Reverse Total Shoulder Arthroplasty Baseplate Stability in Superior Bone Loss With Augmented Implant

Abstract

Background Glenoid bone loss is commonly encountered in cases of rotator cuff tear arthropathy and can create challenges during reverse shoulder arthroplasty. In this study, we sought to investigate the biomechanical properties of a new treatment option for superior glenoid defect, an augmented reverse total shoulder baseplate. Methods Three conditions were examined: non-augmented baseplate without defect, non-augmented baseplate with defect, and augmented baseplate with defect. The augmented baseplates included a 30-degree half wedge which also matched the created superior defect. The samples were cyclically loaded at a 60° simulated abduction angle to mimic baseplate loosening. The migration and micromotion of the baseplate were measured on the superior edge using a 3D Digital Image Correlation System. Results The migration measured in the augmented baseplate showed no significant difference when compared to the no defect or defect cases. In terms of micromotion, the augmented baseplate showed values that were between the micromotions reported for the no defect and defect conditions, but not by a statistically significant amount. Conclusion This study provides biomechanical evidence that augmented baseplates can reduce the amount of micromotion experienced by the RSA construct in the presence of significant superior glenoid bone deficiency, but do not fully restore stability to that of a full contact non-augmented baseplate.

Analysis and 3D correction of glenoid dysplasia with metal hemi-wedge base plate augment: short-term radiographic outcomes

“…This hemi-wedge baseplate allows a correction in at least 2 planes in combination with a bone preserving reaming-technique. In particular, the convenience of this technique combines the adaptability to individually reconstruct defects not only of the glenoid inclination but also of the version, as well as the better adaptation of the baseplate without graft compression like in the BIO-RSA [27][28][29]. In our hands this technique is not time-consuming in the OR after a learning curve, nor it is associated with extensively higher implant expense, and does avoid the need for a bone integration of a wedged bone block.…”

Treating posteriorly eroded glenoids with augmented baseplate or bony increased-offset reverse shoulder arthroplasty: a finite element comparison

“…Numerous biomechanical studies using experimental and computational methods have been undertaken to investigate the fixation of non-augmented implants for cases both with and without posterior glenoid erosion 4,7,11,14,15,17,38,41,42 . However, very few biomechanical studies exist that investigate augmented RSA to treat glenoid erosion 10,28,35 . Unfortunately, because these studies used polyurethane foam bone surrogates that do not replicate true bone properties or erosion patterns, they observed implant micromotions of 100-400 microns, which limit the interpretability and value of the findings.…”