Evaluation of the effectiveness of a metacarpophalangeal ulnar deviation orthosis

Abstract

Rheumatoid arthritis (RA) causes structural damage that precipitates joint deformity, including metacarpophalangeal (MCP) joint ulnar drift (UD). Orthoses have been designed in order to maintain hand function by improving joint alignment, restoring biomechanical balance and reducing stress on supporting diseased tissues. This study investigated the impact an MCP UD (MUD) splint had on: pain, hand function, grip strength, and passive correction of UD when worn for function by RA patients. Twenty seven hands (26 subjects) were evaluated and performances compared with and without the splint. Results showed anatomic alignment improved significantly in all except the index finger. The mean difference for all fingers combined was 10 degrees. Observable correction of subluxation was identified from x-ray film and noted in 14.8% of index fingers, 18.5% of middle fingers, 33.3% of ring fingers, and 48.1% of little fingers. Three point pinch showed a statistically significant change, the mean difference being an improvement of 15% while wearing the splint. There was no significant change in hand function score, pain score, gross grip strength, and lateral pinch. Subjects' perceptions of the MUD splint gained from a questionnaire showed a high acceptance: 79.2% reporting minimal interference in ADL, 95.8% satisfied with cosmesis, 87.5% satisfied with comfort, and 95.8% reported continued use of the orthosis.