Identification of threshold pathoanatomic metrics in primary glenohumeral osteoarthritis

Background An assessment of the pathoanatomic parameters arthritic glenohumeral joint (GHJ) has potential to identify discriminating metrics differentiate glenoid types in shoulders with primary osteoarthritis (PGHOA). The aim was morphometric differences and threshold values between including normal glenoids various Walch classification. We hypothesized that there would be clear discriminators specific numeric allow identification each type. Methods computed tomography scans 707 were analyzed: 585 obtained from PGHOA 122 without pathology. Glenoid morphology classified according All imported a dedicated automatic 3D-software program referenced measurements scapular body plane. humeral modeling performed using best-fit sphere method, root-mean-square error calculated. direction orientation humerus described relationships. Results Among PGHOA, 90% 85% heads directed posteriorly reference Several discriminatory identified: GHJ narrowing < 3 mm metric for type A glenoids. Posterior subluxation > 70% discriminated B1 GHJs. distinguish B2 A, B3, Type B3 differed A2 by greater retroversion (>13°) (>71%). C inferior limit 21°, whereas never presented 16°. Conclusion Pathoanatomic identified can used discriminate PGHOA.