Organotypic culture of human bone marrow adipose tissue.

The precise role of bone marrow adipose tissue (BMAT) in the marrow remains unknown. The purpose of the present study was therefore to describe a novel method for studying BMAT using 3-D collagen gel culture of BMAT fragments, immunohistochemistry, ELISA and real-time reverse transcription-polymerase chain reaction. Mature adipocytes and CD45+ leukocytes were retained for >3 weeks. Bone marrow stromal cells (BMSC) including a small number of lipid-laden preadipocytes and CD44+/CD105+ mesenchymal stem cell (MSC)-like cells, developed from BMAT. Dexamethasone (10 micromol/L), but not insulin (20 mU/mL), significantly increased the number of preadipocytes. Dexamethasone and insulin also promoted leptin production and gene expression in BMAT. Adiponectin production by BMAT was <0.8 ng/mL under all culture conditions. Dexamethasone promoted adiponectin gene expression, while insulin inhibited it. This finding suggests that dexamethasone, but not insulin, may serve as a powerful adipogenic factor for BMAT, in which adiponectin protein secretion is normally very low, and that BMAT may exhibit a different phenotype from that of the visceral and subcutaneous adipose tissues. BMAT-osteoblast interactions were also examined, and it was found that osteoblasts inhibited the development of BMSC and reduced leptin production, while BMAT inhibited the growth and differentiation of osteoblasts. The present novel method proved to be useful for the study of BMAT biology.

Factors influencing the improvement of gait ability after total hip arthroplasty.

We aimed to investigate the factors influencing gait improvement in the patients who had undergone total hip arthroplasty. We performed gait analysis on 43 female patients with unilateral hip osteoarthritis. All the patients were analyzed before and at 2, 6, and 12 months after the surgery. There were significant reductions in spatiotemporal parameters in the patients with hip osteoarthritis compared with the control group. The mean values of the spatiotemporal parameters of the patients showed considerable improvement by 12 months after surgery; however, they did not reach the same values as those observed in the healthy subjects. The stage of osteoarthritis and the changes in the leg-length discrepancies were the factors that most influenced gait improvement after total hip arthroplasty throughout the follow-up period.

Mature and activated osteoclasts exist in the synovium of rapidly destructive coxarthrosis.

We compared histological and functional findings in rapidly destructive coxarthrosis (RDC) and slowly progressive osteoarthritis (OA) to investigate whether osteoclasts contribute to the extensive bone destruction observed in RDC. A histological analysis of tissue specimens from the synovium obtained from 10 cases of RDC and 40 cases with OA of the hip was performed after staining for tartrate-resistant acid phosphatase (TRAP). The cells isolated from these tissue specimens from the synovium were cultured for 24 h, and the numbers of TRAP-positive giant cells were counted. Thereafter, we performed a resorption pit formation assay by isolated cells cultured on dentine slices for 7 days. The number of TRAP-positive multinuclear giant cells present in the synovial membrane obtained from RDC patients was significantly larger than that obtained from OA patients. Large lacunar resorption pits were only seen on the dentin slices in a culture of isolated cells from RDC patients without any stimulators. This is the first report, to our knowledge, to reveal that mature and activated osteoclasts exist only in the synovium of RDC and not in the OA synovium. This result might suggest that the underlying mechanism of RDC is therefore associated with osteoclastogenesis in the synovium.

Effects of glucocorticoid on adipocyte size in human bone marrow.

The pathogenesis of corticosteroid-induced femoral head necrosis is assumed to be related to lipid metabolism. Mature fat cells are believed to play a central role in lipid metabolism. The purpose of this study was to investigate the size of mature fat cells in the human femoral head after steroid treatment. Cancerous bone tissue was obtained from the femoral heads of 20 women who had undergone total hip arthroplasty. This bone tissue was subsequently incubated in a medium containing 10(-7) or 10(-5) M dexamethasone for 5 days. Mature fat cells from the bone marrow were observed by scanning electron microscopy, and the largest diameter of individual fat cells was measured. The size of the mature fat cells in human bone marrow increased after high-dose steroid treatment. The largest fat cell volume after steroid treatment was one and one-half times larger than that observed in the control. Steroid-induced osteonecrosis is known to sometimes occur after high-dose steroid treatment. These findings may indicate the pathogenetic factors in the early stage of steroid-induced osteonecrosis.

[Total Hip Arthroplasty after previous proximal femoral osteotomy].

