Management of failed metal-backed glenoid component in patients with bilateral total shoulder arthroplasty
An 80-year-old male presented with a history of bilateral glenohumeral arthritis status post-bilateral total shoulder replacements (left shoulder in 1996 and right shoulder in 1997). Both shoulders were replaced with the Kirschner modular II-C components (Kirschner Medical Corp., Fair Lawn, New Jersey), which is comprised of a modular humeral head/proximal porous coated stem and a metal-backed pressed fitted glenoid component with proximal and distal interlocking fixation screws. Patient experienced a routine intraoperative and post-operative course after both shoulder replacements without any complications.\nIn terms of the left shoulder, patient reported a few years of good pain relief and functional improvements after the shoulder replacement. However, he started to have intermittent left shoulder pain about 3 years after surgery that progressed to constant pain and significant limitation in terms of his range of motion and also functional activities. On physical examination, his forward flexion (FF) was 0-60, external rotation (ER) of 0-15 and internal rotation to his back pocket only. He also had significant pain with any range of motion on examination. Strength testing demonstrated 4/5 in supraspinatus and 4/5 in ER. Anteroposterior radiograph of the left shoulder showed significant loosening of the metal-backed glenoid component and cavitary bone loss with failure of fixation of both screws []. Computed tomography scan confirms the massive bone loss in the glenoid with associated rotator cuff tear. Due to the significant glenoid bone loss, patient underwent a resection arthroplasty in 2010 (14 years from the original procedure). At the most recent follow-up (2012), patient had no pain on the left shoulder. His range of motion measurements were: FF[] = 0-90, abduction = 0-50, ER = 0-45 []. Radiographs revealed of the resection arthroplasty revealed a small amount of heterotopic bone formation around the humeral shaft []. His simple shoulder test (SST) score was 16 and American Shoulder and Elbow Surgeons (ASES) score was 23.\nOn the right shoulder, patient also reported progressive intermittent pain that started about 4-5 years after the initial procedure. This also progressed to constant pain and significant limitations of his activities of daily living. On physical examination, patient range of motion was FF = 0-90 passive and 0-30 active, ER = 0-20 and internal rotation (IR) to the back pocket only. Patient also demonstrated significant weakness with supraspinatus and ER strength testing. Radiographs revealed failure of the metal-backed glenoid with obvious radiolucency indicating lysis around the glenoid component []. Patient underwent a revision arthroplasty to a large head hemiarthroplasty (2012) with removal of both failed metal-backed glenoid and the loose humeral stem. At the time of surgery, it was noted that the PE was worn with resulting metal on metal articulation and metallosis of the soft-tissue around the failed glenoid component. At the most recent follow-up (7 months post-op), range of motion was: FF = 0-70, abduction = 0-50 and ER = 0-65 []. He reports minimal pain on the right; however, he does have limitations of his daily activities due to his decreased range of motion. Radiographs demonstrate superior migration of the hemiarthroplasty without evidence of loosening []. His outcome scores included a SST score of 16 and an ASES score of 25.