A prospective case-control study of ankle fracture in postmenopausal women.

OBJECTIVES To compare bone mineral density of women with postmenopausal ankle fractures with controls and review patient characteristics, injury mechanisms, and outcomes. DESIGN Prospective case-control study. SETTING University teaching hospital, Hong Kong. PARTICIPANTS Women older than 60 years, admitted with ankle fractures between 2002 and 2003 and controls (age-matched women with femoral neck fractures). MAIN OUTCOME MEASURES Demographic data, bone mineral density, mechanism of injury, fracture pattern, treatment, and the functional outcome. RESULTS The mean age of the study group (18 ankle fracture patients) was 74 years. The fractures usually resulted from a low-energy trauma; isolated lateral malleolar fracture was the most common (8/18), whilst six had bimalleolar fractures. Their mean T-score bone mineral density values at the spine and hip were -1.67 and -1.70, respectively; corresponding Z-scores were +0.73 and +0.99. The bone mineral density of the study group was significantly higher than in patients with fractured neck of femur (controls) and the general population (P<0.05). Nine of the study group had diabetes and one had impaired glucose tolerance. Treatment comprised casting in 10 patients and operative fixation in seven. Good functional recovery was achieved; most patients were able to resume their premorbid level of independent daily activities with a good motor functional independence score (85.18/91) 1 year post-injury. CONCLUSION In this case-control study, postmenopausal ankle fractures were not associated with osteoporosis. Diabetic neuropathy may have been a risk factor for such injury. The functional outcome of such patients was generally satisfactory, provided appropriate treatment was given.