Periosteal entrapment in distal femoral physeal fractures: harbinger for premature physeal arrest ?

We report on two patients who sustained Salter-Harris II fractures of the distal femur with physeal widening after being tackled in football games. Preoperative MRI indicated entrapped periosteum at the physeal fracture site for both patients. Both patients underwent open reduction of the physeal fracture with removal of the entrapped periosteum and achieving an anatomic reduction. Follow-up MRI's revealed premature physeal arrest. Subsequent procedures were performed to address sequelae of premature physeal arrest. The presence of physeal widening and entrapped periosteum may reflect high-energy trauma to the physis. This can result in injury to both the epiphyseal blood supply and to the physeal cartilage (germinal zone) resulting in physeal arrest despite anatomic reduction after removal of the entrapped periosteum. Upon literature review, pre-operative MRI demonstrating entrapped periosteum has not been previously reported. We hypothesize that the presence of entrapped periosteum following distal femoral physeal fractures may be associated with an increased risk for premature physeal arrest.