HETEROTOPIC OSSIFICATION FOLLOWING OPERATIVE TREATMENT OF ACETABULAR FRACTURE - AN ANALYSIS OF RISK-FACTORS

A total of 237 patients with surgically treated acetabular fractures w ere analyzed to identify the risk factors predisposing to development of heterotopic ossification (HO) following operative treatment, and to evaluate both clinical significance of HO and the clinical outcome of operative excision of ectopic bone. All patients had a minimum of 1 y ear followup time. The degree of HO was determined from anteroposterio r radiographs of the pelvis at the 1 gear followup and was classified as Grade 0 or Grade 1 according to the amount of ectopic bone present. Forty patients (17%) who developed a moderate to severe amount of ect opic bone were classified as Grade 1. Nine who developed significant e ctopic bone resulting in 20% or greater loss of hip motion underwent e xcision of the ectopic bone; all six available for followup showed an improvement in range of motion. A significant correlation was found be tween poor clinical results at the I year followup and Grade 1 ectopic bone formation (p < 0.001). Four factors found to highly correlate wi th Grade 1 ectopic bone formation were: (1) the iliofemoral surgical a pproach; (2) multiple (2 or more) operative findings; (3) T type fract ures; and (4) the presence of associated injuries to the abdomen and c hest.