Abstract
A majority of patients present with varus alignment and predominantly medial compartment disease. The secret of success in osteoarthritis (OA) treatment is patient selection and patient specific treatment. Different wear patterns have been described and that knowledge should be utilised in modern knee surgery. In case of isolated anteromedial OA, unicompartmental knee arthroplasty (UKA) should be one of the therapeutic options available to the knee surgeon.
The discussion not to offer a UKA to patients is based on the fear of the surgeon not being able to identify the right patient and not being able to perform the surgery accurately. The common modes of failure for UKA, which are dislocation or overcorrection leading to disease progression, can be avoided with a fixed bearing implant. Wear can probably be avoided with newer polyethylenes and avoidance of overstuffing in flexion of the knee. Revision for unexplained pain and unknown causes should disappear once surgeons understand persistent pain after surgery much better than they do today.
The choice in favor of UKA is a choice of function over survivorship, a choice for reduced comorbidity and lower mortality. Many of the common problems in TKA are not an issue in UKA. Component overhang, decreased posterior offset, changed joint line height, gap mismatch, flexion gap instability, lift off and paradoxical motion hardly exist in UKA if the replacement is performed according to resurfacing principles with respect for the native knee anatomy.
New technologies like navigation, PSI and robotics will help with alignment and component positioning. Surgeon education and training should allow over time UKA to be performed by all of us.
