Precollapse Osteonecrosis Of The Femoral Head Research Articles

Efficacy of Modified Lightbulb Technique by Percutaneous Femoral Neck-Head Fenestration Combined With Compacted Artificial Bone Graft for Treating Precollapse Osteonecrosis of the Femoral Head

BackgroundWhether artificial bone provides comparable outcomes to autogenous bone has not been determined for osteonecrosis of the femoral head (ONFH). This study was conducted to compare the clinical outcomes of autogenous and artificial bone grafting (demineralized bone matrix/calcium sulfate [DBM/CaS]) through a modified lightbulb technique by percutaneous femoral neck-head fenestration for treating precollapse ONFH. MethodsA total of 73 Association Research Circulation Osseous Stage Ⅱ ONFH patients (81 hips) who had a mean follow-up of 61 months (range, 52 to 74) were included in this retrospective study. Among them were 40 hips treated with autogenous bone and 41 hips treated with DBM/CaS grafting through the percutaneous femoral neck-head fenestration. The Harris scores, radiographic progressions, clinical success rates, and survival analyses were analyzed. ResultsAt final follow-up, the mean Harris score was 80 points (range, 63 to 92) in the DBM/CaS group and 76 points (range, 69 to 91) in the autogenous bone group (P = .751). The radiographic progression rate was 29.9% in the DBM/CaS group, without significant difference from the autogenous bone group, which was 37.5% (P = .43). About 73.2% of patients in the DBM/CaS group and 75% in the autologous bone group avoided a total hip arthroplasty (P = .85). Survival analysis for femoral head protection revealed similar outcomes between the 2 groups (P > .05). ConclusionPercutaneous femoral neck-head fenestration combined with artificial bone (DBM/CaS) grafting had comparable clinical outcomes to autologous bone grafting on preventing femoral head collapse and rescuing THA at a mean of 61-month follow-up for treating early ONFH.

Long-term outcomes of conventional core decompression for osteonecrosis of the femoral head in systemic lupus erythematosus: a single-center retrospective study.

Although the therapeutic efficacy of conventional core decompression (CD) for the early-stage osteonecrosis (ON) has been widely investigated in the literature, no study to date has specifically focused on its therapeutic effect on the long-term outcome of ON of the femoral head (ONFH) in systemic lupus erythematosus (SLE). This study aimed to provide a long-term survival analysis of all hips that underwent conventional CD for the management of ONFH in a consecutive case series of patients with SLE. Sixteen hips of 10 consecutive SLE patients that underwent conventional CD for the management of ONFH in a single tertiary referral center were retrospectively identified and included in the study. After a retrospective chart review, several clinical and radiological data were recorded. All the hips treated with CD were stage I or IIA sclerotic and/or cystic based on the classification system of Ficat. Only the 2 hips of 1 patient (12.5%) survived both clinically and radiographically. The median overall survival for all hips after CD was 80 months (95% CI, 60-100). The 5-, 10-, and 15- year survival rates of hip joints following CD were 63%, 31%, and 12.5%, respectively (CI 95% 63.567 to 133.058 months). Conventional CD may not be effective in preventing the progression of pre-collapse ONFH to collapse and eventually end-stage osteoarthritis requiring arthroplasty in patients with SLE.

Intramedullary core decompression combined with endoscopic intracapsular decompression and debridement for pre-collapse non-traumatic osteonecrosis of the femoral head

BackgroundThe effect of core decompression on the treatment of pre-collapse non-traumatic osteonecrosis of the femoral head (ONFH) is still limited. This study aimed to explore the efficacy of core decompression combined with intra-articular decompression (debridement of the hip joint and incision of the hip capsule) under hip arthroscopic guidance in patients with pre-collapse ONFH.MethodsThe clinical data of 101 patients with pre-collapse ONFH were analysed retrospectively. Sixty patients (80 hips) received small-diameter multi-channel core decompression alone in first half review period (group B). Forty-one patients (59 hips) were treated with small-diameter multi-channel core decompression combined with intra-articular decompression under hip arthroscopy guidance in second half review period (group A). The surgical duration; intraoperative bleeding; intra-articular pressure(IAP) before and after surgery; length of hospital stay; hospitalisation expenses; visual analogue scale (VAS) score before, 1 week, 4 weeks, 3 months and 1 year after surgery; and Harris score of the hip joint before, 3 months and 1 year after surgery were recorded and compared between group A and group B. X-ray examination was performed every month to observe the collapse of the femoral head within 2 years after surgery, which was compared using the Kaplan–Meier survival curve analysis.ResultsWhen the two groups were compared, the surgical duration was longer and hospitalisation expenses were higher in group A than in group B (P < 0.05). However, the VAS score and the Harris score of the hip joint after surgery improved significantly compared with those before surgery (P < 0.05), which were more apparent in group A than in group B (P < 0.05). X-ray examination revealed that 6 hips in group A and 22 in group B received femoral head collapse at the 2-year follow-up. The survival rate of the femoral head in group A was significantly higher than that in group B (P < 0.05).ConclusionSmall-diameter multi-channel core decompression combined with intra-articular decompression (debridement of the hip joint and incision of the hip capsule) under hip arthroscopic guidance for treating early ONFH can more effectively alleviate joint pain, improve joint function and delay ONFH progression.

