Relation of Musculoskeletal Strength and Function to Postural Stability in Ambulatory Adults With Cerebral Palsy

OBJECTIVE: To understand the relation of musculoskeletal strength and function to postural stability in ambulatory adults with cerebral palsy (CP) who have already developed muscle atrophy and osteoporosis. DESIGN: Two independent group comparison of adults with CP and those without it. SETTING: Laboratory study. PARTICIPANTS: Thirteen adults with CP with sex (9 women: 4 men), age (21-62y), and Gross Motor Function Classification System I-III, and 13 sex-, age-, and body-weight-matched control participants completed our study (N=26). INTERVENTION: Not applicable. MAIN OUTCOME MEASURE: Bone mineral density (BMD), structural or geometrical deformities (at the proximal region of the femur at the hip joint), and maximal muscular strength (forearm and thigh) were measured. The primary outcome measure was postural stability (balance measured using an automated balance system and a Berg Balance Test). RESULTS: Femoral BMD was significantly lower in the CP group compared to the control group, whereas BMD at lumbar and forearm regions was similar between groups. Geometrical angles, lengths, and diameters at the proximal femur were significantly lower in the CP group. There was a direct relation between BMD in the femoral neck and knee extension peak torque in the control group with no relation in the CP group. Although the control group did not show a relation between muscular strength and balance test, the CP group showed a significant linear relation among improving postural stability with greater levels of muscular strength. CONCLUSION: There were structural differences at the proximal femur and muscular weakness in adults with CP. In adults with CP, balance appears to be more influenced by structural alterations at the femur than muscular strength compared to the control group.