Neurovascular Safety and Clinical Outcome of Outside-in Repair of Tears of the Posterior Horn of the Medial Meniscus

PurposeThe purpose of this study was to evaluate the safety and clinical outcome of a new posterior approach for the known outside-in technique for repair of tears of the posterior horn of the medial meniscus (PHMM).MethodsFirst, a cadaveric study was performed on 6 cadaveric knees to assess the safety of a point just lateral to the semitendinosus tendon as an entry point for outside-in repair. Dissection was done to measure the clearance of this point to the nearby popliteal bundle and saphenous nerve. A prospective case series study was then performed to assess the clinical outcome of such an approach. We treated 41 consecutive cases with PHMM tears by the outside-in technique using a shuttle relay method through the same point. Clinical assessments, magnetic resonance imaging findings, Lysholm scores, and International Knee Documentation Committee subjective scores were recorded for all patients. After a minimum postoperative period of 2 years, all cases were re-evaluated and re-scored.ResultsThe cadaveric study showed a mean clearance distance of 2.4 cm for the popliteal bundle and 4.6 cm for the saphenous nerve. The case series study was done on 41 meniscal repairs; 15 of 41 cases (37%) were performed in conjunction with anterior cruciate ligament reconstruction. There were 22 right knees (54%) and 19 left knees (36%). After a mean follow-up period of 27 months, patients showed a clinical success rate of 88% in terms of disappearance of pain, locking, and swelling, together with improved Lysholm scores (from 34 to 88) and International Knee Documentation Committee scores (from 25 to 88). These improvements were statistically significant (P < .05).ConclusionsAn outside-in repair technique with a posterior entry central to the semitendinosus tendon was used safely with 88% satisfactory clinical results for treatment of PHMM tears.Level of EvidenceLevel IV, therapeutic case series.