An interview with Prof. Mario Randelli from IRCSS Istituto Clinico Humanitas (Milan, Italy).
Dear Prof. Randelli, could you explain the background of your article about Lima’s Metal Back glenoid which is now published on JBJS Br?
Well, we know that total shoulder replacement has proved to be a successful procedure for degenerative or some inflammatory diseases of the shoulder. However, glenoid fixation seems to be the weak link in this kind of procedure. There is still a lot of debate on the features and optimal design of the glenoid implant, but the current published papers that compare the results for cemented all-polyethylene and uncemented metal back glenoid components showed better results for the cemented all-polyethylene glenoid.
How did you perform the study?
We decided to report our experience with 35 consecutive total shoulder replacements performed with a new design of metal back component: the avarage follow up is 6.2 years (48-154 months). The design of the implant differs from others described in the literature because of its fixation mechanism: it has a convex metal back - bone interface and the main stabilizing factor are not the screws but a large hollow central peg.
All the patients were evaluated with standard x-rays and with Constant Score, Simple Shoulder Test and VAS scale.
Prof. Randelli, could you anticipate us any results?
We found an improvement in the scores: for example, the mean Constant score went from 35.2 to 70.8.
From a radiographic point of view, we found 22.8% of periprosthetic radiolucent lines <2mm and no radiolucent lines in the rest of the cases. We also had no glenoid loosening, no polyethylene glenoid disassembly and no other implant related complications.
What were your conclusions after this study?
We basically concluded that a metal back glenoid component with this design can be a good option to choose in total shoulder replacement and that our results are no worse than those using a cemented all-polyethylene glenoid. If we consider that literature showed us that the mean time for a glenoid revision was between 2 and 3 years after the surgery the surgery, a mean follow up of 6.2 years may be enough to have a feedback on the performance of this kind of implant.
In conclusion, in light of our results, we think that such a design of metal back cementless glenoid can be considered a good choice for glenoid replacement.
Prof. M. Randelli
IRCSS Istituto Clinico Humanitas
Milan (Italy)
