Knee osteoarthritis functional classification scheme – Validation of time dependent treatment effect. One year follow-up of 518 patients

Abstract

Purpose: The purpose of the current study was to validate time dependent changes of a recently published novel functional classification for patients with knee osteoarthritis (KOA), following a homebased biomechanical treatment (HBBT). Methods: A retrospective analysis of 518 patients with KOA was conducted. Patients were graded using a novel knee osteoarthritis functional grade (KOFG) classification for KOA, based on spatio-temporal gait analysis. Patients were re-classified after 3 months and 1 year of HBBT. The time dependent changes in the classification were compared to gold-standard self-assessment questionnaires, WOMAC and short form 36 (SF-36). Results: Change in KOFG were demonstrated over time. Most changes were observed after 3 months of treatment with consolidation of the effect at 12 months. For example, of 427 patients that were KOFG 2-4 at baseline 44.9% and 51.5% had lower (better) KOFG at 3 and 12 months of treatment, respectively. The changes in KOFG were validated with WOMAC and SF-36 questionnaires that showed similar trends. SF-36 pain sub-scale showed an improvement of 33.0% and 38.0% following 3 months and 12 months of treatment, respectively (p values <0.0001). Conclusions: The KOFG classification scheme offers an objective measurement tool for the assessment of function in KOA population and is also a valid tool to assess time-dependent treatment effect.