistic as measure of discrimination. It ranges from 0.5 to 1.0, with 1.0 being perfect discrimination and 0.5 poor (no better than chance at making a prediction).

RESULTS

Among the 3021 hips with cell therapy, 1964 hips (65%) were collapse-free survival at ten years, versus 453 (33%) among those 1374 treated with core decompression alone, and versus 115 (15%) among 764 hips with natural evolution. We analyzed factors influencing the prediction of collapse-free period with classical statistics and artificial intelligence among hips with cell therapy. After selecting variables, a machine learning algorithm created a prognosis osteonecrosis cell therapy calculator (POCT). This calculator proved to have good accuracy on validation in these series of 3021 hip osteonecroses treated with cell therapy. The algorithm had a c-statistic of 0.871 suggesting good-to-excellent discrimination when all the osteonecroses were mixed. The c-statistics were calculated separately for subpopulations of categorical osteonecroses. It retained good accuracy, but underestimated ten year survival in some subgroups, suggesting that specific calculators could be useful for some subgroups. This study highlights the importance of multimodal evaluation of patient parameters and shows the degree to which the outcome is modified by some decisions that are within a surgeon's control, as the number of cells to aspirate, the choice of injecting in both the osteonecrosis and the healthy bone, the choice between unilateral or bilateral injection, and the possibility to do a repeat injection.

CONCLUSION

Many disease conditions and the heterogeneities of patients are causes of variation of outcome after cell therapy for osteonecrosis. Predicting therapeutic effectiveness with a calculator allows a good discrimination to target patients who are most likely to benefit from this intervention.

MsgeCNN: Multiscale geometric embedded convolutional neural network for ONFH segmentation and grading

BACKGROUND

The incidence of osteonecrosis of the femoral head (ONFH) is increasing gradually, rapid and accurate grading of ONFH is critical. The existing Steinberg staging criteria grades ONFH according to the proportion of necrosis area to femoral head area.

PURPOSE

In the clinical practice, the necrosis region and femoral head region are mainly estimated by the observation and experience of doctor. This paper proposes a two-stage segmentation and grading framework, which can be used to segment the femoral head and necrosis, as well as to diagnosis.

METHODS

The core of the proposed two-stage framework is the multiscale geometric embedded convolutional neural network (MsgeCNN), which integrates geometric information into the training process and accurately segments the femoral head region. Then, the necrosis regions are segmented by the adaptive threshold method taking femoral head as the background. The area and proportion of the two are calculated to determine the grade.

RESULTS

The accuracy of the proposed MsgeCNN for femoral head segmentation is 97.73%, sensitivity is 91.17%, specificity is 99.40%, dice score is 93.34%. And the segmentation performance is better than the existing five segmentation algorithms. The diagnostic accuracy of the overall framework is 90.80%.

CONCLUSIONS

The proposed framework can accurately segment the femoral head region and the necrosis region. The area, proportion, and other pathological information of the framework output provide auxiliary strategies for subsequent clinical treatment.

Hip Arthroscopy and Core Decompression for Avascular Necrosis of the Femoral Head Using a Specific Aiming Guide: A Step-by-Step Surgical Technique

Avascular necrosis of the femoral (AVN) head is a disabling disease that affects function, mobility, and quality of life in the young adult. Its pathology involves blood circulation disruption of the femoral head and subchondral infarction. This leads to cartilage thinning, femoral head depression, and cartilage breakage, which results in hip osteoarthritis. In the past decade the prevalence of intraarticular pathology has been almost 95%, this revealed with hip arthroscopy (HA). HA and core decompression (CD) of the femoral head can be used effectively and concomitantly to treat AVN with excellent results, HA allows for excellent visualization of the hip joint cartilage, allowing treatment of femoroacetabular impingement syndrome (FAIS) and intra-articular pathology. Our technique demonstrates that retrograde core decompression with allograft and mixed bone matrix is an excellent choice of treatment in the early stages of AVN/ONFH. The femoral head-specific aiming guide is very reliable, is simple to use arthroscopically if placed in the posterolateral portal of the hip, and offers exact pin placement at the necrotic site, as well as less operative time and less radiation to the patient and surgical team.

