The objective of this study is to determine if surgical lengthening of the hamstrings and gastrocnemius/Achilles complex, affect muscle tone in patients with cerebral palsy. The question is if the dynamic component of muscle length changes after orthopedic surgery. A retrospective study was performed on ambulatory children with cerebral palsy who underwent either hamstring lengthening or gastrocnemius/Achilles tendon lengthening. A total of 135 consecutive patients with an average age of 13 years were included in the study. A single random side was selected for children with bilateral surgery and the affected limp was analyzed for those undergoing unilateral surgery. The popliteal angle was performed with a quick and slow stretch, as well as, the ankle dorsiflexion, and measured with a goniometer.

The difference between initial grab with fast stretch, and end of range (EOR) with slow stretch was used as a measure of spasticity. The Bohanon modification of the Ashworth score was also assessed. 18° popliteal angle improvement in end of range and 32° improvement in quick stretch in the hamstrings group were notice postoperatively, with change in slow stretch, quick stretch and Δml (comparison between quick and slow stretch) being significant at p< .0001. In the triceps surae group, 14° ankle dorsiflexion improvement in end of range, and 18° improvement in quick stretch were noticed postoperatively, with change in slow stretch, quick stretch and Δml at p< .0001, p< .0001, and p< .0180 respectively. Asworth scale was reduced by at least one grade in 89% of subjects in the hamstring group and 78% of subjects in the triceps surae group of the children with preoperative Asworth 3 and above. We concluded that significant decreases in spasticity were observed following tendon lengthening in children with cerebral palsy and that the orthopedic surgery can affect both static and dynamic components of muscle tightness in these children.