Glenohumeral subluxation, scapula resting position, and scapula rotation after stroke: a noninvasive evaluation.

Abstract

To determine whether scapular downward tilt (ScDT) and dynamic scapular lateral rotation (ScLR) in subjects with and without stroke is associated with subluxation, and to prove the reliability of a Scapula Locator System in an elderly population. Repeated measures of ScLR by 2 observers. Outpatient rehabilitation department of a district general hospital. To test device reliability, 5 healthy men (mean age +/- standard deviation, 72 +/- 5 yr). To test scapula position, 30 stroke patients (19 men, 11 women; mean age, 73 +/- 6 yr) and 15 healthy controls (12 men, 3 women; mean age, 62 +/- 6 yr). The control subjects' ScDT was compared with stroke subjects' ScDT after stratification according to 3 patterns of ScLR symmetry and the presence of palpable glenohumeral subluxation. For device reliability, 3-way analysis of variance. For scapula position, triangulated location by Scapula Locator System of acromion, inferior angle, and root of the scapular spine; then measurement of scapula motion to determine symmetry, lag, or lead. The inter- and intraobserver reliability of the Scapula Locator System device was high (1% of variance each). Normal ScDT was positive (left side: 10.94 degrees +/- 2.62 degrees; right side: 9.69 degrees +/- 4.36 degrees ), indicating a downward-facing glenoid fossa. This finding was unchanged by stroke (10.46 degrees +/- 2.42 degrees ). All controls and 16 stroke subjects had symmetry between shoulders for ScLR rate and ScDT. Two other patterns (p <.01) of ScLR were found after stroke: 8 subjects had a slower rate of affected arm ScLR (lag) with a correspondingly greater ScDT on the affected side (2.61 degrees +/- 6.7 degrees ); 6 subjects had a faster rate of affected arm ScLR (lead) but with an upward-facing glenoid fossa on the affected side (ScDT: -11.84 degrees +/- 8.48 degrees ). No significant inter- or intrasubject difference in ScDT existed in the 6 cases of glenohumeral subluxation. The scapula normally tilts downward with or without stroke. The effect of stroke is similar on tonic (ScDT) and phasic (ScLR) control of scapula position. Subluxation is not linked with a particular scapular resting position after stroke.