Knee performance after anterior cruciate ligament reconstruction

The aim of this study was to determine differences in isokinetic performance, hop tests, range of motion and thigh circumference between the involved and uninvolved leg in patients after 4, 5, 6 and 8 months after anterior cruciate ligament (ACL) reconstruction and to investigate the possible correlation between the different evaluation methods. Fourteen male subjects submitted to intra-articular reconstruction of the anterior cruciate ligament with patellar tendon graft. All parameters improved from the 4th to the 8th month post-op. The deficits were more pronounced for the quadriceps than for the hamstrings, which regained full function at 5 months. Quadriceps performance and thigh circumference were impaired even after 8 months. According to the Lysholm Score, all subjects scored at least as good function and 54% had excellent results. There was a positive correlation between quadriceps performance and both single and triple hops (0.51-0.63), whilst for the harmstrings the correlations were weak (0.32-0.44). We conclude that: 1) Individuals with anterior cruciate ligament injury present quadriceps weakness even after 8 months of the reconstructive surgery using patellar tendon graft; 2) when an isokinetic dynamometer is not available, horizontal impulse tests can be used to evaluate quadriceps deficiency; 3) thigh circumference should not be used as a measurement to predict muscle performance; 4) the Lysholm Score is not sensitive to detect limitations in muscle performance.