Meniscal sutures: biomechanical study of “mulberry” and horizontal loop techniques

BACKGROUND: This in vitro biomechanical study tested the pullout strength of meniscal repair in human menisci using two different biodegradable suture techniques: the “mulberry” and the horizontal loop. MATERIALS AND METHODS: Fifty-five human menisci were used, to which a longitudinal tear of 1.5 cm was applied. If the thread broke or the knot was pulled inside the suture, as happened with the mulberry technique, the repair was considered a failure. Furthermore, we evaluated possible lesions of the meniscus due to changes the structural properties caused by the suture, leading to the loss of elastic return. RESULTS: The results showed there was a statistically significant difference between the two suture techniques used and the unsutured menisci. Furthermore, five menisci with vertical sutures were analyzed for which the breakup loads were superior to the breakup loads of the mulberry suture and the horizontal loop suture. Nevertheless, the load strengths with respect to elastic return were similar to those of the mulberry and the horizontal loop techniques. Finally, in five menisci, we analyzed the suture–healthy meniscus interface, and found breakup values similar to those of the unsutured meniscus. CONCLUSIONS: Our results show the need to perform meniscal sutures and the futility of sutures that are intended to withstand elevated loads such as traction strengths of >30 N, as these produce irreparable secondary lesions that alter the histological structure of the meniscus and prevent healing.