Background: Ankylosing spondylitis is a seronegative
spondyloarthropathy that primarily affects the sacroiliac joints,
spine, hips, and, less commonly, the knee joints. The purpose of
this study was to evaluate the results in a consecutive group of
patients with ankylosing spondylitis who underwent total knee arthroplasty.
Methods: The results of thirty total knee arthroplasties
in twenty patients with ankylosing spondylitis were reviewed. There were
seventeen men and three women, with an average age of fifty-five
years (range, twenty-eight to sixty-seven years)
at the time of the arthroplasty. The diagnosis of ankylosing spondylitis
was established preoperatively with use of the New York criteria.
All patients received a cemented condylar-type implant.
The average duration of follow-up was 11.2 years (range,
three to sixteen years).
Results: The average Knee Society pain score improved
from 14 points preoperatively to 76.3 points at the time of the
latest follow-up. The improvement in the average Knee Society function
score was less impressive, with an increase from 16.3 points preoperatively
to 58.7 points at the time of the latest follow-up. The average
arc of motion was 84.8° prior to the arthroplasty and 86.7° at the
time of the final follow-up. Six knees (20%) had heterotopic
bone formation. Three knees required manipulation under anesthesia
because of poor motion postoperatively. There was one revision,
due to loosening of a patellar component. All other components were radiographically
stable at the time of the latest follow-up.
Conclusions: Total knee arthroplasty with cement
in patients with ankylosing spondylitis provided excellent pain
relief and durable fixation at an average of 11.2 years postoperatively.
However, patients with ankylosing spondylitis are at increased risk
for the development of stiffness and heterotopic bone formation.