Many PROMs used for evaluation of ankle osteoarthritis are not validated for this purpose. We hypothesize that frequently used PROMs have an early ceiling or floor effect.
We prospectively collected data from patients with ankle osteoarthritis between 2011 and 2013. At baseline visit patients completed the Foot and Ankle Outcome Score, the Ankle Osteoarthritis Score, the American Orthopaedic Foot and Ankle Society scale, a visual analogue scale for pain and quality of life. Outcomes were analyzed for floor or ceiling effects.
197 patients were included in the study. A floor effect was present for the AOFAS and VAS for pain in all groups. Floor and ceiling effect are absent for the FAOS outcome measure for all groups.
Physicians should be aware of floor or ceiling effects when evaluating treatment using patient reported outcome measures. The FAOS outcome measure lacks early ceiling or floor effects.