Morphologic impact of four surgical techniques to correct excessive tibial plateau angle in dogs: A theoretical radiographic analysis.

OBJECTIVE: To determine morphologic differences between four tibial osteotomy techniques used to correct excessive tibial plateau angle (eTPA).

STUDY DESIGN: Retrospective radiographic analysis.

SAMPLE POPULATION: Sixteen dogs (27 tibias) with eTPA.

METHODS: Virtual corrections of eTPA were performed on sagittal plane radiographs of canine tibia using four tibial osteotomy techniques and categorized into respective groups. Group A represented the center of rotation of angulation (CORA)-based leveling osteotomy (CBLO) and coplanar cranial closing wedge ostectomy (CCWO), Group B the tibial plateau leveling osteotomy (TPLO) and CCWO, Group C the modified CCWO (mCCWO), and Group D the proximal tibial neutral wedge osteotomy (PTNWO). Pre- and post-correction TPA, tibial length and mechanical cranial distal tibial angle (mCrDTA) were measured and compared.

RESULTS: Mean TPA prior to correction was 42.67 ± 6.1°. Post-correction mean TPAs were 10.47 ± 2.1°, 6.77 ± 1.6°, 4.76 ± 1.5°, and 7.09 ± 1.3° for Groups A, B, C, and D, respectively. TPA correction accuracy in Groups A and D varied least from target TPAs. Tibial shortening was documented in Group B in contrast to other groups. The greatest mechanical axis shift was identified in Group A.

CONCLUSION: Each technique achieved TPA < 14° despite having different effects on tibial morphology including alteration of tibial length, mechanical axis shift and variation in correctional accuracy.

CLINICAL SIGNIFICANCE: Despite all methods being able to correct eTPA, the choice of technique will affect morphology in unique ways and should be considered prior to surgery to consider the implications in a given patient.