Evaluation of a modified radiographic union scale for tibial fractures scoring system in staged bilateral tibial plateau leveling osteotomy procedures and comparison of first and second side radiographic bone healing.

ABSTRACT

OBJECTIVE: To evaluate the inter- and intra-rater reliability of the tibial plateau leveling osteotomy (TPLO) modified radiographic union scale for tibial fractures (mRUST), a semiquantitative scoring system, as compared with the subjective evaluation of radiographic union for staged TPLOs. STUDY DESIGN: Retrospective study. ANIMALS Forty-eight dogs, 96 stifles. METHODS: Medical records were reviewed for dogs with bilateral cranial cruciate ligament injuries diagnosed at presentation that underwent staged bilateral TPLOs within 6 months and had both immediate and recheck postoperative radiographs. Radiographs were anonymized, reviewers were blinded, radiographic union was evaluated subjectively, and TPLO mRUST scores were assigned. RESULTS: The subjective evaluation's intra-rater reliability was 0.72 (Kappa 95% CI 0.65-0.79) and inter-rater reliability was 0.33 (Kappa 95% CI 0.28-0.39). The TPLO mRUST scoring system intra-rater reliability was 0.73 (95% CI 0.68-0.78) and inter-rater reliability was 0.56 (95% CI 0.41-0.68). There was no difference in the degree of bone healing quantified by the TPLO mRUST scoring system (95% CI - 0.1-1.2, P = .09) or subjective evaluation (P = .48) between the first and second side TPLOs. The TPLO mRUST scores were positively correlated with subjective healing (r = 0.94, 95% CI 0.92-0.96, P < .0001, and for scores ≥10/12, 99%, 244/246) were subjectively assigned as radiographically healed. CONCLUSION: The TPLO mRUST scoring system improved inter-rater reliability compared to subjective evaluation of radiographic union. CLINICAL SIGNIFICANCE: The TPLO mRUST scoring system should be considered as a semiquantitative supplemental tool for evaluating radiographic union.