Multiple drilling is not effective in reducing the rate of conversion to Total hip Arthroplasty in early-stage nontraumatic osteonecrosis of the femoral head: a case-control comparative study with a natural course

BACKGROUND

To determine whether multiple drilling is effective in postponing the need for total hip arthroplasty (THA) in early-stage nontraumatic osteonecrosis of the femoral head (ONFH).

METHODS

We identified 514 patients who were diagnosed with early-stage ONFH between January 2008 and December 2018. One hundred ninety-six patients underwent multiple drilling, and 318 patients had a natural course of progression. One hundred fifty-nine patients were selected for each group after case-control matching for preoperative demographics and modified Ficat and Arlet stage. The rates of THA conversion were compared. We also performed Cox regression to identify risk factors associated with THA conversion in patients who underwent multiple drilling.

RESULTS

Kaplan-Meier survivorship with an endpoint of THA for nontraumatic reasons were not significantly different between the multiple drilling group (75.6, 95% confidence interval 67.8-83.4%) and the natural course group (72.2, 95% confidence interval 64.8-79.6%) at 5 years (log-rank, P = .191). In the Cox regression model, a larger extent of necrotic lesion, bone marrow edema (BME), and higher postoperative work intensity significantly increased the risk of THA conversion (P < .05). Among patients treated with autogenous bone grafting, there was a lower risk of failure in patients with necrotic lesion less than 15% (P < .05).

CONCLUSIONS

Multiple drilling is not effective in reducing the rate of THA conversion in early-stage nontraumatic ONFH. The risk of conversion to THA after multiple drilling is increased by a larger extent of necrotic lesion, presence of BME, and higher postoperative work intensity in patients with early-stage ONFH.

TRIAL REGISTRATION

The trial was registered in the Chinese Clinical Trial Registry ( ChiCTR2000035180 ) dated 2 August 2020.

Frog leg lateral view is a reliable predictor of the prognosis in osteonecrosis of the femoral head

The location and size of necrotic lesions are primary factors that predict the prognosis in osteonecrosis of the femoral head (ONFH). The Japanese Investigation Committee (JIC) classification system, based on the location of the necrotic lesion, has been widely accepted and applied around the world. However, there is no report about whether the location of the necrotic area in lateral view may affect the prognosis predicted initially by the JIC classification. The purpose of this study was to investigate whether the location of the necrotic area in the frog leg lateral (FL) view would affect the prediction of prognosis for patients with ONFH. We retrospectively studied 90 hips in 76 patients with ONFH (Ficat stage I to II) after a mean follow-up of 35.3 months. All patients received standard radiographs including an anteroposterior (AP) and a FL view of the affected hip. The percentage of the necrotic area (necrotic area/whole femoral head area) was measured and compared between AP and FL view. Hips with ONFH were categorized using the JIC classification and the FL view type system, and inter- and intraobserver reliability was compared between them. All patients underwent personalized hip physiotherapy, and the cumulative survival rate with subsequent collapse and/or requirement for further hip surgery as the endpoints was evaluated for the two classification systems. The percentage of the necrotic area was found to be significantly greater in the FL views (47.0 ± 1.5%) than that in the AP views (37.7 ± 1.7%, P < .01). Intraobserver reliability in the JIC classification (mean: 0.91, range: 0.85-0.98) was higher than that in the FL view type (mean: 0.77, range: 0.63-0.89; P < .01), as well as the interobserver reliability in the JIC classification (mean: 0.74, range: 0.38-0.87) was higher than that in the FL view type (mean: 0.58, range: 0.31-0.76; P < .01). Comparisons of survival curves showed that type III in FL view type had the worst prognosis than other two divisions, following the type II. The type I was likely to gain optimal outcomes. These findings provide evidence that the location to which necrosis extended in the FL view is a reliable indicator in predicting the prognosis of ONFH.

