Bone-to-Bone Fixation Enhances Functional Healing of the Porcine Anterior Cruciate Ligament Using a Collagen-Platelet Composite

Abstract

Purpose-The purpose of this study was to determine if providing bony stabilization between the tibia and femur would improve the structural properties of an "enhanced" ACL repair using a collagen-platelet composite when compared to the traditional (Marshall) suture technique.Methods-Twelve pigs underwent unilateral ACL transection and were treated with sutures connecting the bony femoral ACL attachment site to the distal ACL stump (LIGAMENT group), or to the tibia via a bone tunnel (TIBIA group). A collagen-platelet composite was placed around the sutures to enhance the biologic repair in both groups. Anteroposterior (AP) knee laxity and the graft structural properties were measured after 15 weeks of healing in both the ACL-repaired and contralateral ACL-intact joints.Results-Enhanced ACL repair with bone-to-bone fixation significantly improved yield load and linear stiffness of the ACL repairs (p<0.05) after 15 weeks of healing. However, laxity values of the knees were similar in both groups of repaired knees (p>0.10).Conclusions-Using an enhanced ACL suture repair technique that includes bone-to-bone fixation to protect the repair in the initial healing stages resulted in an ACL with improved structural properties after 15 weeks in the porcine model.Clinical Relevance-The healing response of an ACL suture repair using a collagen-platelet composite can be enhanced by providing bony stabilization between the tibia and femur to protect the graft during the initial healing process in a translational model.

Primary Repair of the Anterior Cruciate Ligament: A Systematic Review

“…Murray et al 23 tested a similar hypothesis that boneto-bone (femur-to-tibia) suture fixation at the time of primary ACL repair would improve stabilization and lead to improved healing in a Yorkshire pig model with midsubstance ACL transection. They compared animals that underwent suture anchor primary repair with animals that underwent repair with transtibial suture augmentation.…”

“…Several authors investigated the role of stability during ACL repair. [20][21][22][23] Seitz et al 20 showed that stability obtained through an internal strut augmentation using a 3-mm polyethylene terephthalate (PET) band passed through femoral and tibial bone tunnels improved histologic evidence of healing when compared with the non-augmented repair construct. In their mountain sheep model, serial gross and histologic assessments were performed at varying time intervals up to 52 weeks.…”

Biomechanical Outcomes of Bridge-enhanced Anterior Cruciate Ligament Repair Are Influenced by Sex in a Preclinical Model

“…For all knees, a Kessler suture using No. 1 Vicryl 1 was placed in the tibial stump of the ACL to repair the transected ligament [20,36,37]. Femoral (4.5 mm) and tibial (2.4 mm) tunnels were then drilled in standard positions for ACL reconstruction with the tibial tunnel exiting in the center of the tibial attachment and the femoral tunnel placed at the center of the femoral ACL attachment site.…”

The Effect of Skeletal Maturity on Functional Healing of the Anterior Cruciate Ligament

“…A 2.4-mm drillpin was then used to make a tunnel in the tibia with use of a drill guide (Acufex Director Drill Guide; Smith and Nephew) to ensure that the entrance into the joint was just medial to the anterior cruciate ligament footprint. The tibial tunnel would later serve to secure the repair sutures directly to the tibia as previously described 9,10 . The resorbable sutures bridging the femur and tibia (as shown in purple in Figure 1) served as a temporary stent within the knee.…”