Biomechanical cyclic loading test of a synthetic ligament fixation system used for intra-articular stabilization of deficient canine stifles

Abstract

Background: Cranial cruciate ligament rupture (CCLr) is the most common cause of hindlimb lameness in dogs. Currently, surgical management of CCLr is mostly performed using tibial osteotomy techniques to modify the biomechanical conformation of the affected stifle. These surgical techniques have a significant complication rate, associated with persistent instability of the stifle which may lead to chronic postoperative pain. Over the last decade, studies have been published on various techniques of anatomical CCL reconstruction in veterinary practice, using physiological autografts or woven synthetic implants. Aim: The aim of this ex vivo biomechanical study is to investigate the ex vivo dynamic biomechanical behavior of a synthetic implant (ultra-high molecular weight polyethylene implant) fixed with interference screws for the treatment of cranial cruciate ligament rupture in dogs, according to a fatigue protocol (48h per test). Methods: Seven stifles from four skeletally mature canine cadavers were implanted with the synthetic implant. It was fixed with four interference screws inserted in transversal and oblique tunnels in both the distal femur and the proximal tibia. For each case, 100 000 cycles were performed at 0.58Hz, with traction loads ranging from 100N to 210N. Results: Neither screw-bone assembly rupture nor a pull-out issue were observed during the dynamic tests. The linear stiffness of the implants associated with a fixation system with four interference screws increased over time. The final displacement did not exceed 3mm for five of the seven specimens. Five of the seven synthetic implants yielded to a lengthening in functional range [0: 3 mm]. Linear stiffness was homogeneous among samples, showing a strong dynamic strength of the interference screw-based fixations of the UHMWPE implant in the femoral and tibial bones. Conclusion: This study completes the existing literature on the biomechanical evaluation of passive stifle stabilization techniques with a testing protocol focused on cyclic loading at a given force level instead of driven by displacement. These biomechanical results should revive interest in intra-articular reconstruction after rupture of the cranial cruciate ligament in dogs.

Long-Term Clinical Outcome of Medial Shoulder Instability in a Dog Treated with Synthetic Implant, Cortical Button, and Interference Screw

“…12 Owing to the severe amyotrophy and grade 3 MSI in our case, we were concerned that SM imbrication might have been insufficient. The choice of a UHMWPE implant was based on the biocompatibility of its fibers 22 as well as the ex vivo biomechanical strength [23][24][25] and clinical versatility it demonstrated in various applications. 16,17 In the reported case, its flat and wide shape (compared with other implants 7 ) helped to restore stability while reconstructing a single arm of the MGHL, previously shown to be sufficient for maintaining shoulder stability in young beagles.…”

“…The IS placed in the humerus provided a fixation system with an important pull-out strength. 24 It avoided the use of a knot fixation that tends to slip with UHMWPE, 32 which might be a limitation of toggle pin implants. It also had the advantage of being totally embedded inside the bone allowing to fix the implant near the humeral insertion of the MGHL 6 and the articular space.…”

“…42 Alteration in the mechanical properties of the implant due to cyclic load is another possible cause. 24 Determining the appropriate tension, tunnel angulation and rest period should limit the biomechanical stress exerted on the tunnel bone, thus limiting the widening effect. 41 Two major differences between the reported procedure and human surgery should be highlighted.…”

Intra-articular replacement of the caudal cruciate ligament using an UHMWPE ligament under arthroscopic guidance in a dog: A case report

“…There is no consensus regarding the indications for surgical management of isolated ruptures of the CdCL and no recommended reference techniques. In light of the satisfactory results obtained during ex-vivo biomechanical tests for the reconstruction of the cranial cruciate ligament ( Blanc et al ., 2019 ; Goin et al ., 2019 , 2021 , 2022 ; Rafael et al ., 2020 ) and its clinical utilization in tendon reconstructions ( Buttin et al ., 2020 ), we posited that the use of an ultra-high molecular weight polyethylene (UHMWPE) implant should be efficient for the synthetic reconstruction of the CdCL. This case report describes the arthroscopically-assisted reconstruction of the CdCL in a dog with a UHMWPE implant and its outcome over a 12-month period.…”