Intracapsular Cranial Cruciate Ligament Reconstruction in a Lapine Model Using an Autogenous Semitendinosus Graft: Technique Description

Introduction: While intracapsular repair of the cranial cruciate ligament (CCL) using a semitendinosus (ST) tendon autograft is widely performed in studies using a lapine model of the human knee, description of this technique is lacking.

Materials and Methods: Reconstruction of the CCL using a ST tendon autograft was performed in 36 Flemish Giant rabbits. Following stifle exploration, the insertion of the ST tendon on the caudomedial aspect of the tibial plateau was exposed and followed proximally. The abductor longus was retracted and deep blunt dissection of the abductor magnus was used to isolate the ST and expose its musculotendinous junction (MTJ) which was then transected. Tibial and femoral bone tunnels were drilled. Using a suture loop, the graft was passed through both tunnels, tensioned, and then secured in place with an interference screw and periosteal sutures. The degree of postoperative drawer was assessed following routine closure.

Results: Graft length (mean ± SD) was 5.9 ± 0.8cm. Mild postoperative drawer was present in 50% (18/36) rabbits. In two rabbits, tibial plateau fissures were documented at time of sacrifice 4 weeks postoperatively.

Discussion/Conclusion: Obtaining the longest possible graft is pivotal to the success of this technique. To accommodate shorter grafts, bone tunnels are drilled more vertically. The subsequent steeper graft orientation reduces its ability to eliminate drawer and increases the risk of tibial plateau fissuring. The ST tendon location within the abductor magnus makes exposition of the MTJ challenging. Appropriate retraction and dissection of the abductors are keys to ensuring maximal graft length.

Acknowledgment: Department of Defense Grant W81XWH-16–1-0735.