Improved healing of ligament to bone with point fixation in rabbits

Abstract

Background Secure healing of soft tissue to bone is a prerequisite for many orthopedic operations. This healing can be achieved either by pressing the tissue against the bone (press fixation) or by suturing the soft tissue to the bone (point fixation).Experiments and findings We tested the hypothesis that point fixation of soft tissue to bone results in better mechanical properties than press fixation. 10 skeletally mature New Zealand White rabbits were operated on bilaterally at the knees. The medial collateral ligaments were fixated to the bone just above the original insertion on the tibia. Two types of plates were used for this purpose, one with flat undersurface (left knee) and the other one with a pegged undersurface (right knee). The pegged plate was thought to mimic fixation achieved with suture anchors. After 4 weeks, mechanical testing revealed an almost doubled force at failure, stiffness and energy uptake in the knees operated with the pegged plates.Interpretation Suture anchors or devices with a pegged undersurface are better for soft tissue fixation to bone than devices with a flat surface, such as screws with washers or staples.

In Vivo biomechanical evaluations of suture anchors for repairing grade 3 superficial medial collateral ligament injury in a porcine model

“…The outcome of instability surgery of the knee is supposedly dependent on the secure fixation and healing of soft tissue to bone. 17 Suture anchors were first reported as an easier device to obtain secure stability for use in soft tissue fixation to bone without constructing transosseous suture tunnels. 27 A previous biomechanical study reported that sMCL repair using suture anchors results in better healing compared with fixation with screws or staples.…”

“…16 Khoschnau et al performed bilateral knee sMCL repair in a rabbit model and compared two types of plates: one with a flat undersurface and a second with a pegged undersurface. 17 In that study, mechanical testing of pegged anchors, which mimic suture anchors, was performed 4 weeks after surgery and showed better maximum load, linear stiffness, and energy uptake. Louati et al performed rotator cuff repair in a rabbit model and compared it with a contralateral native rotator cuff.…”

“…14 Forkel et al reported on the successful treatment of grade 3 sMCL injuries by reattachment to the anatomical insertion site using anchors. 15 Additionally, Ono et al 16 and Khoschnau et al 17 described the efficacy of suture anchors for sMCL fixation using a rabbit model. However, no previous in vivo biomechanical studies have used a large animal model to assess the efficacy of suture anchors for sMCL fixation.…”