Radiology Review

There’s No Patellin’ What Happened

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There’s No Patellin’ What Happened

A 30-year-old man is transported by ambulance to your emergency department from the scene of a motor vehicle collision. He was a restrained driver who lost control of his vehicle and hit the back of a tractor-trailer. His airbag deployed, and he thinks he had a brief loss of consciousness. He complains of pain in his neck, right-side chest wall, and right knee.

He denies any significant medical history and takes no medications regularly. He reports smoking a half-pack of cigarettes per day and consuming alcohol socially; he denies drinking this evening.

Primary survey shows a male in no obvious distress who is currently awake, alert, and oriented. His Glasgow Coma Scale score is 15. Primary exam is stable except for some neck pain and right-side rib pain.

During secondary survey, examination of his right knee shows a superficial laceration with controlled bleeding. No significant swelling is present. The patient does have decreased range of motion secondary to a moderate amount of pain. Distal pulses are present, and there is no neurovascular compromise.

You obtain a portable radiograph of the knee (shown). What is your impression?


There’s No Patellin’ What Happened


The radiograph demonstrates an abnormal-appearing patella; there is a longitudinal lucency along the lateral portion. There is some mild soft-tissue swelling but no evidence of a definite joint effusion. The lucency could represent a fracture, especially in the setting of trauma. The other possibility is that the patient has a bipartite patella. This is a rare congenital condition in which the patella does not completely fuse; it remains two separate bones. CT of the knee for further evaluation, as well as orthopedic consultation, were ordered.

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