Thresholds for the Oxford Hip Score after total hip replacement surgery: a novel approach to postoperative evaluation

BACKGROUND: This is a prospective cohort study to define the thresholds to distinguish patients with a satisfactory or unsatisfactory outcome after total hip replacement (THR) based on patient-reported outcome measures (PROMs) including the Oxford Hip Score (OHS), and using patient satisfaction and patient-perceived function as global transition items. The thresholds are intended to be used as a tool in the process of determining which patients are in need of postoperative outpatient evaluation. METHODS: One hundred and three THR patients who had completed a preoperative questionnaire containing the OHS questionnaire were invited to complete the same questionnaire and supplementary questions at a mean of 6 (4-9) months after surgery. Correlations between outcome measures and anchors were calculated using Pearson's correlation coefficient. Thresholds were established by receiver operating characteristic (ROC) analysis, using multiple anchors. RESULTS: Significant correlations were found between outcome measures and anchors. Thresholds were determined for outcome measures coupled with satisfaction, patient-perceived function and a combination thereof using a cut-off of 50 and 70. CONCLUSIONS: We have established a set of thresholds for Oxford scores that may help determine which THR patients are in need of postoperative evaluation. These thresholds can be implemented in clinical practice. LEVEL OF EVIDENCE: Level 3.