Convolutional Neural Network Algorithm Trained with Anteroposterior Radiographs to Diagnose Pre-Collapse Osteonecrosis of the Femoral Head

A convolutional neural network (CNN) is a representative deep-learning algorithm that has a significant advantage in image recognition and classification. Using anteroposterior pelvic radiographs as input data, we developed a CNN algorithm to determine the presence of pre-collapse osteonecrosis of the femoral head (ONFH). We developed a CNN algorithm to differentiate between ONFH and normal radiographs. We retrospectively included 305 anteroposterior pelvic radiographs (right hip: pre-collapsed ONFH = 79, normal = 226; left hip: pre-collapsed ONFH = 62, normal = 243) as data samples. Pre-collapsed ONFH was diagnosed using pelvic magnetic resonance imaging data for each patient. Among the 305 cases, 69.8% of the included data samples were randomly selected as the training set, 21.0% were selected as the validation set, and the remaining 9.2% were selected as the test set to evaluate the performance of the developed CNN algorithm. The area under the curve of our developed CNN algorithm on the test data was 0.912 (95% confidence interval, 0.773–1.000) for the right hip and 0.902 (95% confidence interval, 0.747–1.000) for the left hip. We showed that a CNN algorithm trained using pelvic radiographs would help diagnose pre-collapse ONFH.

Multiple Drilling with Recombinant Human Bone Morphogenetic Protein-2 in Korean Patients with Non-Traumatic Osteonecrosis of the Femoral Head: A Prospective Randomized Pilot Study with a Minimum Two-Year Follow-Up.

We sought to determine whether multiple drilling (MD) combined with the injection of recombinant human bone morphogenetic protein-2 (rhBMP-2) and β-tricalcium phosphate (β-TCP) could improve survival of the femoral head in pre-collapse lesions of non-traumatic osteonecrosis of the femoral head (ONFH) as compared with MD alone. We conducted a single-site, off-label, comparative and prospective cohort study between November 2017 and May 2019. We enrolled 25 hips (25 patients) with non-traumatic ONFH (Ficat–Arlet stage 2A or less). We performed a survival analysis, and the primary outcome was the occurrence of femoral head collapse on follow-up radiograph. Our cohort consisted of 11 men and 9 women of age 52.5 ± 8.8 years and a body mass index of 24.3 ± 3.0 kg/m2. The femoral heads were preserved in 9 hips (45.0%) and collapsed in 11 hips (55.0%) at the final follow-up; mean survival to collapse was 6.9 (range 2.8–13.5) months. There were no significant differences in the survival of the femoral head between the MD alone group and the MD with rhBMP-2 and β-TCP group (five hips survived, 50% vs. four hips survived, 40%, respectively; p = 0.83). MD combined with the injection of rhBMP-2 and β-TCP did not improve femoral head survival compared to MD alone in the pre-collapse non-traumatic ONFH lesion.

Clinical results of free vascularized fibula graft in the management of precollapse osteonecrosis of the femoral head: A retrospective clinical study.

This study aimed to evaluate clinical results, femoral head survival, and the need for total hip arthroplasty (THA) in patients with precollapse osteonecrosis of the femoral head (OFH) (Steinberg stage II and III) treated by free vascularized fibula graft (FVFG) application. We retrospectively reviewed 54 hips of 47 patients (39 males, eight females; mean age 36 ± 14 years) who underwent FVFG due to OFH, with at least two years of follow-up. The patient data, including Harris Hip Score (HHS), Visual Analogue Scale (VAS), and conversion to THA, were documented. The right hip of 26 patients and the left hip of 28 patients were involved. Bilateral FVFG surgery was performed on seven patients due to bilateral OFH. The mean follow-up time was 5.5 (range 2-14) years. Survival of the femoral head was observed in 39 hips (72.2%), while the femoral head collapse was observed in 15 femoral heads (27.8%). The mean preoperative HHS increased from 46.5 (range=12-85) to 86.5 (range=33-100) postoperatively (P < 0.001). The mean preoperative VAS score improved from 8.2 (range=2-10) to 1.3 (range=0-10) postoperatively (P < 0.001). THA was performed on seven hips at a mean follow-up time of 1.8 years (range=0.7-3.3). There was no significant difference in the collapse rate between unilateral or bilateral OFH (P=0.175). A higher survival rate was observed in the Steinberg stage II femoral head patients compared to the stage III femoral head (P=0.021). This study has shown that FVFG surgery can be a good option for managing patients with Steinberg stage II and III precollapse OFH to prevent femoral head collapse and joint function. Level IV, Therapeutic Study.

