Assessment of quadriceps/hamstring strength, knee ligament stability, functional and sports activity levels five years after anterior cruciate ligament reconstruction

The purpose of this study was to examine individuals 5 years after ACL reconstruction and analyze changes involving strength, stability, function, and sports activi ties. Nineteen males and six females, mean age =31.4± 7.31 years, participated in this study. Fifteen subjects had received extraarticular and ten subjects had re ceived intraarticular ACL reconstructions. Subjects completed a 100 point subjective functional activity questionnaire and a sports participation survey. Knee ligament stability was assessed during an objective knee examination. Isokinetic quadriceps and hamstring muscle strength were tested at 240 and 120 deg/sec using the Cybex II dynamometer. Anterolateral rotatory instability and positive Lachman were elicited on the operated leg for 80% of the subjects. No significant relationship was found between objective instability and the functional activity score. For the intraarticular group, a significant correlation (P < 0.05) was found between increased quadriceps and hamstring strength on the operated leg and return to functional activities. Sub jects' functional activity score was positively correlated (P < 0.001) with their ability to participate in sports. Subjects participating in sports involving cutting and twisting motions were less successful in returning to their preinjury participation levels and reported more subjective complaints of pain, swelling, and/or instabil ity. These results indicate that long-term progressive rehabilitation emphasizing increased quadriceps and hamstring strength to approximate the nonoperated leg may enhance successful return to functional and sports activities after ACL reconstruction.