Institutional Review Board approval was obtained from Thomas Jefferson University Hospital prior to conducting this retrospective analysis (IRB No. 45 CFR 46.110, Control #17D.020). All data collection was retrospective and all patients provided informed consent preoperatively for retrospective data review. Our institutional billing database was queried using the CPT code 23472 (arthroplasty, glenohumeral joint; total shoulder) to identify all patients who underwent a TSA or RSA from 2004 to 2015. A retrospective chart review was performed to identify all patients who underwent staged bilateral TSAs for OA or staged bilateral RSAs for CTA. Inclusion criteria were patients who underwent bilateral TSAs for OA or bilateral RSAs for CTA with at least 2 years of clinical follow-up from the latest arthroplasty surgery. Exclusion criteria were patients (1) undergoing bilateral TSAs for any diagnosis other than OA, (2) undergoing RSAs for any diagnosis other than CTA, (3) undergoing revision arthroplasty surgery, and (4) having chronic neurologic conditions (cerebrovascular accident, multiple sclerosis, and Parkinson disease). Rotator cuff integrity was assessed intraoperatively for all patients undergoing a TSA procedure. If their rotator cuff was determined to be insuffient, they received an RSA and were thus excluded from the study. For primary OA, all patients had Smilson-Prieto grade 2 or greater changes; for primary CTA, all patients had Hamada grade 2 or greater changes.2021) From 2004 to 2015, 5,261 primary shoulder arthroplasties were performed at our institution. After retrospective chart review, 26 TSA patients (52 shoulders) were matched 2 to 1 with 13 RSA patients (26 shoulders) according to sex, age at first surgery, and time from first arthroplasty surgery.

Preoperative and postoperative active ranges of motion (ROMs) in forward elevation (FE), external rotation (ER), and internal rotation (IR) were assessed by chart reviews of clinician-documented ROM. Postoperative complications, readmissions, and reoperations were recorded. Identified patients were then assessed at follow-up visits or contacted via phone for activities of daily living external and internal rotations (ADLEIR; 0–36 point scale of ADL performance) scores, American Shoulder and Elbow Surgeons (ASES) shoulder scores, Single Assessment Numerical Evaluation (SANE), and visual analog scale (VAS) pain and VAS patient satisfaction scores of both shoulders.22232425) All procedures were performed by one of five fellowship-trained shoulder and elbow surgeons (CLG, MDL, MLR, GRW, JAA). All surgeries were performed either through a standard deltopectoral approach or through a superolateral deltoid–splitting approach if prior surgical incisions required this approach.26) Full details of the surgical procedures can be found in Table 1. All patients were immobilized in a sling for 2–4 weeks postoperatively and then were enrolled in a standardized postoperative physical therapy protocol. The main difference in rehabilitation protocols was that patients undergoing TSA begin passive FE and passive ER starting the day of surgery while RSA patients typically do not. All patients begin active assisted ROM at 6 weeks and then begin strengthening at 12 weeks.

Study population characteristics are reported by using measures of central tendency (mean) and variability (standard deviation). Patients' shoulders were compared by using independent samples t-tests for continuous variables and chi-square analyses for categorical variables to detect differences between groups. For all statistical tests, a p-value < 0.05 was used to determine significance. All statistics were calculated with Microsoft Excel (2013; Microsoft, Redmond, WA, USA).

This retrospective cohort comparison shows that in general patients who received bilateral TSAs had better postoperative ROM and patient-reported functional outcomes than patients who received bilateral RSAs. Patients with bilateral TSAs had better postoperative ROM in every measured plane except IR of their non-Dom arms. However, the only plane in which bilateral TSA patients had significantly better improvement in ROM was ER. Bilateral TSA patients also had significantly better functional outcome scores (ASES, SANE, and ADLEIR) than did their bilateral RSA counterparts. Despite the superior functional outcome scores in the bilateral TSA cohort, these two groups had equal final satisfaction for their Dom arms and equal pain relief (VAS pain score) in both arms.

Surgeons remain concerned with the ability of patients to perform all of their ADLs after RSA given the inherent limitations in IR with this arthroplasty design. However, recent evidence suggests that these deficits may not be as profound as previously thought. Stevens et al retrospectively reviewed the outcomes of 15 consecutive patents who underwent staged bilateral RSA for CTA and found that all patients were able to adequately perform ADLs that require IR including maintaining perineal hygiene.13) Wirth et al.14) reported the results of 57 staged bilateral RSAs at least 1 year from their second arthroplasty surgery and found that at 1 year postoperatively 21% of patients had insufficient IR after their first surgery and 33% had insufficient IR after their second surgery. However, at 2 years postoperatively, only 5% of patients lacked sufficient IR bilaterally. At a mean follow-up of 48.4 months, Levy et al.11) reported the results of 19 patients who underwent staged bilateral RSAs and all patients had no limitations in their leisure activities or ADLs including maintaining perineal hygiene. In the largest cohort study published to date, Mellano et al.12) retrospectively reviewed 50 patients who underwent staged bilateral RSA for CTA, OA, massive rotator cuff tear, or revision shoulder arthroplasty and found that all patients remained independent with ADLs and personal hygiene 2 years postoperatively. All of these studies clearly demonstrate that patients can remain functional with bilateral RSAs. Similarly, all of the patients in our bilateral RSA cohort reported that they were able to adequately maintain personal hygiene. While the bilateral TSA cohort had superior functional outcomes and superior ADL scores (over 35/36 in ADLEIR testing for both arms), the bilateral RSA cohort still achieved reasonable ADL scores (over 32/36 in both arms).

Certainly, this study has several weaknesses. First, this is a purely retrospective study and is therefore subject to the limitations of retrospective data specifically on the inability to elucidate causal relationships rather than simply correlative ones. The ROM measurements were obtained by retrospectively reviewing the physical examinations dictated by physicians. These measurements would be more accurate if they were assessed using a goniometer. We did not have preoperative patient-reported functional outcome scores or ADLEIR scores to compare with the postoperative scores and therefore could not assess net improvement in functional outcomes between cohorts. There were also some variations in surgical details and specific TSA and RSA systems patients received may have influenced the results. However, all procedures were performed by high-volume fellowship-trained shoulder and elbow surgeons, so we do not believe these variations would significantly affect the results. Additionally, this sample size may be underpowered to show a significant difference between cohorts. This is an inherent limitation of a retrospective analysis and cannot be modified. Despite these weaknesses, we were able to achieve a direct matched comparison of bilateral TSA to RSA. We found superior functional outcomes in the bilateral TSA cohort, equal pain relief in both cohorts, and a satisfactory ability to perform ADLs in both cohorts.

Overall, patients who underwent bilateral TSAs for OA and bilateral RSAs for CTA exhibited improved ROM and patient-reported functional outcomes. Patients who underwent bilateral TSAs had superior functional results to patients who underwent bilateral RSAs. Both groups exhibited equal pain relief. Despite the difference in functional results, patients with bilateral RSAs were satisfied with their results and able to perform their ADLs with minimal limitations.