Background: Although initial reports on posterior
cruciate ligament-retaining total knee arthroplasty in patients
with rheumatoid arthritis have been encouraging, a high rate of
late instability necessitating revision has been reported recently.
The purpose of the present prospective study was to analyze the
results of posterior cruciate ligament-retaining total knee arthroplasty
in patients with rheumatoid arthritis.
Methods: Seventy-two posterior cruciate
ligament-retaining total knee arthroplasties in fifty-one
patients with rheumatoid arthritis were studied prospectively. All
procedures were performed with the Miller-Galante I prosthesis.
Eighteen patients (twenty-four knees) died before the eight-year
follow-up and one patient (two knees) was lost to follow-up,
leaving forty-six knees (thirty-two patients) for review. These
forty-six knees were evaluated clinically (with particular attention
to posterior instability) and radiographically at annual intervals for
a mean of 10.5 years (range, eight to fourteen years).
Results: Forty-four (95%) of forty-six
knees had a good or excellent result at a mean of 10.5 years. However,
nine (13%) of the original seventy-two knees had revision
of the implant, with six of the revisions performed because of failure
of a metal-backed patellar component. The rate of survival
at ten years was 93% 4% with femoral or tibial
revision for any reason as the end point and 81% 5% with
any reoperation as the end point. There was no aseptic loosening
in any knee. Posterior instability was identified clinically and/or
radiographically in two (2.8%) of the original seventy-two
knees; both unstable knees were in the same patient.
Conclusion: Posterior cruciate ligament-retaining
total knee arthroplasty yielded satisfactory clinical and radiographic
results in patients with rheumatoid arthritis at intermediate-term
follow-up (mean, 10.5 years). Therefore, we believe that
it remains an excellent treatment option for these patients.