Evaluation of femoral isometric placement accuracy of internal brace implants and its impact on stifle stability in the management of pivot shift phenomenon following TPLO

Abstract Objective To evaluate the impact of accurate isometric placement of internal brace implants on stifle stability following tibial plateau leveling osteotomy (TPLO) in dogs with pivot shift phenomenon and to propose a novel classification system for pivot shift grading. Study design Retrospective observational study. Animals A total of 39 dogs (46 stifles) undergoing TPLO with internal brace augmentation using SwiveLock and FASTak implants. Methods Medical records, intraoperative assessments, and radiographs were reviewed. Femoral implant positioning was classified as accurate or inaccurate. Pivot shift was graded pre‐, intraoperatively, and at 6‐week follow‐up using a simplified two‐grade system. Learning curves for implant accuracy were compared between implant types. Statistical analyses included χ 2 and t ‐tests, with significance set at p < .05. Results Accurate implant positioning was achieved in 29 of 46 stifles (63.0%). SwiveLock implants were significantly more likely to be accurately placed than FASTak anchors ( p = .016), with higher patient weight correlating with improved accuracy ( p = .012). SwiveLock implants reached an accuracy rate of 78.6% compared to 38.9% for FASTak ( p = .014). At follow‐up, mean pivot shift grade improved in 90.9% of stifles ( p < .001). Inaccurate implant positioning was significantly associated with increased internal tibial rotation ( p = .009) but not with the pivot shift grade ( p = .142). Conclusion Accurate isometric placement of internal brace implants is critical for optimizing stifle stability and addressing pivot shift following TPLO. Clinical significance Enhanced implant accuracy and a standardized pivot shift classification may improve surgical outcomes and guide postoperative management in dogs.