Summary

Two year results for reverse total shoulder arthroplasty with an augmented baseplate displayed high survivorship and improved patient outcomes.

Abstract

Purpose

Glenoid fossa bone loss can compromise reverse total shoulder arthroplasty (RTSA) fixation integrity. The study objective was to evaluate patient clinical outcomes and radiographic evaluations at 1 and 2 years post-primary or revision RTSA using an augmented baseplate.

Methods

A prospective multicenter trial was performed at 6 different clinical sites. Seventy-four subjects (71 primary cases, and 3 revisions) with 54.1% women were enrolled with clinical, functional, and radiographic evaluation performed at 1 and 2 years post-RTSA. Rotator cuff arthropathy (50%) and osteoarthritis with a non-functional rotator cuff (28.4%) were the surgical indications. To date, 65 patients have completed the 2 year follow up. A deltopectoral surgical approach (11.4 ± 2.1 cm incision length) was used in all cases with an average operating time of 88.1 ± 27.4 minutes. Patient reported outcomes surveys administered at study entry and at 1 year, and 2 years post-RTSA included the American Shoulder and Elbow Society (ASES) score, visual analog scale (VAS) shoulder pain and instability scores, and the European Quality of Life Survey (EQ-5D-5L), a 5 dimension (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression), and 5 response level (no problems, slight, moderate, severe, and extreme problems) quality of life measurement instrument. A score of 1 represents the best health state.

Results

Mean ASES scores improved from 38.6 at study entry to 83.6, and 87.6, at 1 year, and 2 years post-RTSA, respectively. Mean VAS shoulder pain scores improved from 5.7 at study entry to 0.8 and 0.4 at 1 year, and 2 years post-RTSA, respectively. Mean VAS shoulder instability scores also improved from 3.1 at study entry to 0.7 at 1 year, and 0.4 at 2 years post-RTSA. The EQ-5D-5L improved from 0.5 pre-RTSA to 0.8 at both 1 year, and 2 years post-RTSA. By the 2 year follow up mean active shoulder forward elevation had improved 57° and mean active adducted shoulder external rotation had improved 26° compared to study entry measurements. At present, only 1 revision has been necessary to correct glenoid component migration from central screw breakage. One patient death occurred prior to the 2 year follow-up, however, it was not study related. No additional major complications occurred. Kaplan-Meier two year survivorship is currently 98.6%.

Conclusion

At 2 year follow up, RTSA with an augmented baseplate demonstrated excellent patient outcomes, minimal complications, and good survivorship. Further study over longer time periods with randomized augmented baseplate assignment are indicated.