Inconsistent Patient Responses May Limit the Value of Using Multiple Total Knee Arthroplasty Assessment Tools to Define Implant Performance

Prior studies have suggested that using single validated instruments may not adequately characterize total knee arthroplasty (TKA) performance. However, the consistency of patient responses when answering multiple inventories has not been defined. We retrospectively evaluated 269 patient responses to four postoperative TKA inventories, including 24 parallel questions related to 6 low demand activities. The influence of patient age, sex, and race on response consistency was assessed. Thirty percent of patients gave discordant responses for at least 2 of 11 question categories, unaffected by chronological or categorical age. Discordant answers were more commonly obtained from minority and female patients (P < 0.01). Combining multiple instruments to assess TKA outcomes may introduce confounding effects that limit their benefit.