Conversion of shoulder arthroplasty to reverse implants: clinical and radiological results using a modular system

Revision of a shoulder arthroplasty to a reverse arthroplasty is a highly demanding procedure. The aim of this study is to report the clinical results of hemi and total shoulder prosthesis revisions to reverse implants without removal of the humeral stem, using a modular shoulder replacement system (SMR Lima LTD). We retrospectively reviewed 26 patients who underwent an operation from 2004 to 2009. The patients were divided into two groups: in Group I, 18 patients underwent a revision of hemiarthroplasty implanted for fracture; in Group II, eight patients underwent a revision of anatomical total prosthesis. All patients were evaluated at a mean follow-up of 32.3 (+/- 12.7) months using the Constant score rating scale and by range of motion evaluation, EQ-VAS, X-ray and CT scan. The Constant score of each patient was 47.88 (+/- 5.88) after the revision. The EQ-VAS improved from 40 (+/- 20) to 70 (+/- 10). All patients improved in terms of range of motion. The radiographs and CT scans obtained after revision showed good integration and no signs of loosening of the implant. The mean time of surgery was recorded as 62' (+/- 8'), with a maximum blood loss of less than 300 ml in all cases. Our study demonstrates that using a full modular system at the time of the first implant allows avoidance of the step to remove the humeral stem and metal back in cases of shoulder prosthesis revision to a reverse prosthesis, resulting in a short operative time, few intraoperative complications and a satisfactory clinical outcome at medium-term follow-up.