The epidemiology of developmental dysplasia of the hip in Japan: Findings from a nationwide multi-center survey.

BACKGROUND: It has been reported that the national incidence of developmental dysplasia of the hip (DDH) has decreased in Japan. This is because of prevention activities after birth since around 1970. However, cases of late-diagnosed DDH have still been noted in some children's hospitals. There has been no recent survey of DDH in Japan. The purpose of this study was to investigate the current epidemiology of DDH using a comprehensive nationwide survey. METHODS: A questionnaire was sent to orthopedic surgeons in 1987 facilities nationwide, who were asked to complete and return a survey card on each DDH patient treated between April 2011 and March 2013. RESULTS: A total of 783 (39%) facilities completed and returned the card. Of these, 79% reported no cases of DDH-related dislocation over the 2-year period, while the remaining facilities reported 1295 cases. The characteristics of children diagnosed with DDH-related dislocation were as follows: girls (89%), left side involvement (69%), bilateral involvement (4%), positive family history (27%), first-born (56%), and pelvic position at birth (15%). Seasonal variation showed an increase in DDH incidence among those born in the winter. Overall, 199 cases (15%) were diagnosed at >1 year of age, and these included 36 cases diagnosed very late, at >3 years of age. The majority of the 199 cases of late diagnosis had received earlier routine screening at <1 year of age. CONCLUSION: The characteristics of the children diagnosed with DDH nationwide were similar to past data from local regions. However, many children were diagnosed late (>1 year of age), particularly in the more populous regions. The findings identify a need for improved early routine screening for DDH in Japan.

Economic Impact of Venous Thromboembolism Following Major Orthopaedic Surgery in Japan.

OBJECTIVES: Venous thromboembolism (VTE) is the most frequent complication following major orthopaedic surgery (MOS). Although studies in Western populations have demonstrated significantly higher costs for patients with VTE versus those without VTE after MOS, there is a paucity of such data in Japan. This study was conducted to understand the costs and VTE rates in Japanese patients. METHODS: Data were extracted from a hospital claims database. MOS was defined as total hip replacement, total knee replacement, or hip fracture repair. Subjects who underwent more than one MOS during the same admission were excluded. Identified VTE cases were matched on a 1:2 matching scheme on the basis of surgery type, hospital, and date of surgery (±6 months). The primary outcome was the difference in 90-day costs. Secondary outcomes included differences in total 6-month costs postsurgery and average length and cost of initial hospital stay. RESULTS: The 90-day cumulative VTE incidence was 0.774%, with 94% of the cases occurring within 30 days postsurgery. Total 90-day costs were significantly higher in patients with VTE (difference of 864,153 Japanese yen [US $10,538]). Average length of stay was longer for patients with VTE (66 days vs. 42 days). Costs incurred by patients with VTE were on average much higher than those incurred by patients without VTE throughout 5 months postsurgery. CONCLUSIONS: The development of a VTE in patients undergoing MOS results in a 1.5-fold increase in the length of stay and a 1.7-fold increase in 90-day costs. Findings indicate that the avoidance of VTEs through more effective prophylaxis will help to reduce the economic burden associated with MOS.

Characterization of human synovial fluid cells of 26 patients with osteoarthritis knee for cartilage repair therapy.

AIM: To investigate the possibility of chondrogenic differentiation and cartilage repair of synovial fluid cells of osteoarthritis (OA) knee. METHODS: Synovial fluids from 26 patients with OA knee were aspirated from each knee joint and cultured in vitro. The morphology of cultured synovial fluid cells, cell proliferation rate, the phenotype, and chondrogenic differentiation were analyzed in in vitro. Also, human autologous synovial fluid cells were transplanted to OA cartilage, and the cells were traced in ex vivo. RESULTS: In 19 of 26 materials, the cells proliferated satisfactorily. The cell proliferation in six materials was very slow and one material contaminated. Culture-expanded synovial fluid cells had a fibroblastic morphology and the phenotype was negative for CD10, CD14, and CD45, and positive for CD13, CD44, and CD105. Pellet culture of synovial fluid cells showed chondrogenic differentiation. In the ex vivo study, autologous transplanted synovial fluid cells were observed in repaired or enhanced regenerative cartilage areas and showed a tendency to infiltrate the original degenerative cartilage of OA. CONCLUSIONS: This study proved the possibility of chondrogenic differentiation of synovial fluid cells of OA knee joints despite the pathologic environment within a diseased joint. Synovial fluid cells were actually heterogeneous cells but they showed chondrogenic differentiation, similar to that of bone marrow-derived mesenchymal progenitor cells (BMMPCs). The Ex vivo study suggested that synovial fluid cells had a tendency to adhere to OA degenerative cartilage in humans.