Favorable outcomes after all-inside repair of complete lateral meniscus oblique radial tears in patients undergoing anterior cruciate ligament reconstruction: A case-series study

<h2>Abstract</h2><h3>Objectives</h3> To evaluate the outcomes of repairing lateral meniscus oblique radial tears of the posterior horn (LMORT) that are complete and originate >1 cm from the posterior root (type 4), during anterior cruciate ligament reconstruction (ACLR) at minimum 2-years of follow-up. <h3>Methods</h3> In this case series (March 2018-March 2023), we included adults undergoing primary ACLR with type 4 LMORT all-inside repair and complete ≥2-year postoperative complication data. We assessed change from baseline and minimal clinical important difference (MCID) rate for Patient Reported Outcome Measures Information System Pain Interference (PROMIS-PI) and Mobility (PROMIS-MO), International Knee Documentation Committee Subjective Knee Form (IKDC), Activity Rating Scale (ARS) and Single Assessment Numeric Evaluation (SANE). Return-to-sport (RTS), same-level RTS and complication (re-tear of lateral meniscus, reoperation, ACLR graft failure, infection, contralateral knee surgery) rates were reported. When available, we evaluated second-look arthroscopy and postoperative magnetic resonance imaging (MRI) findings. <h3>Results</h3> In 16 cases (median follow-up; 37.3 [29.1-65.3] months), improvement was noted in median PROMIS-PI (60.3 [57.7-65.8] vs 43.0 [39.0-48.9]; p<0.001), PROMIS-MO (38.5 [33.5-40.8] vs 61.1 [54.0-66.8]; p<0.001), IKDC (42.0 [23.5-48.0] vs 91.4 [82.8-96.6]; p<0.001) and SANE (25.0 [10.0-38.3] vs 89.0 [80.0-95.0]; p=0.002). No statistically significant differences were observed for ARS (16.0 [13.0-16.0] vs 12.0 [8.0-14.5] p=0.099). MCID rates were 85.7%, 92.9%, 100%, 57.1% and 78.6% for PROMIS-PI, PROMIS-MO, IKDC, ARS and SANE, respectively. RTS and same-level RTS rates were 12/14 (85.7%) and 8/14 (57.1%), respectively. Three (18.8%) patients underwent ipsilateral knee reoperations; none for lateral meniscus re-tear. There was one (6.3%) contralateral knee operation. Excellent LMORT repair healing patterns were observed on available second-look arthroscopies and MRIs. <h3>Conclusions</h3> Our study of patients with type 4 LMORT repair during ACLR supports the limited existing evidence by demonstrating statistically significant improvement in patient reported outcome measures, low complication rates and satisfactory healing patterns. Our findings should further encourage all-inside repair of type 4 LMORTs during ACLR, as it results in high RTS and substantial same-level RTS. <h3>Level of evidence</h3> IV. Case-series. Clinical study