Combining frog-leg lateral view may serve as a more sensitive X-ray position in monitoring collapse in osteonecrosis of the femoral head

ABSTRACTLoad-bearing capacity of the bone structures of anterolateral weight-bearing area plays an important role in the progressive collapse in osteonecrosis of the femoral head (ONFH). The purpose of this study is to assess the efficacy of combined evaluation of anteroposterior (AP) and frog-leg lateral (FLL) view in diagnosing collapse. Between December 2016 and August 2018, a total of 478 hips from 372 patients with ONFH (268 male, 104 female; mean age 37.9 ± 11.4 years) were retrospectively evaluated. All patients received standard AP and FLL views of hip joints. Japanese Investigation Committee (JIC) classification system was used to classify necrotic lesion in AP view. Anterior necrotic lesion was evaluated by FLL view. All patients with pre-collapse ONFH underwent non-operative hip-preserving therapy. The collapse rates were calculated and compared with Kaplan–Meier survival analysis with radiological collapse as endpoints. Forty-four (44/478, 9.2%) hips were classified as type A, 65 (65/478, 13.6%) as type B, 232 (232/478, 48.5%) as type C1 and 137 (137/478, 28.7%) as type C2. Three hundred cases (300/478, 62.5%) were collapsed at the initial time point. Two hundred and twenty six (226/300, 75.3%) hips and 298 (298/300, 99.3%) hips collapse were identified with AP view and FLL view, respectively. An average follow-up of 37.0 ± 32.0 months was conducted to evaluate the occurrence of collapse in 178 pre-collapse hips. Collapses occurred in 89 hips (50.0%). Seventy-seven (77/89, 86.5%) hips were determined with AP view alone and 85 (85/89, 95.5%) hips were determined with the combination of AP and FLL views. The collapse rates at five years were reported as 0% and 0%, 16.2% and 24.3%, 58.3% and 68.1% and 100% and 100% according to AP view alone or combination of AP and FLL views for types A, B, C1 and C2, respectively. The collapse can be diagnosed more accurately by combination of AP and FLL views. Besides, JIC type A and type B ONFH can be treated with conservative hip preservation, but pre-collapse type C2 ONFH should be treated with joint-preserving surgery. Type C1 needs further study to determine which subtype has potential risk of collapse.

Lateral pillar is the key in supporting pre-collapse osteonecrosis of the femoral head: a finite element model analysis of propensity-score matched cohorts

BackgroundThis study was designed as a cohort study using propensity-score matching to age, gender, and body mass index (BMI) for finite element model (FEM) analysis from pre-collapse CT images of collapsed and non-collapsed hips. Through FEM analysis, a global graphical output around the hip joint can provide simple impression of stress distribution: concentration or dispersion.MethodsA total of 32 hips with ARCO stage 2 or 3 ONFH who were on follow up for over a one-year period were retrospectively reviewed. 16 hips with no interval progression of collapse were set as the study group, then 16 hips with progression of collapse which required arthroplasty were set as the control group using propensity-score matching. FEM was generated through Mechanical Finder for each patient, then 4500 N of load was applied to 1000 mm2 area at the top of iliac crest to analyze the models in terms of equivalents for yield stress.ResultsAge, sex, and BMI had no significant differences between the two groups, while location (p = 0.015) was lateral, and size (p = 0.015) was significantly greater in the collapsed group. Non-collapsed hips mostly exhibited stress dispersion allocated to medial and lateral pillars, while collapsed hips exhibited stress concentration focused on the lateral pillar and the primary compression trabecula. (p = 0.001).ConclusionThrough FEM analysis, stress concentration to the lateral pillar and the primary compression trabeculae can be used to predict future collapse in ONFH with high probability. Results provide a simple and intuitive, yet valuable information to aid surgeons. Therefore, especially for young patients, holding out the lateral pillar through joint preserving procedures might be the key in preventing further collapse.

