Background: Heterotopic ossification is defined as pathological bone formation in soft tissue, it usually occurs postoperatively and varies in amount from faint to massive ossification, which are frequently asymptomatic. The cause of heterotopic ossification is unknown, but it occurs more commonly after the procedure, in which considerable bone and soft tissue are dissected extensively. The heterotopic ossification in the abductor region of the hip following closed femoral nailing has rarely been documented.
Objective: To assess the prevalence and type of heterotopic ossification after closed antegrade femoral nailing.
Material and Method: A retrospective study was performed in patients who underwent closed antegrade femoral nailing. The occurrence of heterotopic bone was assessed by reviewing of the series of the follow-up films in this group of patients with sufficient duration of at least after 6 months post-operation. The size and extent of the heterotopic ossification were measured and graded according to Brumback classification.
Results: From 100 patients who were completely followed-up. There were 54 cases (54%) presented with heterotopic ossification. The heterotopic ossification are classified as grade I in 16 cases(16%), grade II in 13 cases (13%), grade III in 24 cases (24%) and grade IV in 1 case (1%). There was a significant different between the prevelence of heterotopic ossification in patients with trochnateric fractures when compared to patients with femoral shaft fractures (p-value < 0.05).

Keywords: Ossification, Nailing, Femur, Fracture