192 Preserving Glenoid Subchondral Bone in aTSR

Abstract

Abstract Aim Glenoid loosening remains a major concern in anatomical Total Shoulder Replacement (aTSR). Preoperative planning software and patient specific guides allow implantation optimization in aTSR. This study aims to examine and compare the amount of bone resected with prescribed adjusted angles to respecting the subchondral plate with minimal resection, using a freehand technique. Method Two groups of shoulder CT scans were assessed, normal and osteoarthritic of patients who had undergone aTSR. Preoperative planning software was used to place the glenoid component in prescribed adjusted angles, with neutral (0o,0o), retroverted (-10o,0o) and inclined alignment (0o,10o). This was then compared to positioning the component using a freehand technique, whereby the component was placed in a position to maintain the subchondral plate with minimal bone loss and respecting the integrity of the vault. Results The number of CT scans was 68, 34 normal and 34 osteoarthritic. The freehand technique resulted in statistically superior cortical bone seating in the osteoarthritic group with a mean (standard deviation) of 53.27% (14.32), while neutral alignment resulted in 36.68% (10.81), retroversion 40.40% (13.06), and inclination 39.34% (13.52), p<0.001. Similarly in the normal scans, cortical bone seating in the freehand scenario was 46.71% (15.96), neutral 25.65% (12.27), retroverted 26.73% (15.03), and inclined 32.93% (12.12), p<0.001. Conclusions The freehand method for positioning the guidewire resulted in significantly superior cortical bone seating, when compared to prescribed adjusted angles. Applying this technique in the clinical setting may achieve superior glenoid component seating and hence reduce the risk of aseptic loosening in aTSR.