English to French Medical Medical: Instruments shoulder surgery (rotator

This is a technical medical document dealing with the affinis inverse system (reverse total shoulder arthroplasty).

Context:
The common reverse total shoulder arthroplasty (RTSA) has “soft” polyethylene (UHMWPE) inlays and “hard” cobalt– chromium (CoCr) glenospheres.
In inverted bearing reverse total shoulder arthroplasty "(IB-RTSA)", such as the Affinis Inverse (Fig. 1), the humeral inlays are made from metal or ceramic and the glenospheres from PE.
The notching phenomenon of a “hard” and wear-resistant humeral inlay with the scapula results in a different characteristic.
Excessive abrasive wear on the scapular bone, respectively, PE-induced osteolysis is eliminated.
With the humeral inlay made from metal or ceramic, the characteristic remains with a simple mechanical notching"

I have no problem with the RTSA as it is translated "Prothèse totale de l'épaule inversée" (PTEI)

But I do not know how to translate the "IB"part. Matériaux inversés? which would lead to the acronym MI-PTEI but althouth PTEI often appears on google, MI alone or in association with PTEI as a double jointed acronym does not appear.

So actually my question only really relates to IB (inverted bearing) and the correct acronym for this. IT could also be translated "support inversé"but there again the acronym SI is missing...

Experts please feel free!