[Does footprint and foot progression matter for ankle power generation in spastic hemiplegic cerebral palsy?].

OBJECTIVES: We investigated how foot pressure pattern and foot progression relate to power generation from the ankle joint in children with spastic hemiplegic cerebral palsy (CP).

METHODS: The study included 35 children (13 girls, 22 boys; mean age 8.8 years; range 4 to 19.8) with CP, all having independent ambulation. The children underwent three-dimensional gait analysis and a set of pedobarographic data were obtained. The pedobarographs were analyzed by dividing the foot into five segments.

RESULTS: The mean power generation from the ankle was 7.6 watts/kg on the hemiplegic side, and 15.9 watts/kg on the uninvolved side (p=0.000). Based on the pedobarographic data, hemiplegic feet exhibited significantly less heel pressure/impulse (8.0 vs. 24.7; p=0.000), time to heel rise (32.1% of stance phase vs. 61.9%; p=0.000), and decreased pressure of the medial forefoot segment (40.8 vs. 52.2; p=0.009). The children were divided into two groups depending on the ankle power generated on the hemiplegic side (<8.0 watts/kg and =/>8.0 watts/kg). Those with an ankle power generation of =/>8.0 watts/kg had significantly longer step length (49 cm vs. 41 cm; p=0.001) and increased velocity (109 cm/sec vs. 89 cm/sec; p=0.000) in gait analysis, and in pedobarographic measurements, increased heel impulse (11.6 vs. 4.4; p=0.047), time to heel rise (46.6% vs. 17.1%; p=0.000), and less varus/valgus positioning (11.1 degrees vs. -34.6 degrees ; p=0.013). In bivariate correlation analysis, ankle power generation on the hemiplegic side demonstrated a significant association with time to heel rise (r=0.574; p=0.000) and varus/valgus positioning (r=0.420; p=0.017), and almost a significant association with heel pressure (r=0.342; p=0.052).

CONCLUSION: Deviations in the pedobarographic data are reflected in the power generation of the ankle joint and can be of help in decision making of treatment in spastic hemiplegic CP. We speculate that efforts to normalize the heel segment pattern may result in decreased power generation differences.