Comparison of elastic versus rigid suture material for peripheral sutures in tendon repair

Abstract Background For secure tendon repair, while core suture materials have been previously investigated, the optimum material for peripheral sutures remains unclear. Methods Transected bovine gastrocnemius tendons were repaired by 2-strand side-locking loop technique using no.2 braided polyblend polyethylene thread for the core suture. Then, 8-strand peripheral cross-stitches were added using either 2–0 rigid sutures (braided polyblend polyethylene) or USP 2-0-sized elastic sutures (nylon). The holding area of each peripheral suture was set at either 3 × 1 mm (shallow holding) or 6 × 2 mm (deep holding). Therefore, 4 groups were compared (the shallow-rigid, deep-rigid, shallow-elastic, and deep-elastic groups). The gap formation, ultimate tensile strength, and suture migration state were measured after 500 cyclic loadings (from 10 to 200 N). Methods The shallow-rigid group had inferior outcomes compared to the other groups. Although the deep-rigid group had the smallest gap and highest ultimate strength, all peripheral sutures had failure prior to core suture rupture. The two elastic groups showed no significant differences, irrespective of the size of the holding area. Suture migration did not occur in the two elastic groups until the ultimate strength was reached and the core suture ruptured. Interpretation Depending on the suturing method, rigid suture material may not be appropriate for peripheral sutures, when accompanying rigid core suture material. If peripheral sutures can be made with accurate deep holding, rigid suture material will provide favorable outcome. However, in other cases, elastic suture material is considered best for supporting a rigid core suture, as elasticity is another important factor for peripheral sutures.