Outcomes of lateral meniscus posterior root tear repair combined with anterior cruciate ligament reconstruction after at least two years of follow-up

OBJECTIVES: The purpose of this study was to review the outcomes of lateral meniscus posterior root tear (LMPRT) repair at a minimum follow-up of two years. It was hypothesized that LMPRT repair would result in a low rate of surgical revision with good knee laxity control and satisfactory objective and subjective scores. METHODS: This was a retrospective study analyzing prospectively collected data. All patients who underwent primary ACL reconstruction from March 2015 to August 2018, performed by two surgeons (blinded), were considered for study eligibility. Clinical evaluations were performed at 3, 6,12 and 24 months. Patients were assessed pre- and postoperatively with the objective and subjective International Knee Documentation Committee (IKDC) evaluation form, the Lysholm score and the Tegner Activity Scale (TAS). Complications and revision surgeries were also recorded. RESULTS: The final study population comprised 99 LMPRT repairs. Ten (10.1%) patients underwent ipsilateral revision surgery at a mean follow-up of 42 months, for a total of 11 procedures. There was one graft failure with concomitant LMPRT at 25 months follow-up due to a high-risk sport trauma in a professional athlete. Postoperative side-to-side laxity significantly decreased at the last follow-up with a mean of 0.6 ± 0.7 mm (p <0.0001). The mean preoperative subjective IKDC score was 56.2 ± 13.9 and increased to 86.9 ± 7.6 postoperatively (p <0.0001). The Lysholm score was 61.6 ± 13.1 before surgery and 90.7 ± 6.7 after surgery (p <0.0001). The mean preoperative TAS was 7.1 ± 1.1 and decreased to 6.6 ± 1.3 postoperatively (p <0.006). Arthroscopic healing was obtained for the ten patients who underwent revision surgery. Nine of these patients (90%) had arthroscopic proof of a fully healed LMPRT. One patient did not heal completely and required arthroscopic resection. CONCLUSION: LMPRT occurs concomitantly with ACL injury in 6 to 12% of the cases and repair should be routine. This is supported by excellent postoperative results after LMPRT repair at a minimum follow-up of 2 years.