Lower Risk of Death with an Ankle Fracture than with a Hip Fracture
A newly published study shows that compared with hip fracture, an ankle fracture does not appear to be a sentinel event for older patients.
Kenneth J. Mroczek, MD
Hsu R, Lee Y, Hayda R, DiGiovanni C, Mohr V, Bariteau J. Morbidity and Mortality Associated with Geriatric Ankle Fractures. A Medicare Part A Claims Database Analysis. JBJS Am 2015;97:1748-55.
The 2008 Medicare Part A database was retrospectively reviewed for patients admitted for an ankle fracture, a hip fracture, or another diagnosis. The 1-year mortality rate was analyzed, taking into account patient age and pre-exisiting comorbidity. Morbidity was measured by length of stay, discharge disposition, readmissions, and medical complications.
The authors included only patients who required admission for ankle fractures in an attempt to select patients who were physiologically older and would thus be a more appropriate comparison to older patients with hip fractures.
The results showed that 19,648 patients were admitted for an ankle fracture, 193,980 patients for a hip fractures, and 5,801,831 for another diagnosis. The 1-year mortality rate was 28.2% for hip fractures, 21.5% for other diagnoses, and 11.9% for ankle fractures.
The authors found a statistically significant difference in age and comorbidity between ankle fractures and hip fracture, with the ankle fracture patients tending to be younger and healthier. Even when factoring in age and comorbidity, the 1-year mortality hazard ratio was 1.088 for a hip fracture and 0.557 for an ankle fracture.
The mean length of stay, discharge to a nursing home, 30-day readmission rate, 30-day mortality rate, and 90-day complication rate were all significantly higher in patients with hip fracture as compared with patients with ankle fractures. The rate of surgical site infection was higher in ankle fracture patients.
With the advent of modern techniques, there has been a trend toward surgical treatment of unstable ankle fractures in older patients. Many physicians, patients, and family may be naturally concerned about the morbidity and mortality risks in this group. This large study provides information that may assist in counseling both patients and their loved ones.
Compared with a hip fracture, an ankle fracture does not appear to be a sentinel event for the patient. These patients were shown to be younger and healthier than patients with hip fractures. Furthermore, this study only analyzed patients who required admission after an ankle fracture in an attempt to capture those who may have had more comorbidities. As a result, the data may overestimate the morbidity and mortality rates in the older adult ankle fracture population in general.
A higher rate of surgical site infection was observed for ankle fractures as compared with hip fractures. The authors rightfully mention that this 3.6% did not include other local wound complications, osteomyelitis, failure of fixation, need for reoperation, or amputation.
Surgical treatment of ankle fractures must take into account the often-osteoporotic nature of the bone and the need for gentle soft-tissue management. Postoperative management may need to be altered to involve a prolonged period of protective immobilization and slower advancement in returning to activities.
Kenneth J. Mroczek, MD, is an Assistant Professor of Orthopaedic Surgery and Chief of the Division of Foot and Ankle Surgery, Department of Orthopaedic Surgery, NYU Langone Medical Center – Hospital for Joint Diseases, New York, New York.