MR of physeal fractures of the adolescent knee

The aim of this study was to assess physeal fractures of the pediatric knee identified by MR imaging and to describe the MR findings of such fractures. The authors reviewed 315 consecutive pediatric knee MR examinations done to assess for traumatic injury. The MR images were reviewed for evidence of physeal fracture. Fractures were classified by the Salter-Harris system, and associated findings and injuries were noted. Plain radiographs and medical records were reviewed. Seven distal femoral physeal fractures (Salter II, n = 6; Salter III, n = 1) and two proximal tibia physeal fractures (Salter III, n = 1; complex Salter IV, n = 1) were identified. Magnetic resonance demonstrated widening of a portion of the physis with visualization of a metaphyseal/epiphyseal fracture line. Periosteal elevation was observed in six cases. Four patients had associated ligamentous or meniscal injuries. Plain radiographs were available for review in eight patients. Bone abnormalities suggesting fracture were evident in six of eight patients; however, the fracture was fully delineated in only one patient. The diagnosis or confirmation of fracture by MR changed clinical management in seven of eight patients in whom follow-up was available. Physeal fractures of the pediatric knee are occasionally diagnosed by MR. Magnetic resonance provides improved delineation of non-displaced physeal fractures of the knee, while simultaneously allowing for evaluation of soft tissue structures.