Comparative injury rates of uninjured, anterior cruciate ligament-deficient, and reconstructed knees in a skiing population

To evaluate the risks of skiing after anterior cruciate ligament injury wit h or without reconstruction, we performed a 3-year study of 5646 skiers emp loyed by a large ski resort. All skiers underwent knee ligament examination s before entering the study. The participants were divided into three group s based on whether they had never had an anterior cruciate ligament injury (N = 4748), were unilaterally deficient of the ligament (N = 138), or had u ndergone a unilateral reconstruction of the ligament at least 1 year before (N = 274). The rates of knee injuries requiring evaluation by a physician or time off work were calculated. The results of the reconstructed knees we re further evaluated to determine whether ligament repair with semitendinos us/gracilis or patellar tendon autograft had a higher injury rate. Compared with knees with intact anterior cruciate ligaments, ligament-deficient kne es had a 6.2-times higher rate of injuries, and knees in which the ligament had been reconstructed had a 3.1-times higher rate. The differences betwee n each of the three groups were significant. Injuries to ligament-intact kn ees were less severe, with 13% requiring surgery, while 39% of the injuries in the ligament-deficient and 41% of the injuries in the reconstructed-lig ament knees required surgery. The rates of injury for the graft types were not significantly different, but skiers with a semitendinosus/gracilis tend on autograft were significantly more likely to rupture their graft than ski ers with a patellar tendon autograft.