Two cases of Parkinson's disease(PD) with recurrent dislocation of the shoulder causing a large bone defect at the humeral head and permanent dislocation were reported. Case 1 was a 74-year-old woman with PD. First dislocation of her right shoulder occurred with no major trauma. Dislocation of the shoulder occurred three times after the first visit. Finally, a large bone defect was observed at the humeral head and the dislocated humeral head was impacted at the anteroinferior rim of the glenoid. Her shoulder pain gradually became stronger. Operation was performed for the purpose of relief of pain. The humeral head was resected and a subscapularis tendon was interposed into the glenohumeral joint using two metal anchors. At the final follow-up, active elevation showed 60 degrees and ADL was limited, but the preoperative shoulder pain decreased. Case 2 was a 75-year-old woman with PD. First dislocation of her right shoulder occurred by falling down forwards. Dislocation of the shoulder was occurred six times after the first visit. Finally, this dislocation was hard to manually reduce and conservative therapy was performed. A large bone defect was observed at the humeral head and the dislocated humeral head was impacted at the anteroinferior rim of the glenoid. Her shoulder pain gradually decreased. At the final follow-up, active elevation decreased 70 degrees and ADL was limited. But the pain gradually decreased by conservative therapy. The dislocations and fractures of the shoulder often occurred in patients with PD due to akinesia,postual instability, muscle weakness and osteoporosis. First dislocation can easily develop into recurrent and permanent dislocation of the shoulder caused by the difficulty of reduction due to rigidity and resting tremor. Resection arthroplasty and conservative therapy were performed. ROM of the shoulder and ADL were limited, but severe shoulder pain was relieved.