Core Decompression Combined with Intraosseous Ibandronate for Pre-collapse Osteonecrosis of the Femoral Head: Report of a Novel Technique, its Safety and Early Outcomes in Five Cases.

Background:Core decompression (CD) is an effective method in the management of pre-collapse stage of osteonecrosis of the femoral head (ONFH). It has been combined with various adjuvants to increase the efficacy including bone marrow aspirate concentration and platelet rich plasma. We evaluated a cheaper alternative in the form of ibandronate as an adjuvant to CD and to highlight the technique, safety, and early outcomes.Methods:The patients in the age group of 18–60 presenting with atraumatic ONFH in the pre-collapse stage were included in the study. The patients were followed up to a period of 1 year and evaluated in terms of radiologic progression and functional outcome (Modified Harris Hip Score [MHHS] and Visual Analog Scale [1]).Results:The study included six hips in five patients (three females and two males) ranging from 18 to 57 years. There was no sign of stage progression or collapse on radiography. The average post-operative MHHS was 87.4 (73.7-96.7) while VAS score improved from 2.8 to 1.3 postoperatively (p=0.00395).Conclusion:The use of ibandronate as an adjuvant with CD shows promise. It is safe and provides good clinical improvement and is a cheaper alternative. However, the interpretation is limited due to the small number of patients and short duration of follow-up.

Comparison of cell therapy and other novel adjunctive therapies combined with core decompression for the treatment of osteonecrosis of the femoral head

AimsThe value of core decompression (CD) in the treatment of osteonecrosis of the femoral head (ONFH) remains controversial. We conducted a systematic review and meta-analysis to evaluate whether CD combined with other treatments could improve the clinical and radiological outcomes of ONFH patients compared with CD alone.MethodsWe searched the PubMed, Embase, Web of Science, and Cochrane Library databases until June 2020. All randomized controlled trials (RCTs) and clinical controlled trials (CCTs) comparing CD alone and CD combined with other measures (CD + cell therapy, CD + bone grafting, CD + porous tantalum rod, etc.) for the treatment of ONFH were considered eligible for inclusion. The primary outcomes of interest were Harris Hip Score (HHS), ONFH stage progression, structural failure (collapse) of the femoral head, and conversion to total hip arthroplasty (THA). The pooled data were analyzed using Review Manager 5.3 software.ResultsA total of 20 studies with 2,123 hips were included (CD alone = 768, CD combined with other treatments = 1,355). The combination of CD with other therapeutic interventions resulted in a higher HHS (mean difference (MD) = 6.46, 95% confidence interval (CI) = 2.10 to 10.83, p = 0.004) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score (MD = −10.92, 95% CI = -21.41 to -4.03, p = 0.040) and a lower visual analogue scale (VAS) score (MD = −0.99, 95% CI = -1.56 to -0.42, p < 0.001) than CD alone. For the rates of disease stage progression, 91 (20%) progressed in the intervention group compared to 146 (36%) in the control group (odds ratio (OR) = 0.32, 95% CI = 0.16 to 0.64, p = 0.001). In addition, the intervention group had a more significant advantage in delaying femoral head progression to the collapsed stage (OR = 0.32, 95% CI = 0.17 to 0.61, p < 0.001) and reducing the odds of conversion to THA (OR = 0.35, 95% CI = 0.23 to 0.55, p < 0.001) compared to the control group. There were no serious adverse events in either group. Subgroup analysis showed that the addition of cell therapy significantly improved clinical and radiological outcomes compared to CD alone, and this approach appeared to be more effective than other therapies, particularly in precollapse (stage I to II) ONFH patients.ConclusionThere was marked heterogeneity in the studies. There is a trend towards improved clinical outcomes with the addition of stem cell therapy to CD.Cite this article: Bone Joint Res 2021;10(7):445–458.

Femoral head collapse rate among Japanese patients with pre-collapse osteonecrosis of the femoral head.

