Occult distal femoral physeal injury with disruption of the perichondrium

The authors describe a case of distal femoral physeal injury with disruption of the perichondrium in a 9-year-old girl after a sledding accident. The patient presented with knee pain, limited range of motion, and inability to bear weight. Initial radiographs were normal. A magnetic resonance imaging of the knee demonstrated abnormal signal and widening of the distal femoral physis with elevation of the posterior distal femoral periosteum. This case illustrates the main magnetic resonance imaging findings in an occult Salter Harris type I injury: increased physeal thickness and signal intensity on water-sensitive sequences, perichondrial disruption, and intracartilaginous fracture.