Defining the tipping point for revision reverse shoulder arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Patient-Reported Outcomes

Background:

• Revision reverse total shoulder arthroplasty (rTSA) is increasingly common.
• Understanding patient-defined thresholds for surgery is crucial for appropriate intervention.
• Previous research has not clearly defined these functional tipping points for revision rTSA.

Purpose of the Study:

• To characterize the functional tipping point values for patients undergoing their first revision reverse total shoulder arthroplasty (rTSA).
• To establish preoperative score and range of motion benchmarks that indicate patient readiness for revision surgery.

Main Methods:

• Retrospective review of a prospectively collected single-institution database.
• Analysis of 125 first revision rTSA cases between August 2015 and December 2019.
• Evaluation of preoperative American Shoulder and Elbow Surgeons (ASES), Constant, Shoulder Pain and Disability Index (SPADI), Simple Shoulder Test (SST), and University of California-Los Angeles (UCLA) scores, along with active range of motion (abduction, forward elevation, external rotation, internal rotation).

Main Results:

• Identified tipping points: ASES 37.6, raw Constant 30.5, normalized Constant 35.5, SPADI 68.1, SST 3.7, UCLA 13.2, abduction 64°, forward elevation 69°, external rotation 23°, internal rotation 3.1.
• Higher SST scores correlated with older age and lower BMI.
• Lower abduction and forward elevation tipping points were observed in revisions for rotator cuff failure, unexplained pain, and implant wear.

Conclusions:

• Established specific functional score and range of motion tipping points for first revision rTSA.
• These findings provide objective criteria for surgical decision-making and patient counseling.
• Understanding these thresholds can optimize the timing of revision surgery for improved patient outcomes.