[Assessment of absolute knee joint linear and angular velocity in patients with spastic cerebral palsy after operative treatment of lever arm disfunction deformities--prospective study].

Introduction: Lever arm dysfunction (LAD) deformities in patients with CP are based on imbalanced forces acting in lower limbs during gait. Muscle imbalance results in bone axial deformities, simultaneously magnifying biomechanical disturbances. Goal. Analysis of knee joint velocity in patients with spastic dipegia treated with use of single event multi level surgery (SEMLS).

Material: 15 patients (21 limbs), mean age--15 years (12-23) at operation, with spastic CP treated with use of SEMLS were included. In all ceases the distal derotational femoral osteotomy, combined with various additional operative correction were performed. Patients were divided into two groups depending on distal RF transfer as a single criteria.

Method: Patients were examined with use of VICON 460 motion analysis system: before and 12 months after operative treatment. Lower limb joints ROM, with changed parameters of coronal and sagittal plane moments, was subjected to detailed analysis, with assessment of influence of mentioned moments on knee joint absolute LV and AV during terminal stance (TS), toe off (TO) and initial swing (IS).

Results: The statistically significant increase in knee joint LV in TS, TO, IS, p < 0,001, before (mean: TS--536.3 mm/s; TO--668.7 mm/s; 826.1 mm/s) and after (mean: TS--828 mm/s; TO--1007.5 mm/s; 174.5 mm/s) treatment was observed and compared to normal healthy adults. The difference in knee joint AV was statistically significant in TS p = 0.018 (mean: before: 82.2 deg/s; after: 81.2 deg/s) and IS p = 0.023 (mean: before: 53 deg/s; after: 20.2 deg/s).

Conclusions: Joints moments improvement, as an outcome of operative treatment, resulted in increase of absolute LV and AV of knee joint towards values of healthy adults, consequently improving CP patients gait.