Bipolar lateralization in reverse shoulder arthroplasty for avoidance of scapular notching

Abstract

Introduction Reverse shoulder arthroplasty (RSA) has become a well-established treatment option for multiple disorders of the shoulder joint. In recent years, implant designs and configurations have been modified in order to improve function and avoid complications. Lateralization on the glenoid and the humeral side has been described to improve function and decrease radiographic scapular notching. Data on the clinical and radiographic results of bipolar lateralization in RSA are lacking. Methods In 38 cases, RSA was performed using an uncemented humeral short-stem component with a 145° neck–shaft angle in combination with bone lateralization on the glenoid side (Bony Increased-Offset Reversed Shoulder Arthroplasty, BIO-RSA; Wright Medical Inc., Memphis, TN, USA). Mean follow-up was 19 months (range 12–34 months). Patients were followed clinically using the Constant score as well as range of motion for shoulder flexion and external rotation. Radiographs in two different plains were analyzed for implant seating and the occurrence of scapular notching. Results There was a significant increase in all measured clinical parameters. Forward flexion increased from a mean of 75° preoperatively to 151° postoperatively, and mean Constant score increased from 21 to 71 points postoperatively (p < 0.001). Glenoid notching of grade 1 according to Sirveuax was observed in 3 out of 35 cases (9%); no grade 2, 3, or 4 notching was present. Revision surgery was necessary in one case (3%). Conclusion RSA with bipolar lateralization leads to excellent clinical outcomes, low complication rates, and low rates of radiographic scapular notching. Longer follow-up and prospective randomized trials are needed. Level of evidence Level IV.

Analysis of three different reverse shoulder arthroplasty designs for cuff tear arthropathy – the combination of lateralization and distalization provides best mobility

“…On the other hand, similar studies with small patient cohorts did not report any significant differences in functional outcomes of ROM, abduction strength, pain, or any other patient-reported scores in short-term follow-up (up to 2 years) [ 30 , 46 ]. When humeral lateralization was introduced, higher functional outcome with glenoid lateralization and a BIO-RSA (CS: 70–71 points) [ 40 , 47 ] or metallic baseplate offset (CS: 79 points) [ 48 ] was achieved.…”