Prominent Resident’s Ridge as a Potential Cause of Anterior Cruciate Ligament Impingement: A Case Report

BACKGROUND: The resident’s ridge is an arthroscopic landmark that is consistent with the anterior border of the anterior cruciate ligament (ACL) femoral attachment. The identification of the landmark allows for accurate graft placement. CASE REPORT: We report a case of a 30-year athletic individual with an ACL-deficient knee, who had an abnormally large resident’s ridge, abutting the midsubstance of the torn ACL; the residual femoral attachment was behind the ridge. Resection and burring of this ridge were needed to expose the posterior aspect of the intercondylar notch; even after bone-patellar tendon-bone graft placement, some additional removal of bone had to be done to reduce graft impingement on this area in extension. CONCLUSION: Abnormal resident’s ridge may be misleading about the anatomy of the lateral femoral condyle area. Appropriate resection of abnormal bone is the key to the identification of femoral footprint and graft placement. We speculate that this bony projection may even have contributed to the ACL injury, and extra bone had to be removed to minimize subsequent impingement.