In a recent study, lateral UKA (unicompartmental knee arthroplasty) illustrated good long-term survivorship, comparable to medial UKA, with excellent long-term satisfaction and good functional results. The principal reason for revision surgery was OA (osteoarthritis) progression in other compartments. It is therefore essential to respect surgical indications, with rigorous technique.

A multicenter retrospective study aimed to conduct long term assessments of lateral UKA for knee OA.

Six French health establishments took part in this retrospective analysis, including all lateral UKAs carried out between January 1988 and September 2014. During follow-up, paraclinical data (radiologicangles), clinical data (IKS; International Knee Society, knee and function scores, range of motion, satisfaction), and complications were entered in medical files. At the end of follow-up, the data were analyzed retrospectively.

Using 5 fixed-bearing implant models, 311 lateral UKAs were carried out in 295 patients during the study period. Within 5 years, 28 patients died, and 15 (4.8%) were lost to follow-up. Overall, 268 lateral UKAs in 63 men and 205 women patients (mean age of 68.8 ± 10.5years ), including four aseptic osteonecrosis cases and seven post-traumatic OA cases were included in the series. The subjects were followed for a mean of 9.1 years.

The implant survivorship with failure defined as all-cause revision surgery at 10 and 20 years is shown in the following table:

At last follow-up, the values for IKS knee score, IKS functions core, and maximal flexion are shown in the following table:

Satisfaction was reported by 94.3% of patients. In 66.7% (n=26) patients, the primary cause of revision surgery was OA in another knee compartment.

For isolated LCOA (lateral compartment osteoarthritis of the knee), lateral UKA is a reliable option.