title: Validation of the Foot and Ankle Outcome Score for Hallux Rigidus.
abstract: BACKGROUND
  There is a clear call for improved patient-centered outcomes. The Foot and Ankle Outcome Score (FAOS) is a region-specific patient-reported measure that has been validated for a number of foot and ankle diagnoses, but not hallux rigidus.
  
  
  OBJECTIVE
  The aim of this study was to validate the FAOS in patients with hallux rigidus.
  
  
  METHODS
  From 2007 to 2013, 211 patients with hallux rigidus (HR) were included in the study. For the construct validity portion of the study, 125 patients completed a Short-Form 12 (SF-12) and FAOS survey. Forty additional HR patients were prospectively given questionnaires to assess the relevance of each FAOS question as it pertained to their HR. Reliability was assessed in 36 HR patients via administration of a second FAOS an average 1 month following the first. In 55 patients, preoperative and postoperative FAOS scores were compared to determine responsiveness.
  
  
  RESULTS
  All FAOS subscales demonstrated moderate correlation coefficients with the physical functioning, role physical, bodily pain, and physical health component scores of the SF-12, with all subscales demonstrating poor correlation with the SF-12 mental health-related domains. Content validity was high for all FAOS scores, with the exception of the daily activities subscale. All subscales achieved acceptable test-retest reliability with correlation coefficients of ≥0.72. Furthermore, all subscales were rated as responsive to change in postoperative patients (p < 0.001).
  
  
  CONCLUSIONS
  This study demonstrates the acceptable construct and content validity, reliability, and responsiveness of the FAOS for hallux rigidus. Due to its broad applicability and proven validation across multiple foot and ankle pathologies, the FAOS represents a patient-centered outcome measure that can be reliably used for the assessment of patients with hallux rigidus.
authors: Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, 5200 Centre Avenue, Suite 415, Pittsburgh, PA 15232 USA.
authors: MaCalus V
authors: MV
authors: Hogan
authors: Georgetown University School of Medicine, Washington, DC USA.
authors: Sriniwasan B
authors: SB
authors: Mani
authors: Foot and Ankle Service, Hospital for Special Surgery, 535 East 70th Street, New York, NY USA.
authors: Jeremy Y
authors: JY
authors: Chan
authors: Department of Epidemiology and Biostatistics, Hospital for Special Surgery, 535 East 70th Street, New York, NY USA.
authors: Huong
authors: H
authors: Do
authors: Foot and Ankle Service, Hospital for Special Surgery, 535 East 70th Street, New York, NY USA.
authors: Jonathan T
authors: JT
authors: Deland
authors: Foot and Ankle Service, Hospital for Special Surgery, 535 East 70th Street, New York, NY USA.
authors: Scott J
authors: SJ
authors: Ellis
keywords: FAOS; hallux rigidus; patient-reported outcomes; validation