Overlooked Hoffa Fracture in a Patient With Neurofibromatosis-1

Hoffa fractures are rare fractures of either one or both femoral condyles in the coronal plane. They usually occur as a result of high-velocity, high-energy trauma with axial compression of the lower limb and a typically flexed position of the knee. The lateral condyle is affected more frequently. Diagnosis of a coronal fracture is often missed in conventional radiography, so additional CTs of the knee are highly recommended in unclear cases. Because of permanent shearing forces, fracture healing is unlikely without surgical treatment. In the case we present here, the Hoffa fracture occurred after minimal trauma and was associated with an ipsilateral patellar dislocation and a meniscal tear. The fracture was initially overlooked. Bone quality was affected by a preexisting neurofibromatosis-1 condition.