Assessment of Disability Related to Femoroacetabular Impingement Syndrome by Use of the Patient-Reported Outcome Measure Information System (PROMIS) and Objective Measures of Physical Performance.

BACKGROUND: The National Institutes of Health (NIH)-sponsored Patient-Reported Outcomes Measurement System (PROMIS) has been described as a valuable tool for characterizing outcomes among patients with specific musculoskeletal conditions. Additionally, previously proposed objective measures of physical performance among patients with nonarthritic hip abnormalities are costly and not practically incorporated into routine clinical practice.

PURPOSE: (1) To determine the ability of the PROMIS to differentiate between patients with femoroacetabular impingement (FAI) and asymptomatic controls, (2) to determine the effect of FAI on subjects' completion of timed physical performance measures, and (3) to determine whether associations exist between established patient-reported outcome (PRO) measures and subjects' completion of physical performance measures.

STUDY DESIGN: Cross-sectional study; Level of evidence, 3.

METHODS: Twenty-two asymptomatic controls (CON group) and 20 patients with FAI completed multiple activities to assess physical ability: self-selected walking velocity (SSWV), timed stair ascent (TSA), four-square step test (FSST), and sit-to-stand five times test (STS5). All subjects also underwent a battery of PRO questionnaires: Visual Analog Scale for Pain (VAS), Modified Harris Hip Score (mHHS), International Hip Outcome Tool (iHOT-33), Hip Disability and Osteoarthritis Outcome Score (HOOS), and PROMIS. Descriptive analyses were performed and comparisons between groups were made by use of paired t tests with Bonferroni-Holm correction. Spearman's rank correlation coefficients were used to determine associations between physical performance measures and PRO. The magnitude of differences between groups for each measured variable was calculated by use of Cohen's d.

RESULTS: Significant differences between CON and FAI groups were observed for all hip-specific PRO measures (CON vs FAI for all; HOOS 99.2 vs 42.8, P < .001, iHOT-33 99.0 vs 26.6, P < .001, mHHS 99.6 vs 62.2, P < .001). Similarly, PROMIS scores were significantly different between groups for 8 of 9 tested domains. Patients with FAI demonstrated significant decrements in performance of all tested physical measures compared with asymptomatic controls (CON vs FAI, SSWV: 1.51 vs 1.32 m/s, P = .002; TSA: 3.05 vs 5.92 s, P = .017; FSST: 4.83 vs 8.89 s, P = .006; STS5: CON 5.53 vs FAI 10.75 s, P = .005.) Deficits in activities involving hip flexion-TSA, STS5-were strongly associated ( r < -0.7, P < .001) with increased reports of disability.

CONCLUSION: FAI has a negative effect on patient-reported and objectively measured function. Hip-specific and general measures such as PROMIS, FSST, TSA, and STS5 are responsive to FAI-associated debility and may be used to objectively assess surgical or rehabilitative outcomes.