Shigenori Inao

Minimum 10-year results of Sugioka's osteotomy for femoral head osteonecrosis.

Sugiokas transtrochanteric rotational osteotomy was performed on 14 hips (12 patients) before 1987 for avascular necrosis of the femoral head involving a large part of the weight-bearing area. Three hips required a secondary total hip arthroplasty within 5 years after the osteotomy. The remaining 11 hips were examined at a mean of 13.2 years after surgery (range, 10-17.7 years). The clinical and radiologic results were related to the preoperative radiographic stage of the disease. In the hips with less than 2 mm of collapse, highly satisfactory results were maintained more than 15 years after surgery, with minimal development of degenerative changes. In hips with 2 mm or more of collapse or with acetabular changes, the results tended to deteriorate gradually during the long course of observation but were fairly acceptable. This study shows the osteotomy can enable hip joints to survive and function well for more than 10 years with proper patient selection and operative procedure.

Valgus-extension osteotomy for advanced osteoarthritis in dysplastic hips

We treated 31 consecutive patients of mean age 43 years (22 to 59) with severe osteoarthritis of the hip secondary to dysplasia by valgus-extension osteotomy. The clinical results were analysed for factors which may have affected the outcome. The procedure was carried out only on one side and was combined with a Chiari pelvic osteotomy in four patients. The angle of valgus was between 30 and 40° with 10 to 20° of extension. The mean follow-up was 15 years (12 to 18). Clinical evaluation using Charnley’s modification of the system of Merle d’Aubigne and Postel showed that the mean score for pain had improved from 2.3 before operation to 4.2 at 15 years, and function from 2.3 to 4.2. Range of movement had decreased from 4.2 to 3.5. Fifteen patients (48.4%) had a pain score of 5 or 6 and were evaluated as satisfactory. Kaplan-Meier survivorship analysis showed a survival rate of 51% at 15 years after operation. Two preoperative factors had a significant positive correlation with the radiological results, namely the thickness of the capital drop osteophyte and the length of the roof osteophyte. We suggest that this procedure is effective for advanced osteoarthritis in the dysplastic hip in young and active patients if these factors are satisfactory on the preoperative radiographs.

Characterization of the phosphoenzyme that is involved in the Ca2+-Ca2+ exchange catalyzed by the Ca2+-ATPase of sarcoplasmic reticulum vesicles

The rate of Ca2+ efflux was determined with 45Ca2+ -loaded sarcoplasmic reticulum vesicles (mainly with the light fraction of vesicles) at pH 6.5 and 0 degrees C. The efflux depended on external Ca2+, Mg2+, ATP and ADP, but it was not activated by AMP. The results indicate that the efflux is derived from Ca2+ -Ca2+ exchange mediated by the phosphoenzyme (EP) of membrane-bound Ca2+ -ATPase. EP was formed with Ca2+ -loaded vesicles (light fraction) under similar conditions without added ADP. The subsequent addition of EGTA and ADP induced triphasic EP dephosphorylation. Three species of EP (EP1, EP2, and EP3) were distinguished on the basis of this dephosphorylation kinetics, EP1, EP2, and EP3, corresponding to the first, second, and third phases of the dephosphorylation. Dephosphorylation of EP1 and EP2 resulted in stoichiometric ATP formation, while dephosphorylation of EP3 led to stoichiometric Pi liberation. The rate of Ca2+ efflux was compatible with that of EP2 dephosphorylation, whereas it was much lower than the rate of EP1 dephosphorylation and much higher than the rate of EP3 dephosphorylation. The intravesicular Ca2+ concentration dependence of the rate of EP2 dephosphorylation agreed with that of the rate of Ca2+ efflux. The results suggest that isomerization between EP1 and EP2 is the rate-limiting process in the Ca2+ -Ca2+ exchange and that EP3 is not involved in this exchange.

PRIMARY CHARNLEY TOTAL HIP ARTHROPLASTY FOR CONGENITAL DYSPLASIA

We performed Charnley total hip arthroplasties on 64 patients (71 hips) between 1976 and 1984 for moderate congenital acetabular dysplasia in which a superolateral cement thickness of less than 20 mm was expected when the cup was placed in the true acetabulum at an angle of 45 degrees. Of these, 59 hips were examined 10 to 17 years after operation; 37 (group A) had been operated on between 1976 and 1982 using Charnleys original technique of cementing the acetabulum and 22 (group B) between 1983 and 1984 using more modern techniques. In group A, aseptic loosening of the socket was observed in ten hips (27.0%) and the 17-year survival rate was 81.5%. In group B, loosening was noted in only one socket (4.5%) and the 13-year survival rate was 100%. The improved techniques produced significantly better long-term results in fixation of the cup in dysplastic hips without bone grafting.

Safety of Fettweis squatting position in congenital dislocation of the hip: Experimental study of prevention of deformity of the femoral head and neck in pigs

The safety of the Fettweis squatting position for immobilization after reduction in congenital dislocation of the hip was evaluated in an experimental model in pigs. In seven neonatal pigs, the hips were fixed in a plaster cast for 3 h in the Fettweis squatting position after the insertion of an allogenic meniscus into the hip joint. Three to 5 months later, no obvious deformity of the femoral head or neck was noted. The results demonstrate that the squatting position is an appropriate position for immobilization after the reduction of dislocated hip joints.

Collagen synthesis activities of chondrocytes from histologically distinct zones of chick embryo tibia

Monolayer cultures of 12-day chick embryo chondrocytes from the regions of dividing (zone 1), elongated (zone 2), and hypertrophied (zone 3) chondrocytes in the tibial cpiphyseal growth plate were analyzed for their capacity to synthesize types II, IX, X, and XI collagens. Synthesis of types II and IX collagens was markedly elevated in the zone 2 culture, while type X collagen synthesis was maximal in zone 3. Type XI collagen was synthesized at low rates in all cultures, with some elevation of its rate in zones 2 and 3. In terms of mol percent of total collagen synthesis, types II and IX collagens decreased from zone 1 to zone 3, while type X collagen increased progressively. Thus, the composition of the extracellular collagens produced by the different zones changed markedly during chondrocyte differentiation. In addition, type X collagen was released exclusively into the culture medium, whereas type XI collagen was retained in the extracellular cell-associated matrix. In contrast, types II and IX collagens were found in both the culture medium and the cell matrix pools. Although types II and IX collagens showed similar changes during differentiation, the synthetic molar ratios of these two collagens varied from 3 to 18 in different cultures, suggesting that the synthesis of these two products is not tightly coupled in these cells.