404 Mechanisms of a Dynamic Stability Protocol for Persons with Thumb Osteoarthritis

Abstract

OBJECTIVES/GOALS: Our aims are to 1) describe changes in thumb Carpometacarpal (CMC1) joint stability following an 8-week clinic-based dynamic stability exercise program using computerized tomography (CAT) and 2) to evaluate the agreement between ultrasound and CAT (reference standard) when quantifying thumb CMC stability. METHODS/STUDY POPULATION: Aim 1: We have enrolled 13/49 participants in a prospective pre-post interventional study of an 8-week clinic-based occupational therapy dynamic stability program. The primary outcome will be change in stability (thumb metacarpal subluxation in mm) when forcefully loading the thumb as per CAT from pre-treatment to post-treatment at 9 weeks. Aim 2: Same 49 participants are undergoing a one-time ultrasound during baseline assessment. Agreement of ultrasound and CAT measurements (thumb metacarpal subluxation in mm) will be assessed by the Bland-Altman method. RESULTS/ANTICIPATED RESULTS: Exercise is a first-line treatment of CMC1 OA yet there is insufficient evidence to support this. Progression of CMC1 OA is characterized by altered joint mechanics. Joint replacement surgery may reduce pain but often worsens thumb mechanics and overall hand function. This study is the first to test the sustained biomechanical effects of non-invasive thumb exercises. Should these benefits exist, this will further support exercise as a first-tier intervention. Should ultrasound be a suitable proxy for CAT, therapists/physicians could monitor thumb CMC mechanics in response to treatment without risk of radiation exposure. We anticipate 1) a statistically significant reduction in thumb CMC subluxation at 9 weeks follow up and 2) high agreement between sonographic and CAT measures of thumb stability. DISCUSSION/SIGNIFICANCE: This study will lay the foundation for future work and may offer critical support for the use of a non-pharmacological and non-surgical approach as first-line treatment of a highly disabling disease. Future study should include controlled trials where hand function, activity limitation, disease progression, and costs are the outcomes in interest.