Recurrence after femoral derotational osteotomy in cerebral palsy.

The authors studied the long-term results of femoral derotational osteotomy (FDO) for medial femoral torsion in ambulatory children with cerebral palsy. Thirty children with 45 femurs that underwent distal FDO were followed for a mean of 6.5 years. Although correction was achieved after surgery, recurrence occurred during follow-up in 15 femurs. Preoperative mean external hip rotation of 10.7 +/- 7.2 degrees increased to 41.3 +/- 16.6 degrees 1 year after surgery and decreased to 28.2 +/- 14.7 degrees 5 years after surgery. On kinematic data, maximum hip rotation in stance of 30 degrees before surgery decreased to 8.7 degrees 1 year after surgery and increased to 16.1 degrees 5 years after surgery. Minimum hip rotation of 10.4 degrees before surgery was corrected to -4.3 degrees 1 year after surgery and was 0.8 degrees 5 years after surgery. Passive hip external rotation and kinematic hip rotation showed progressive deterioration of the initial correction. Patients having surgery prior to age 10 were more likely to show deterioration.