When do patient-reported assessments peak after revision knee arthroplasty?

ABSTRACT

BACKGROUND: The best timing for patient visits after revision TKA is unclear. Predictors of pain and function reported in the literature typically look at the influence at a given time that might not be ideal if the score is not at a peak or the earliest possible time. Moreover, most reports of predictors include revisions for infection, which typically have a poorer outcome, or for other indications with variable outcome. QUESTIONS/PURPOSES: We therefore determined (1) the trend of recovery after revision TKA to determine the best time to measure the peak patient-reported pain and function scores and (2) the influence of comorbidities and age on the patterns of recovery. METHODS: We prospectively followed 120 patients who had revision TKAs from 2003 to 2008. The patients were assessed within 6 weeks before surgery and at 12 weeks, 1 year, and annually thereafter. We obtained WOMAC and SF-36 scores at each visit. We used a linear mixed model analysis to assess predictors. The minimum followup was 2 years (mean, 3 years; range, 2-7 years). RESULTS: The majority of improvements in the WOMAC and SF-36 scores occurred during the first year after surgery after which the scores stabilized. One of the seven independent preoperative variables studied (comorbidities) predicted a trend toward improvement of WOMAC pain, WOMAC function, and SF-36 bodily pain scores. The greater the numbers of comorbidities, the worse were the scores. Age, gender, BMI, indication for surgery, and surgeon did not independently influence the WOMAC or SF-36. CONCLUSION: Our data suggest that one of the times for patient visits after revision TKA should be 1 year after surgery. This time allows for key discrimination of implant performance. The data also confirm that patients with a greater number of comorbidities had less functional benefit from revision surgery. LEVEL OF EVIDENCE Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.