The Results of Revision Total Knee Replacement Arthroplasty

PURPOSE: To evaluate the results of revision total knee replacement arthroplasty (TKRA) and compare those outcomes according to the reasons for the revision TKRA. MATERIALS AND METHODS: We reviewed the results of 27 revision TKRAs followed at a minimum of 2 year after revision surgery with American Knee Society clinical and radiological rating system and satis-faction survey. There were 25 females and 1 male with the average age of 65.6 years (52~77). The origi-nal diagnosis was osteoarthritis in 24 cases and rheumatoid arthritis in 3 cases in the study group. The patients were followed for 2 year to 7 years 2 months (average 2 year 11 months). The reasons for revi-sion TKRA were osteolysis and loosening in 10 knees (37%), polyethylene wear in 10 knees (37%), infection in 3 knees (11.1%), stiffness in 3 knees (11.1%) and instability in 1 knee (3.8%). RESULTS: The knee score was average 84.7 (65~100) and function score was 68 (15~100) at final fol-low-up examination. The patients expressed, 11 knees (40.7%) were as very satisfactory knee, 5 knees (18.6%) as satisfactory knee, 8 knees (29.6%) as improved knee and 3 knees (11.1%) as got no change on their knees. There was no stastistically difference on the result from the original diseases and we got a good to excellent results for the infected TKRA with 2 staged revision TKRA. Isolated exchange of the tibial polyethylene insert performed in 10 knees (29%), but there was no statistical significance in the results between isolated polyethylene exchange and revision TKRA with new prosthesis. CONCLUSION: Although we can get 59.3% of the patients' satisfaction and 81.5% of good to excellent results, the overall outcomes of revision TKRA were not as good as primary TKRA. This study clearly does not support the premise that isolated polyethylene exchange is favorable for the long-term results.

Assessment of Failure Modes in Total Knee Replacement Arthroplasty

PURPOSE: To analyze the causes of revision total knee arthroplasty and evaluate the difference in failure modes according to the revision interval after a primary total knee arthroplasty. MATERIALS AND METHODS: We retrospectively analyzed the failure mode of 60 cases assessable by clinical, radiological and operative findings according to the following intervals after primary total knee arthroplasty: under 5 years; from 5 to 10 years; and after 10 years. RESULTS: In 50% of the cases osteolysis and loosening was the cause for revision total knee arthroplasty. In comparison, tibial polyethylene insert wear occurred in 25% of the cases, infection in 13%, instability in 7%, and stiffness in 5%. The average duration from primary total knee arthroplasty to revision arthroplasty due to infection, stiffness and instability was less than 5 years. In contrast, revision arthroplasty resulting from tibial polyethylene wear, osteolysis and loosening took place after 5 years. CONCLUSION: The most common failure mode is osteolysis and loosening regardless of the revision interval. Infection and instability was common in the under-5-year period and osteolysis and loosening was common after 5 years.