Surgical treatments of atraumatic avascular necrosis of the shoulder

Humeral head atraumatic avascular necrosis is a rare diagnosis. It concerns young patients with a high functional demand. The treatments are mostly surgical. The radiographic classification of Cruess assesses the severity of the humeral head avascular necrosis and guides surgical indications. This chapter reports a review of the literature based on meta-analyses and clinical series. Surgical treatments may be conservative or prosthetic. Conservative treatments include core decompression, bone grafting and arthroscopic debridement. Prosthetic replacements are performed by resurfacing, hemiarthroplasty or total arthroplasty. For low-grade asvascular necrosis, core decompression may be functionally effective and doesn't impair later surgical procedures. For high grades, prosthetic replacements achieve good functional outcomes. Hemiarthroplasty should be preferred if the glenoid cartilage is intact, with low rates of wear complications and better long-term outcome than shoulder arthroplasty.

Evidence-Supported HBO Therapy in Femoral Head Necrosis: A Systematic Review and Meta-Analysis

Although many studies have shown that hyperbaric oxygen (HBO) therapy can significantly improve symptoms and quality of life of patients affected by femoral head necrosis, this therapy is not worldwide approved yet. This meta-analysis was performed to evaluate its clinical effect. Relevant studies published before May 2020 were systematically searched using terms related to HBO and femoral head necrosis. Fixed and random-effects models were used to estimate the odds ratio (OR) with 95% confidence intervals (CI). Subgroup analyses and publication bias tests were carried out to explore potential study heterogeneity and bias. Ten studies involving 353 controls and 368 HBO-treated cases were included, most of which were conducted on Asian population. The clinical effect in the HBO therapy group was 3.84 times higher than in the control group (OR = 3.84, 95% CI (2.10, 7.02), p < 0.00001). Subgroup analyses showed that the clinical effect of HBO therapy was statistically significant in the Asian subpopulation which represented most of the subjects (OR = 3.53, 95% CI (1.87, 6.64), p < 0.00001), but not in the non-Asian subpopulation, probably because of insufficient numerosity (OR = 7.41, 95% CI (0.73, 75.71), p = 0.09). The results of this meta-analysis suggest that patients with femoral head necrosis treated with HBO therapy can achieve a significant clinical improvement.

Hip survival after plain core decompression alone versus bone morphogenetic protein and/or bone marrow reinjection with core decompression for avascular osteonecrosis of the femoral head: a retrospective case control study in ninety two patients

INTRODUCTION

Injecting bone marrow or bone morphogenetic protein 7 (BMP) during core decompression for avascular osteonecrosis (AVN) may improve survival. We hypothesized that adding a complementary technique (injection of BMP and/or non-concentrated bone marrow) to core decompression would reduce the number of patients requiring a subsequent total hip arthroplasty (THA).

METHODS

We retrospectively reviewed 92 cases from 2003 to 2018 with a minimum of 2 years of follow-up and an average follow-up of 64 months (24-204). Twenty-four patients had a core decompression (CD) (26.1% (24/92)), 25 had a CD associated with reinjection of bone marrow and BMP (rhBMP7) (27.2% (25/92)), and 43 patients had a CD with bone marrow reinjection (46.7% (43/92)).

RESULTS

Hip survival after CD was 66.3% (61/92) at two years and 59.8% (55/92) at 10 years. CD with bone marrow and BMP reinjection had a better hip survival at ten years (HR: 0.492 (CI95%: 0.254-0.952) p = 0.035). A volume of necrosis greater than 30% (HR = 12.97 (CI95 [3.88-43.3] (p < 0.001))) and a Kerboul angle greater than 60° (HR: 12.5 (CI95 [2.84-54.6] (p < 0.001))) were risk factors for a subsequent THA.

CONCLUSIONS

CD is an interesting non-invasive technique to preserve the native hip after AVN of the femoral head. Reinjection of bone marrow and/or BMP improved CD hip survival.

