Cut-off values of the Japanese Orthopaedic Association score corresponding to Constant scores for evaluating outcomes in rotator cuff tear

Abstract

Purpose: To clarify the cut-off value of the Japanese Orthopaedic Association (JOA) score corresponding to rotator cuff tear outcome as evaluated by the Constant score. Methods: The subjects were 230 patients with rotator cuff tear. The Constant and JOA scores on the first examination in our hospital were evaluated. After investigation of the correlation between the Constant and JOA scores, the cut-off JOA score was calculated, corresponding to excellent, good and fair outcomes as evaluated by the Constant score. Results: The Constant and JOA scores on the first examination were 49.64 ± 12.84 and 72.52 ± 12.84, respectively, with a strong correlation ( r = 0.87, p < 0.01). Receiver operating characteristic analysis revealed that the cut-off JOA score was 87.0 for excellent outcome (area under the curve, AUC: 0.93; sensitivity: 100%; specificity: 88.6%; p < 0.01), 84.0 for good outcome (AUC: 0.94; sensitivity: 100%; specificity: 83.4%; p < 0.01) and 78.0 for fair outcome (AUC: 0.88; sensitivity: 100%; specificity: 71.3%; p < 0.01). Conclusions: In patients with rotator cuff tear, good outcome as judged by a Constant score of ≥80 corresponds to a JOA score cut-off of 84.0. Judgement of the treatment outcomes and evaluation of the surgical method may be more accurate when using clear cut-off values for the scoring system employed, such as those determined in our study.