Validation of PROMIS Physical Function for Evaluating Outcome After Acute Achilles Tendon Rupture

Background: There is increased demand for valid, reliable, and responsive patient-reported outcome measures (PROMs) to evaluate treatment for Achilles tendon rupture, but not all PROMs currently in use are reliable and responsive for this condition. Purpose: To evaluate the measurement properties of the Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS PF) compared with other PROMs used after treatment for acute Achilles tendon rupture. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A retrospective cohort study with a follow-up questionnaire was performed. All adult patients with an acute Achilles tendon rupture between June 2016 and June 2018 with a minimum 12-month follow-up were eligible for inclusion. Functional outcome was assessed using the PROMIS PF computerized adaptive test (CAT), Foot and Ankle Ability Measure (FAAM) Activities of Daily Living (ADL), FAAM-Sports, and Achilles Tendon Total Rupture Score (ATRS). Pearson correlation (r) was used to assess the correlations between PROMs. Absolute and relative floor and ceiling effects were calculated. Results: In total, 103 patients were included (mean age, 44.7 years; 74% male); 82 patients (79.6%) underwent operative repair, while 21 patients (20.4%) underwent nonoperative management. The mean time between treatment and collection of PROMs was 25.3 months (range, 15-36 months). The mean scores were 55.4 +/- 9.2 (PROMIS PF), 92.9 +/- 12.2 (FAAM-ADL), 77.7 +/- 22.9 (FAAM-Sports), and 83.0 +/- 19.4 (ATRS). The ATRS was correlated with FAAM-ADL (r = 0.80; 95% CI, 0.72-0.86; P < .001) and FAAM-Sports (r = 0.86; 95% CI, 0.80-0.90; P < .001). The PROMIS PF was correlated with the FAAM-ADL (r = 0.66; 95% CI, 0.53-0.75; P < .001), FAAM-Sports (r = 0.65; 95% CI, 0.53-0.75; P < .001), and ATRS (r = 0.69; 95% CI, 0.58-0.78; P < .001). The PROMIS PF did not show absolute floor or ceiling effects (0%). The FAAM-ADL (35.9%), FAAM-Sports (15.8%), and ATRS (20.4%) had substantial absolute ceiling effects. Conclusion: The PROMIS PF, FAAM-ADL, and FAAM-Sports all showed a moderate to high mutual correlation with the ATRS. Only the PROMIS PF avoided substantial floor and ceiling effects. The results suggest that the PROMIS PF CAT is a valid, reliable, and perhaps the most responsive tool to evaluate patient outcomes after treatment for an Achilles tendon rupture.