Staged bilateral total shoulder arthroplasty: a single institutional experience with mid-term follow-up

Background The preferred surgical approach for surgical treatment of advanced glenohumeral arthritis is shoulder arthroplasty (SA). Considering the growing volume and success of shoulder arthroplasty, patients with bilateral shoulder disease are likely to undergo surgery on both shoulders. There are numerous studies evaluating the outcomes of bilateral hip and knee arthroplasty, but a paucity of information examining bilateral shoulder arthroplasty. This study intends to evaluate the clinical outcomes of patients undergoing staged bilateral anatomic shoulder arthroplasty (aTSA) or reverse total shoulder arthroplasty (rTSA). Methods Institutional records were queried for patients who underwent staged bilateral aTSA or rTSA from 2009 to 2020. Patient records were retrospectively reviewed to assess pre- and postoperative range of motion and strength measurements, demographic information, and complications. Mean±standard deviation was reported for all continuous variables. Mean functional measurements were compared using a 2-Sample t-Test, ordinal variables via Wilcoxon-Mann Whitney test, and categorical variables via Chi-squared test. Patients were included in the outcome analysis if they had a bilateral TSA with the same procedure (i.e. aTSA on both sides, or rTSA on both sides). Results 43 patients (15 male, 28 female) were included. There was an average time of 1.8 years between surgeries. Of the 43 patients, 26 patients had staged bilateral aTSAs and 14 had staged bilateral rTSAs with three patients who had different surgeries on each shoulder. The three patients with different surgeries on each shoulder were excluded from outcome analysis. Patients who had staged aTSA operations demonstrated significant improvement in external rotation (ER) (p = 0.0191, p < 0.001), forward elevation (FE) (p = 0.0004, p<0.001), and internal rotation (IR) (p = 0.0183, p = 0.0166) after the first and second surgeries (Table 1). Staged rTSA patients showed significant improvement in FE after the first (p = 0.0043) and second surgeries (p =0.016). Patients demonstrated significant increase in strength of ER (p = 0.0136), FE (p = 0.0088), and IR (p = 0.0206) after the first rTSA. There was no corresponding increase in strength testing after the second bilateral rTSA surgery (Table 2). The average SANE, Contralateral SANE, ASES, and SST scores for all surgeries were 84±10, 83±13, 75±20, and 9±2, respectively for the first surgery and 82±13, 83±13, 71±21, and 8±3 for the second surgery. Conclusion Individuals that undergo staged aTSA procedures gain a better range of motion and internal rotation strength after both operations. However, individuals that undergo staged rTSA procedures have an improved ROM and strength after the first surgery but limited improvement after the second.