Background: Malunion proximal humerus with secondary osteoarthritis in young patient is a problem to most of the surgeons because of its difficulty and poor result. Total shoulder arthroplasty with tuberosity osteotomy is an option to improve pain and function of shoulder.
Objective: To report the results of total shoulder arthroplasty with tuberosity osteotomy in young patient with malunion 4 parts proximal humerus fracture with secondary osteoarthritis of glenohumeral joint.
Materials and Methods: Case report was a 35-year-old female with painful and stiff right shoulder after 16 years of untreated proximal humerus fracture. She received total shoulder arthroplasty with tuberosity osteotomy in our institute. Range of motion, quick Disabilities of Arm, Shoulder, and Hand score (Q-DASH), and Visual analog score (VAS) were compared pre- and postoperatively.
Results: Total follow-up duration was 30 months. Range of motions in all directions were improved. Q-DASH score and VAS score were improved (72.73 to 0 and 5 to 0, respectively).
Conclusion: With limited options of management in malunion proximal humerus fracture with secondary osteoarthritis in young patient, the total shoulder arthroplasty with tuberosity osteotomy is a considerable option for the patient who has a good quality of rotator cuff and can achieve tuberosity union.

Keywords: Malunion proximal humerus; Osteoarthritis of glenohumeral joint; Young patient; Total shoulder arthroplasty; Tuberosity osteotomy