Case: Unicompartmental Knee Arthoplasty (UKA/UNI) is a surgical procedure used to repair a damaged knee joint, when the damage is only contained to one of the knee compartments. Read more
Unlike Total Knee Preplacement procedure, UNI typically requires a smaller incision, less tissue damage, and faster recovery time. For the patient, what separates different UNI systems is how natural the articulation of the implant through the full motion of the knee. The client turned to us to help them develop implant concepts for the new UNI line. (https://djoglobal.com/our-brands/djo-surgical/empowr/partial-knee)
Solution: Tri-Power Design spent a considerable amount of time analyzing the competitive landscape, reviewing and articulating surfaces derived from anatomical scans, and presenting the development data to the surgeon design team to gather their feedback. A lot of consideration was also given to ensuring appropriate surface contact between the femoral and tibial implants along the full range of motion. Final implants became an anthropometric design, which allowed for unconstrained articulation and bone sparing preparation, while minimizing potential overhang.
Design Challenges: Providing benefits of the good implant design across all of the different bone sizes and ensuring that no more than two sets of implants be used to fulfill 4 compartments of variation. Based on the bone size database, and inputs of the surgical team, the implant sizes were split into 6 variations. Articulating an outline of the implant was split into a composite curve composed of 4 radii. Anterior/posterior shape was then later edited based on the anatomic database finding. Distal and Posterior condyle lengths were adjusted to ensure under-capping, also based on anatomic shapes. All 6 sizes were then thoroughly reviewed to ensure similar articulation across the board.