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Glenosphere and baseplate failure in reverse shoulder arthroplasty

2016; Elsevier BV; Volume: 25; Issue: 6 Linguagem: Inglês

10.1016/j.jse.2015.11.046

1532-6500

Danielle Casagrande, Samuel Harmsen, Tom R. Norris,

Shoulder and Clavicle Injuries

Introduction: Reverse shoulder arthroplasty (RSA) has been an invaluable development for patients with deficient rotator cuff or significant glenoid-sided bone loss. However, complications involving baseplate failure can be devastating and are poorly understood. Purpose: The purpose of this study was to review the etiologies associated with baseplate failure in RSA and the outcomes following subsequent revisions. Methods: We reviewed the first 1000 RSAs, including primaries and revisions, performed by the senior author. Failure was defined as loosening of the baseplate or baseplate-graft construct from the scapula and a successful revision was defined as no loosening identified by the time of study completion. All grafts were structural unless otherwise stated. Results: The senior author treated 37 shoulders for 56 baseplate failures. Failures included: 16 status post primary RSA (13 autografts, 3 without structural grafts), 21 status post revision from hemiarthroplasty or total shoulder arthroplasty (3 allografts, 14 autografts, 4 without structural grafts), and 19 status post revision from RSA (5 allografts, 10 autografts, 4 without structural grafts). Autografts most commonly included humeral head or tricortical iliac crest bone graft. Structural allografts most commonly included femoral shaft or femoral neck. Patients without a structural graft often had cancellous croutons, OP-1, BMP-2, Plexur M, and/or Grafton employed. Failure occurred for various reasons. Seven failures from intra-operative techniques included inadequate lateralization in grade 3 bone loss glenoid leading to recurrent dislocations and loosening (1), intra-operative scapula fracture (2), and malpositioning of glenosphere/ baseplate construct (4), which was anteverted (1) or superiorly placed (3). Seven failures occurred after a trauma. Bone loss from osteolysis, notching, or medialization resulted in 13 failures and occurred, on average, 4 years from surgery. Fourteen cases failed secondary to infection, four of which occurred in patients with a previous history of peri-prosthetic infection in the same shoulder. Sixteen failures occurred from failure of fixation or nonunion of bone graft, on average, 7.5 months from surgery: 4 allografts, 10 autografts, and 2 without structural grafts. The fraction of shoulders that failed early from poor fixation or nonunion versus those that failed for any reason were: 4/8 with allograft, 10/37 with autograft, and 2/11 without structural grafts. Twenty shoulders that underwent revision RSA, for a previously loosened RSA baseplate, were successful. The average time from the revision to the end of the study was 3 years and 10 months. Four shoulders did not have a structural graft, 12 had an autograft, and 4 had an allograft. This is similar to the number of revision RSAs, for loosened baseplates, which failed: 4 without structural graft, 10 with autograft, and 5 with allograft (Table 1). Conclusion: Baseplate failure is rare and the etiologies are varied. Revision surgery has increased risk of failure due to increasing bony glenoid defects and infection. However, successful revision after these failures is possible. Our study revealed that approximately 50% of revision RSAs, for failed baseplates, did not present with loosening after an average of 3 years and 10 months while the other half went on to loosening for various reasons.