Graft Angle, Intercondylar Notch Osteophytes, and Tibial Tunnel Abnormalities Influence Graft Impingement After Anterior Cruciate Ligament Reconstruction: A Retrospective MRI-Based Study

Graft impingement is a critical cause of anterior cruciate ligament reconstruction (ACLR) failure. Identifying its contributing factors is essential for improving surgical outcomes. This retrospective study aimed to evaluate the incidence of graft impingement following ACLR using magnetic resonance imaging (MRI) and to investigate potential anatomical and surgical risk factors. The findings are intended to provide theoretical support for reducing impingement rates and enhancing functional recovery. We retrospectively reviewed clinical and MRI data of 122 patients (68 males and 54 females) who underwent ACLR at our institution from January 2015 to December 2023. MRI was used to identify graft impingement and to measure potential anatomical and surgical factors, including graft angle, posterior tibial slope, tibial intercondylar eminence angle, intercondylar notch width, notch height, and roof inclination, tibial tunnel position, preoperative and postoperative tibial displacement (measured as anterior tibial translation), and concomitant injuries. Patients were categorized based on the presence or absence of impingement. Univariate analysis was followed by multivariable logistic regression to identify independent risk factors. Graft impingement occurred in 65 patients (53.3% of cases). Multivariable logistic regression revealed that smaller graft angles (odds ratio [OR] = 0.930, 95% confidence interval [CI]: 0.873-0.991, <i>p</i> = 0.026), anterior-inferior osteophytes of the intercondylar notch roof (OR = 3.620, 95% CI: 1.408-9.311, <i>p</i> = 0.008), bony abnormalities at the tibial tunnel inlet (OR = 3.814, 95% CI: 1.509-9.632, <i>p</i> = 0.005) and postoperative tibial displacement >5 mm (OR = 6.573, 95% CI: 1.120-38.582, <i>p</i> = 0.037) were independent risk factors for graft impingement. Graft impingement after ACLR is independently associated with reduced graft angle, anterior-inferior osteophytes of the intercondylar notch, excessive postoperative tibial displacement, and bony protrusions at the tibial tunnel inlet. These findings emphasize the importance of accurate tunnel positioning and anatomical assessment during surgery to improve patient outcomes.