Distal Radius Malunion Increases Risk of Persistent Disability 2 Years After Fracture: A Prospective Cohort Study.

BACKGROUND: Studies concerning the relationship between distal radius fracture malunion and a persistent arm-related disability have produced conflicting results. QUESTIONS/PURPOSES: We investigated (1) how arm-related disability changes during the first 2 years after a fracture and (2) whether fracture malunion causes persistent disability. METHODS: One hundred twenty-three patients with distal radius fractures, treated with closed reduction and casts or external or percutaneous pin fixations, completed the DASH questionnaire at baseline, 3 months, 6 months, 1 year, and 2 years after fracture. Radiographic measurements were made at 1 year. Using a definition of malunion as ulnar variance of 1 mm or more and dorsal tilt greater than 10°, the patients were classified into three groups: no malunion (n = 35), malunion involving either ulnar variance or dorsal tilt (n = 65), and malunion involving ulnar variance and dorsal tilt (n = 23). The changes in the DASH scores with time (baseline to 2 years), in relation to malunion, were analyzed using generalized estimating equations adjusted for age, sex, fracture type (extraarticular or intraarticular), and treatment method. RESULTS: The mean change in DASH scores from baseline to 2 years was worse for patients with malunions involving ulnar variance and dorsal tilt than for patients with no malunions (mean difference, 13; 95% CI, 1.4-25) and for patients with malunions involving either ulnar variance or dorsal tilt (mean difference, 13; 95% CI, 2.2-24). CONCLUSION: After distal radius fracture, arm-related disabilities are more likely to persist at least 2 years in patients with fractures that healed with shortening and dorsal angulation than in patients with only shortening or dorsal angulation or without malunion. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence