Is There an Association Between Noncontact Anterior Cruciate Ligament Injuries and Decreased Hip Internal Rotation or Radiographic Femoroacetabular Impingement? A Systematic Review.

PURPOSE: To perform a systematic review to determine if there is (1) an association between decreased hip internal rotation and anterior cruciate ligament (ACL) tear rates; (2) an association between radiographic femoroacetabular impingement (FAI) and ACL tear rates; and (3) biomechanical evidence demonstrating increased strain in the ACL of patients with decreased hip internal rotation.

METHODS

A systematic review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies investigating relationships between hip motion, hip radiographs, and ACL tear were sought. Studies with Levels of evidence I-IV were eligible for inclusion. Study methodology/evidence were evaluated using Methodological Index for Non-Randomized Studies (MINORS), Strengthening the Reporting of Observational Studies in Epidemiology (STROBE), and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria.

RESULTS

Eleven studies were analyzed (2 cadaveric in vitro models, 8 clinical studies measuring hip internal rotation (2 concurrently assessing radiographic FAI), and 1 clinical study assessing radiographic FAI alone). Mean MINORS, STROBE, and GRADE for the studies was 82.4%, 20.9 out of 22, and "low," respectively. A total of 959 subjects (84.8% male; mean age 23.6 ± 3.8 years) were analyzed. Overall, 378 subjects sustained 427 ACL tears (399 primary ACL ruptures, 28 reruptures). Six of 8 clinical studies identified a significant association between limited rotation (internal rotation [IR; loss greater than 10°-20°], external rotation [ER], or combined IR + ER [loss greater than 20°]) and ACL tears. Two studies found an association between ACL ruptures and radiographic cam/pincer impingement. Two cadaveric models found a significant association between ACL strain and limited hip internal rotation.

CONCLUSIONS

This systematic review identified a significant association between ACL tear and both limited hip rotation and radiographic FAI.

LEVEL OF EVIDENCE: Level IV, systematic review of Levels II-IV studies.