Biomechanical changes after reverse total shoulder arthroplasty: a systematic review of advanced measurement technologies.

In 30 seconds

This systematic review examined quantitative biomechanical outcomes after reverse total shoulder arthroplasty (rTSA), drawing on 24 observational studies: 10 cohort and 14 case-control studies, all classified as Level III evidence. Motion capture studies consistently found improved forward elevation, but glenohumeral contribution, axial rotation, and scapulohumeral rhythm remained reduced compared with contralateral or healthy shoulders. Elevation relied mainly on greater scapulothoracic motion and deltoid-driven strategies. Wearable sensors indicated increased arm use and improved interlimb symmetry, while time spent above shoulder height remained limited.

Key findings

• All 24 included studies were Level III; 21 had moderate risk of bias and 3 had high risk.
• Forward elevation improved consistently, while glenohumeral contribution, axial rotation, and scapulohumeral rhythm remained reduced relative to comparison shoulders.
• Elevation relied predominantly on increased scapulothoracic upward rotation, retraction, and posterior tilt.
• EMG studies found increased deltoid and upper-trapezius activation, with limited posterior cuff recruitment.

Why it matters

The review suggests that improved elevation after rTSA does not necessarily reflect normalized shoulder-joint mechanics. Compensatory scapulothoracic motion and deltoid activation appear central to functional recovery, while some motion and muscle recruitment patterns remain altered. Understanding these adaptations can help frame postoperative function and highlights the need for consistent biomechanical assessment across studies.

What to keep in mind

The evidence comprised observational Level III studies, most with moderate risk of bias. Implant designs, surgical indications, and follow-up durations were heterogeneous, and measurement methods were not standardized.