Abstract
INTRODUCTION: The risk of post-traumatic osteoarthritis remains high even after anterior cruciate ligament reconstruction (ACLR). Medial meniscal extrusion (MME) is a valuable clinical sign as an early morphological change. This study aimed to analyze MME before and after ACLR and investigate the factors affecting postoperative MME. MATERIALS AND METHODS: This study included patients who underwent anatomical double-bundle ACLR between January 2016 and July 2021. MME was measured using MRI preoperatively and one year postoperatively. The medial meniscus (MM) treatments were categorized into three groups: no MM injury and no repair (no injury/no repair (N/N)), MM injury but no repair (injury/no repair (I/N)), and MM injury and repair (injury/repair (I/R)). We investigated the factors influencing MME after ACLR using multiple linear regression analysis and compared MME before and after ACLR using paired t-tests. RESULTS: This study included 133 patients, of whom 90 (37 males and 53 females) were analyzed. The mean age of the patients at surgery was 27.5 years, and 41, 27, and 22 patients were assigned into N/N, I/N, and I/R groups, respectively. Preoperative MME (p<0.001) and I/R (p<0.001) had significant effects on postoperative MME in a regression analysis. Postoperative MME had greater effects than the preoperative MME in all cases (1.16 and 1.53 mm (p<0.01)) and in every MM treatment group (N/N: 1.02 and 1.32 mm (p<0.01), I/N: 1.16 and 1.44 mm (p<0.01), and I/R: 1.42 and 2.05 mm (p<0.001)). CONCLUSIONS: Larger preoperative MME and receiving MM repair were significantly associated with a larger MME after ACLR. Postoperative MME in ACLR patients was significantly greater than preoperative MME.