Background: Rheumatoid arthritis often leads to severe destruction
of the glenohumeral joint, including synovitis and inflammation-induced
alterations of the rotator cuff. Cup arthroplasty, or surface replacement of
the shoulder, was introduced in the 1980s. The aim of this study was to
evaluate the midterm results of the DUROM cup surface replacement for patients
with rheumatoid arthritis affecting the glenohumeral joint.
Methods: From 1997 to 2000, forty-two DUROM cup hemiprostheses were
implanted in a cohort of thirty-five patients (forty-two shoulders), who were
evaluated preoperatively and again at three, twelve, and more than sixty
months postoperatively. Six patients (seven shoulders) were lost to follow-up.
Thirty-five shoulders in twenty-nine patients (twenty-one women and eight men
with an average age of 61.4 years) could be evaluated prospectively after an
average follow-up period of 73.1 months. Patients were evaluated clinically
with the use of the Constant score, and a detailed radiographic analysis was
performed to determine the presence of endoprosthetic loosening, glenohumeral
subluxation, and glenoid bone loss.
Results: The mean Constant score for the thirty-five shoulders
increased from 20.8 points preoperatively to 64.3 points at a mean of 73.1
months postoperatively. There were three revisions: one to replace an implant
that was too large, another to treat glenoid erosion, and a third due to
loosening of the implant. No additional cases of loosening of the prosthesis
or changes in cup position were observed radiographically. Over the five-year
follow-up period, proximal migration of the cup increased in 63% of the
shoulders, and the glenoid depth increased in 31%. With the numbers studied,
no differences in clinical outcome were identified between patients with a
massive rotator cuff tear and those with a smaller or no tear.
Conclusions: The midterm results of the cemented DUROM cup surface
replacement for patients with advanced rheumatoid arthritis of the shoulder
are very encouraging, even for patients with a massive tear of the rotator
cuff. The advantage of this cup arthroplasty is the less complex bone-sparing
surgery. In the event of failure of the implant, other reliable salvage
Level of Evidence: Therapeutic Level IV. See Instructions
to Authors for a complete description of levels of evidence.