Stretching the triceps surae muscle after 40 degrees C warming in patientswith cerebral palsy

Purpose of the study Equinus in patients with cerebral palsy results from at least two factors: excessive contracture of the triceps surae and muscle retraction. Tendon su rgery and progressive lengthening techniques using plaster walking boots ca n provide variable improvement in retraction. We compared the effect of thi s technique when applied with or without prior 40 degreesC warming in the s ame patients. We also assessed the efficacy of this treatment method in ter ms or degree of retraction, patient age, puberty maturity, and sex. Materials and methods This series included 70 muscles in 52 patients with cerebral palsy aged 2 y ears 11 months to 21 years (mean 8 years 3 months). Common features in thes e patients were: - equinus mainly explained by triceps retraction, - no history of prior surgery on the triceps tendon, - knee flexion less than 15 degrees in the upright position, - easily reduced lateral deformation of the foot, - absence of mediotarsal dislocation, - triceps stretching could be achieved without triggering unacceptably inte nse contracture. The retraction of the triceps surae was measured from the maximal passive d orsal flexion angle of the foot, before and after applying each stretching boot. The difference between these measurements gave the gain obtained with the plaster boot. Protocol R- (stretching with plaster boot) consisted in a series of slow stretchings for 10 minutes before making the boot which wa s worn 7 days. Recurrent retraction in these same patients warranted anothe r treatment within a delay of 3 to 17 months (mean delay 8.7 months). The s ame treatment then followed protocol R+ where the stretching was preceded b y immersion of the segment in a 40 degreesC water bath for 10 minutes. Results Mean gain obtained with protocol R+ (warming) was 6.8 degrees knee extended and 7.1 degrees knee flexed. These differences were highly significant in both cases (p < 0.0001). We had no failures with protocol R+ while with pro tocol R- (stretching without warming) the gain was nil or less than 5<degre es> for 29 muscles knee extended and for 32 muscles, knee flexed. The gain was not related to age, sex or puberty maturity. It was not related to the angle of dorsal flexion of the foot prior to stretching. Discussion Our findings demonstrate that when the conditions allowing prolonged stretc hing of the triceps surae are present, prior warming at 40 degreesC for 10 minutes leads to an improvement in muscle lengthening in all patients, even in those for whom prior treatment had been unsuccessful without warming. T his observation would indicate that the mechanisms allowing greater lengthe ning are present in all patients with cerebral palsy but that they cannot b e triggered due to abnormal muscle viscosity related to distal vasomotor di sorders frequently observed in this condition. Further research is needed t o detail this point.