Most patients don’t think much about the design of their new knee joint replacement. But doctors give this much thought and study. These implants don’t last forever. The typically only last from 10 to 20 years. That’s why researchers are trying to find ways to make implants last longer.
The author of this report reviewed the results of 16 studies. Each study looked at the final outcome of knee replacement surgery, also called total knee arthroplasty (TKA). The hope is to find what makes an implant last without breaking down or coming loose.
Recent changes were made in the design of implants. A way to stabilize the implant from the backside of the joint was added. This improves stair climbing ability and increases range of motion. A metal backing was also added to help distribute the load more to the front of the lower leg bone (the tibia).
According to this study, these changes did not increase the life of the implant. Lower contact stress and reduced wear weren’t any lower. All implants lasted at least 10 years in all patients. This was true whether metal or polyethylene (manmade plastic) was used in the implant.
The author reports that these are short-term findings. No studies beyond 10 years were reported. Findings are fairly limited. For example, only one study comparing all-polyethylene with metal-backed implants was published. More studies are needed to find out which implant lasts the longest and why.