Results of rotating-platform, low-contact-stress knee prosthesis

Low-contact-stress (LCS) rotating-platform knee arthroplasties in 31 consecutive patients with 50 deformed knees were evaluated at a mean follow-up of 4.5 years (range, 4-6 years). Overall results were good in 72% of 22 osteoarthritic knees and 71.4% of 28 rheumatoid knees. None of the knees showed any change in component position and alignment, osteolysis, or cement-bone radiolucency during follow-up. LCS prosthesis takes care of some rotational component mismatch. Complications included 2% dislocation, 4% anteroposterior instability, and 10% subluxation of the rotating platform. The overall reoperation rate of 10% was significantly higher than reported for the fixed bearing series, and we feel that LCS prosthesis is unsuitable for severely deformed knees.