Variation of the glenohumeral and scapulothoracic motion in progressive severity of glenohumeral osteoarthritis

Abstract

IntroductionThe aim of this study is to investigate the variation of the glenohumeral and scapulothoracic motion in progressive severity of glenohumeral osteoarthritis using a 3-D-motion analysis. Moreover, the variation of the Constant Score is evaluated. HypothesisThe hypothesis is that the motion of the scapulothoracic joint may partly compensate for the loss of the glenohumeral joint movement in patients with increasing severity of glenohumeral osteoarthritis. Material and methodsA total of 21 patients with primary osteoarthritis of the glenohumeral joint were clinically examined, divided in three groups (SP1-SP3) according to size of their caudal osteophyte. The contribution of the scapulothoracic (acromioclavicular and sternoclavicular) joint to the total arm (humerothoracical) elevation in sagittal and frontal plane was measured with 3D motion analysis and the Constant Score was evaluated. DiscussionIn sagittal plane elevation (anteversion) the contribution of the scapulothoracic joint to the total elevation was while arm raising 32.7% (SD 8.0%) in Group SP1, 36.6% (SD 11.0%) in Group SP2 and 49.6% (SD 9.0%) in Group SP3 (p=0.002). The contribution of the scapulothoracic joint to the total elevation while arm lowering was 31.4% (SD 9.0%) in Group SP1, 39.0% (SD 13.0%) in Group SP2 and 49.7% (SD 12.0%) in Group SP3 (p=0.043). In frontal plane elevation (abduction) the contribution of the scapulothoracic joint was while arm raising 33.7% (SD 8.0%) in Group SP1, 34.0% (SD 10.0%) in Group SP2 and 42.3% (SD 9.0%) in Group SP3 (p=0.071). While arm lowering the contribution of the scapulothoracic joint was 30.8% (SD 10.0%) in Group SP1, 36.3% (SD 12.0%) in Group SP2 and 44.8% (SD 8.0%) in Group SP3 (p=0.022). The group SP1 achieved a Constant Score of 78.00 (SD 9.823) points. The group SP2 achieved a Constant Score of 53.57 (SD 13.92) and the group SP3 38.64 (SD 10.40). There is a significant difference between the three groups (p<0.001). Increasing severity of glenohumeral osteoarthritis leads to a reduced motion of the glenohumeral joint. Instead the magnitude of the scapulothoracic motion increases. Level of ProofV, Case Series.