Biomechanical Properties of Meniscal Repair Versus Meniscectomy for Horizontal Meniscal Tears: A Systematic Review.

Background: Limited biomechanical evidence exists describing how horizontal meniscus tears (HMTs), meniscal repair (MR), and meniscectomy alter the knee's biomechanical environment.

Purpose: To evaluate changes in knee contact mechanics following HMTs, MR, and meniscectomy.

Study Design: Systematic review; Level of evidence, 5.

Methods: PubMed, EMBASE, and CINAHL databases were systematically searched for biomechanical cadaveric studies of HMTs up to January 16, 2023, using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies that (1) did not examine MRs or meniscectomies, (2) did not report contact area (CA) or pressure, (3) involved concomitant injuries (eg, anterior cruciate ligament tear), (4) were nonbiomechanical studies (eg, review, technique, and clinical), and (5) were non-English language articles were excluded. The endpoints were peak contact pressure (PCP) and mean CA.

Results: Out of 1526 initial results, 6 studies were included for final review. PCP and CA were measured in 59 intact menisci, 59 HMTs, 59 partial meniscectomies (PM), 59 complete meniscectomies (CM), and 33 MR. Among all HMTs versus the intact state, pooled PCP increased by 14.2%, and pooled CA decreased by 7.1%. Among all PMs versus the intact state, 4 of 6 studies found significantly increased PCP (27.1%), and 5 found significantly reduced CA (22.1%). Among all CMs versus the intact state, all 6 studies found significantly increased PCP (54.5%), and 5 found significantly reduced CA (33%). Among the 3 studies directly comparing PM to CM, 2 studies found PM to have significantly smaller increases in PCP (23.3% vs 52.4%) and significantly smaller reductions in CA (16.7% vs 28.1%) from the intact state.) The 3 studies evaluating MR versus the intact state found no significant difference in PCP or CA.

Conclusion: After an HMT, MR had the smallest deviations in contact mechanics; only MR restored contact mechanics to the uninjured state. These findings support MR's superiority, illustrate that maintaining contact mechanics requires preserving meniscal tissue, and are consistent with clinical evidence. More clinical comparisons are needed to understand the differences among treatments.