Responders to Medial Opening Wedge High Tibial Osteotomy for Knee Osteoarthritis.

OBJECTIVE: Medial opening wedge high tibial osteotomy (HTO) aims to improve symptoms for patients with knee osteoarthritis (OA) and varus alignment, yet the likelihood of achieving a minimum clinical threshold of response and the factors predictive of response are unclear. We evaluated the proportion of patients meeting responder criteria based on the Outcome Measures in Rheumatology-Osteoarthritis Research Society International consensus 2 years after medial opening wedge HTO and investigated predictors of response. METHODS: Patients in a prospective cohort with symptomatic knee OA and varus alignment completed the Knee Injury and Osteoarthritis Outcome Score questionnaire < 3 months before and 2 years after HTO. For our primary analysis, we calculated the proportion of responders with ≥ 20% relative improvement and an absolute change of ≥ 10 points in pain and function from baseline. We performed logistic regression to evaluate the association of predictors with response and completed sex-disaggregated analyses. RESULTS: At a mean of 20.3 (SD 6.2) months post-HTO, 406 patients (78%) met the responder criteria. Older age, higher BMI, and larger postoperative mechanical axis angles (ie, slight valgus) were associated with increased odds of achieving responder criteria, although odds ratios were small. When stratified by sex, 316/405 male patients (78%) and 90/118 female patients (76%) met the responder criteria. CONCLUSION: Based on responder criteria for knee OA, 78% of patients undergoing medial opening wedge HTO were responders at 2 years postsurgery. Although patients who are younger, male, and nonobese are viewed as appropriate candidates for HTO, patients who are female, are older, and have a high BMI also achieve sizable improvements in pain and function.

Clinically meaningful effect of strontium ranelate on symptoms in knee osteoarthritis: a responder analysis.

OBJECTIVES: The aim of this study was to assess the efficacy of strontium ranelate in improving symptoms in knee OA. METHODS: Symptoms were assessed over 3 years in patients with primary knee OA receiving strontium ranelate 2 g/day (n = 454), 1 g/day (n = 445) or placebo (n = 472) in the Strontium Ranelate Efficacy in Knee Osteoarthritis Trial. Clinical response was evaluated using WOMAC subscores, minimal perceptible clinical improvement (MPCI), minimal clinically important improvement (MCII) and a modified OMERACT-Osteoarthritis Research Society International (OARSI) responder definition. Patients who withdrew prematurely from the study were considered non-responders. RESULTS: There was no significant effect on symptoms for strontium ranelate 1 g/day. At the dosage of 2 g/day, strontium ranelate was associated with greater response than placebo in terms of ≥20% improvement in WOMAC pain from baseline to the last visit (58% vs 47%, P = 0.002) and ≥50% improvement in WOMAC pain (42% vs 36%, P = 0.083). Significant differences were found in MPCI response for WOMAC pain (52% vs 40%, P < 0.001), stiffness (47% vs 39%, P = 0.009) and physical function (46% vs 37%, P = 0.009) and in MCII response for WOMAC physical function (46% vs 37%, P = 0.013). There were also more OMERACT-OARSI-like responders with strontium ranelate (44% vs 35%, P = 0.004). The treatment-placebo difference in MPCI response for WOMAC pain was significant after 6 months (P = 0.024), while that in MPCI and MCII response for WOMAC physical function reached significance after 12 months (P = 0.027 and P = 0.019, respectively). CONCLUSION: Treatment with strontium ranelate 2 g/day over 3 years is associated with a clinically meaningful improvement in pain from 6 months as well as physical function and stiffness as assessed by the number of responders above thresholds of clinical relevance. TRIAL REGISTRATION: Current Controlled Trials. http://www.controlled-trials.com/ (ISRCTN41323372).