Primary total hip replacement in Ficat-Arlet stage 3 and 4 osteonecrosis: a retrospective study at a minimum 12-year follow-up

INTRODUCTION

Results of total hip replacement (THR) for aseptic osteonecrosis are controversial and conflicting according to implant type and generation. The present study consisted in a retrospective assessment of implant survival in primary THR for aseptic osteonecrosis, using a cemented stem, standard polyethylene press-fit acetabular component, and metal-metal bearing. The study hypothesis was that THR results are equivalent between aseptic osteonecrosis and osteoarthritis of the hip.

MATERIAL AND METHOD

A single-center retrospective study included 54 patients with metal-on-metal THR for femoral head osteonecrosis. The main endpoint was revision surgery for all causes, whether implant related or procedure related; secondary endpoints were complications and progression in clinical scores.

RESULTS

Mean follow-up was 13.9 ± 1.6 years (range 12.0-17.1 years). Eighteen of the 54 patients (33.3%) died. Implant survival at last follow-up was 93.8% (95% CI, 87.1-100). There were 12 complications (22.2%): 1 intraoperative, 5 (9.3%) immediate postoperative, and 6 (11.1%) long term. Clinical assessment found a significant 43.1 point improvement in mean Harris score (p = 8.4E-33) and a 5.6 point improvement in mean PMA score (p = 2.9E-22).

CONCLUSION

Survival in primary THR for aseptic osteonecrosis was good. Follow-up needs to be rigorous to screen for onset of complications. Primary THR is thus justified in Ficat-Arlet stage 3 and 4 aseptic osteonecrosis of the hip.

LEVEL OF EVIDENCE

IV.

Classification systems of hip osteonecrosis: an updated review

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

QUESTIONS/PURPOSES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

Level III, diagnostic study.

Cell therapy versus simultaneous contralateral decompression in symptomatic corticosteroid osteonecrosis: a thirty year follow-up prospective randomized study of one hundred and twenty five adult patients

PURPOSE

Symptomatic osteonecrosis related to corticosteroids has a high risk of progression to collapse in absence of treatment. The purposes of this study were to evaluate the results of autologous bone marrow grafting of the symptomatic hip in adult patients with osteonecrosis and to compare the results with core decompression alone in the contralateral symptomatic hip.

MATERIALS AND METHODS

A total of 125 consecutive patients (78 males and 47 females) with bilateral osteonecrosis (ON) and who had both hips symptomatic and at the same stage on each side (stage I or II) were included in this study from 1988 to 1998. The volume of osteonecrosis was measured with MRI in both hips; the smaller size ON was treated with core decompression, and the contralateral hip with the larger ON was treated with percutaneous mesenchymal cell (MSC) injection obtained from bone marrow concentration. The average total number of MSCs (counted as number of colony forming units-fibroblast) injected in each hip was 90,000 ± 25,000 cells (range 45,000 to 180,000 cells).

RESULTS

At the most recent FU (average 25 years after the first surgery, range 20 to 30 years), among the 250 hips included in the study, 35 hips (28%) had collapsed at the most recent follow-up after bone marrow grafting, and 90 (72%) after core decompression (CD). Ninety-five hips (76%) in the CD group underwent total hip replacement and 30 hips (24%) in the bone marrow graft group (p < 0.0001). Hips undergoing only CD were approximately three times more likely to undergo a primary THA (odds ratio: 10.0278; 95% CI: 5.6117 to 17.9190; p < 0.0001) as compared with hips undergoing an initial bone marrow grafting. For the 90 hips treated with bone marrow injection and without collapse, the mean volume of repair evaluated by MRI at the most recent follow-up was 16.4 cm³ (range 12 to 21 cm³) corresponding to a decrease of the pre-operative average volume from 22.4 cm³ (range 35-15 cm³) to 6 cm³ (range 12-0 cm³); as percentage of the volume of the femoral head, the decrease moved from 44.8 to 12%.

