Transtibial repair of medial meniscus posterior root tears: Interference screw fixation improves primary stability in a porcine model.

Purpose: This porcine study aimed to evaluate surgical refixation methods for medial meniscal root tears. We compared biomechanical characteristics of tibial fixation using an interference screw (IS) and fixation with an Endobutton (EB). Methods: Forty porcine knee joints were prepared with radial section for a complete detachment of the medial meniscus posterior root (MMPR), followed by transtibial pull-out refixation. Specimens were randomly assigned to four groups based on fixation method and suture material: IS (STORZ PEEK Power Fix 7 × 25 mm, Storz, Tuttlingen, Germany) or EB (Smith & Nephew, London, UK), each combined with two single stitch sutures of either FiberWire size 2 (FW; Arthrex, Naples, USA) or SutureTape 1.3 mm (ST; Arthrex, Naples, USA). Constructs were subjected to cyclic loading (1000 cycles), followed by load-to-failure testing. Biomechanical parameters assessed included elongation, stiffness, yield load, maximum load to failure and failure mode. Results: Fixation with IS (Groups 1 and 2) demonstrated significantly lower elongation and greater stiffness compared to EB fixation (Groups 3 and 4). Specifically, Group 2 (IS + FW) showed significantly reduced elongation versus both EB groups ( Conclusion: In this porcine model, transtibial pull-out repair of MMPR tears using IS demonstrated superior primary biomechanical stability compared to EB fixation. Constructs with IS showed reduced elongation and increased stiffness under load. However, to confirm the clinical relevance of these findings, further investigations in clinical settings are necessary. Level of Evidence: N/A.