A prospective cohort study of anterior cruciate ligament injuries in elite Norwegian team handball.

The purpose of this study was to examine gender differences in the incidence of anterior cruciate ligament (ACL) injuries in a population of high-level team handball players. We also wanted to examine injury mechanisms and possible risk factors for ACL injuries, including menstrual status. The study was done prospectively during the 1993-94, 1994-95, and 1995-96 seasons. We found 28 ACL injuries, 23 among women (incidence: 0.31 +/- 0.06 injuries per 1000 player hours) and 5 among men (0.06 +/- 0.03 inj./1000 h; P < 0.001 vs women; risk ratio: 5.0). Of the 28 injuries, 24 occurred during competition (0.91 +/- 0.19 inj./1000 h; women: 1.60 +/- 0.35 inj./1000 h; men: 0.23 +/- 0.13 inj./1000 h; P < 0.001 vs. women; risk ratio: 7.0) and 4 during training (0.03 +/- 0.02 inj./1000 h; P < 0.001 vs. competition; risk ratio: 29.9). Nearly all the injuries (n = 25) occurred in non-contact situations when the players performed high-speed plant-and-cut movements which they were well accustomed to. A reliable menstrual history could be obtained in 17 of the 23 cases among females. Five of the injuries occurred in the menstrual phase, 2 in the follicular phase, 1 in the early luteal phase and 9 in the late luteal phase (chi-square3 d.f. = 13.2; P < 0.01). The results suggest that there may be an increased risk of ACL injury during the week prior to or after the start of the menstrual period.