Changes in lower limb rotation after soft tissue surgery in spastic diplegia

BACKGROUND AND PURPOSE Rotational osteotomies are usually necessary to correct pronounced rotational deformities in ambulant children with cerebral palsy. The effects of soft tissue surgery on such deformities are unclear. In this retrospective study, we determined whether multilevel soft tissue surgery, performed to correct deformities in the sagittal plane, would also have an effect on rotational parameters. PATIENTS AND METHODS We examined 28 ambulant children with spastic diplegia with an average age of 12 (7-19) years. They underwent multilevel soft tissue surgery (with 6 surgical procedures per child on average). 3-dimensional gait analysis was performed preoperatively and at an average follow-up of 1-2 years. The indications for surgery were abnormalities in the sagittal plane. Gait analysis data from healthy children were used in defining normal ranges of kinematic variables. For assessment of changes in the transverse plane, the angles of foot progression, hip rotation, and pelvic rotation were studied. RESULTS The transverse plane kinematic results showed no statistically significant postoperative changes when the preoperative parameters were within the normal range (within 2 SD of the mean of the normal material). In limbs where the preoperative values were abnormal (more than 2 SD above the normal mean), there was a mean reduction in internal foot progression of 12 degrees (p = 0.01) and a mean reduction in external pelvic rotation of 6 degrees (p = 0.02). The effect was more pronounced in children under 12 years of age. Internal hip rotation was not significantly reduced. INTERPRETATION When the preoperative rotational parameters were abnormal, multilevel soft tissue surgery resulted in improved transverse plane kinematics. This could be of importance in preoperative decision making, especially when there is doubt as to whether to include rotational osteotomies in multilevel operations in younger children.