Long-Term Radiographic Stability of Tibial Plateau Angle Following TPLO in Small-Breed Dogs: A Retrospective Study

Cranial cruciate ligament disease (CCLD) is among the most common orthopedic conditions in dogs, and tibial plateau leveling osteotomy (TPLO) is the current standard of care; however, long-term radiographic data on tibial plateau angle (TPA) stability specific to small-breed dogs (<10 kg) remain limited. This retrospective study evaluated radiographic correction and long-term stability of TPA following TPLO in small-breed dogs and assessed whether observed TPA changes fell within the range of measurement error. Thirty stifles from 25 small-breed dogs (body weight 2.56–9.46 kg) that underwent TPLO between 2022 and 2025 were reviewed, with a mean follow-up of 12.6 ± 6.8 months. TPA was measured preoperatively, immediately postoperatively, at 1–2 months, and at ≥6 months using digital orthopedic planning software. Preoperative TPA averaged 31.23 ± 4.60° and decreased to 4.68 ± 1.84° immediately after surgery; at ≥6 months, mean TPA was 5.19 ± 1.83°. The mean change (ΔTPA) was 0.52 ± 0.64° (95% CI: 0.28–0.75°). Although statistically significant (p < 0.001), this fell below the 1.5° intraobserver measurement error previously reported. Body weight showed no correlation with ΔTPA (r = −0.059, p = 0.756). These findings were robust in a sensitivity analysis restricted to one stifle per dog (n = 25; mean ΔTPA 0.56 ± 0.67°) and in the subgroup without concurrent medial patellar luxation (n = 19; mean ΔTPA 0.40 ± 0.49°), both remaining within the reported measurement error. TPLO achieved effective and radiographically stable TPA correction in small-breed dogs.