The purpose of this study was to evaluate knee muscle strength following anterior cruciate ligament (ACL) reconstruction in female. We treated 12 female patients with a bone-patellar tendon-bone autograft (BTB) and 29 female patients with a semitendinosus-gracilis autograft (STG) in ACL reconstruction. Knee extensor and flexor strength were measured by KIN-COM before operation, and 3 months, 6 months and 9-12 months after operation. The angular velocity was set at 60 and 180 degrees/second. The results showed that the STG group was better than BTB group on extensor and flexor muscle strength after 3 and 6 months, but there were no significant differences after 9 to 12 months. BTB group patients over 30 years of age showed the worst recovery of extensor muscle strength after 9 to 12 months. The results suggest a delay or deficit in the recovery of knee muscle strength in middle-aged female with BTB in ACL reconstruction.
