A PhD-bound bioengineering student researcher at Clemson University (Clemson, SC, USA) and his team have constructed a knee simulator designed to capture the key motion characteristics of a normal knee with artificial bones and implant. The goal of the project is to determine the effects of alignment and ligament configurations on the movement and contact pressure distributions on the knee among patients undergoing unicompartmental knee arthroplasty (UKA). The knowledge obtained from tests using the rig may help physicians and researchers to improve implant designs, surgical techniques, patient selection criteria, or better inform the patient about possible postoperative or rehabilitation risks.
UKA is a surgical procedure used to treat osteoarthritis when the damage is only limited to one compartment of the knee, writes PhD student Roy Junius Rusly in a blog post describing the research. The main advantages of this procedure over total knee replacement (TKR) include preservation of bone stock, more physiologic joint movement, improved proprioception, increased range of motion and faster recovery time. Despite its reported success rates—87 to 98% survivorship at 10 years—UKA has not gained universal recognition as the appropriate procedure of arthritis of a single condyle. This is mainly because it is a more complex procedure than TKA and reportedly has a slightly lower success rate, adds Rusly.
Cadaveric specimens will be used in the knee simulator, which provides a reasonable simulation of the entire lower extremity in activities such as rising from a seated or crouching position while allowing measurements of internal loadings (contact pressures), which could not be performed accurately in a living patient. The researchers are using a motion tracking system that allows 3-D position tracking of knee movement during simulation. The contact pressure and area of the articulating surfaces are measured using paper-thin film pressure sensors which can be inserted in between the knee joint.
The research is taking place at the Frank H. Stelling and C. Dayton Riddle Orthopaedic Education and Research Laboratory located on the Clemson University Biomedical Engineering Innovation Campus.
For more information, go to Rusly’s blog post.Norbert Sparrow