Oxinium™ Knee Implants

Smith & Nephew Knee Systems, Solving the Wear Issue from Every Angle

From the beginning, a principal objective for the design of Smith & Nephew knee systems has been to address the leading problem confronting orthopaedic surgeons and manufacturers: the generation of wear debris, particularly polyethylene wear.

The Oxinium™ material represents a giant leap forward in our ongoing effort to create effective solutions to this issue, but our approach doesn’t stop there.

Numerous proven design features as well as processes have been incorporated into Smith & Nephew knee systems to help reduce the generation of wear debris.

Increased contact area

Genesis® II and Profix™ Systems feature a femoral component design combined with conforming tibial inserts to increase contact area and reduce contact stress.

Tightest Tibial Insert Locking Mechanism

The tibial inserts for both Genesis II and Profix incorporate a peripheral dovetail lock that is the tightest on the market. Not only does the dovetail lock maintain structural integrity under loads that greatly exceed normal loads, it also limits micromotion and the associated risk of osteolysis.

Highly Polished Tibial Base Plate

While the dovetail locking design of the Smith & Nephew tibial locking mechanism helps reduce micromotion, there is no way to completely eliminate it. By polishing the surface of the tibial baseplate, we have reduced the abrasiveness of the surface, thereby reducing the amount of backside wear that occurs.

Improved Patellar Tracking

Our patella and femoral components are designed to reduce stress as well as improve tracking. Helping keep the patella in an optimal position throughout the full range of motion is a critical element to address the overall need of reducing wear.

Non-degrading Sterilization

Smith & Nephew uses a gas sterilization process to sterilize its polyethylene knee inserts. This process does not cause oxidative degradation of the polyethylene. Polyethylene components sterilized using this alternative method have demonstrated better wear properties in direct tests against gamma-irradiated components.

Addressing Wear in Uni-compartmental Knees

The Smith & Nephew Oxinium™ Unicompartmental Femoral Component as part of the Accuris system, combines the superior wear characteristics of this extraordinary bearing material with precise instrumentation to deliver yet another first from the leader in unicompartmental knee replacement.

From our initial market entry in the early 1970s with the Marmor/Mod I design, to the innovative Accuris instrumentation, we’ve been at the forefront of the uni market. And now we’re doing it again, with a particular focus on improving wear.

Component malalignment has been suggested as a possible cause of early polyethylene wear and failure in unicompartmental knee implants.

The Accuris system utilizes precise instrumentation to help ensure proper alignment and positioning for maximum contact area. This, combined with the benefits of an Oxinium™ material femoral component addresses the wear issue from multiple angles.

Engh, Gerard, MD, et al., American Academy of Orthopedic Surgeons, "Tibial Baseplate Wear: A Major Source of Debris with Contemporary Modular Knee Implants" 67th Annual Meeting, March 15-19, 2000, Orlando, Florida.

Todd, Dwight, et. al., Orthopedic Abstract, "The Effect of Tibial Tray Surface Roughness and Insert Micromotion on Backside Wear." Smith & Nephew, Memphis, TN

S.H. Palmer, et al., “Early Catastrophic Tibial Component Wear after Unicompartmental Knee Arthroplasty”, Clinical Orthopaedics and Related Research, 1998;350:143-148