Intercondylar notch encroachment following anterior cruciate ligament reconstruction: a prospective study.

Intercondylar notch impingement is a recognized cause of graft failure following anterior cruciate ligament (ACL) reconstruction and typically is attributed to anterior tibial tunnel placement or inadequate notchplasty. This prospective study assessed the incidence and nature of notch regrowth following initial ACL reconstruction. The study population was comprised of 36 patients who underwent ACL reconstruction using a patellar tendon-bone autograft. A 3- to 5-mm notchplasty was performed in all patients, and an intraoperative radiograph was taken confirming proper tunnel placement. Magnetic resonance imaging (MRI) was performed the first week following surgery and again at 6 months. The MRIs were reviewed by two skeletal radiologists to evaluate postoperative notch and graft changes. Of the 36 study patients, 28 (78%) knees showed no evidence of graft impingement as defined by graft indentation and intra-substance edema. The MRIs of 8 (22%) patients showed evidence of graft impingement. Four patients had clinical signs of graft impingement, namely persistent effusion or lack of full extension. Arthroscopically, 3 of these patients demonstrated graft encroachment and impingement by fibrocartilage with areas of immature bone. These results indicate that graft impingement from regrowth of the notch is a clinically relevant phenomenon that could potentially result in late graft demise in the ACL-reconstructed knee.