Abstract
Introduction: Concern remains in loosening of glenoid component reversed prostheses. This study is to analyze glenoid location of stem and 4 screws of glenoid component.
Material and method: 34 reversed prostheses included. Mean age 74,10, 33 females/1 male. Preoperative CT study : glenoid version; measure of anterior-posterior osteophytes. Postoperative CT study: central stem location and superior, inferior, anterior, posterior screws location. Study of influence of glenoid version and presence of osteophytes in location of glenoid implant.
Results: 27 retroverted glenoids (mean 6,5°); 7 ante-verted (mean 5,3°). 17 cases with anterior osteophyte and 12 of posterior. In 52% the central stem was centered inside glenoid, 33% anterior end was outside glenoid and 14% the posterior end. When central stem was anteriorly outside 85% presented retroverted glenoid (mean 8,33°). When the central stem was posteriorly outside 66% presented anteverted glenoid (mean 9,5°). Inferior screw was fully in place in 38%, ¾ part inside in 19%, 2/4 part in 23%, ¼ part in 19%. Superior screw was fully in place in 47%, ¾ part inside in 23%, 2/4 part in 19%, ¼ part in 9%. Anterior screw was fully in place in 66%, ¾ part in 23% and 2/4 part in 9%. Posterior screw was fully in place in 38%, ¾ part in 42%, 2/4 part in 14%, ¼ part in 4%. The correct positioning of superior screw correlates with less coverture of inferior screw. Anterior and posterior osteophytes did not correlated with stem nor screw positioning.
Conclusions: Positoning of central stem correlates with glenoid version. Anteriorly extruded stems correlate with higher retroverted glenoids and posteriorly extruded stems correlate with higher anteversion.
Positioning the inferior screw fully inside the lateral border of the scapula correlates with lower bony coverture of superior screw.
Correspondence should be addressed to Ms Larissa Welti, Scientific Secretary, EFORT Central Office, Technoparkstrasse 1, CH-8005 Zürich, Switzerland
