Radiology Review

A Pain He Can’t Walk Off

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A Pain He Can’t Walk Off

A 70-year-old man presents to the urgent care clinic for evaluation of right knee pain. He denies any specific injury or trauma. For the past several months, he says, he has had a “deep aching pain” that is exacerbated by walking and weight bearing.

His medical history is significant for mild hypertension and diabetes. His surgical history is significant for remote right total knee arthroplasty.

On examination, you note an elderly male in no obvious distress. His vital signs are normal. Inspection of the right knee shows a well-healed incision with no obvious effusion or erythema. He demonstrates a fairly good active range of motion. There is no evidence of ligament laxity.

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


 

A Pain He Can’t Walk Off

ANSWER

The radiograph shows a right knee prosthesis in place with no evidence of failure or displacement. Of note, there is a hyperdense, somewhat elongated lesion along the distal third of the femur. Radiographically, this is most likely consistent with an enchondroma. Enchondromas are typically benign bone lesions that originate from cartilage. They seldom cause pain and are usually found incidentally. No specific treatment is warranted.

The patient was referred to his orthopedist for follow-up.

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