Comparison of Radiographic Outcomes Between TPLO + TTT and CTWO + TTT in Dogs with Concurrent Cranial Cruciate Ligament Rupture and Medial Patellar Luxation

Cranial cruciate ligament (CrCL) rupture frequently occurs with medial patellar luxation (MPL) in small-breed dogs, and both conditions may be corrected during surgery using a proximal tibial osteotomy—tibial plateau leveling osteotomy (TPLO) or cranial tibial wedge osteotomy (CTWO)—combined with tibial tuberosity transposition (TTT). Because these osteotomies differ in patellar ligament displacement, they may interact differently with TTT. We retrospectively compared TPLO + TTT and CTWO + TTT in 20 stifles from 18 small-breed dogs. Tibial length was quantified using a normalized effective tibial length (NEL) referenced to the tibial mechanical axis, and patellar position was assessed using the Guénégo–Verwaerde index (GVI). Both outcomes were expressed as the within-limb relative changes to reduce the influence of positioning differences. NEL changed by −5.65 ± 1.29% after CTWO + TTT and −0.98 ± 0.93% after TPLO + TTT, with non-overlapping ranges in this sample. Postoperative GVI decreased in all 10 CTWO + TTT stifles (mean −14.6%) but was unchanged after TPLO + TTT (+1.7%, p = 0.73; between-group p = 0.002). Patellar descent corresponded to only about 26% of tibial shortening. Radiographic union was more advanced after TPLO + TTT at 8–10 weeks, although callus was present in every stifle and no non-union occurred. TPLO + TTT preserved tibial length and the patella–tibial plateau relationship.