Surgical Technique and Initial Clinical Experience with a Novel Extracapsular Articulating Implant for Treatment of the Canine Cruciate Ligament Deficient Stifle Joint

Objective: To describe the surgical technique, clinical efficacy, and complications using the Simitri Stable in Stride (R) extracapsular articulating implant (EAI) to treat naturally occurring stifle instability due to cranial cruciate ligament (CrCL) insufficiency. Study Design: Prospective case series. Animals: Client-owned dogs with CrCL-deficient stifles (n=60 dogs; 66 stifles). Methods: An EAI was applied to the medial aspect of the distal femur and proximal tibia after stifle exploration and treatment of joint pathology. Outcome measures included lameness score, time to weight bearing, and bilateral assessment of stifle stability, stifle range of motion (ROM), and thigh circumference (TC). Outcome measures were determined preoperatively and at intervals from 4.5 to 16.0 months (median 8.9 months) postoperatively. Data were excluded from bilaterally affected dogs <6 months after CrCL surgery on the contralateral limb, and from dogs with contralateral limb lameness. Results: Within 24 hours of EAI surgery, dogs were weight bearing on 64 of 66 limbs at the walk. Incidence of major complications requiring surgical revision was 15.3% and minor complications was 10.2%. Postoperatively, there were significant improvements in lameness scores and ROM in 34 EAI-treated limbs meeting inclusion criteria, and the mean ROM returned to within normal limits. TC did not change in the operated limb, but decreased significantly in the control limb. Conclusion: The EAI effectively stabilized the CrCL-deficient stifle, and significantly improved lameness scores and stifle ROM. Decreased TC in control limbs may have been due to early return to mobility and weight bearing on the EAI-treated limb.