Description of a novel method of femoral torsion correction in dogs: An <i>in vitro</i> study.

Objective: The objective of this study was to describe a novel method of femoral torsion correction in dogs and partially validate the technique by applying it to femoral bone models. Models and procedure: study using 12 femoral bone models. Twelve bone models, consisting of 6 replicas of each of 2 right femurs (Bone Model 1 and Bone Model 2), were reconstructed, using stereolithography, from femoral computed tomographic scans of 2 chondrodystrophic dogs. An intramedullary pin-assisted distal femoral osteotomy (IPA-DFO) was done on all bone models to correct 30° of torsion (CTA2). Preoperative and postoperative femoral anteversion angle (FAA) and anatomical lateral distal femoral angle (aLDFA) were measured. The magnitude of torsional correction was defined as the T angle, calculated as the difference between postoperative and preoperative FAA. Results: Mean T angle was 31.7 ± 1.7° for Bone Model 1 and 30.8 ± 0.9° for Bone Model 2. No significant differences were detected between CTA2 and T angles in either bone model. No significant differences were observed between preoperative and postoperative aLDFA values. Conclusion and clinical relevance: The IPA-DFO consistently reproduced the planned femoral torsion correction in the bone models studied without inducing unintended frontal plane alignment change.