Unicondylar knee arthroplasty: a cementless perspective

To compare the results of cementless unicondylar knee arthroplasty (UKA) with those already reported in a similar study on cemented UKA.

A case-series cross-sectional study.

The Queen Elizabeth II Health Sciences Centre, Dalhousie University, Halifax.

Fifty-one patients who underwent a total of 57 UKAs between May 1989 and May 1997. Inclusion criteria were osteoarthritis involving the predominantly the medial compartment of the knee, relative sparing of the other compartments, less than 15 degrees of varus, minimal knee instability, and attendance at the postoperative clinical visit.

Cementless UKA.

Clinical parameters that included pain, range of motion and the Knee Society Clinical Knee Score. Roentgenographic parameters that included alpha, beta, gamma and sigma angles and the presence of periprosthetic radiolucency or loose beads.

Age, weight, gender and follow-up interval did not significantly affect the clinical results in terms of pain, range of motion or knee score. Knees with more than 1 mm of radiolucency had significantly lower knee scores than those with no radiolucency. Knees that radiologically had loose beads also had significantly lower knee scores. The clinical outcomes of cementless UKA were comparable to those already reported on cemented UKA. Cementless femurs had less radiolucency than the cemented femurs, whereas cementless tibias had more radiolucency than their cemented counterparts.

Cementless UKA seems to be as efficacious as cemented UKA. However, there is some concern about the amount of radiolucency in the cementless tibial components. A randomized clinical trial comparing both cementless and cemented tibial components with a cementless femur (hybrid knee) is needed to further assess this controversial issue in UKA.