Defining clinically significant outcomes following high tibial osteotomy with or without concomitant procedures

Introduction: The threshold values needed to achieve MCID and PASS following HTO with or without concomitant procedures are not well known. Objectives: To determine values and variables predictive for achieving the minimally clinically important difference (MCID) and patient acceptable symptom state (PASS) of patient-reported outcome (PRO) scores following high tibial osteotomy (HTO) with or without associated restoration procedures for the correction of varus deformity. Methods: A prospectively collected HTO outcomes registry was retrospectively reviewed for patients who underwent HTO between 2001 and 2018. Collected PROs included International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Lysholm scores. A distribution-based approach was used to calculate MCID, and an anchor-based approach was used for the calculation of PASS. Results: Fifty-five patients were identified (n = 43 males; n = 12 females) with a mean age of 37.9 ± 9.0 years at surgery and average follow-up of 3.3 ± 3.1 years. The MCID and PASS for IKDC were calculated as 12.5 and 40.23, respectively. MCID and PASS values for each of the KOOS subscales were as follows: symptoms: 9.9 and 71.43; pain: 11.3 and 72.22; daily living: 12.0 and 77.94; sports: 16.0 and 40; quality of life: 15.1 and 56.25, respectively. Conclusions: Based on calculated values for MCID and PASS following HTO using IKDC and KOOS subscales, higher preoperative PROs, prior medial meniscectomy, higher BMI, concomitant ACL reconstruction and worker's compensation status were associated with failure to achieve clinically significant outcomes. Prior ACL reconstruction was found to be predictive of MCID for KOOS-symptoms