RESUMO
PURPOSE: Femoroacetabular impingement may be associated with anterior cruciate ligament (ACL) injuries. The purpose of this study was to determine the head-neck offset, as measured by 45° Dunn's view alpha angles, in patients with ACL injuries compared to control subjects. METHODS: In this retrospective study, 140 consecutive non-professional athletes with primary ACL ruptures confirmed with knee arthroscopy and 100 consecutive patients with non-ACL injury were enrolled. Hip range of motion was assessed in lower extremities in all participants, and alpha angle was calculated according to 45° Dunn's view radiographs. RESULTS: There is not any difference in age, gender distribution, height, weight, and BMI between groups. Internal rotation, abduction, and adduction of the hip were significantly decreased in ACL-injured patients comparing with control subjects (p < 0.001). ACL-injured patients had also a significantly higher alpha angle comparing to the control individuals (p < 0.001). The mean of alpha angle in the ACL-injured patients was 56.1 (SD 10.1) and in the non-ACL-injured group was 49.3 (SD 9.4). CONCLUSIONS: The patients in ACL-injured group showed a significant restriction in hip range of motion and also a diminished femoral head-neck offset suggesting a possible role of these findings in the outcome assessed. LEVEL OF EVIDENCE: III.