Atypical biceps-related complication of proximal humerus fracture leading to internal shoulder impingement due to tendon stump dislocation.

Non-displaced proximal humerus fractures are usually managed non-operatively despite of minor malalignment. Biceps tendon rupture due to attrition after malunion is rare around the proximal humerus. Rupture of the long head of biceps (LHB) tendon usually occurs inside the joint close to the origin at the labrum. Treatment is usually non-operative with good outcomes. We report a rare case of a 48-year-old female patient with persistent locking and internal impingement 8 months after a proximal humerus fracture with anterior angulation leading to extra-articular reversed LHB tendon rupture with intra-articular dislocation of the proximal stump. Interposition of the tendon (3.5 cm) between the glenoid and the humeral head was confirmed on MRI arthrogram. Arthroscopic proximal tenotomy and stump removal resulted in immediate relief with improved function (subjective shoulder value 95%; Constant Score: 96). False interpretation of symptoms as posttraumatic stiffness should be avoided by a thorough examination and complementary MRI arthrogram investigation.