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. Cite this article: Bone Joint Res 2024;13(6):294–305

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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).

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To investigate whether idiopathic osteonecrosis of the femoral head (ONFH) is related to impaired osteoblast activities.

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We compared the clinical outcomes of curved intertrochanteric varus osteotomy (CVO) with bone impaction grafting (BIG) with CVO alone for the treatment of osteonecrosis of the femoral head (ONFH).

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The purpose of this study was to examine whether leg-length discrepancy (LLD) following unilateral total hip arthroplasty (THA) affects the incidence of contralateral head collapse and subsequent THA in patients with bilateral osteonecrosis, and to determine factors associated with subsequent collapse.

Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides with limited coding potential, which have emerged as novel regulators in many biological and pathological processes, including growth, development, and oncogenesis. Accumulating evidence suggests that lncRNAs have a special role in the osteogenic differentiation of various types of cell, including stem cells from different sources such as embryo, bone marrow, adipose tissue and periodontal ligaments, and induced pluripotent stem cells. Involved in complex mechanisms, lncRNAs regulate osteogenic markers and key regulators and pathways in osteogenic differentiation. In this review, we provide insights into the functions and molecular mechanisms of lncRNAs in osteogenesis and highlight their emerging roles and clinical value in regenerative medicine and osteogenesis-related diseases.

Cite this article: J. Zhang, X. Hao, M. Yin, T. Xu, F. Guo. Long non-coding RNA in osteogenesis: A new world to be explored. Bone Joint Res 2019;8:73–80. DOI: 10.1302/2046-3758.82.BJR-2018-0074.R1.

Non-traumatic osteonecrosis of the femoral head is a potentially devastating condition, the prevalence of which is increasing. Many joint-preserving forms of treatment, both medical and surgical, have been developed in an attempt to slow or reverse its progression, as it usually affects young patients. However, it is important to evaluate the best evidence that is available for the many forms of treatment considering the variation in the demographics of the patients, the methodology and the outcomes in the studies that have been published, so that it can be used effectively. . The purpose of this review, therefore, was to provide an up-to-date, evidence-based guide to the management, both non-operative and operative, of non-traumatic osteonecrosis of the femoral head. . Cite this article: Bone Joint J 2017;99-B:1267–79

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Transtrochanteric rotational osteotomy (TRO) is performed for young patients with non-traumatic osteonecrosis of the femoral head (ONFH) to preserve the hip. We aimed to investigate the long-term outcomes and the risk factors for failure 15 years after this procedure.

Introduction. A transtrochanteric curved varus osteotomy (TCVO) is an excellent joint preserving surgical modality if the necrotic lesion can be moved to the non-weight bearing area as assessed by maximum abduction antero-posterior radiographs. The purpose of this article was to elucidate whether TCVO can reduce the volume of osteonecrosis after an index osteotomy as assessed by magnetic resonance imaging (MRI). Methods. Twenty patients (twenty hips) with non-traumatic osteonecrosis of the femoral head were followed for more than three years after an index operation and MRI examinations both before and at two years after surgery were retrospectively investigated. The average age at the time of operation was 40 years (range, 18 to 60 years), consisting of 13 men (13 hips) and 7 women (7 hips). The etiology and/or associated risk factors was steroid-associated osteonecrosis in 11 hips, alcohol associated in 7 hips, and idiopathic in 2. According to the classification of the Japanese Investigation Committee there was Type B in one hip, Type C-1 in 17 hips, and Type C-2 in 2 hips. Eight hips were in Stage 2, 10 in Stage 3A, and 2 in Stage 3B. Average follow-up was 4 years (range, 3 to 5 years). Results. The average varus angle was 26.5 degrees (range, 15 to 35 degrees), and the average leg length shortening was 11.8 millimeters (range, 2.5 to19 millimeters). The pre-operative average Harris hip score improved from 68 points to 97 points three years after TCVO. The bone union of the osteotomy was obtained at an average of 4 months (range, 3 to 8 months). A progression to collapse of the femoral head was observed in three hips. The pre-operative average necrotic volume by MRI was 12.8 cm. 3. (range, 6.4 to 20.9 cm. 3. ) and at two years after surgery the average necrotic volume significantly decreased to 9.2 cm. 3. (range, 1.7 to 16.3 cm. 3. ). Conclusion. The volume of osteonecrosis of the femoral head significantly decreased at two years after TCVO. The early clinical and radiographic results of TCVO were satisfactory

