Joint surgery in severe ankylosing spondylitis

Twenty-three patients with ankylosing spondylitis with severe deformities of hips, knees, and ankles were treated by a variety of surgical procedures followed by a comprehensive rehabilitation program. The surgery included 35 total hip replacements, six knee arthroplasties, and seven femoral osteotomies. Elongation of the Achilles tendon (eight procedures) was done on 6 patients. Shortening of the femur was performed in patients with long-standing flexion contractures when straightening of the limb during the operation caused traction on the vessels and the nerves. When there was both hip and knee involvement, hip arthroplasty was performed first. Preoperative planning aimed at obtaining plantigrade position of the feet and lower limb-length equality. Availability of custom-made and miniaturized components was essential. Positioning of patients on the operating table necessitated special supports. Six patients were completely bedridden before surgery and 17 were severely disabled or deformed. All the patients but 2 improved markedly, became mobile, independent, and self-supporting. Revision arthroplasty was performed in 4 patients; 3 others deteriorated functionally, but refused further treatment. Heterotopic bone formation was observed after operation in 6 patients. Surgery for severe ankylosing spondyloarthritis requires highly specialized and well-equipped centers.