Conversion of Stemmed Hemi- or Total to Reverse Total Shoulder Arthroplasty: Advantages of a Modular Stem Design

Abstract

Background If revision of a failed anatomic hemiarthroplasty or total shoulder arthroplasty is uncertain to preserve or restore satisfactory rotator cuff function, conversion to a reverse total shoulder arthroplasty has become the preferred treatment, at least for elderly patients. However, revision of a well-fixed humeral stem has the potential risk of loss of humeral bone stock, nerve injury, periprosthetic fracture, and malunion or nonunion of a humeral osteotomy with later humeral component loosening. Questions/purposes The purposes of this study were to determine whether preservation of a modular stem is associated with (1) less blood loss and operative time; (2) fewer perioperative and postoperative complications, including reoperations and revisions; and/or (3) improved Constant and Murley scores and subjective shoulder values for conversion to a reverse total shoulder arthroplasty compared with stem revision. Methods Between 2005 and 2011, 48 hemiarthroplasties and eight total shoulder arthroplasties (total = 56 shoulders; 54 patients) were converted to an Anatomical TM reverse total shoulder arthroplasty system without (n = 13) or with (n = 43) stem exchange. Complications and revisions for all patients were tallied through review of medical and surgical records. The outcomes scores included the Constant and Murley score and the subjective shoulder value. Complete clinical followup was available on 80% of shoulders (43 patients; 45 of 56 procedures, 32 with and 13 without stem exchange) at a minimum of 12 months (mean, 37 months; range, 12-83 months). Results Blood loss averaged 485 mL (range, 300-700 mL; SD, 151 mL) and surgical time averaged 118 minutes (range, 90-160 minutes; SD, 21 minutes) without stem exchange and 831 mL (range, 350-2000 mL; SD, 400 mL) and 176 minutes (range, 120-300 minutes; SD, 42 minutes) with stem exchange (p = 0.001). Intraoperative complications (8% versus 30%; odds ratio [OR], 5.2) and reinterventions (8% versus 14%; OR, 1.9) were substantially fewer in patients without stem exchange. The complication rate leading to dropout from the study was substantial in the stem revision group (six patients; 43 shoulders [14%]), but there were no complication-related dropouts in the stemretaining group. If, however, such complications could be avoided, with the numbers available we detected no difference in the functional outcome between the two groups. Conclusions Patients undergoing revision of stemmed hemiarthroplasty or total to reverse total shoulder arthroplasty without stem exchange had less intraoperative blood loss and operative time, fewer intraoperative complications, and fewer revisions than did patients whose index revision procedures included a full stem exchange.

Reverse total shoulder arthroplasty for acute head-splitting, 3- and 4-part fractures of the proximal humerus in the elderly

“…Furthermore, failed hemiarthroplasties can successfully be revised with RTSA. 35,46 The primary use of RTSA for acute fractures has been reported in several small single-center series. 4,7,8,11,24,26,39,40,42 Our series reports the outcomes from 2 independent centers using the same implant and technique.…”

Functional Outcomes of Modular Conversion of Hemiarthroplasty or Total to Reverse Total Shoulder Arthroplasty

“…2). In cases of instability from rotator cuff dysfunction, proper tensioning of the deltoid and soft tissues is paramount in order to achieve the ideal joint compressive forces [12].Similarly, rotator cuff dysfunction with instability was the leading indication for surgery in a modular conversion study by Wieser et al [27]. They compared a cohort of 13 hemiarthroplasty or TSA patients who retained their stem and 43 patients who had the stem removed at the time of conversion to RTSA.…”

Influence of glenosphere diameter and lateralization on instability of reverse shoulder arthroplasty

“…Reverse shoulder arthroplasty (RSA) has gained a prominent role in the treatment of unreconstructable fractures of the proximal humerus as well as of other pathologies such as cuff tear arthropathy and failure of anatomical shoulder prostheses [4,5,9,10,29]. By shifting the center of rotation (COR), the Grammont design and the more recent reverse shoulder prosthesis designs achieve an improvement of the abductor lever arm of the deltoid muscle, therefore compensating for deficiencies of the cuff or loss of the tuberosities [5,9,10].…”