Introduction. The purpose of this study was to investigate the long-term outcome of Sugioka's transtrochanteric rotational osteotomy (TRO) for nontraumatic osteonecrosis of the femoral head. Methods. Seventy-eight patients (87 hips) were consecutively treated by TRO from 1989 to 1994. All patients followed 15 years or more were included. Four patients (4 hips) with traumatic osteonecrosis and five patients (5 hips) followed less than 15 years were excluded. A total of 69 patients (78 hips) were included. Average age at the time of operation was 42 years. There were 51 men (57 hips) and 18 women (21 hips). The average follow-up was 17 years (range, 15 to 20 years). Type of osteonecrosis was as follows: Type B; 2 hips, Type C1; 50 hips, and Type C2; 26 hips. Stage was as follows: stage 2; 29 hips, stage 3A; 34 hips, stage 3B; 13 hips, and stage 4; 2 hips. Transtrochanteric anterior rotational osteotomy was performed in 76 hips and posterior rotational osteotomy was performed in 2 hips. Clinical evaluation was evaluated by Harris hip score. Kaplan-Meier survivorship analysis was performed based on the end point of conversion to total hip arthroplasty (THA) or re-collapse. Results. Twenty-nine hips (37.2%) were converted to THA, and 38 hips (48.7%) were re-collapsed. Average Harris hip score before operation was improved from 67 to 82 points at final follow-up. The reasons for conversion to THA within five years after osteotomy were cervical fracture or fixation failure, and 10 years after osteotomy progression of osteoarthritis due to re-collapse. Kaplan-Meier survivorship at 10 years after surgery was 69.2% (95% confidence interval: 58.8-79.6) and 15 years after surgery was 61.3% (95% CI: 49.9-72.7) with THA as the end-point. Kaplan-Meier survivorship at 10 years after surgery 50.0% (95% CI: 38.6-61.4) and at 15 years after surgery 50.0% (95% CI: 38.6-61.4) when re-collapse was defined as the end point. Type C1 was significantly better than Type C2. There was no significant difference between the corticosteroid-induced and non-corticosteroid-induced patients. There was no significant difference between the patients with early and late stage. Conclusion. The long-term outcome of transtrochanteric rotational osteotomy for osteonecrosis of the femoral head was excellent. Sixty-three percent of the hips were not converted to THA. Type C2 was a significant risk factor for TRO

The introduction of a trabecular tantalum rod has been proposed for the management of early-stage osteonecrosis of the femoral head but serves as a single-point of support of the necrotic lesion. We describe a technique using two or three 4.2 mm (or later 4.7 mm) tantalum pegs for the prevention of collapse of the necrotic lesion. We prospectively studied 21 patients (26 hips) with non-traumatic osteonecrosis of the femoral head treated in this manner. Of these, 21 patients (24 hips) were available for radiological and clinical evaluation at a mean follow-up of 46 months (18 to 67). Radiological assessment showed that only eight hips deteriorated according to the Association Research Circulation Osseous classification, and four hips according to the Classification of the Japanese Investigation Committee of Health and Welfare. Functional improvement was obtained with an improvement in the mean Harris hip score from 65.2 (33.67 to 95) to 88.1 (51.72 to 100), the mean Merle D’Aubigné-Postel score from 13 (6 to 18) to 16 (11 to 18), a mean visual analogue score for pain from 5.2 (0 to 9.5) to 2.6 (0 to 7), and the mean Short-Form 36 score from 80.4 (56.8 to 107.1) to 92.4 (67.5 to 115.7). Of these 24 hips followed for a minimum of 18 months, three were considered as failures at the final follow-up, having required total hip replacement. One of the hips without full follow-up was also considered to be a failure. In more than two-thirds of the surviving hips a satisfactory clinical outcome was achieved with promising radiological findings. The estimated mean implant survival was 60 months (95% confidence interval 53.7 to 66.3)

We investigated the factors related to the radiological outcome of a transtrochanteric curved varus osteotomy in patients with osteonecrosis of the hip. We reviewed 73 hips in 62 patients with a mean follow-up of 12.4 years (5 to 31.1). There were 28 men and 34 women, with a mean age of 33.3 years (15 to 68) at the time of surgery. The 73 hips were divided into two groups according to their radiological findings: group 1 showed progression of collapse and/or joint-space narrowing; group 2 had neither progressive collapse nor joint-space narrowing. Both of these factors and the radiological outcomes were analysed by a stepwise discriminant analysis. A total of 12 hips were categorised as group 1 and 61 as group 2. Both the post-operative intact ratio and the localisation of the necrotic lesion correlated with the radiological outcome. The cut-off point of the postoperative intact ratio to prevent the progression of collapse was 33.6%, and the cut-off point to prevent both the progression of collapse and joint-space narrowing was 41.9%.

The results of this study indicate that a post-operative intact ratio of 33.0% is necessary if a satisfactory outcome is to be achieved after this varus osteotomy.

