AOSSM/AANA Specialty Day 2020-Surgical Outcomes in the Frequency, Etiology, Direction, Severity (feds) Classification System for Shoulder Instability

Surgical Outcomes in the Frequency, Etiology, Direction, Severity (feds) Classification System for Shoulder Instability

Pdf Summary

This multicenter study from the MOON Shoulder Instability group examined surgical outcomes for shoulder instability using the Frequency, Etiology, Direction, Severity (FEDS) classification system. The FEDS system categorizes shoulder instability based on four factors: frequency of episodes (solitary, occasional, frequent), cause (traumatic vs atraumatic), direction of instability (anterior, posterior, inferior), and severity (dislocation or subluxation). The study aimed to describe the epidemiology of these subtypes in a surgical cohort and assess 2-year patient-reported outcomes (PROs) and failure rates.<br /><br />Data were prospectively collected from 1204 patients treated by 25 surgeons across 11 institutions, primarily young males (mean age 24.6, 82% male), with 72% injured during sports. Seven FEDS categories represented over 75% of the cohort, predominantly traumatic anterior instability with various frequencies and severity subtypes. Follow-up data at two years were available for 636 patients.<br /><br />Key patient-reported outcomes included ASES, WOSI, and SANE scores, all showing significant improvements postoperatively across groups (p<.001). For anterior subluxation, outcomes were similar regardless of episode frequency. However, anterior dislocation groups showed a trend toward worse outcomes with increasing frequency. Failure rates, including recurrent subluxation (28.8%), dislocation (7.0%), and revision surgery (3.9%), were higher with greater initial frequency for anterior instability but were lowest in solitary traumatic posterior subluxation, which had zero revision surgeries.<br /><br />The results demonstrate that surgical stabilization yields excellent improvements overall, though recurrent subluxations reported by patients do not always equate to surgical failure. The data suggest earlier surgical intervention may prevent progression to more frequent, severe instability associated with poorer outcomes and greater glenoid bone loss. This prognostic information supports surgeon-patient discussions to optimize treatment timing. Ongoing research focuses on predictors and the impact of bone loss.<br /><br />Funding was provided by the University of Iowa and the John and Kim Callaghan Endowed Chair. Additional resources and updates are available via MOON Shoulder Instability’s website and social media.

Keywords

MOON Shoulder Instability

FEDS classification

shoulder instability surgery

frequency etiology direction severity

patient-reported outcomes

anterior shoulder instability

surgical failure rates

recurrent subluxation

sports-related shoulder injury

surgical stabilization outcomes