Adult distal humeral metaphyseal fractures: epidemiology and results of treatment.

OBJECTIVES To examine the epidemiology and results of treatment of fractures of the distal humeral metaphysis. DESIGN Observational cohort study. SETTING An orthopaedic trauma unit, which provides all the fracture care for a well-defined catchment population. PATIENTS/PARTICIPANTS A consecutive series of 320 patients with distal humeral fractures admitted to the unit between January 1988 and June 1997. INTERVENTION We adopted a protocol of open reduction and fixation of all displaced fractures (greater than 5 mm of displacement in any plane) in patients who were medically fit for anesthesia. Postoperative immobilization was a cylinder cast for 6 weeks. Patients with undisplaced fractures or who were medically unfit were also treated nonoperatively in cylinder casts for 6 weeks. MAIN OUTCOME MEASUREMENTS Epidemiological examination of patient subgroups and the incidence of complications of treatment. RESULTS The overall incidence of distal humeral fractures in adults during this time was 5.7 cases per 100,000 in the population per year with an almost equal male to female ratio. There was a bimodal age distribution, simple falls were the most common overall cause of fracture, and the majority of the fractures were extra-articular (AO/OTA type A) or complete articular fractures (AO/OTA type C). The risk of complications during treatment was generally low in most patients, and the majority healed their fractures uneventfully. Overall, 90.6% of fractures united within 12 weeks and just under half of the remaining 9.4% patients with union complications healed without requiring further operative intervention by 24 weeks. The risk of union complications was higher following high-energy injuries, open fractures, and nonoperative treatment. Although the AO/OTA classification was not predictive of union complications, the "low" transcondylar (type A2.3 and A3) and simple intercondylar fracture (type C1.3) configuration had a greater risk of union complications than the "high" subtype. The rate of infection, myositis ossificans, and other implant-related complications were higher following operative treatment of type C fractures than type A and B fractures. CONCLUSIONS The epidemiology of a consecutive unselected series of adult distal humeral fractures is defined in this study. The majority of these fractures are best treated surgically by rigid open reduction and internal fixation, except for "low" Type A and C fractures, which have a higher risk of union complications. The role of total elbow arthroplasty to treat these more complex injuries requires further evaluation.