Description
Objectives: The aim of this study was to investigate whether the tibial spine volume and femoral notch volume are risk factor for ACL injury. We hypothesized that the tibial spine volume and femoral notch volume would be smaller in individuals who sustained ACL injury compared to uninjured athletes.
Methods: Participants were enrolled following institutional review board approval and providing informed consent. CT scans of both knees were acquired for all participants and the images were segmented using Mimics (Materialise) to create 3D subject-specific bone models. In the same software, the tibial spine volume (Figure 1) and femoral notch volume (Figure 2) were measured from the 3D bone models of the contralateral knee for the ACL injury group and the left knee for the ACL intact group. Tibial spine volume, femoral notch volume, and each of these volumes normalized by tibial plateau area were compared between the ACL injury group and the ACL intact group using the Mann-Whitney U-test.
Results: Fifty-one knees undergoing unilateral anatomical ACL reconstruction (17 female, 34 male: average age 22.0 ± 7.5 yrs.) and 19 knees from healthy collegiate athletes with no previous knee injury (8 female, 11 male: average age 20.1±1.3 yrs.) were included in this study. The tibial spine volume in the ACL injury group (2.14 ± 0.52 cm3) was significantly smaller than in the ACL intact group (2.70 ± 0.72 cm3) (p=0.005). This difference remained even when the tibial spine volume was normalized by tibial plateau area (normalized values: 0.59 ± 0.14, 0.77 ± 0.16 mm3/mm2; p<0.001) (Figure 3). No differences were observed between the femoral notch volume in the ACL injury group (9.50 ± 2.14 cm3) and the ACL intact group (8.73 ± 2.76 cm3) (p=0.121). This difference approached significance when the femoral notch volume was normalized by tibial plateau area (normalized values: 2.59 ± 0.38, 2.44 ± 0.40 mm3/mm2; p=0.069) (Figure 3).
Conclusions: The main finding of this study was that the tibial spine volume of the ACL injury group was smaller than the ACL intact group, however, no differences in femoral notch volume were observed between groups. The tibial spine volume may be a useful measurement for assessing ACL injury risk.
