Abstract
Since its introduction in Christchurch in 1989, the mobile bearing LCS prosthesis has been used in over 3 500 total knee arthroplasty (TKA) procedures. The prosthesis is unique in that it has a mobile articulation not only at the tibiofemoral joint but also at the patellofemoral joint. The tibiofemoral articulation may be posterior cruciate retaining (meniscal bearings - MB) or sacrificing (rotating platform - RP).
Clinical and radiological assessment of 569 patients over three to nine years shows no significant difference between MB and RP groups with respect to Knee Society and New Jersey knees or the WOMAC functional score. In 93% of patients results were good or excellent. There were more early complications among MB patients, with five MB dislocations. However, four of these dislocations occurred in the early years this prosthesis and may reflect surgical inexperience. Clinical evidence of posterior cruciate laxity was present in 15% of the MB group, but there was no significant difference between knee scores of this group, the rest of the MB group, or the RP group.
When resurfaced patellae were compared to knees that were not resurfaced, there was no significant difference. Patellae with more than 4 mm of lateral subluxation were identified, but their knee scores were not significantly different.
The early to medium-term results of our continuing study of the LCS mobile bearing prosthesis are at least comparable to those of studies of fixed bearing prostheses. We continue to use this implant with confidence, but await long-term results.
The abstracts were prepared by Professor M. B. E. Sweet. Correspondence should be addressed to him at The Department of Orthopaedic Surgery, Medical School, University of Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193 South Africa
