Sliding Total Ankle Replacement System Offers More Flexibility

A new prosthetic total ankle replacement device functions as an alternative to fusion surgery for those with arthritic or deformed ankles.

The Scandinavian Total Ankle Replacement System (STAR) is a new treatment option for moderate to serious ankle arthritis, relieving pain and mimicking normal anatomical movement while restoring motion. The cementless prostheses feature a bioactive double coating of pure titanium and hydroxyapatite; however, in special cases, cemented or hybrid versions are available.


The STAR system, in both versions, consists of three components: A tibial component with a highly polished flat articulation surface and two cylindrical fixation bars on the proximal side of tibia, used to anchor the implant in the subchondral bone of the tibia. The tibial component is available in five sizes.
A talar component, also available in five different sizes, and comes with versions for right and left ankles. A ridge running anteroposteriorly in the middle of the gliding surface guides the ultra high molecular weight polyethylene (UHMWPE) sliding core.

A UHMWPE sliding core, the flat surface of which articulates with the tibial component, while the concave underside articulates with the convex talar component. The anteroposterior articulation is guided by the longitudinal ridge on the talar component and the matching longitudinal groove in the underside of the sliding core. The sliding cores are available in five heights: 6, 7, 8, 9, and 10 milimeters.

The instrument set used for implantation of the prosthesis consists of drill and saw guides, trial prostheses, and auxiliary instruments that allow precise, reproducible bone resection. The STAR is made by Small Bone Innovations (SBi, Morrisville, PA, USA), and has been approved by the U.S. Food and Drug Administration (FDA).

"This device offers another treatment alternative to fusion surgery, and more closely imitates the function of a natural ankle,” said Daniel Schultz, M.D., director of the FDA's Center for Devices and Radiological Health.

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Small Bone Innovations