CONCLUSION

Core decompression with bone marrow injection improved the outcome of the disease as compared with core decompression alone in the same patient.

Lesion size measurement in femoral head necrosis

BACKGROUND

Management of patients with early stages of osteonecrosis of the femoral head remains controversial. Uniform use of an effective method of evaluation and classification, including both stage and lesion size, would allow for comparison and would significantly improve treatment of patients. There is no consensus on how best to determine lesion size. The purpose of this study was to evaluate and compare accuracy and ease of use of different techniques for determining the size of femoral head lesions.

METHODS

Twenty-five hips with stages I or II osteonecrosis were evaluated with radiographs and MRI. 3-D MRI measurements of lesion size were used as the standard against which to compare visual estimates and angular measurements: necrotic angle of Kerboul, index of necrosis, and adjusted index of necrosis.

RESULTS

3-D measurements (necrotic volume) showed regular progression from 2.2 to 59.2% of the femoral head. There was a rough correlation with angular measurements; index of necrosis was closer than the necrotic angle. Visual estimates from serial MRI images were as accurate as angular measurements.

CONCLUSIONS

Simple visual estimates of lesion size from serial MRI images are reasonably accurate and are satisfactory for clinical use. Angular measurements provide some indication of prognosis and treatment; however, they have limited accuracy, with considerable variability between techniques. 3-D MRI volumetric measurements are the most accurate. Using current techniques and software, they are easier to use, requiring similar time and effort to angular measurements. They should be considered for clinical research and publications when the most accurate measurements are required.

Hip resurfacing arthroplasty in treatment of avascular necrosis of the femoral head

Background

Hip resurfacing is a conservative type of total hip arthroplasty but its use is controversial, especially in patients with osteonecrosis. The aim of this study was analysis of the clinical and radiographic outcomes of hip resurfacing in patients with osteonecrosis.

Material/Methods

Between 2007 and 2008, 30 hip resurfacing arthroplasties were performed due to osteoarthritis secondary to avascular necrosis of femoral head staged as Ficat III and IV.

Patients were qualified to resurfacing arthroplasty when the extent of avascular necrosis using Kerboul’s method was <200° and the angle between avascular necrosis and head-neck junction was >20°. All patients were evaluated clinically and radiologically before and 60 months after the operation.

Results

The mean Harris Hip Score (HHS) score increased from 47.8 to 94.25 (p<0.05). Physical activity level (University of California, Los Angeles activity score – UCLA activity score) improved from 3.7 to 7.55 (p<0.05). No implant migration was observed.

Conclusions

Management of osteonecrosis of the hip with resurfacing arthroplasty seems to be effective in strictly-selected patients.

Analysis of altered microRNA expression profile in the reparative interface of the femoral head with osteonecrosis

The reparative reaction is considered to be important during the occurrence of collapse in the femoral head with osteonecrosis (ONFH), but little is known about the long-term reparative process. The aim of this study was to determine and analyze the altered microRNA expression profile in the reparative interface of ONFH, and further validate the expression of the involved genes in the predicted pathways. Microarray analysis was performed comparing the reparative interface of patients with ONFH and normal tissue of patients with fresh femoral neck fracture (FNF) and partly validated by real-time PCR. Potential target genes of differentially expressed miRNAs were predicted by TargetScan and miRanda, and the target genes were used for further bioinformatics analysis such as Gene Ontology and Pathway assay. The filtered miRNAs and genes in the predict pathways were further examined by real-time PCR in another 6 independent ONFH patients. Among the 2578 miRNAs identified, 17 were consistently differentially expressed, 12 of which are up-regulated and 5 down-regulated. GO classification showed that the predicted target genes of these miRNAs are involved in signal transduction, cell differentiation, methylation, cell growth and apoptosis. The Kyoto Encyclopedia of Genes and Genomes (KEGG) classification indicated that these genes play a role in angiogenesis and Wnt signaling pathways. The expression of miR-34a and miR-146a and genes in the predict pathways were significantly up-regulated. This study presented a global view of miRNA expression in the reparative interface of osteonecrosis. In addition, our data provided novel and robust information for further researches in the pathogenesis and molecular events of ONFH.

