Decrease in peripheral muscle strength and ankle dorsiflexion as long‐term side effects of treatment for childhood cancer

BACKGROUND: This study investigated muscle strength, passive ankle dorsiflexion, and their association with motor performance in children after treatment for acute lymphoblastic leukemia, Wilms tumor, B-non-Hodgkin lymphoma, and malignant mesenchymal tumors. PROCEDURE: Muscle strength was assessed with a hand-held dynamometer and ankle dorsiflexion with a goniometer in 92 and 64 survivors, respectively. Motor performance was measured with the Movement Assessment Battery for Children (movement-ABC). Age at testing: 6.1-12.9 years. Mean time since completing treatment: 3.3 years. Results were compared to 155 healthy controls. RESULTS: Muscle strength of the survivors was reduced in ankle dorsiflexors on both sides (P < 0.001), wrist dorsiflexors on the non-dominant side (P < 0.001), and pinch grip on the non-dominant (P = 0.001) and dominant side (P = 0.01). Passive ankle dorsiflexion of the survivors was significantly less on both sides (P < 0.01). Movement-ABC percentile score was affected by pinch grip strength on the non-dominant (P < 0.004), and dominant side (P = 0.024) but not by strength of other muscle groups or by passive ankle dorsiflexion. CONCLUSION: Peripheral muscle strength and ankle dorsiflexion are reduced in the long-term in children treated for cancer with chemotherapy. However, neither decreased muscle strength nor reduced ankle dorsiflexion could completely explain reduced scores on the movement-ABC.