ObjectiveIn this study, we aimed to elucidate the relationship between the duration from diagnosis to femoral head collapse and the collapse rate among patients with pre-collapse osteonecrosis of the femoral head (ONFH).MethodsIn this retrospective, observational, multicenter study, we analyzed 268 patients diagnosed with ONFH and classified them using the Japanese Investigation Committee classification. The primary endpoint was duration from the time of diagnosis to femoral head collapse for each type of ONFH.ResultsThe 12-, 24-, and 36-month collapse rates among participants were 0%, 0%, and 0% for type A, respectively; 0%, 2.0%, and 10.8% for type B, respectively; 25.5%, 40.8%, and 48.5% for type C-1, respectively; and 57.4%, 70.3%, and 76.7% for type C-2 ONFH, respectively. A comparison of unilateral and bilateral ONFH, using Kaplan–Meier survival curves demonstrated similar collapse rates.ConclusionsThe lowest collapse rate was observed for ONFH type A, followed by types B, C-1, and C-2. Additionally, a direct association was observed between the collapse rate and location of the osteonecrotic lesion on the weight-bearing surface.

Recombinant Human Fibroblast Growth Factor-2 Treatment to Prevent Femoral Head Collapse in Patients With Osteonecrosis of the Femoral Head: Trion, a Single-Arm, Historical Control, Multicenter, Phase II Trial

Background: Osteonecrosis of the femoral head (ONFH) is a rare disease requiring joint replacement even in young patients due to progressive femoral head collapse. Regenerative medicine is considered the next treatment of interest to prevent collapse. Methods: We percutaneously administered gelatin hydrogel containing 800-µg recombinant human fibroblast growth factor-2 (rhFGF-2) [TRION] to 64 patients with nontraumatic, precollapse, and large ONFHs. Using the endpoint of radiological collapse, we analyzed the joint-preservation period of the historical control comprising patients with nonsurgically treated ONFH. The primary outcome was an expected collapse rate <35% (joint-preservation rate ≥ 65%) at 24 months after rhFGF-2 treatment. We compared the joint-preservation duration with that of an exactly matched historical control (1:1), with radiological collapse as the endpoint. Secondary outcomes were changes in two validated clinical scores (Harris Hip Score [HHS], University of California, Los Angeles [UCLA] score), bone regeneration assessment, and safety. Findings: From 02.17.2016 to 12.07.2016, 64 patients underwent rhFGF-2 treatment. Of the 63 eligible patients, 7 discontinued the trial and were analyzed as worsened cases. The collapse rate was 42 ·9% at 24 months posttreatment. Under the exact matching analyses, median joint-preservation time was significantly higher in the rhFGF-2 group (45·8 months) than in the control group (11·1 months), with a hazard ratio of 2·6 (95% CI 1·5–4·5; p = 0·0003). The ONFHs tended to improve with bone regeneration to smaller ONFHs, according to the postoperative images. The postoperative clinical scores significantly improved, with an increase of 0·15/month for HHS (95% CI 0·03–0·29; p = 0·008) and 0·06/month for UCLA score (95% CI 0·04–0·08; p < 0·0001). 13 serious adverse events were recorded, these cases showed recovery. Interpretation: Our study suggests that rhFGF-2 treatment increases joint-preservation time with clinical efficacy, radiological bone regeneration, and safety. Clinical Trial Registration Details: University Hospital Medical Information Network clinical trials registry (number, UMI20340). Funding Information: Japan Agency for Medical Research and Development. Declaration of Interests: This investigator-initiated trial was supported by competitive grants from the Japan Agency for Medical Research and Development. rhFGF-2 was provided by Kaken Pharmaceutical Co. (Tokyo, Japan). The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Ethics Approval Statement: Conducted in accordance with the latest regulatory requirements, including the Declaration of Helsinki and the International Council for Harmonisation - Good Clinical Practice regulations. Approved by the institutional review board or ethics committee of each hospital (Approval number, K023). All patients in TRION provided written informed consent.

Modified Kerboul Angle Predicts Outcome of Core Decompression With or Without Additional Cell Therapy

BackgroundCore decompression is the most common procedure for early-stage osteonecrosis of the femoral head (ONFH). This study investigated outcomes of core decompression with/without bone marrow aspirate concentrate (BMAC), based on the Kerboul combined necrotic angles using magnetic resonance imaging. MethodsWe reviewed 66 patients (83 hips) with early ONFH, Association Research Circulation Osseous stages I-IIIa, who underwent core decompression alone (26 patients, 33 hips) or in combination with BMAC (40 patients, 50 hips). Survival rate and progressive collapse were analyzed using the Kaplan-Meier method, and conversion to total hip arthroplasty (THA) was evaluated. Subgroup analyses based on the modified Kerboul angle were performed: grade I (<200°), grade II (200°-249°), grade III (250°-299°), and grade IV (≥300°). ResultsMean follow-up was 36 ± 23 months. Femoral head collapse with BMAC (16 hips, 32%) was significantly lower than without BMAC (19 hips, 58%, P = .019). Conversion THA was significantly lower with BMAC (28%) than without (58%, P = .007). Survival rates among groups showed significant differences (P = .017). In grade I, 0/12 hips with BMAC collapsed while 3/9 (33%) without BMAC collapsed (P = .063); in grade II, 2/16 hips (12%) with BMAC collapsed while 7/13 (54%) without BMAC collapsed (P = .023). There was no significant difference in collapse with (64%) or without (82%) BMAC in grade III-IV hips (P = .256). ConclusionCore decompression with/without BMAC had a high failure rate, by increasing disease progression and the necessity for THA, for combined necrotic angles >250°. In our study, addition of BMAC had more reliable outcomes than isolated core decompression for precollapse ONFH if the combined necrotic angles were <250°.

