This study was performed to determine 1) the rate of ankle fractures in the elderly in the United States stratified by hospital referral region, and 2) whether the percentage of ankle fractures treated surgically is affected by factors, such as fracture location, hospital referral region, concentration of orthopaedists, presence of a teaching hospital in that region, patient age, race, gender, or the number and type of specific medical comorbidities.
A 20% sample of Medicare Part B claims from the years 1998 to 2000 was analyzed.
The CPT codes for operative and nonoperative treatment of isolated medial malleolar, isolated lateral malleolar, bimalleolar, and trimalleolar fractures were identified. These codes were used to determine the overall rate of ankle fractures and individual fracture types.
: The rate of ankle fractures was evaluated by hospital referral region, patient age (groups of 5 years, aged 65 years or older), gender, and race. The percentage of surgical treatment was determined for each fracture type as the number of surgically treated fractures over the total number of ankle fractures within each subtype and analyzed by fracture type, hospital referral region, and concentration of orthopaedists in that region, presence of a teaching hospital within the hospital service area, patient age, gender, race, and number and type of specific medical comorbidities. Regression was performed by using the above variables.
We identified 33,704 ankle fractures: 7.6% were isolated medial malleolar, 50.8% were isolated lateral malleolar, 27.4% were bimalleolar, and 14.2% were trimalleolar fractures. The overall United States average was 4.2 ankle fractures per 1000 Medicare enrollees. The rate of ankle fractures varied by a factor of 8, from 1 per 1000 Medicare enrollees in San Francisco, CA, to 8.3 in Hickory, NC. The rate of ankle fractures was highest in white women at 5.8 and lowest in nonwhite men at 1.5 per 1000 Medicare enrollees. The overall rate of ankle fractures that underwent surgical stabilization was 33%, ranging from 14% in Binghampton, NY, to 72% in Napa, CA. The rate of surgical intervention was 22% for isolated medial malleolar fractures, 11% for isolated lateral malleolar fractures, 58% for bimalleolar fractures, and 74% for trimalleolar fractures. In regression analysis, the factors associated with nonoperative care after ankle fracture were: older age, female gender, increasing number of comorbidities as measured by the Charlson index, presence of diabetes or peripheral vascular disease, and living in a hospital service area that had a designated teaching hospital. Beneficiaries living in areas in which a hospital was a member of the Council of Teaching Hospitals were less likely to receive surgical treatment of their ankle fracture. Increasingly older age was strongly associated with decreased likelihood of having surgical intervention, with each 5 year age grouping progressively less likely to have surgical treatment. The concentration of orthopaedists in the region was not associated with the likelihood of having surgical treatment.
The term ankle fracture involves a wide spectrum of injuries. We found a large variation through the United States in both the rate of ankle fractures and the percentage of those that undergo surgical intervention.