This study was to investigate the effect of stability of the anterior cruciate ligament (ACL)-reconstructed knee between lateral meniscus posterior root (LMPRT) repair and partial meniscectomy.

The patients with ACL tear and LMPR injury were enrolled in this study (group A: ACL reconstruction+LMPR repair, 17 patients; group B: ACL reconstruction+LMPR partial meniscectomy, 10 patients). At the same time, the patients who underwent ACL reconstruction for simple ACL tear were randomly matched as the control group (group C). All patients had at least 12-month follow-up. Lysholm score and International Knee Documentation Committee (IKDC) score were used to assess the knee function of the patients. The physical examination was assessed using the pivot shift test. Anterior tibial subluxation (ATS), lateral meniscal extrusion (LME), Tibial Tubercle-Trochlear Groove (TT-TG) distance, femorotibial rotation (FTR) angle, and the lateral compartment cartilage of the knee were assessed via magnetic resonance imaging (MRI).

A total of 45 patients were enrolled in this study, with 30 males and 15 females, and an average age of (33.98±11.00) years. The follow-up period was (14.54±1.88) months. Compared to the preoperative measurements, at the latest follow-up, patients in all groups demonstrated significant improvements in Lysholm scores, IKDC scores, ATS, TT-TG, and FTR results (P<0.05). There was a significant difference in the degree of preoperative LME in group A patients compared with the values of the last follow-up (P<0.05). Intergroup comparison: (1) Preoperatively, there were significant differences in Lysholm score, IKDC score, pivot shift test, ATS, and LME in group C compared with groups A and B (P<0.05), and there was no significant difference in TT-TG and FTR in each group (P>0.05). (2) Postoperatively, there was a significant difference in the results of the pivot shift test in group B compared with groups A and C (P<0.05), and there was no significant difference in the results of the pivot shift test between groups A and C (P>0.05). (3) At the last follow-up, there were significant differences in the patient-reported scores and LME in group B compared with groups A and C (P<0.05). There was a significant difference between group B and group C in ATS, and there was no significant difference between group A and group C in patient-reported scores, ATS, and LME (P>0.05). There was no significant difference in TT-TG and FTR in each group (P> 0.05).

LMPRT repair further improves the anterior and rotational stability of the ACL-reconstructed knee, leading to reduced the LME, and improves the patient-reported scores.