Abstract
Introduction There are only a limited number of long term studies of total knee arthroplasty but none with a minimum 15 year survivorship of a modular fixed bearing posterior cruciate-retaining prosthesis.
Methods We present a consecutive series of 139 total knee arthroplasties (109 patients, average age 67 years), using a non-conforming posterior cruciate-retaining prosthesis, followed for a minimum of 15 years (range, 15.0 to 16.9 years). The patella was resurfaced with an all-polyethylene component in 83% of knees. The tibial component was always cemented, while a porous coated femoral component was used in 84% of knees. Fortyfive patients (59 knees) were followed-up for a minimum of 15 years, 57 (70 knees) had died, five patients (8 knees) were too ill to assess, two patients (two knees) were considered lost to follow-up.
Results In this series there were five re-operations, four of which were for polyethylene insert wear. At two of these, the patella was exchanged for early surface wear and one patella was resurfaced for the first time. There was one loose cemented femoral component after more than 15 years. The survival without revision or need for revision for any reason was 99% at 10 years and 95.6% (worst case scenario of 94.2%) at 15 years. The mean Knee Society Score and Function Score at 15 year follow-up was 96 and 78 respectively. The total incidence of radiolucent lines was 13%, with two percent around the femur, 11% around the tibia and zero percent around the patella. None of these lines were of any clinical relevance. There was no evidence of progressive radiolucent lines or component loosening, and one case of zone four femoral osteolysis.
Conclusions This single-surgeon series with a minimum 15 year follow-up, and excellent clinical, radiological and survivorship results provides a benchmark upon which other long term studies of modular fixed bearing posterior cruciate retaining total knee arthroplasty can be compared.
In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source.
The abstracts were prepared by Mr Jerzy Sikorski. Correspondence should be addressed to him at the Australian Orthopaedic Association, Ground Floor, William Bland Centre, 229 Macquarie Street, Sydney NSW 2000, Australia.
