The history and future of unlinked total elbow arthroplasty

Unlinked total elbow arthroplasty (TEA), which has no mechanical connection between the humeral and ulnar components, has theoretical advantages based on its near-normal elbow kinematics and the preservation of bone stock. Unlinked TEA is appropriate only for patients who have limited bone loss or limited deformity and good ligamentous function. This is because postoperative instability has been a major complication of unlinked prostheses. The concept and goal of unlinked TEA is to share the loading stress on the bone implant interface with the surrounding tissues. Although the loosening rate of unlinked prostheses theoretically should be lower than that of linked prostheses (which have a mechanical connection between the humeral and ulnar components), there is no clear evidence that unlinked TEAs are superior to linked TEAs in this respect. However, we believe that primary TEA should be performed using an unlinked TEA, especially for younger patients, because revision surgery for unlinked TEA results in longer prosthesis survival than revision surgery for linked TEA. Improvement of the design of unlinked prostheses and the introduction of less invasive surgical techniques are required to reduce postoperative instability.