How do radiologists evaluate osteonecrosis?

OBJECTIVES

Management of patients with osteonecrosis of the hip remains controversial and challenging. Because the prognosis and treatment are determined in large part by the stage and extent of the disease, it is important to use a reliable and efficient method for evaluation and staging. The objective of this study was to determine how musculoskeletal (MSK) radiologists evaluate osteonecrosis and whether this evaluation is adequate.

MATERIALS AND METHODS

A 12-part questionnaire was designed to determine how MSK radiologists evaluate patients with osteonecrosis of the femoral head (ONFH). This was sent to 888 members of the Society of Skeletal Radiology.

RESULTS

One hundred and twenty-one members responded to essentially all questions. Patients were evaluated using plain radiographs and MRI. All agreed that it is clinically important to determine the extent of necrosis and joint involvement, and 115 (95 %) stated that this should be part of the radiologists' evaluation. However, only 55 (46 %) said that in practice they used a specific system of classification, and most of these used the Ficat and Arlet classification, which does not indicate the extent of involvement. One hundred and seven (88 %) respondents included a simple visual estimate of the extent of involvement, and a small number added a specific measurement of lesion size. The majority indicated that they were infrequently consulted about which imaging studies should be obtained.

CONCLUSIONS

Although radiologists recognize the clinical importance of determining the extent of necrosis and joint involvement in patients with ONFH, in practice the methods used to evaluate these patients often do not accomplish this satisfactorily. The use of an effective classification, which includes both stage and extent of involvement, should be stressed, as it will lead to improved treatment of patients with ON. Physicians who order imaging studies for patients with ON should be encouraged to consult routinely with their radiology colleagues regarding which studies to request, as well as on the interpretation of these studies.

Are we evaluating osteonecrosis adequately?

PURPOSE

It is well recognised that to evaluate a patient with osteonecrosis of the femoral head (ONFH) adequately, it is necessary that the size of the infarct and the extent of femoral head joint involvement be indicated, in addition to the type or stage of the pathological process. The purpose of this study was to determine whether patients with ONFH are being evaluated adequately in studies published during the past 25 years and to see if any trends can be identified.

METHODS

Articles describing treatment of patients with ONFH, published between 1985 and 2011, were reviewed to determine the methods used to indicate the type and extent of pathology present on radiographs and magnetic resonance imaging (MRI) studies. The classification systems cited were identified and divided between those which indicated only the stage and those which indicated both stage and extent of involvement.

RESULTS

In 208 studies published between 1985 and 2011, specific classification systems were cited 237 times. During this period, non-quantitative systems, which only indicate stage, were cited 139 times (59 %) and quantitative systems, which indicate both stage and extent of involvement were cited 77 times (32 %). Between 2006 and 2011, non-quantitative systems were cited 30 times (48 %) and quantitative systems were cited 27 times (44 %).

CONCLUSIONS

During the past 25 years there has been a trend towards the use of more comprehensive and effective methods of evaluating patients with ONFH. However, during the past five years, approximately half of the published studies continued to use limited, non-quantitative methods of evaluation. This should be brought to the attention of the orthopaedic community. Future investigations and publications on ONFH should employ comprehensive methods of classification which include not only the stage of disease but also measurements of the size of the necrotic segment and the extent of femoral head and joint involvement.

