Total Knee Arthroplasty Following Prior Unicompartmental Replacement

The majority of failed unicompartmental knee arthroplasties (UKAs) are revised to total knee arthroplasty (TKA). In cases where appropriate indications are met, liner exchange or revision UKA is possible, but in general, these procedures have poor longevity and a higher failure rate compared to revision to TKA. Revisions of failed UKA to TKA appear to have a slightly inferior outcome compared to primary TKA, but better outcome than revision TKA. The mechanism of failure and the potential challenges at revision are influenced by the type of implant used, the surgical technique at the time of primary UKA, the patient pathology at the time of index surgery, and patient-related factors. While most revisions can be accomplished using primary TKA implants, a system that allows for the use of augments, stems, and metaphyseal sleeves or cones should be available at the time of surgery.