Restoring normal gait after limb salvage procedures in malignant bone tumours of the knee.

Eleven patients exhibiting decreased strength of knee extension following wide resection and prosthetic reconstruction for malignant bone tumors of the knee performed gait exercises with compensatory muscle training. Two patients whose knee extension strength was assessed as manual muscle test (MMT) grade 4 were able to develop a gait with double knee action and to maneuver stairs, step-by-step, due to compensation by the gluteus maximus, biceps femoris, and gastrocnemius muscles. Four patients whose knee extension strength was less than MMT grade 4, and whose ankle dorsal and plantar flexion was MMT grade 4 or higher, acquired the ability to go up and down stairs step-by-step, although their gait pattern was a knee-extended gait. Electromyographic studies demonstrated continuous discharges of the gluteus maximus, biceps femoris, and gastrocnemius muscles during the stance phase as compensation for decreased strength in knee extension.