Review Question - QID 136

Lateral compartment arthroplasties have not been shown to have higher failure rates than medial compartment arthroplasties.

Heck et al determined survivorship and risk factors for failure in their study of 294 UKA's with an average follow-up of 6 years. No statistically significant difference in the need for revision was demonstrated between those knees in which a medial as compared with a lateral compartmental arthroplasty had been performed. Female gender had a RR of revision of 1.7 compared to men. They also found that the average patient requiring revision had a BMI of 32.6 kg/m2, and an association between obesity (wt >81kg) and revision was statistically significant. However more recent data, summarized below, has called this particular finding into question.

Pandit et al sought to determine whether potential and previously described contraindications to UKA should apply to patients with a mobile-bearing UKR. With regards to BMI, they found no significant clinical or functional outcome difference, failure rate or survival between 551 UKRs performed in ideal weight patients (44-82kg) compared to non-ideal (82-185kg).

Weale et al evaluated the radiographic changes in 50 UKA's at 5 years post-op. They found no correlation between the post-op tibiofemoral angle and the extent of recurrent varus recorded at five years, and stated that changes in alignment may be indicative of minor polyethylene wear or of subsidence of the tibial component. They also found that the incidence of progressive osteoarthritis within the knee was very low after UKA.