'Fat fracture' - a physical sign mimicking tendon rupture

The imaging techniques available to aid the diagnosis of ruptures of tendo Achillis, the rotator cuff and the tendon of tibialis posterior in rheumato id patients are well described. However, ruptures of tendon or muscle at ot her sites are uncommon and may be overlooked. Diagnosis is often made by lo calised tenderness, swelling and a lack of active movement associated with a palpable defect. Clinical examination may be inconclusive and can be aide d by imaging studies. We report two cases in which ruptures of a tendon wer e suspected, and ultrasound imaging demonstrated the palpable defect to be a cleavage plane in the subcutaneous fat - a 'fat fracture'.