Short-Form New Knee Society Score: What Is Its Responsiveness and Convergent Validity with Other Scores?

The short-form version of New Knee Society Score (SF-NKSS) was designed with a purpose to reduce respondent burden. Literature review revealed only one report by Scuderi et al on responsiveness of derived SF-NKSS, but it was evaluated in two separate patient cohorts pre- and postsurgery. Our study had evaluated responsiveness and convergent validity of derived SF-NKSS in a single, large patient cohort followed longitudinally from preoperative status to over 1 year.

What is the Responsiveness and Respondent Burden of the New Knee Society Score?

Background: Although the new Knee Society score (NKSS) has been validated by a task force, a longitudinal study of the same cohort of patients to evaluate the score's responsiveness and respondent burden has not been reported, to our knowledge.

Questions/purposes: We analyzed the NKSS for (1) responsiveness; (2) respondent burden; and (3) convergent validity in 148 patients studied longitudinally during more than 1 year.

Methods: During an 8-month period, 165 patients underwent TKA by the same surgeon at our institution, of whom 148 (90%) completed this study; the others were excluded because of distance to travel or loss to followup at the specified time.