The objective of this study was to compare simulated range of motion (ROM) for reverse total shoulder arthroplasty (rTSA) with and without adjustment for scapulothoracic orientation in a global reference system. We hypothesized that values for simulated ROM in preoperative planning software with and without adjustment for scapulothoracic orientation would be significantly different. A statistical shape model of the entire humerus and scapula was fitted into ten shoulder CT scans randomly selected from 162 patients who underwent rTSA. Six shoulder surgeons independently planned a rTSA in each model using prototype development software with the ability to adjust for scapulothoracic orientation, the starting position of the humerus, as well as kinematic planes in a global reference system simulating previously described posture types A, B, and C. ROM with and without posture adjustment was calculated and compared in all movement planes.Aims
Methods
Reverse total shoulder arthroplasty (rTSA) can be used in complex cases when the glenoid requires reconstruction. In this study, a baseplate with composite bone autograft and a central trabecular titanium peg was implanted, and its migration was assessed for two years postoperatively using radiostereometric analysis (RSA). A total of 14 patients who underwent a rTSA with an autograft consented to participate. Of these, 11 had a primary rTSA using humeral head autograft and three had a revision rTSA with autograft harvested from the iliac crest. The mean age of the patients was 66 years (39 to 81). Tantalum beads were implanted in the scapula around the glenoid. RSA imaging (stereographic radiographs) was undertaken immediately postoperatively and at three, six, 12, and 24 months. Analysis was completed using model-based RSA software. Outcomes were collected preoperatively and at two years postoperatively, including the Oxford Shoulder Score, the American Shoulder and Elbow Score, and a visual analogue score for pain. A Constant score was also obtained for the assessment of strength and range of motion.Aims
Methods
If a modular convertible total shoulder system
is used as a primary implant for an anatomical total shoulder arthroplasty,
failure of the prosthesis or the rotator cuff can be addressed by
converting it to a reverse shoulder arthroplasty (RSA), with retention
of the humeral stem and glenoid baseplate. This has the potential
to reduce morbidity and improve the results. In a retrospective study of 14 patients (15 shoulders) with a
mean age of 70 years (47 to 83) we reviewed the clinical and radiological
outcome of converting an anatomical shoulder arthroplasty (ASA)
to a RSA using a convertible prosthetic system (SMR system, Lima,
San Daniele, Italy). The mean operating time was 64 minutes (45 to 75). All humeral
stems and glenoid baseplates were found to be well-fixed and could
be retained. There were no intra-operative or early post-operative
complications and no post-operative infection. The mean follow-up was 43 months (21 to 83), by which time the
mean visual analogue scale for pain had decreased from 8 pre-operatively
to 1, the mean American Shoulder and Elbow Surgeons Score from 12
to 76, the mean Oxford shoulder score from 3 to 39, the mean Western
Ontario Osteoarthritis of the Shoulder Score from 1618 to 418 and
the mean Subjective shoulder value from 15 to 61. On radiological review, one patient had a lucency around the
humeral stem, two had stress shielding. There were no fatigue fractures
of the acromion but four cases of grade 1 scapular notching. The use of a convertible prosthetic system to revise a failed
ASA reduces morbidity and minimises the rate of complications. The
mid-term clinical and radiological results of this technique are
promising. Cite this article:
