Distraction forces on repaired bucket-handle lesions in the medial meniscus

Background: Numerous studies have investigated the biomechanical properties of meniscal repair techniques. One of the most commonly discussed parameters is the failure load in the axis of insertion, although little is known about the distraction forces actually occurring at repaired bucket-handle lesions. Hypothesis: There are clinically relevant distraction forces on repaired meniscus bucket-handle lesions. Study Design: Controlled laboratory study. Methods: Meniscus bucket-handle lesions were created and repaired in human cadaveric knees with a vertical suture made from a braided steel wire. A small-sized load sensor was connected to the wire at the periphery of the meniscus. The distraction forces acting on the lesion were measured at different knee joint angles (0 degrees-120 degrees of flexion) with internal and external rotation and with and without weight loading. Forces in excess of 10 N were considered to have clinical relevance. Results: Mean forces on the meniscus repair ranged from 1.64 to 4.72 N.. Irrespective of the modalities (ie, different flexion angles, weight load, direction of rotation), it was found that the forces were well below the cutoff value of 10 N (P <.01). Increasing flexion angles generally did not cause an increase in distraction forces. Conclusion: The data suggest that distraction forces are riot the primary factor in the mechanical stability of meniscal repair. It must therefore be assumed that other factors such as shear forces are of greater significance. Clinical Relevance: The results may help to validate the biomechanical properties of different, meniscal repair techniques.