Endoscopic observation finding in the core decompression procedure of osteonecrosis of femoral head and effect of additional treatments.

To observe necrotic findings of the femoral head through the endoscopic examination when performing the decompression procedure widely used in the treatment of osteonecrosis of femoral head. To assess the efficacy of injection of bone marrow aspirated from the iliac crest and new vascularized bone graft into the core of femoral head based on the endoscopic findings. The first stage of osteonecrosis of femoral head based on ARCO classification includes 23, second stage 36, and third stage eightfemoral heads. Bone marrow transplantations have been performed in 49 hip joints and new vascularized bone grafts in 18 hip joints. The endoscopic findings of osteonecrosis of femoral heads are varied, and they can be divided into fivecategories. The average time in core decompression and bone marrow injection was 15minutes, and the average time of new pedicled bone grafts was 65minutes (45-90minutes). The efficacy of bone marrow injection was 93.88%, and the efficacy of vascularized bone graft was 94.44% when performed based on the endoscopic findings. It is possible to increase the treatment efficacy of the osteonecrosis of the femoral head when appropriate additional treatments are applied based on endoscopic findings in the decompression procedures of pre-collapse osteonecrosis of the femoral head.

Recombinant human FGF-2 therapy for osteonecrosis of the femoral head: 5-year follow-up.

Aim: To evaluate the 5-year outcomes from the prospective study of recombinant human FGF-2 (rhFGF-2) for osteonecrosis of the femoral head (ONFH). Methods: Ten patients (average age 39.8years) with nontraumatic, precollapse ONFH were percutaneously administered with 800μg rhFGF-2 contained in gelatin hydrogel. Radiological changes and the prevalidated Harris hip score (HHS), visual analogue scalefor pain and University of California, Los Angeles activity-rating scale scoring systems were evaluated. Results: The 5-year comparison in type C2 showed higher joint preservation in the rhFGF-2 group (71.4%) than in the natural course group (15.4%). Two of three clinical scores (Harris hip score and visual analogue scale for pain) improved significantly. Postoperative MRIdemonstrated significant reduction in ONFH size. There were no adverse events. Conclusion: rhFGF-2 treatment for ONFH appears to be safe and effective and may have the potential to prevent disease progression.

Is bone mineral density lower in the necrotic lesion in pre-collapse osteonecrosis of the femoral head?

The purpose of this study was to clarify whether bone mineral density (BMD) of the necrotic lesion in precollapse osteonecrosis of the femoral head (ONFH) is reduced according to Hounsfield unit (HU) values on computed tomography (CT). The superior one-third of the femoral head in the coronal section was set as the region of interest (ROI) for the measurement of HU values. First, HU values of 101 control participants were assessed to identify relevant confounding factors. Next, the relationship between HU values and BMD on dual-energy X-ray absorptiometry (DXA) was verified. Then the mean HU value of the ROI in patients with pre-collapse ONFH was compared with that in propensity score-matched control participants. Finally, the HU values of the lateral boundary in the patients with and without subsequent collapse were compared. Multivariable analysis showed that both age and BMI were significantly correlated with the HU value, which showed a strong correlation with the BMD of the femoral neck on DXA (r = 0.92). In 25 ONFH patients and 25 propensity-matched control participants, no significant difference was found in the HU value of the ROI (p = .54). The mean HU value of the lateral boundary in patients with subsequent collapse was found to be significantly higher than that in patients without subsequent collapse (p < .01). The assessment of HU values on CT was useful for the evaluation of BMD of the femoral head. The current assessment did not demonstrate reduced bone mineral density of the necrotic lesion in pre-collapse ONFH.

Did Osteoblastic Cell Therapy Improve the Prognosis of Pre-fracture Osteonecrosis of the Femoral Head? A Randomized, Controlled Trial.

