Salter-Harris type III epiphyseal fractures of the proximal phalanx.

Of 823 pediatric hand fractures treated between 1981 through 1996, only 11 (1.3%) were Salter-Harris type III fractures of the proximal phalanx. We review the anatomic basis, etiology, age prevalence, treatment, and results of these epiphyseal injuries. The average age at injury was 14.9 years, with a narrow range from 14 years 2 months to 15 years 11 months. Nine of 11 fractures were displaced and treated with open reduction and internal fixation. At an average follow-up of 21 months, 9 of 11 had full joint motion. The other two had minimal loss of motion, and all had normal function and collateral ligament stability. The displacement and size of the epiphyseal fragment, avulsed and rotated by the collateral ligament, are often underestimated by radiographs. We found that anatomic reduction and fixation yielded good results in all displaced fractures. This restores both the stability of the collateral ligament and a smooth articular surface.

Cyclosporin A does not affect the absolute rate of cortical bone resorption at the organ level in the growing rat.

The weanling rat, an animal model of rapid bone turnover, was used to evaluate the effects of various doses of cyclosporin A (CsA) on various bones during different time periods. Sprague-Dawley male rats were extensively prelabeled with 3H-tetracycline during 1-3 weeks of age. At 4 weeks of age, four groups of rats were given daily subcutaneous injections: vehicle or CsA--low dose (10 mg/kg), intermediary dose (20 mg/kg), or high dose (30 mg/kg) for 7, 14, or 28 days. Three different whole bones--the femur (low turnover), scapula (moderate turnover), and lumbar-6 vertebra (high turnover) were harvested intact at 4, 5, 6, and 8 weeks of age. The whole bones were assayed weekly for total dry defatted weight, calcium mass (formation), and loss of 3H-tetracycline (bone resorption) following treatment with CsA. Serum CsA levels, calcium creatinine, and alkaline phosphatase were measured weekly. Significant decreases in serum calcium and alkaline phosphatase were observed at 1 and 2 weeks, and were normalized by 4 weeks of treatment. No significant changes in serum creatinine were noted. For all three doses of CsA, no effect was observed on the absolute rate of cortical bone resorption of three different, whole bones over three time periods. Body weight and bone formation in treated animals was significantly smaller in a dose- and time-related fashion compared with control animals at sacrifice. However, compared with the initial control animals, body weights and bone masses of the final treated animals were much larger, suggesting that the smaller bone masses were due to insufficient growth and slow gain in bone mass.(ABSTRACT TRUNCATED AT 250 WORDS)