In a retrospective review of the cases of twenty-nine patients who had a
revision of a failed unicondylar unicompartmental knee replacement, the
cause of failure of the original unicondylar arthroplasty was found to be
loosening of one or both components in sixteen patients, progression of
disease in the opposite compartment in nine, patellofemoral symptoms in
two, ligamentous instability in one, and malposition of the tibial
component in one. A technical error had been made in sixteen of the
patients, and ten of the errors were associated with the ultimate failure
of the original unicondylar procedure. Ninety-three per cent of the failed
unicompartmental arthroplasties were revised using a posterior
cruciate-sparing total knee replacement. Bone grafts, augmentation with
screws and cement, a long-stem component, or a combination of these were
used in half of the patients. The average follow-up after the revision
arthroplasty was 4.6 years.