Fibrosis of the gluteus maximus: a cause of limited flexion and adduction of the hip in children.

In 71 children with fibrosis of the gluteus maximus, the affection was nearly always bilateral and of variable severity. The diagnosis was made at ages ranging from 18 months to 15 years. The contraction results in an inability to flex the hips with the knees together and produces an awkward gait and difficulty in running and climbing stairs. Half of these patients were treated surgically. Complete correction was achieved in most instances by Z lengthening of the gluteus maximus. At operation the subcutaneous tissue was found to be thin and fibrotic. The underlying aponeurosis was thickened by fibrosis, which also affected the muscle. The muscle lesion appears to evolve from muscular interfascicular fibrosis to the formation of a tendinous-like tissue with a concomitant reduction in the number and size of muscle fibers. There is a strong etiologic relationship between this condition and intragluteal injections. All the patients studied had received antibiotics by intramuscular injection since early childhood; 58 patients received extraordinary large numbers of injections. However, there may have been an individual predisposing factor in the collagenous tissue reaction and in the muscle itself in the production of the condition.