Purpose of the study: We conducted a retrospective study of 66 cases of non-traumatic osteonecrosis of the femoral head by percutaneous drilling and autograft. This technique associated drilling with graft conductor effects and bone marrow inducers. Material and Methods: Forty-six patients (41 male, 5 female) with non-traumatic osteonecrosis were included in this study. Mean age at surgery was 46 years (22–68). The 66 cases involved 32 right hips and 34 left hips (21 bilateral cases), six asymptomatic. Osteonecrosis was related to corticosteroid therapy (n=17), chronic ethylism (n=14), dyslipidaemia (n=7), barotraumatism (n=3), and renal transplantation (n=1). Four were found idiopathic. The preoperative ARCO classification was: 8 stage IIA, 21 stage IIB, 15 stage IIC, 7 stage IIIB, 13 stage IIIC and 2 stage IV. A minimally invasive surgical technique combined simple percutaneous drilling with a cancellous iliac bone graft harvested percutaneously homolaterally. Metaphyseal grafts were excluded from this analysis. Minimum postoperative follow-up was two years. The main outcome was rate of prosthesis conversion at two years. Results: Considering all stages, 38 hips did not have a total prosthesis at two years (58% success) with a mean follow-up of 40 months (25–65). Twenty-eight hips had total prosthesis at two years (42% failure) with mean follow-up of 11 months (3–23). Mean survival was 29 months (3–65) with stabilisation of the initial lesions in 50% of hips. For the 44 stage II hips, success was achieved in 28 (64%). The success rate for stages IIA and IIB was 70% with mean follow-up of 29 months (19–65). For the 20 stage III hips success was achieved in nine (45%), with 30% for stage IIIB and 54% for stage IIIB and mean follow-up of 21 months (12–45). There were no cases of mechanical complications. One superficial skin infection cured favourably. Discusssion and conclusion: Subchondral fracture (stage III) and necrosis volume > 30% appear to be unfavourable factors for outcome with this technique. There are other conservative treatments but all with technical difficulties or cost considerations despite sometimes questionable results. This technique is simple and very attractive. In one hand, it combines the advantages of the decompression-effect for the local vascularization with the bone inducer effect of the marrow auto-graft. And in the other, it is a non-invasive and conservative procedure which does not modify the morphology of the upper extremity of the femur and does not jeopardize a future total hip replacement. This is a reliable technique which merits confirmation with a larger series. The best indication remains stage IIA and IIB

We report a case of osteonecrosis of the femoral head in a young man who is a carrier of the prothrombin gene mutation. We suggest that an electrical injury to his lower limb may have triggered intravascular thrombosis as a result of this mutation with subsequent osteonecrosis of the femoral head. No case of osteonecrosis of the femoral head secondary to a distant electrical injury has previously been reported.

Introduction: The progression of the collapse is influenced by the extent and location of the necrotic focus of the necrotic femoral head. The authors studied the extent of the necrotic focus on the joint surface by conventional antero-posterior radiographs in neutral position, and antero-posterior radiographs at the 45 degrees flexion position. The differences of the lesions in these two types of radiographs were analyzed. Materials and Methods: The conventional antero-posterior radiographs of the neutral position, and the antero-posterior radiographs at the 45 degrees flexion positions in 115 hip joints of 86 patients with non-traumatic osteonecrosis of the femoral head were obtained for this study. These 115 hips showed extensive lesions and could be divided into two groups: Type C-1 or C-2 by classification of the Specific Disease Investigation Committee under the auspices of the Japanese Ministry of Health Labor and Welfare. Type C1 lesions occupy more than the medial 2/3 of the femoral head and C2 lesions extend laterally to the acetabular edge. Results: At the neutral position, Type C-1 lesions were noted in 42 joints (36%). In these 42 hips, 13 showed Type C-1 (30%) at the 45 degrees flexion position. In contrast, 29 joints (70%) were Type C-2. Type C-2 lesions in 73 joints (64%) were shown in the neutral position. In these 73 hips, Type C-2 lesions were disclosed on 69 joints (95%) in the 45 degrees flexion position and Type C-1 was noted on 4 hips (5%). Conclusions: Based on these results, the authors propose that location of the lesion on the joint surface varies with different hip positions

We followed, prospectively, 77 patients (90 hips) with early-stage, non-traumatic osteonecrosis of the femoral head for a mean period of nine years. At the time of final review, 56 (62%) were symptomatic. Using the Cox model, the initial radiological stage, the progression of staging, the reduction in size of the lesions and the percentage of necrotic volume on MRI were identified as risk factors. Using the Harris score of < 70 or surgery as the endpoint, the cumulative rates of survival were 60.0% at one year, 43.3% at two years, 38.9% at five years and 37.2% at ten years. Survival curves demonstrated that clinical deterioration could occur 90 months after the initial diagnosis, suggesting that asymptomatic patients should be followed carefully for several years. Radiological time-dependent reduction in size without progressive collapse may represent repair even when the collapse is minimal

Six major and seven minor diagnostic criteria have been developed by the Japanese Investigation Committee for osteonecrosis of the femoral head (ONFH). We have carried out a multicentre study to clarify these.

We studied prospectively 277 hips in 222 patients, from six hospitals, who had ONFH and other hip pathology and from whom histological material was available. We identified five criteria with high specificity: 1) collapse of the femoral head without narrowing of the joint space or acetabular abnormality on radiographs, including the crescent sign; 2) demarcating sclerosis in the femoral head without narrowing or acetabular abnormality; 3) a ‘cold-in-hot’ appearance on the bone scan; 4) a low-intensity band on T1-weighted images (band pattern); and 5) evidence of trabecular and marrow necrosis on histological examination. With any combination of two of these criteria, the sensitivity and specificity of the diagnosis were 91% and 99%, respectively.