JSES - 2026-08-01 - Journal Article
Glenohumeral arthritis impairs shoulder mobility and promotes dynamic compensatory strategies during overhead reach.
Morriss N, Castle P, Greif DN, Pezzullo J, Ambalavanar M, Manning J, Shu Y, Earnhart J, Ramirez G, Nicandri G, Mannava S, Haddas R, Voloshin I
Topics
Key Takeaway
Glenohumeral arthritis reduces overhead flexion by 38° (84° vs. 122°) and drives compensatory lumbar rotation tripling (9° vs. 3°) and elbow flexion increase of 22° (26° vs. 4°) compared to the contralateral asymptomatic shoulder.
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Summary
This study quantified glenohumeral motion loss and whole-body kinematic compensation during an overhead reach task in 86 GHA patients using motion-capture laboratory analysis, comparing symptomatic to contralateral asymptomatic shoulders. The symptomatic shoulder showed 38° less flexion, 22° less internal rotation, and 4° less abduction. Compensatory strategies included tripling of lumbar rotation (9° vs. 3°), contralateral pelvic rotation (6° vs. 2°), halved cervical flexion (9° vs. 18°), and a 22° increase in elbow flexion (26° vs. 4°).
Key Limitation
Cross-sectional design prevents determination of whether compensatory kinematic patterns resolve after total shoulder arthroplasty or become fixed movement habits requiring independent rehabilitation.
Original Abstract
BACKGROUND
Glenohumeral arthritis (GHA) decreases shoulder range of motion, yet the extent of glenohumeral motion loss and accompanying whole-body compensations are not well quantified.
METHODS
Eighty-six patients with GHA completed an overhead reach task using both symptomatic and asymptomatic shoulders in a motion-tracking laboratory. Range of motion and peak angles of symptomatic to asymptomatic contralateral shoulders were compared.
RESULTS
The symptomatic shoulder demonstrated 38° less flexion (84° symptomatic vs. 122° asymptomatic, P < .001), 4° less abduction (25° vs. 29°, P < .001), and 22° less internal rotation (21° vs. 43°, P < .001) compared to the asymptomatic shoulder. Patients compensated for these deficits via greater lumbar extension (6° vs. 5°, P < .01), greater lumbar rotation (9° vs. 3°, P < .001), contralateral pelvic rotation (6° vs. 2°, P < .001), reduced cervical flexion (9° vs. 18°, P < .001) with altered lateral bending (7° vs. 11°, P < .001), and greater elbow flexion (26° vs. 4°, P .001).
CONCLUSIONS
GHA is associated with substantial loss of shoulder motion during an overhead reach task that mimics daily activities, which leads to compensatory increases in cervical, lumbar, pelvic, and elbow kinematics.