ON ARTHRODESIS AND REPLACEMENT OF THE HUMAN ANKLE

Abstract: Of 30 primary ankle fusions in patients with osteoarthrosis, 25 ankles underwent clinical evaluation by two independent observers. In 29 cases, two independent radiologists, unanimously found 26 ankles to be radiographically fused, and three not fused. The consistency between the two orthopaedic surgeons evaluations was somewhat lower. A complete consistency between the evaluations of all four observers was found in 20 of 25 cases. Thus, clinical evaluation, whether an ankle joint has fused or not, is difficult.Therefore, radiographic evaluation appears to be more reliable. 51 uncemented, consecutive STAR prostheses, implanted either due to osteoarthritis or to rheumatoid arthritis, were followed prospectively for 3-8 years. 12 underwent re-operation, seven due to component loosening, two due to failure of the meniscus and three for other reasons. Another eight showed radiographic signs of loosening, but are not yet revised. 31 of 39 patients who had not been re-operated were satisfied with the result. Two were somewhat satisfied, and six not satisfied. The 5-year survival, with replacement or removal of any component as end-point was 70%. 26 patients with rheumatoid arthritis had their ankle fused using a retrograde intramedullary nail. 25 of the ankles healed radiographically at the first attempt. A loss of sensibility at the plantar aspect of the foot occurred in eight cases. Although permanent, it was not a major problem for the patients. Five different nails were used and eight different surgeons had performed the operations, indicating that the method seems to be easy to learn. Ankle fusion as a salvage procedure for failed ankle prosthesis is a more complicated task than in the primary situation. In spite of that we found that 13 of 16 resulted in radigraphic healing after having been operated on with a retrogade intramedullary nail. Of 35 rheumatic ankles operated on with compression screws, 26 became radiographically healed at the first attempt and another 5 after repeat arthrodesis. The clinical outcome scores were lower than in patients undergoing the same procedure but due to osteoarthrosis. The most commonly used function scores for evaluation of the hind-foot function are not well suited to cases with rheumatoid arthritis. An ankle damaged by rheumatic disease may be successfully treated by both arthrodesis, using a retrograde intramedullary nail, or by an ankle replacement. Also an ankle injured due to trauma of the ankle may in selected cases be treated with an ankle prosthesis. When fusion is indicated, the use of compression screws seems to be reliable.