Comparison of TPA, bone healing, and intra-articular screw placement using conventional nonlocked application of surgeon-contoured versus locked application of precontoured TPLO plates in dogs.

Objective: To determine the influence of conventional nonlocked application of surgeon-contoured (NL-SXc) and locked-hybrid application of precontoured (L-Pc)- TPLO plates on the tibial plateau angle (TPA) immediately postoperatively and longterm after tibial plateau leveling osteotomy (TPLO) in dogs as well as to evaluate their influence on the incidence of intra-articular screw placement and bone healing.

Study Design: Retrospective, cross-sectional, clinical study.

Animals: Dogs (n = 101) with cruciate ligament insufficiency that had TPLO.

Methods: Collected data included signalment, plate size/type, preoperative (PreTPA), postoperative (PostTPA), and recheck TPA (ReTPA). Tibial plateau rotation achieved during surgery (RotaTPA = PreTPA-PostTPA) and TPA shift during healing (ShiftTPA = ReTPA-PostTPA) were calculated. Radiographic evidence of stability and time to radiographic recheck were recorded. Variables were compared by plate type using a 2-sample t-test or χ(2) as appropriate (significance at P < .05).

Results: Median time to radiographic follow-up was 75 days (range, 43-2815 days). The remaining data are reported as means. Forty-two stifles had NL-SXc, 59 stifles had L-Pc. PreTPA of NL-SXc and L-Pc was 28.3° and 29.1°, respectively (P = .22). PostTPA (13.2° and 7.9°), RotaTPA (15.0° and 21.2°) and ReTPA (14.9° and 10.3°) for NL-SXc and L-Pc, respectively, were all significantly different (P< .0001). ShiftTPA for these constructs (1.7° and 2.4°, respectively) was not significantly different (P = .25), and 92.1% of dogs were considered to have radiographically stable osteotomies at last recheck.

Conclusions: A higher degree of tibial plateau rotation was achieved and maintained in osteotomies with L-Pc. There was no significant difference in ShiftTPA or radiographic osteotomy stability between constructs.