It is technically difficult to perform total hip arthroplasty (THA) after osteotomy because the proximal femur may be deformed after primary osteotomy. For the deformity of femur, combination with femoral osteotomy should be performed. The results obtained on performing THA after osteotomy have been described by some investigators. The main reasons of failure were malposion of stem, intraoperative fracture, dislocation, nonunion, and infection. This paper treats regards to avert these complications.

The incidence of heterotopic ossification after cementless total hip arthroplasty.

The purpose of this study was to determine the incidence of heterotopic ossifications (HOs) after total hip arthroplasty in Japanese patients and the predisposing factors associated with this condition. One thousand hips of 885 patients undergoing cementless total hip arthroplasties were examined with respect to the incidence and severity of HO; the data analysis was conducted by using the univariate and multivariate methods. The overall incidence of HO was 5.2%, with severe HO in 0.9% of the patients. A significant increase in the frequency of HO was observed in patients with ankylosed hips (odds ratio, 11.1; 95% confidence interval, 2.5-49.9), hypertrophic osteoarthritis (odds ratio, 2.7; 95% confidence interval, 1.2-5.9), and with a particular type of prosthesis used (ceramic-on-ceramic vs ceramic-on-polyethylene) (odds ratio, 2.5; 95% confidence interval, 1.3-4.8).

A simple method to determine the pelvic inclination angle based on anteroposterior radiographs.

BACKGROUND: The aim of this study was to propose a simple method to determine the pelvic inclination angle using anteroposterior radiographs of the hip. METHODS: The 283 subjects were randomly selected from patients who had undergone hip surgery at our institution from July 2002 to June 2004. Anteroposterior (AP) and lateral radiographs of the pelvis were obtained in the standing position. To assess the pelvic inclination angle from AP radiographs, a formula was determined by a trigonometric function. A significant correlation between the angle calculated by the formula and the measured angle (theta(0)) on lateral radiographs was confirmed. The calculated angle (theta(1)) was obtained from two measured values: the pelvic foramen height (H) on AP radiographs and the pelvic foramen distance (D) on lateral radiographs. The formula used was as follows: sin theta = H/D. The calculated angle (theta(2)) was obtained from one measured value--the pelvic foramen height on AP radiographs--because the pelvic foramen distance on lateral radiographs substituted for the average of the pelvic foramen distance investigated in 236 patients. The formula was sin theta = H/average. RESULTS: The correlation between the calculated angle (theta(1)) and the measured angle (theta(0)) was significant, and the correlation between calculated angle theta(1) and calculated angle theta(2) was also significant. CONCLUSIONS: The pelvic inclination angle can be estimated by measuring the height of the pelvic foramen according to our formula. Our formula was shown to have adequate reliability and reproducibility.

A new device for a V-shaped subtrochanteric osteotomy combined with total hip arthroplasty.

Subtrochanteric femoral shortening and a corrective osteotomy are considered to be an integral part of total hip arthroplasty for a completely dislocated hip or a severe deformity of the proximal femur. A precise subtrochanteric osteotomy is mandatory to achieve good results for such cases. We herein describe a new simple device for accurately performing precise subtrochanteric V-shaped osteotomy.

Effects of hydrogen peroxide solutions on artificial hip joint implants.

This study was designed to elucidate the erosive effect of hydrogen peroxide solutions on the materials used for total-hip arthroplasty (THA). As test materials, cross-linked polyethylene, Ti-6Al-4V alloy, and thermal sprayed hydroxyapatite (HA) were used. Changes upon soaking in 3% hydrogen peroxide, before soaking, 1 minute after soaking, 10 minutes after soaking, and 180 minutes after soaking were examined. Scanning electron microscope, Fourier transform infrared analysis, and x-ray diffraction were used for this examination. Hydrogen peroxide did not affect polyethylene, although notable changes in the Ti-6Al-4V alloy and HA did occur. These results indicate that caution should also be exercised to minimize erosion of prosthesis consisting of HA and Ti alloy when hydrogen peroxide solutions are used during total-hip arthroplasty.

Giant vascular leiomyoma with extensive calcification in the forearm.

Vascular leiomyoma or angioleiomyoma is a benign solitary smooth muscle tumor that occurs in the forearm relatively rarely. Most of these tumors are composed of venous vessels, but in some reports small arteries have been traced in the tumors. We describe a 72-year-old man who presented with a slowly enlarging mass in the distal forearm with extensive calcification. Our case had the following three peculiarities compared with common findings in patients with a vascular leiomyoma: (1) elderly age; (2) giant size tumor; and (3) tumor with extensive calcification. The ulnar artery was involved in the tumor. Simple excision of the tumor, including the ulnar artery, was performed. There was no recurrence and no cold intolerance.