Intrinsic Constraint of Elbow Prostheses

Principal Investigator: Kai-Nan An, Ph.D.
Project Coordinator: Mark Zobitz — zobitz.mark@mayo.edu

This study considered the intrinsic constraint of various unlinked total elbow replacements. Unlinked elbow joint arthroplasty is a procedure that uniformly relieves pain, but varies widely regarding stability and long-term survival of the implants. Many unlinked designs exist, with radically differing articular geometries, suggesting no optimal design. A feature inherent to the articular design is the intrinsic constraint afforded to the joint by the implant. Our aim was to directly compare the intrinsic joint constraint of 5 widely used unlinked implants to that of the normal ulno-trochlear joint in a cadaveric model. The data was able to segregate the five implants into those that had normal elbow type behavior, and those that did not. Whereas the best data of implant behavior is from long-term clinical results, an understanding of fundamental in-vitro behavior is important to improve results and understand failures. Implants designed to be anatomically correct do not necessarily replicate normal kinematics.