The use of an eccentric glenosphere compared with a concentric glenosphere in reverse total shoulder arthroplasty: two-year minimum follow-up results

Abstract

Purpose The current models of reverse shoulder arthroplasty (RSA) expose the procedure to the risk of scapular notching, possibly leading to loosening of the glenoid. We compared the clinical and radiographic results obtained with a concentric or eccentric glenosphere to assess whether the eccentric design might give better clinical results and avoid or decrease the risk of scapular notching Methods Of our patients, 31 underwent RSA using a concentric glenosphere (group A), while 29 had an eccentric glenosphere (group B). Postoperatively, patients were followed-up at one to 12 months and annually thereafter, with the mean being 33 months in group A and 27.5 in group B. In both groups the minimum follow up (F-U) was 24 months. Preoperatively and at each F-U starting from six months, patients were assessed using the Constant score. On radiographs, prosthesis scapular neck angle (PSNA), distance between scapular neck and glenosphere (DBSNG) and peg-glenoid rim distance (PGRD) were calculated. The severity of notching was classified in four grades. ResultsIn group A the mean Constant score increased by 30 points compared to the preoperative score and the active ROM increased considerably. At latest F-U, the mean PSNA, DBSNG and PGRD were, respectively, 87°, 3.4 mm and 19.8 mm.Glenoid notching was present in 42 % of cases. In group A, the mean Constant score increased by 34 points and the mean ROM was better than in group A. The average PSNA, PGRD and DBSNG were, respectively, 92°, 21.2 mm and 4.3 mm. Radiographs showed no inferior scapular notching. Conclusions The eccentric glenosphere yielded better clinical results than the concentric glenosphere and was associated with no scapular notching.

Clinical and radiological outcome of the Total Evolutive Shoulder System (TESS®) reverse shoulder arthroplasty: a prospective comparative non-randomised study

“…We found that overhang and peg-glenoid distance over 20 mm significantly decreased SN. Our findings are consistent with Simovitch et al [8,18].…”

Inferior Glenosphere Placement Reduces Scapular Notching in Reverse Total Shoulder Arthroplasty

“…Patients with the eccentric glenosphere showed no scapular notching (concentric glenosphere, 42% notching) and better clinical outcome as measured by both Constant-Murley scores and anterior elevation. 39 Mizuno et al 40 also reported a significant decrease in the severity of radiographic notching with an eccentric glenosphere compared with Grammontstyle reverse shoulder arthroplasty. Roche et al 41 also recommended inferior positioning of the base plate with greater overhang of the glenosphere to decrease the incidence of scapular notching and inferior osteophyte formation.…”

Complications of Shoulder Arthroplasty

“…Raiss et al demonstrated a reduction in survivorship at 10 and 15 years after TSA performed with cement secondary to pain and implant loosening; revision procedures occurred at a mean of 8.8 years from the date of implantation 125 . The five RSA studies with minimum follow-up of 5 years noted scapular notching and instability as the most common complications 28 [33][34][35][36][37][38][39][44][45][46][47][48]50,51,53,54,[56][57][58][59]61,64,65,67,69,70,73,75,79,81,[88][89][90][91][92][93][94][95][96][97][98][99][100][101][102]104,105,…”