Time required to achieve the minimal clinically important difference after open proximal hamstring repair

Understanding the minimal clinically important difference (MCID) for a given procedure and its associated patient-reported outcome measures (PROMs) are critical for evaluating success in orthopedic surgery. The MCIDs for the International Hip Outcome Tool (iHOT-33) and Modified Harris Hip Score (mHHS) have been defined for open proximal hamstring repair (OPHR); however, the speed and reliability at which patients achieve these are unknown. A retrospective review of prospectively collected data from our institution's hip preservation registry was performed, examining pre-operative and 6-, 12-, and 24 months post-operative mHHS and iHOT-33 scores. The percentage of patients achieving MCID at each time point was determined, and factors associated with achieving MCID were assessed. A total of 37 patients were included in this analysis (n = 36 for iHOT-33 and n = 32 for mHHS). At 6 months, 83% and 78% of patients achieved MCID for iHOT-33 and mHHS, respectively. Patients with chronic symptoms (pain >6 months) were significantly less likely to achieve at least one of the MCIDs at 6 months (60% vs. 12.5%, P = .04), while patients with more severe preoperative pain were significantly more likely to achieve at least one of the MCIDs at 6 months (P = .004). Most patients who achieve the MCID for iHOT-33 and mHHS following OPHR do so by 6 months postoperatively. Chronic symptoms were associated with failure to achieve either one of the MCIDs at 6 months post-operatively. Patients with more severe preoperative pain were more likely to successfully achieve one of the MCIDs at 6 months.