Osteoarthritis hip joints in Japan: involvement of acetabular dysplasia.

BACKGROUND: We conducted a nationwide epidemiologic study regarding hip osteoarthritis (OA) in Japan, and a previous report found these patients to be unique in comparison to Caucasians. This report focused on the data regarding each hip joint, and the involvement of acetabular dysplasia with hip OA was analyzed. METHODS: Seven hundred twenty OA hips were examined. Sixty-five joints with osteonecrosis of the femoral head and 215 non-OA contralateral joints of the unilateral patients were examined as controls. The revised system of stage classification for hip OA of the Japanese Orthopedic Association (JOA) was used according to the reproducibility in order to ensure reliable data from the multiple institutions. The acetabular dysplasia indexes were also chosen according to the reproducibility and measured in the radiograph of bilateral hip joints. The clinical score was assessed using the JOA scoring system. The relative risk of the grade of acetabular dysplasia indexes for hip OA was calculated as the odds ratio and the 95% confidence interval. RESULTS: The stage of the OA joints deteriorated with increasing age. The clinical scores also decreased. The grade of the acetabular dysplasia indexes of the OA joints was significantly higher than that of the control joints. Each index of acetabular dysplasia demonstrated significantly increased odds ratios for hip OA. Among the OA joints, the deterioration of the OA stage was found to be significantly associated with an increasing grade of acetabular dysplasia. The odds ratio for OA deterioration in the acetabular dysplasia index was also obtained. The joints of females tended to have a higher grade and prevalence of acetabular dysplasia than those of males. CONCLUSIONS: These findings confirmed a high prevalence of acetabular dysplasia in hip OA joints in Japan. Acetabular dysplasia was one of the most important factors associated with hip OA.

Prevention of osteonecrosis by intravenous administration of human peripheral blood-derived CD34-positive cells in a rat osteonecrosis model.

Aseptic idiopathic osteonecrosis of the femoral head is a painful disorder of the hip that can lead to collapse of the femoral head and the need for total hip replacement following joint destruction. Treatment of this disease still remains a clinical challenge. Adult human circulating CD34(+) cells have been demonstrated to contribute to vasculogenesis and osteogenesis in immunodeficient rat non-union models in vivo. We hypothesized and proved that the transplantation of CD34(+) cells could have a role for improvement of osteonecrosis by promoting vasculogenesis and osteogenesis. Vascular deprivation-induced femoral head necrosis was developed in immunodeficient rats and we then administered human G-CSF mobilized CD34(+) cells intravenously. At 4 weeks after administration, the structure of the femoral head and neck were evaluated histologically and morphometrically with haematoxylin and eosin (H&E) staining and micro-CT imaging. Microangiography was carried out for macroscopic evaluation of neovascularization, and the contribution of human cells to vasculogenesis and osteogenesis was evaluated by immunofluorescent staining with human-specific antibodies. Our treatment resulted in an obvious improvement of osteonecrosis after CD34(+) cell administration and demonstrated the differentiation potential of CD34(+) cells into endothelial cells and osteoblasts. In conclusion, this new therapeutic approach using circulating cell fraction could be a promising cell-based therapy for early-stage osteonecrosis of the hip.

Analysis of interobserver reliability for radiographic staging of coxarthrosis and indexes of acetabular dysplasia: a preliminary study.

BACKGROUND: We are planning a multicenter survey on coxarthrosis and acetabular dysplasia in Japan. To collect reliable data, we performed a preliminary study to elucidate the observer agreement on assessment items. METHODS: We collected radiographs of hip joints in eight patients with various findings of coxarthrosis. Twelve registered orthopedic specialists evaluated them regarding the roentgenographic stage of coxarthrosis and five indexes of acetabular dysplasia (acetabular angle, center-edge angle, acetabular roof obliquity, acetabular head quotient, approximate acetabular quotient). To assess observer agreement, we calculated the value of the kappa statistic for stages and the coefficient of variation for the indexes. The same 12 specialists then assessed the coxarthritis stage on the same radiographs 1 month after the first evaluation based on our own descriptions of the roentgenographic stages. RESULTS: For the first evaluation of the roentgenographic stage, the value of the kappa statistic was 0.448; and for the second evaluation it was 0.600. The results of the coefficient of variation for the indexes of acetabular dysplasia, ranked in ascending order, were as follows: acetabular angle, acetabular head quotient, acetabular roof obliquity, center-edge angle, approximate acetabular quotient. CONCLUSIONS: For the upcoming multicenter survey, clear descriptions of the stages of coxarthrosis and selection of appropriate indexes can be helpful for collecting dependable results.

Multiple drillings of the acetabular fossa induce early joint remodeling after rotational acetabular osteotomy for hip dysplasia.

INTRODUCTION: We previously observed medial and/or lateral expansion of the subchondral bone in the acetabulum 3 years postoperatively in two out of three cases in which rotational acetabular osteotomy (RAO) was performed. Then we performed multiple drillings at the acetabular fossa in order to induce expansion of the medial subchondral bone in the acetabulum. The purpose of this study is to evaluate the effect of multiple drillings on early joint remodeling after RAO. PATIENTS AND METHODS: Twenty-one women (21 joints) who had undergone RAO with multiple drillings at acetabular fossa (group D) were included. As a control group, 12 women (14 joints) without drillings in RAO procedure were observed (group C). The center-edge angle (CE angle), acetabular roof obliquity (AC angle), head lateralization index (HLI), and the angle between medial and lateral edge of acetabular roof (LOM angle) were measured on the radiographs preoperatively, at 1 month, 2 years postoperatively, and at the last follow-up. RESULTS: As regards the mean CE angle, AC angle, and HLI, there was no significant difference between the two groups. The mean LOM angle at 2 years and the last follow-up demonstrated significant difference between the two groups. INTERPRETATION: Biomechanical and anatomical changes after RAO cause increasing stress to the medial side of the acetabulum. Moreover, bone marrow-stimulating procedure at acetabular fossa might be beneficial to develop early joint remodeling affected by bone marrow derived cells such as mesenchymal stem cells.