Satoshi Nakasone

Multiinstitutional epidemiological study regarding osteoarthritis of the hip in Japan

Background. Osteoarthritis (OA) of the hip is a major disease that affects the healthy lifespan of a population. It is necessary to fully understand the patients’ conditions before a systematic treatment can be applied. However, a nationwide epidemiological study regarding hip OA has not yet been conducted in Japan. The present study examined the current status of patients with hip OA, including the disease etiology. Methods. This is a multiinstitutional study of new patients presenting with hip OA at the orthopedic outpatient clinics of 15 institutions in fi ve geographical areas of Japan. The collected data from each patient included the sex, age, treatment history for developmental dysplasia of the hip (DDH), the clinical score of the hip joints based on the Japanese Orthopaedic Association (JOA) scoring system, and the pelvic inclination according to anteroposterior radiographs. In addition, the etiology was determined from the following 17 options: primary OA, acetabular dysplasia, intragluteal dislocation, osteonecrosis, trauma, Perthes disease, slipped capital femoral epiphysis, infection, rheumatoid arthritis, ankylosing spondylitis, neuroarthropathy, endocrine diseases, metabolic diseases, hereditary bone diseases, synovial chondromatosis, generalized OA, and others. Results. There were a substantially larger number of female patients than male patients. This difference regarding sex was present in each generation. The mean age of the patients was 58 ± 14 years. The peak age at presentation was approximately 50 years. Most patients had no history of therapy for DDH. The older patients had lower gait and activities of daily living scores. The etiology was assessed to be acetabular dysplasia in most of the patients. A lower frequency of elderly patients demonstrated acetabular dysplasia. The patients who had a pelvic posterior inclination increased with increasing age. Conclusions. The patients with hip OA in Japan were unique in regard to age distribution, sexual heterogeneity, and disease

Osteoarthritis hip joints in Japan: involvement of acetabular dysplasia

BackgroundWe 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.MethodsSeven 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.ResultsThe 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.ConclusionsThese 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.

Definitions of severely mentally and physically disabled children in Japan: Do the differences affect the prevalence rates of these children?

The prevalence rate of severely mentally and physically disabled children (SDC) aged 6–15 years in Okinawa prefecture on 1 May 1989 was 0.74/1000 (143/192 038) according to Oshimas classification, compared with 0.89/1000 (170/192 038) according to the Ministry of Educations classification with minor modifications. The number of children in region classes 1, 2, 3 and 4 of Oshimas classification for SDC were 100, 34, 6 and 3, respectively. The difference (n = 27) between the total numbers of SDC according to the two classifications was mainly because of 21 children categorized as ‘walking with support’ who were included as SDC according to the Ministry of Educations classification but not as SDC according to Oshimas classification. Only region class 1 of Oshimas classification corresponded with region class 25 of the Ministry of Educations classification. The results of the present study indicate that the differences between the two definitions of SDC affect the reported prevalence rates of SDC. Therefore, changing patterns in the prevalence of SDC should be assessed by serial surveys using the same method in each district.

Three-dimensional analysis of deformities of the radius and ulna in congenital proximal radioulnar synostosis

We reconstructed three-dimensional images of radius and ulna in 38 forearms of 25 patients with congenital proximal radioulnar synostosis from their computed tomographic studies. We also analysed correlations between the deformities of radius and ulna and degrees of fixed pronation of these forearms. The average ulnar deviation, flexion and internal rotation deformities of the radius were 6°, 3° and 18°, respectively. The average radial deviation, extension and internal rotation deformities of the ulna were 3°, 4° and 30°, respectively. The flexion deformity of the radius and the internal rotation deformity of the radius and ulna were correlated significantly with degree of fixed pronation. We conclude that the patients with congenital proximal radioulnar synostosis have remarkable flexion deformity of the radius and internal rotation deformity of the radius and ulna, which might impede forearm rotation after corrective surgery in the proximal part of the forearm.

A Study of bone Mineral Density of the Proximal Tibia

We reported a comparative study of bone mineral density (BMD) of the proximal tibia with age, sex, weight and height.We measured the BMD of the proximal tibia of 74 healthy men and 76 women from the 2nd to 8th decades, with dual photon absorptiometer, LUNAR DP3, using gadolinium 153.BMD of the proximal tibia decreased according to age particularly in women. Age-related decreases of BMD of the femoral neck and lumbar supine were also recognized. The linear regression coefficient of the proximal tibia on age was greater than that of other skeletal sites. The most relative factor of BMD of the proximal tibia was age in women and weight in men. And BMD at medial and lateral sides of the proximal tibia, which were the weight bearing area, was higher than that of central side, non-weight bearing area. The value of the BMD of the proximal tibia may be influenced by physical activity other than aging.