In patients with nontraumatic osteonecrosis of the femoral head (ONFH), implantation of bone marrow aspirate concentrate (BMAC) could delay the progression of osteonecrosis and improve symptoms in pre-fracture ONFH. However, the BMAC content, especially in osteoblastic stem cells, could have an important individual variability. An autologous osteoblastic cell product could improve the effect of such cell-based therapy. (1) Does autologous osteoblastic cell therapy decrease the likelihood of progression to subchondral fracture with or without early collapse corresponding to Association Research Circulation Osseous (ARCO) classification Stage III or higher, and provide a clinically important pain improvement compared with BMAC treatment alone? (2) Were patients treated with osteoblastic cell therapy less likely to undergo subsequent THA? (3) What proportion of patients in the treatment and control groups experienced adverse events after surgery? Between 2004 and 2011, we treated 279 patients for Stage I to II hip osteonecrosis (ON) with surgery. During that time, our general indications for surgery in this setting included non-fracture ON lesions. To be eligible for this randomized, single-blind trial, patients needed to have an ONFH Stage I or II; we excluded those with traumatic ONFH, hemoglobinopathies and positive serology for hepatitis B, C or HIV. Of those treated surgically for this diagnosis during the study period, 24% (67) agreed to participate in this randomized trial. Hips with pre-fracture ONFH were randomly treated with a core decompression procedure associated with either implantation of a BMAC (BMAC group; n = 26) or osteoblastic cell (osteoblastic cell group; n = 30). The groups were not different in terms of clinical and imaging characteristics. The primary study outcome was treatment response, defined as the absence of progression to subchondral fracture stage (ARCO stage III or higher) plus a clinically important pain improvement defined as 1 cm on a 10-cm VAS. The secondary endpoint of interest was the frequency in each group of subsequent THA and the frequency of adverse events. The follow-up duration was 36 months. We used an as-treated analysis (rather than intention-to-treat) for our efficacy endpoint, and an intention-to-treat analysis for adverse events. Overall, 26 of 26 patients in the BMAC group and 27 of 30 in the osteoblastic cell group completed the trial. At 36 months, no clinically important differences were found in any study endpoint. There was no difference in the proportion of patients who had progressed to fracture (ARCO stage III or higher; 46% of the BMAC hips [12 of 26] versus 22% in the hips with osteoblastic cells [six of 27], hazard ratio, 0.47 [95% CI 0.17 to 1.31]; p = 0.15). There was no clinically important difference in VAS pain scores. No differences were found for either the WOMAC or the Lequesne indexes. With the numbers available, there was no difference in the proportion of patients in the groups who underwent THA at 36 months 15% (four of 27) with osteoblastic cells versus 35% (nine of 26) with BMAC; p = 0.09 With the numbers available, we found no differences between the treatment and control groups in terms of the frequencies of major adverse events. We found no benefit to osteoblastic cells over BMAC in patients with pre-collapse ONFH; side effects were uncommon and generally mild in both groups. This study could be used as pilot data to help determine sample sizes for larger (presumably multicenter) randomized controlled trials. However, this novel treatment cannot be recommended in routine practice until future, larger studies demonstrate efficacy. Level II, therapeutic study.

Prediction of Collapse Using Patient-Specific Finite Element Analysis of Osteonecrosis of the Femoral Head.

ObjectiveTo develop a prediction method for femoral head collapse by using patient‐specific finite element analysis of osteonecrosis of the femoral head (ONFH).MethodsThe retrospective study recruited 40 patients with ARCO stage‐II ONFH (40 pre‐collapse hips). Patients were divided into two groups according to the 1‐year follow‐up outcomes: patient group without femoral head collapse (noncollapse group, n = 20) and patient group with collapse (collapse group, n = 20). CT scans of the hip were performed for all patients once they joined the study. Patient‐specific finite element models were generated based on these original CT images following the same procedures: segmenting the necrotic lesion and viable proximal femur, meshing the computational models, assigning different material properties according to the Hounsfield unit distribution, simulating the stress loading of the slow walking gait, and measuring the distribution of the von Mises stress. Receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive performance of the maximum level of the von Mises stress. The optimal cut‐off value was selected based on the Youden index and the corresponding predictive accuracy was reported as well.ResultsThe mean level of the maximum von Mises stress in the collapse group was 2.955 ± 0.539 MPa, whereas the mean stress level in the noncollapse group was 1.923 ± 0.793 MPa (P < 0.01). ROC analysis of the maximum von Mises stress found that the area under the ROC curve was 0.842 (95% CI: 0.717–0.968, P < 0.01). The maximum Youden index was 0.60, which corresponded to two optimal cut‐off values: 2.7801 MPa (sensitivity: 0.70; specificity: 0.90; predictive accuracy: 80.00%; LR+: 7), and 2.7027 MPa (sensitivity: 0.75; specificity: 0.85; predictive accuracy: 77.50%; LR+: 5).ConclusionFinite element analysis is a potential method for femoral head collapse prediction among pre‐collapse ONFH patients. The maximum level of the von Mises stress on the weight‐bearing surface of the femoral head could be a good biomechanical marker to classify the collapse risk. The collapse prediction method based on patient‐specific finite element analysis is, thus, suitable to apply to clinical practice, but further testing on a larger dataset is desirable.

