Unicompartmental Knee Arthroplasty safe for younger patients

Oxford Prosthesis’ 10-year survival rate: 93.9% in younger patients, 95% in older patients

Unicompartmental knee arthroplasty is safe and effective in patients both over and under age 60, according to a joint Swedish-British study. Results showed “no statistical difference” between the prosthesis’ survival rates in younger and older patients, researchers said.

The study focused on the age at which patients may receive the Oxford Unicompartmental Knee System in lieu of undergoing high tibial osteotomy, said corresponding author Ulf Svärd, of Skövde, Sweden, at the 7th European Federation of National Associations of Orthopaedics and Traumatology Congress.

Svärd and co-author A.J. Price of Oxford, United Kingdom, grouped 42 patients as young (mean age 55 years, range 34 to 59 years) and 433 as older (mean age 73 years, range 60 to 86 years ). The prostheses’ survival rate was 93.9% in the younger group and 95% among the older patients, Svärd said.

Study results showed that “a patient in his early 30s well could be operated with this type of prosthesis,” Svärd said. Some surgeons in the audience would have opted for performing osteotomy in patients in their early under 30 instead, he noted.

Oxford surgeons and Biomet engineers developed the Oxford Unicompartmental Knee System, the only FDA-approved, free-floating meniscal partial knee system available in the U.S.

Unicompartmental knee replacement involves replacing only one side of the knee joint. Total knee replacement involves removing all knee joint surfaces. Osteoarthritis commonly occurs first in the medial compartment, which carries the most weight. The unicompartmental procedure leaves the outer compartment and all ligaments intact, according to a 10-year survival study.

The Oxford device is the first implant featuring an artificial meniscal bearing that closely reproduces normal movement, the survivor study said.

For more information:
Svärd Ulf, Price A.J. Ten-year survival results of Oxford Unicompartmental Knee Arthroplasty. Presented at the 7th European Federation of National Associations of Orthopaedics and Traumatology Congress. June 4-7, 2005. Lisbon, Portugal.
Additional information is from Murray D.W., O'Conner J.J. and Goodfellow, J.W. The Oxford Medial Unicompartmental Knee Arthroplasty: A ten-year survival study.