Occult Interpositional Rotator Cuff - an Extremely Rare Case of Traumatic Rotator Cuff Tear

Traumatic rotator cuff tendon tears in young patients are unusual and they are commonly associated with high-energy trauma. The entrapment of a rotator cuff tendon in the glenohumeral (GH) joint is even rarer and this malady is prone to be missed. We experienced a case of a pseudo-paralyzed shoulder after trauma. The cause turned out to be interposition of the rotator cuff tendons in the GH joint. We present the imaging of this rare condition with the operative correlation. We also speculate on the possible trauma mechanism from the evidence of the concomitant injuries and the image findings.