Surgical Management of Horizontal Cleavage Tears of the Medial Meniscus: A Biomechanical Analysis During Simulated Gait

BACKGROUND: Horizontal cleavage tears (HCTs) comprise one-quarter of all diagnosed meniscal pathologies. Despite several static/quasi-static cadaveric studies showing that HCTs and their repairs do not change contact mechanics while leaflet resections do, it is unclear if these conclusions hold during activities of daily living. HYPOTHESIS/PURPOSE: The purpose of this study was to quantify the comparative biomechanical effects of meniscal HCT, HCT repair, and leaflet resection on joint contact forces throughout simulated gait. It was hypothesized that HCT repair would not change contact mechanics relative to the intact meniscus, while inferior meniscal leaflet resection would lead to increased contact stress and decrease contact areas throughout simulated gait. STUDY DESIGN: Controlled laboratory study. METHODS: Six human cadaveric knees were placed on a multidirectional dynamic simulator. Electronic pressure sensors were inserted across the medial tibial plateau, and contact forces throughout simulated gait were quantified. Contact stress, contact area, and percent meniscal loading were quantified for intact, HCT, HCT repair, and inferior leaflet conditions. RESULTS: No significant differences in contact mechanics occurred between the intact meniscus and HCT or between the intact meniscus and HCT repair. Inferior leaflet resection resulted in a statistically significant decrease in contact area during the early, mid-, and late stance of the simulated gait cycle; a significant decrease in percent meniscal loading between 8% and 60% of simulated gait; and a small but significant increase in peak contact stress during the midstance phase of the simulated gait cycle between 19% and 30% of simulated gait. CONCLUSION: The authors failed to reject the null hypothesis as there was no significant difference observed between meniscal HCT repair and the intact meniscus, while resection of the inferior leaflet was associated with a small but statistically significant increased peak contact stress, decreased contact area, and decreased percent meniscal loading during simulated gait. Taken together, these results support that when an HCR tear is symptomatic, meniscal preservation is preferable over inferior leaflet resection in the biomechanical management of horizontal cleavage meniscal tears. CLINICAL RELEVANCE: These cadaveric tests suggest that horizontal cleavage meniscal tears of the medial meniscus posterior horn are not biomechanically detrimental to joint contact forces during simulated gait. If they must be surgically treated for symptomatic reasons, meniscal repair is biomechanically favorable over inferior leaflet resection.