Custom 3D Printed Jigs in Salvage Reverse Shoulder Arthroplasty for Failed Four-Part Proximal Humerus Fracture Fixation: A Case Report

INTRODUCTION: Complications of open reduction and internal fixation (ORIF) in four-part proximal humerus fractures (PHFs) include non-union, malunion, avascular necrosis of humeral head, and glenoid defect due to implant failure. Reverse total shoulder arthroplasty is a salvage procedure for cases of failed fixation. In cases with significant abnormal glenoid anatomy, custom-made patient-specific 3D printed jigs play a major role in pre-operative planning and accurate positioning of the glenoid component, thereby improving the final outcome. We report a case of salvage reverse shoulder arthroplasty done using the patient-specific custom-made 3D printed jig. CASE REPORT: A 58-year-old female sustained bilateral PHF due to electrocution and was treated with bilateral ORIF in single stage in February 2018.At 4 months from the time of surgery, the fracture on the left side had united, but there was non-union on the right side with screw penetration eroding the glenoid. Reverse shoulder arthroplasty was planned as a salvage procedure. Intraoperative, the glenoid was found to be small (2.7cm × 1.72cm) and there was a posterior glenoid defect due to screw penetration. During drilling for central peg, an iatrogenic glenoid fracture occurred. The procedure was deferred. After 4 months of conservative treatment, the glenoid fracture had united and then a definitive procedure with the reverse shoulder prosthesis was planned. 3D glenoid bone model was made based on the computed tomography scan and custom-made jigs are designed and 3D printed, which are specific for the patient. Reverse shoulder arthroplasty was done, and surgery went uneventful. The patient achieved active forward elevation of 110°, lateral elevation of 90°, and an external rotation of 10° at 1-year follow-up. CONCLUSION: Reverse shoulder arthroplasty can be considered as a salvage procedure for failed fixation of PHF with predictable outcomes. Custom-made patient-specific 3D printed jigs in reverse shoulder arthroplasty are useful in assessing the position and direction of central peg in case of small glenoid and glenoid bone defects. 3D bone models are useful in implant selection also.