Abstract
The aim of this study was to analyze long-term changes in muscle strength and jumping ability and to assess the relationship between these parameters after anterior cruciate ligament (ACL) reconstruction. Sixty-three patients (39 men) with a mean age of 30.3 years (range 19–42) who underwent an ACL reconstruction between 1990–1992 participated in the study. Quadriceps and hamstring isometric and isokinetic strength as well as one-leg hop test for distance were measured preoperatively and six months 1, 2, 3 and 10 years postoperatively. The injured leg was significantly weaker than the non-injured leg in knee extension strength on all test occasions and in knee flexion strength except at ten years. There was a strong correlation between the muscle strength tests at different speeds. The one leg hop for distance showed significant differences between the injured and non-injured leg on all test occasions. A moderate to high correlation was observed between muscle strength and jumping ability with higher values for the non-injured leg. In our study we found a persisting weakness in the quadriceps as well as jumping ability during ten years. This is an indication that it is hard to recover the preoperative functional level after an ACL reconstruction.