Z-plasty for severe gluteal muscle contracture in children.

Purpose: To review the records of 363 patients with severe gluteal muscle contracture to determine its mechanism, underlying pathology, and treatment outcome.

Methods: Records of 136 males and 227 females aged 5 to 18 (mean, 12.2) years who underwent Z-plasty for bilateral (n=347) or unilateral (n=16) severe gluteal muscle contracture were reviewed. Severe gluteal muscle contracture was classified as typical (n=52) or special (n=311). The typical type is associated with symptoms of positive out-toe gait, Ober sign, back-extending test, cross-leg test, squatting with knee side-by-side test, and hip dysfunction. It is further subdivided into mild (n=0), moderate (n=40), or severe (n=12). The special type is associated with additional symptoms of pelvic tilt and leg length discrepancy (<2 cm in 181 hips, 2-4 cm in 82 hips, and >4 cm in 48 hips). 311 hips had pelvic tilt and 47 hips had lumbar compensatory scoliosis. Treatment outcome was assessed at 6 months. Hip functional score was assessed at the final follow-up.

Results: The mean hospitalisation period was 11 days. After a mean follow-up of 1.5 years, the mean hip functional score improved from 8.03 to 11.69; improvement was higher in children (age 5-13 years) than in adolescents (age 14-18 years) [3.7 vs. 2.9, p<0.001]. At 6 months, outcome was excellent in 280 hips, good in 80, fair in 3 hips, and poor in 0. The 3 hips with fair outcome had persistent slight pelvic tilt and swaying gait. Two of them had preoperative leg length discrepancy >4 cm, and intra-operatively the contracture band severely affected the joint capsule. The third patient did not comply with postoperative exercises.

Conclusion: Surgical treatment for severe gluteal muscle contracture achieved good outcome.