Introduction of a new outcome measure for total shoulder arthroplasty: subjective patient outcome tracker (SPOT)

Abstract

Background

Patient-reported outcome measures (PROMs) provide a quantifiable rating of a patient's subjective symptoms prior to and following treatment of shoulder pathology. Shoulder Subjective Patient Outcome Tracker (SPOT) is a novel outcomes measure with 10 satisfaction domains to pinpoint shoulder-specific functions. The purpose of this study is to introduce and demonstrate the utility of SPOT for patients undergoing total shoulder arthroplasty. The authors hypothesize SPOT will demonstrate high correlations to existing PROMs with a corresponding large effect size.

Methods

Over a 1-year evaluation period, SPOT, American Shoulder and Elbow Surgeons (ASES) assessment, and Single Assessment Numeric Evaluation (SANE) scores were administered preoperatively and at 2 years postoperatively for patients undergoing anatomic total shoulder arthroplasty (aTSA) and reverse shoulder arthroplasty (rTSA). Additionally, nonsurgical patients with glenohumeral osteoarthritis were administered SPOT at 2 separate time points. Interoutcome agreement, correlation, and sensitivity of SPOT to ASES and SANE were evaluated, and the floor/ceiling effect of SPOT was assessed. Test-retest reliability was conducted on the nonsurgical cohort.

Results

A total of 139 patients were included with 73 postoperative aTSA and 66 postoperative rTSA patients. Twelve patients managed nonoperatively were included in test-retest analysis. Preoperatively, there was low correlation between SPOT and ASES and moderate correlation between SPOT and SANE. At 2 years postoperatively, there was high correlation between SPOT and ASES and between SPOT and SANE. There was good agreement between SPOT and ASES in both aTSA and rTSA cohorts and between SPOT and SANE in the aTSA cohort. Additionally, the large effect size of SPOT was similar to the effect size of ASES and SANE. There was high correlation in the test-retest evaluation in a nonoperative cohort indicating reliability of SPOT at the 2 time points assessed.

Conclusion

SPOT is a shoulder-specific, effective PROM with a low administrative burden, tailored for patients undergoing aTSA or rTSA. It demonstrates high reliability, strong correlations, and a large effect size comparable to established shoulder-specific PROMs. SPOT is more discriminatory and specific than the SANE score, offering valuable, detailed insights into patients’ perceived deficits before and after shoulder arthroplasty.