Hamstring graft technique for stabilization of canine cranial cruciate ligament deficient stifles.

Lopez MJ, Markel MD, Kalscheur V, Lu Y, Manley PA.

Comparative Orthopaedic Research Laboratory, School of Veterinary Medicine, University of Wisconsin, Madison, WI.

OBJECTIVE-To investigate the harvest and application of hamstring grafts for canine cranial cruciate ligament (CrCL) reconstruction.

STUDY DESIGN-Experimental study.

ANIMALS-Four adult female hounds, weighing 26.3 +/- 1.6 kg (mean +/- SEM).

METHODS-One stifle in each dog was randomly chosen for hamstring graft CrCL reconstruction after native CrCL transection. Arthroscopy was performed to evaluate graft integrity at 12 weeks. Gait analysis and stifle radiographs were performed preoperatively and up to 52 weeks after graft placement. Dogs were killed 12 (n = 2) or 52 weeks (n = 2) after CrCL reconstruction. Tissues were evaluated grossly and with light and confocal laser microscopy.

RESULTS-Hamstring grafts were intact in all stifles at 12 weeks (n = 4) and 52 weeks (n = 2). Grossly, there was no osteoarthritis in stifles at 12 weeks and only chondrophytes along the trochlear ridges at 52 weeks. Minimal radiographic evidence of osteoarthritis developed in stifles with grafts during the study. Lameness in limbs with grafts resolved by 52 weeks. Graft tissue was highly vascular, ligamentized, and undergoing active remodeling at 12 weeks. Fifty-two weeks after graft placement, intraarticular graft tissue was well vascularized, mature, and encapsulated by synovium, and graft-bone interfaces were characterized by Sharpey's fiber insertions. There was no evidence of graft necrosis using confocal laser microscopy at either time point.

CONCLUSIONS-The hamstring graft technique may be a viable method of canine CrCL reconstruction. CLINICAL RELEVANCE-Hamstring grafts may be an alternative technique for canine CrCL reconstruction. Further study is needed before clinical application.