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Friday, March 17, 2000

TKA for younger patients not recommended: study

A study of total knee arthroplasties (TKA) on 52 patients aged 50 years or younger indicates that while TKA is an option for younger patients, the results are inferior to those for older patients and the procedure should be reserved for only those cases where no other option exists.

Presented in scientific paper 185 on Thursday, the authors of the paper examined the results of 71 knee arthroplasties in 52 patients between 1978 and 1994. The mean age was 44 years (range: 22 to 50 years). Bilateral arthroplasties were performed in 19 patients.

The researchers found that over-all, 17.9 percent of the knees had been revised at a mean follow-up of 9.6 years. The survivorship at 10 years was 78 percent and at 15 years, 71 percent.

In general, the researchers said they would not recommend total knee arthroplasty to patients younger than 50 years of age. For that age group, they would prefer to consider alternatives such as high tibial osteotomy.

The researchers observed that the patients in the study were all difficult cases where arthroplasty was seen as a "last resort." Forty-four percent of the knees had been previously operated on and 68 percent of those had been operated on two or more times. "We consider that these arthroplasties represent some of the 'worst case scenarios' seen at out institutions," the researchers said.

The diagnosis leading to the initial arthroplasty was rheumatoid arthritis for 35 knees (49 percent), osteoarthritis for 27 knees (38 percent), post-traumatic for four (6 percent), psoriatic arthritis for two knees (3 percent) and avascular necrosis, post-septic arthritis and multiple epiphyseal dysplasia each for one knee (1 percent).

Surgical procedures including high tibial osteotomy, arthroscopy and synovectomy had been performed on 31 of the knees prior to arthroplasty. Of the total TKAs, 67 arthroplasties in 48 patients were followed for a mean of 9.6 years.

Twelve of the 67 arthroplasties had been revised. The indications for revision were aseptic loosening (four knees), infection (three knees), instability (two knees), periprosthetic fracture (one knee), osteolysis (one knee), and pain (one knee). Revision was performed at a mean of 8.7 years post-primary arthroplasty.

Of the 35 knees with rheumatoid arthritis, five were revised. Six of the 23 knees with osteoarthritis were revised. Two of the seven knees that had a previous high tibial osteotomy were revised. Three of the 17 knees that had a previous arthroscopy were revised.

Co-authors of the paper, all from the London Health Sciences Centre, London, Ontario, are J.W. Taylor, MD; R.B. Bourne, MD; C.H. Rorabeck, MD; and Kevin Inman, MSc.

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Last modified 17/March/2000 by IS