Computed tomography in primary glenohumeral osteoarthritis without humeral head elevation.

Few studies have evaluated computed tomography in glenohumeral osteoarthritis without humeral head elevation. Two recent studies included only ten and 11 patients, respectively. We evaluated computed tomography findings in 113 cases of primary glenohumeral osteoarthritis without humeral head elevation. Glenoid retroversion was substantially increased, with a mean of 16 degrees versus 8 degrees in a control group. The method used to measure this parameter was reproducible, with a mean interobserver variability of 4 degrees for a 95% confidence interval (P < or = 0.05). Humeral retrotorsion was apparently decreased (8 degrees), but osteoarthritis-related changes in the humeral head resulted in substantial measurement errors (interobserver variability, 11 degrees for a 95% confidence interval; P < or = 0.05). Humeral head subluxation was found in 35% of cases and measurement of this parameter was reproducible (interobserver variability, 4 degrees for a 95% confidence interval). Changes in the glenoid over time were dependent on the position of the humeral head in the glenoid fossa, which classified the shape of the glenoid with satisfactory reproducibility (intra- and interobserver Kappa, 0.68). The subscapularis and infraspinatus muscles were normal (stage 0 or 1) in 98% and 91% of cases, respectively and the method of Goutallier and Bernageau used for muscle evaluation proved highly reproducible (Kappa, 0.85). Computed tomography is invaluable for planning surgical treatment for primary glenohumeral osteoarthritis without humeral head elevation.