Humeral head resurfacing in central bone defects: in vitro stability of different implants with increasing defect size

We examined the rotary motions of two distinct cementless surface replacement arthroplasties of the shoulder that were implanted on humeri with central spherical bone defects of 8%, 17%, and 37% of the head volume (n = 5 each). Rotary motions were measured under a cyclic torque application and translated into relative micromotions. Implant A with a perforated central crown had micromotions < 150 µm in all bony defects and during all simulated shoulder activities. Implant B with a central tapered tri-fin pin had no micromotions > 150 µm in defects of 0% and 8% during a strenuous activity like lifting 10 kg, but did exhibit micromotion > 150 µm in 40% of the experiments in defects of 17% and 37%, which could impair bony ingrowth. Implant B displayed a significant increase in micromotions for defects of 8% and 17% (p < 0.05). Our results suggest that implant A could be used without risk in spherical head defects up to 37% of volume, even in strenuous shoulder activities immediately after its implantation. Implant B, however, is recommended in spherical defects starting from 8% and only during light shoulder activities until bony integration of the implant has occurred.

Treatment of early stage osteonecrosis of the femoral head with autologous implantation of bone marrow-derived and cultured mesenchymal stem cells

BACKGROUND

Treatment of early-stage osteonecrosis of the femoral head (ONFH) with autologous implantation of iliac crest bone marrow-derived mononuclear cells, which contain tens of thousands of bone marrow mesenchymal stem cells (BMMSCs), recently achieved a promising outcome.

METHODS

One hundred patients with early-stage ONFH were recruited and randomly assigned to BMMSC treatment or core decompression (CD) treatment. Each BMMSC-treated hip received femoral head (FH) implantation of 2×10(6) autologous subtrochanteric bone marrow-derived and ex vivo expanded BMMSCs. The radiographic stage of ONFH according to the Association Research Circulation Osseous classification, Harris hip score (HHS), and the volume of the necrotic lesion or the low signal intensity zone (LowSIZ) in the FH were assessed before and 6, 12, 24, and 60 months after the initial operation.

RESULTS

Sixty months after the operation, only 2 of the 53 BMMSC-treated hips progressed and underwent vascularized bone grafting. In CD group, 7 hips lost follow-up, and 10 of the rest 44 hips progressed and underwent vascularized bone grafting (5 hips) or total hip replacement (5 hips). Compared with the CD group, BMMSC treatment significantly improved the HHS as well as decreased the volume of femoral head LowSIZ of the hips preoperatively classified at stage IC, IIB, and IIC (P<0.05, respectively; stage IIA, P=0.06, respectively). No complication was observed in both treatment groups.

CONCLUSIONS

Ex vivo expansion of autologous BMMSCs can reliably provide a greater number of BMMSCs for FH implantation. This intervention is safe and effective in delaying or avoiding FH collapse, which may necessitate total hip replacement.

Inter-observer and intra-observer reliabilities of the Japanese Ministry of Health, Labor and Welfare type classification system for osteonecrosis of the femoral head

The aim of this study was to clarify the reproducibility of the Japanese Ministry of Health, Labor and Welfare (JMHLW) type classification for osteonecrosis of the femoral head. We performed inter-observer and intra-observer trials using 40 sets of magnetic resonance imagings, 20 of which were produced by a 0.5 Tesla (T) superconductive unit and the other 20 produced by a 1.5 T unit, in patients with non-collapsed and asymptomatic osteonecrosis of the femoral head (JMHLW stage 1 or 2). The JMHLW type classification (A, B, C1, or C2) was determined from T1-weighted coronal images at the center of the femoral head. Six orthopedic surgeons independently assessed all 40 images twice, with an interval of 4-5 weeks between sessions. Regarding inter-observer reliability, the percent agreement was 85% and weighted kappa was 0.709 for 0.5 T, versus a percent agreement of 82% and weighted kappa of 0.724 for 1.5 T. Regarding intra-observer reliability, the percent agreement was 82% and weighted kappa was 0.780 for 0.5 T versus a percent agreement of 80% and weighted kappa of 0.800 for 1.5 T. Inter-observer and intra-observer reliabilities did not differ significantly between the 0.5 and 1.5 T units. The JMHLW type classification provided high inter-observer and intra-observer reliabilities.

