The occurrence of ACL injury influenced by the variance in width between the tibial spine and the femoral intercondylar notch.

PURPOSE: The purpose of this study was to reveal the influence of the variance in width between the tibial spine and the femoral intercondylar notch on the occurrence of ACL injury. METHODS: Thirty-nine subjects undergoing anatomical ACL reconstruction (30 female, 9 male; average age 29 +/- 15.2) and 37 subjects with intact ACL (21 female, 16 male; average age 29 +/- 12.5) were included in this study. In the anterior-posterior knee radiograph, tibial spine height, and the length between the top of the medial and lateral tibial spine (tibial spine width) were measured. In axial knee MRI exhibiting the longest femoral epicondylar length, intercondylar notch outlet length was measured and notch width index was calculated. Tibial spine width/notch outlet length, and tibial spine width/notch width index were compared between the ACL tear and intact groups. RESULTS: Tibial spine width/notch outlet length of the ACL tear and intact groups was 0.6 +/- 0.1 and 0.7 +/- 0.1, respectively. Tibial spine width/notch width index of the ACL tear and intact groups was 0.4 +/- 0.1, and 0.6 +/- 0.1, respectively. Both parameters were significantly larger in the ACL intact group. CONCLUSION: Both tibial spine width/notch outlet length and tibial spine width/notch width index were significantly smaller in the ACL tear group when compared with the ACL intact group. The occurrence of ACL injury influenced by the variance in width between the tibial spine and the femoral intercondylar notch. LEVEL OF EVIDENCE: III.