Background Reverse total shoulder arthroplasty (rTSA) is an increasingly common surgical procedure often performed to treat pain related to glenohumeral osteoarthritis or to rotator cuff arthropathy. Although surgical outcomes are generally excellent, recent evidence has found that postoperative pain (≥ 3/10) two years following surgery is reported by an estimated 18% of patients. Recently, the NIH Acute-to-Chronic Pain Signatures program recommended longitudinal studies using select biomarkers to describe and predict individual patient responses to surgery. These data are not yet available for rTSA procedures.

Methods This was a longitudinal cohort study performed at a single academic medical center. Twenty participants undergoing rTSA surgery were included, recruited from a tertiary hospital system in the southern United States. The first objective of this study was to describe changes in general pain intensity (Numerical Pain Rating Scale), widespread body pain, anxiety (General Anxiety Disorder-7), depression (Patient Health Questionnaire-9), neuropathic pain symptoms (painDETECT), and quantitative sensory testing from baseline to 6 weeks following rTSA. The second objective was to identify the baseline demographic and pain-related factors associated with 6-week postsurgical improvements in pain intensity.

Results From before to after surgery, our cohort demonstrated significant improvement in shoulder pain intensity, widespread body pain, PainDETECT score, and temporal summation magnitude measured at the surgical deltoid. Degree of 6-week pain intensity improvement was associated with baseline pain intensity (F=18.79, p=0.0004) and temporal summation magnitude of the tibialis anterior (F=5.06, p=0.0380).

Conclusions Pain intensity, location, nature, and mechanism can serve as biomarkers of the short-term postsurgical changes that can be expected following rTSA. Baseline pain intensity and temporal summation magnitude of the tibialis anterior were associated with the degree of pain improvement, suggesting their use for preoperative risk assessment. Future research should evaluate whether these 6-week biomarker changes are associated with the development of chronic postoperative pain at longer durations after surgery.

Level of Evidence Level I, Prognostic Study

The authors have declared no competing interest.

This study and REDCap electronic data capture tools were supported in part by the UT Southwestern School of Health Professions Collaborative Research Grant Program. This was also supported in part by an Interdisciplinary Research Program grant from the University of Texas at Arlington. The use of REDCap in this publication was supported by the National Center for Advancing Translational Sciences of the National Institutes of Health under the CTSA Program award number 1UL1TR003163-04. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

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This study was approved by the Institutional Review Board at the University of Texas (UT) Southwestern Medical Center (STU2021-0495).

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