Pelvic heterotopic ossification following total hip replacement causing fusion of femur shaft to pelvis

Background: There is scarcity of literature exploring the risk factors for Heterotopic Ossification (HO) after Total Hip Replacement (THR) being performed for comminuted proximal femur fractures. HO occurring after THR usually involves the lateral side. HO occurring between the pubis and femur has rarely been reported, and if occurring, have not been reported to be joining the femur and pelvis. Case details: We present a case of HO occurring in a 60 year old gentleman after THR was done for a comminuted proximal femoral fracture. The HO was noted to be joining the medial aspect of the femur shaft to the pelvis. This bridging HO was found to restrict the range movements of the hip and adversely impact the functional outcome of the THR. Conclusion: This report is a lesson for orthopaedic surgeons performing THR following proximal femoral fractures to avoid leaving behind any loosely attached fracture fragments as they could increase the risk of HO.