Forty-eight patients with perinatal static encephalopathy were treated with unilateral varus rotational femoral osteotomy for hip subluxation. Twenty-one of the 48 also had concomitant pelvic osteotomy. Twenty-seven of the patients were nonambulators. Bilateral soft-tissue releases had been performed previously in 20 patients. At the time of varus rotational osteotomy, the mean age was 8 years, 11 months. The indication for a varus rotational osteotomy was femoral head subluxation or dislocation in all cases. The preoperative center-edge angle ranged from -8 degrees to 18 degrees (mean, 4 degrees), and on the contralateral side, the center-edge angle ranged from 0 degree to 32 degrees (mean, 19 degrees). The center-edge angle on the operative side at follow-up averaged 25 degrees (-10 degrees to 78 degrees), an improvement of 21 degrees, and on the contralateral side averaged 27 degrees (range, 9 degrees-40 degrees), an improvement of 8 degrees. Forty-seven patients have had no subsequent surgery on the contralateral hip. One patient had a varus rotational osteotomy on the contralateral hip 5 years postoperatively; however, this hip was subluxated at the time of the index procedure. Twelve patients have had no surgery at any time on the contralateral side. None of these patients had deterioration of the contralateral hip. Surgery on one hip should not, in itself, be an indication for surgery on the contralateral concentrically reduced hip with adequate abduction in patients with acetabular dysplasia secondary to perinatal static encephalopathy.