Hip resurfacing after failed free vascularized fibular graft

Metal-on-metal resurfacing of the hip is a bone sparing arthroplasty that may be an option when a head-sparing nonarthroplasty option fails. We present the first published report of 5 cases of failed free vascularized fibular graft treated with modern hip resurfacing arthroplasty. This selected group of patients had avascular necrosis with less than 20% head involvement and cysts less than 1 cm in diameter. Follow-up ranging from 2 to 5 years (mean, 38 months) showed improvement in hip function without evidence of prosthesis loosening. There were no femoral neck fractures or revisions. A vascularized fibular bone graft does not prevent good early results with hip resurfacing but may add technical complexity owing to its position within the femoral head and neck.

The use of alendronate in the treatment of avascular necrosis of the femoral head

The use of bisphosphonates in the treatment of avascular necrosis of the femoral head is an encouraging but relatively new option with most published data being derived from small trials with limited follow-up. We present a clinicoradiological analysis of 395 hips with avascular necrosis which were treated with oral alendronate for three years with a mean follow-up of four years (1 to 8).

Our results show an improvement in the clinical function, a reduction in the rate of collapse and a decrease in the requirement for total hip replacement, compared with the findings of other studies in which no treatment was given. This improvement is particularly marked if the treatment is begun in the pre-collapse stages of the disease. Even in Ficat stage-III hips some benefit was obtained from treatment with alendronate by at least a delay in the need for total hip replacement.

Outcome measures for evaluation of treatments for osteonecrosis

With the advent of cell-based therapies, biologics, and pharmaceuticals for the potential treatment of osteonecrosis, it is important to conduct evaluations using scientifically accepted outcomes measures. For the treatment of osteonecrosis, most studies have focused on pain relief, surgery, or the need for surgery, disease progression (advancing stage), and change in lesion size. Quantification of imaging techniques continue to gain in sophistication but have not yet been validated for use in clinical trials. Despite recent interest in using biomarkers or genetic markers in the diagnosis and analysis of disease progression, more research is needed to determine the sensitivity and specificity of these techniques with respect to osteonecrosis.

Untreated asymptomatic hips in patients with osteonecrosis of the femoral head

Because there is no consensus regarding the factors predicting femoral head collapse in asymptomatic osteonecrosis of the hip, we studied the risk factors for collapse. Between 1990 and 2000, we used MRI to confirm asymptomatic osteonecrosis of the femoral head in 81 patients (81 hips) whose other hip had nontraumatic symptomatic osteonecrosis and we monitored them prospectively. The minimum followup was 5 years (mean, 8.3 years; range, 5-16 years). At the latest followup, 31 hips (38%) were symptomatic and 26 hips (32%) had collapsed. The mean interval between diagnosis and collapse was 4.1 years. We observed no correlation between femoral head collapse and patients' age, gender, weight, presumed cause of osteonecrosis, or length of followup. With combined factors, only extent of large necrotic lesion (hazard ratio, 4.06; 95% confidence interval, 1.29-12.77) and location of Type C2 necrotic lesion (hazard ratio, 6.35; 95% confidence interval, 1.18-34.11) predicted collapse.

Untreated asymptomatic hips in patients with osteonecrosis of the femoral head

Because there is no consensus regarding the factors predicting femoral head collapse in asymptomatic osteonecrosis of the hip, we studied the risk factors for collapse. Between 1990 and 2000, we used MRI to confirm asymptomatic osteonecrosis of the femoral head in 81 patients (81 hips) whose other hip had nontraumatic symptomatic osteonecrosis and we monitored them prospectively. The minimum followup was 5 years (mean, 8.3 years; range, 5-16 years). At the latest followup, 31 hips (38%) were symptomatic and 26 hips (32%) had collapsed. The mean interval between diagnosis and collapse was 4.1 years. We observed no correlation between femoral head collapse and patients' age, gender, weight, presumed cause of osteonecrosis, or length of followup. With combined factors, only extent of large necrotic lesion (hazard ratio, 4.06; 95% confidence interval, 1.29-12.77) and location of Type C2 necrotic lesion (hazard ratio, 6.35; 95% confidence interval, 1.18-34.11) predicted collapse.