In 2005 Lima developed an eccentric glenosphere, with the aim of lowering the centre of rotation, maintaining the correct position of the metal back, in order to prevent the scapular notching occurring with concentric designs. We performed a retrospective study with the aim to evaluate clinical andradiographic outcomes of the eccentric glenosphere and to ascertain if this design can be a solution to prevent scapular notching. This study reports the results of 20 patients, treated between 2006 and 2008, with a minimum 24-month follow up.
Clinical and radiographic evaluation was performed preoperatively and at 1 month, 3, 6 months, 1 year and annually thereafter.
All patients have been evaluated with MRI or CTscan preoperatively and with x-rays postoperatively to evaluate the scapular notching and to measure prosthesis-scapular neck angle (PSNA), peg-glenoid rim distance (PGRD) and the distance between the scapular neck and glenosphere.
At last follow up (average 27.5 months, range 24-46 months) the Constant Score and ROM improved significantly.
The average PSNA was 92°± 25 mm, the average PGRD was 21.2 mm ± 9 mm and the average distance between the inferior bony glenoid rim and the inferior edge of the glenosphere was 4.3mm ± 0.8 mm.
No scapular notching and no implant-related complications were observed.
Our conclusion is that this data suggest that the use of an eccentric glenosphere allows the lowering of the COR, with correct positioning of the metal-back in reverse shoulder arthroplasty. And this can reduce the risk of scapular notching.
Carlo F. De Biase, MD*, Giantony Di Giorgio, MD°,
Andrea Vitullo, MD^, Hans R. Bloch, MD§
* San Carlo di Nancy Hospital, Rome (Italy)
° Sapienza University of Rome, Rome (Italy)
^ Villa San Pietro Hospital, Rome (Italy)
§ Ars Medica Clinic, Gravesano-Lugano (Switzerland)
