Preoperative 3-dimensional planning optimizes glenoid retroversion correction in shoulder arthroplasty using hemi-wedged augmented baseplates

Abstract

Background

Glenoid version and inclination can be corrected with an augmented baseplate during reverse shoulder arthroplasty (rTSA) procedures. To achieve an optimal correction of both glenoid version and inclination, this study investigated whether the preoperative use of a 3-dimensional planning system improved the correction of glenoid anatomy in terms of glenoid version (0°) and inclination (rTSA 0°).

Methods

We measured preoperative and postoperative glenoid version and inclination by rTSA angle by x-ray and computed tomography scans in 50 prospective cases of rTSA with wedged baseplates. All patients underwent an rTSA due to osteoarthritis and rotator cuff insufficiency. All 50 patients underwent rTSA with the use of a hemi-wedge to correct the glenoid morphology. Twenty five patients additionally underwent a preoperative planning with the Signature ONE Planner to determine the exact rotational position of the hemi-wedge. rTSA angle was determined in preoperative and postoperative x-rays, and glenoid version was determined in preoperative and postoperative computed tomography scans at 3 different glenoid levels. The Signature ONE Planner system determined the rotation, position, and size of the hemi-wedge (10°, 20°, or 30°). A control group of 25 patients underwent hemi-wedge rTSA without preoperative planning. The position of the sphere and the sphere bone overhang distance (mm) was determined in both groups.

Results

In all 50 patients, the inclination was almost corrected anatomically from a preoperative rTSA angle of 16.2° ± 6.4° to 2.4° ± 3.5° postoperatively, irrespective of the use of Signature ONE Planner. In comparison, the average correction of retroversion was worse and achieved to a lower degree but the use of Signature ONE Planner significantly improved the correction of retroversion in all 3 parts of the glenoid to an almost anatomical level (P < .0001). In both groups, the sphere bone overhang distance was between 4 and 5 mm without scapular notching.

Discussion and Conclusion

The anatomical correction of a retroverted glenoid with a hemi-wedge baseplate can be considerably improved by the preoperative use of the Signature ONE planning system. Preoperative planning can thus help surgeons to achieve an optimal baseplate position and may thus improve the correction of the glenoid retroversion after rTSA.