Performance of a Deep Learning Algorithm in Detecting Osteonecrosis of the Femoral Head on Digital Radiography: A Comparison With Assessments by Radiologists.

OBJECTIVE. The objective of our study was to compare the sensitivity of a deep learning (DL) algorithm with the assessments by radiologists in diagnosing osteonecrosis of the femoral head (ONFH) using digital radiography. MATERIALS AND METHODS. We performed a two-center, retrospective, noninferiority study of consecutive patients (≥ 16 years old) with a diagnosis of ONFH based on MR images. We investigated the following four datasets of unilaterally cropped hip anteroposterior radiographs: training (n = 1346), internal validation (n = 148), temporal external test (n = 148), and geographic external test (n = 250). Diagnostic performance was measured for a DL algorithm, a less experienced radiologist, and an experienced radiologist. Noninferiority analyses for sensitivity were performed for the DL algorithm and both radiologists. Subgroup analysis for precollapse and postcollapse ONFH was done. RESULTS. Overall, 1892 hips (1037 diseased and 855 normal) were included. Sensitivity and specificity for the temporal external test set were 84.8% and 91.3% for the DL algorithm, 77.6% and 100.0% for the less experienced radiologist, and 82.4% and 100.0% for the experienced radiologist. Sensitivity and specificity for the geographic external test set were 75.2% and 97.2% for the DL algorithm, 77.6% and 75.0% for the less experienced radiologist, and 78.0% and 86.1% for the experienced radiologist. The sensitivity of the DL algorithm was noninferior to that of the assessments by both radiologists. The DL algorithm was more sensitive for precollapse ONFH than the assessment by the less experienced radiologist in the temporal external test set (75.9% vs 57.4%; 95% CI of the difference, 4.5-32.8%). CONCLUSION. The sensitivity of the DL algorithm for diagnosing ONFH using digital radiography was noninferior to that of both less experienced and experienced radiologist assessments.

Differences in magnetic resonance findings between symptomatic and asymptomatic pre-collapse osteonecrosis of the femoral head

PurposeThe purpose of this study was to assess the differences in magnetic resonance (MR) findings between the symptomatic and asymptomatic pre-collapse stage of osteonecrosis of the femoral head (ONFH). Materials and methodsThis study reviewed 123 consecutive hips in 91 patients in the pre-collapse stage of ONFH based on plain radiographic findings. These 123 hips were divided into symptomatic and asymptomatic groups according to the pain domain score in the Harris hip score system. Bone marrow edema (BME), synovial fluid effusion, and subchondral fracture were evaluated using MR imaging. Odds ratios (ORs) were calculated between these three parameters and symptoms. The subsequent clinical course after MR examination was also assessed for each hip that could be followed more than 1 year. ResultsForty-six hips (37.4%) were categorized as symptomatic and 77 hips (62.6%) as asymptomatic. The prevalence of BME, synovial fluid effusion, and subchondral fracture were 87.0% (40/46), 80.4% (37/46), and 34.8% (16/46), respectively, in the symptomatic group, and 0%, 28.6% (22/77), and 0%, respectively, in the asymptomatic group, indicating significant differences between the two groups (p < 0.0001). Among these parameters, BME showed the highest OR with regard to the presence or absence of symptoms (BME, 965.8; joint effusion, 10.3; subchondral fracture, 83.9). Due to persistent pain and subsequent collapse, 30 of 35 (85.7%) symptomatic hips with BME subsequently underwent surgical treatment at a mean interval of 3.47 months after MR examination, while 25 of 66 (37.9%) asymptomatic hips without BME underwent surgical treatment at a mean interval of 20.7 months after MR examination. ConclusionsThis study demonstrated that symptomatic pre-collapse ONFH diagnosed based on plain radiographic findings could be distinguished from asymptomatic pre-collapse ONFH by the presence of BME on MR imaging, and thus BME may be a sign of occult fracture.