Background: Myosin is a molecular motor and the essential part of the thick filament of striated muscle. The expression of myosin heavy-chain (MyHC) isoforms is developmentally regulated. The embryonic isoform encoded from MYH3 (OMIM *160720) is expressed during fetal life. Recently, mutations in MYH3 were demonstrated to be associated with congenital joint contractures, that is, Freeman-Sheldon and Sheldon-Hall syndromes, which are both distal arthrogryposis syndromes. Mutations in other MyHC isoforms cause myopathy. It is unknown whether MYH3 mutations cause myopathy because muscle tissue has not been studied.Objectives: To determine whether novel MYH3 mutations are associated with distal arthrogryposis and to demonstrate myopathic changes in muscle biopsy specimens from 4 patients with distal arthrogryposis and MYH3 mutations.Design: In a cohort of patients with distal arthrogryposis, we analyzed the entire coding sequence of MYH3. Muscle

We reviewed, at an average age of 46 years, a series of 61 patients treated for unilateral slipped upper femoral epiphysis. At maturity there had been slipping of the contralateral hip in 11 patients (18%) and another 14 (23%) had originally had evidence of bilateral slipping when the primary radiographs were reviewed. In only two of these 25 patients (8%) was the slipping of the contralateral hip symptomatic. The incidence of early osteoarthritis of the contralateral hip was 7 of 36 with no slip, 5 of 16 with an untreated slip and 1 of 9 with a slip pinned in situ. If all 61 contralateral hips had been prophylactically pinned at the primary admission, 36 of the operations (59%) would have been unnecessary. We recommend that prophylactic pinning of the contralateral hip should not be standard, but that lateral radiography by the Billing technique be repeated every third to fourth month until closure of the growth plate begins. Hips in which a slip occurs should be pinned in situ.

The most common form of arthrogryposis multiplex congenita (AMC) is amyoplasia. Diagnostic criteria are highly specific, with decreased muscle mass, typical contractures and limb positioning at birth. Intellectual development is normal. The aims of this study were to investigate how muscle strength and contractures affect motor function in amyoplasia, and to relate current functional status to joint positions at birth. Medical records were reviewed and a clinical examination was performed, with investigation of muscle strength, range of motion, and motor function. Thirty-five patients with amyoplasia participated and were divided into three functional groups: 11 community ambulators, 11 household ambulators, and 7 non-ambulators. Six children less than 2 years old were not categorized. Community ambulators had the best muscle strength and none had knee flexion contractures extending 20 degrees. Household ambulators had severe contractures in the lower limbs, but good muscle strength in the upper limbs. Non-ambulators had most severe contractures and most severely reduced muscle strength. Most of the non-ambulators were born with hips in severe abduction, flexion and external rotation. Good and very good correlations were found between muscle strength and motor function, and only moderate correlations between range of motion and motor function. We conclude that more attention should be paid to developing muscle strength, with early stimulation of active movement, and that periods of immobilization should be minimized. Further, ultrasound or MRI of muscle tissue in the newborn period would be useful to evaluate prerequisites for future development of muscle strength and thereby anticipate response to therapy.

The aim of this study was to compare the outcome after anterior cruciate ligament reconstruction in recreational and competitive athletes, with a minimum follow-up of two years. Forty-nine patients (24 males and 25 females) who, at the time of the index injury, were classified as recreational athletes (Tegner level 2-5) were compared with 226 patients (61 females and 165 males) who, at the time of the index injury, were classified as competitive athletes (Tegner level 9-10). At the follow-up, no significant differences were found between the study groups in terms of the Lysholm score, IKDC evaluation system, one-leg-hop test, KT-1000 laxity measurements, anterior knee pain and the patients' subjective evaluation of the results. However, the competitive athletes displayed a significantly higher reduction in Tegner activity level than the recreational athletes. The functional and objective results after anterior cruciate ligament reconstruction were comparable for the recreational and competitive athletes. We, therefore, conclude that anterior cruciate ligament reconstruction could be recommended for recreational athletes as well as competitive athletes.

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