Artroplasica de reemplazamiento de la capa superficial del hombre en la artritis reumatoide.
Ofer Levy, MD, MCh(Orth)1, Lennard Funk, MSc, FRCS(Tr and Orth)2, Giuseppe Sforza, MD3 and Stephen A. Copeland, FRCS4
1 Reading Shoulder Unit, Royal Berkshire Hospital, Reading RG1 5AN, United Kingdom. E-mail address: firstname.lastname@example.org 2 Hope Hospital, Manchester M6 8HD, United Kingdom 3 Unita di Ortopedia, Ospedale «S. Maria delle Grazie,» Matera 70125, Italy 4 Reading Shoulder Unit, Berkshire Independent Hospital, Reading RG1 6UZ, United Kingdom
Investigation performed at Reading Shoulder Unit, Royal Berkshire Hospital, Reading, United Kingdom
Background: Shoulder arthroplasty with a stemmed prosthesis is a recognized treatment for rheumatoid arthritis of the shoulder. The humeral component of the Copeland cementless surface replacement arthroplasty consists of a cup for surface replacement with a short central peg for primary fixation to the bone. We hypothesized that surface replacement may offer some advantages over stemmed prostheses.
Methods: Between 1986 and 1998, seventy-five shoulders underwent surface replacement arthroplasty (thirty-three hemiarthroplasties and forty-two total shoulder arthroplasties) for the treatment of rheumatoid arthritis. The results of these procedures were reviewed after an average duration of follow-up of 6.5 years. Patients were assessed with use of the Constant score, a patient satisfaction score, and radiographs.
Results: The average Constant score was 47.9 points (age and sex-adjusted score, 71%) in the hemiarthroplasty group and 53.4 points (age and sex-adjusted score, 76%) in the total shoulder replacement group. The mean range of active flexion improved from 50° in the hemiarthroplasty group and 47° in the total shoulder replacement group to 101° and 104°, respectively. Seventy-two of the seventy-five shoulders were considered by the patients to be much better or better at the time of the review. Of the sixty-eight humeral implants that were evaluated radiographically, fifty-six (82%) showed no lucencies, eleven (16%) showed localized lucencies of <1 mm in width, and one was definitely loose. Of the thirty-nine glenoid implants that were evaluated radiographically, nineteen (49%) showed no lucencies, nineteen showed localized lucencies of <1 mm, and one was definitely loose. No lucencies were observed adjacent to the hydroxyapatite-coated implants. Thirty-nine (57%) of the sixty-eight shoulders showed some degree of superior subluxation. Three patients required a major reoperation: two required a revision because of loosening of both components, and one patient with pain at the site of a hemiarthroplasty had a revision to a total shoulder arthroplasty to provide relief.
Conclusions: The indications for this surface replacement are the same as those for the conventional stemmed prostheses, but the surface replacement has the advantage of bone preservation as well as avoidance of the potential complications associated with a long humeral stem in rheumatoid bone. This procedure is not suitable for severely damaged joints in which the humeral head is insufficient or too soft.