What You Need to Know About Smart Knee Implants

Did you know that knee replacement surgery is the most common joint replacement procedure? Knee replacement surgeries are often done to replace an older implant or an implant that has worn out from physical activity. That means a young patient may need to undergo knee replacement surgery every 5 to 10 years. Balancing healthy physical activity with avoiding damage to the knee implant can be tricky to balance. However, that may change when smart, self-powered knee implants are introduced.

How do traditional knee implants work? 

With a traditional knee joint replacement, damaged cartilage, and bone are removed from the knee and replaced with manmade pieces of metal, ceramic, or plastic. There are many different types of implants based on a patient’s knee problems, knee anatomy, age, weight, activity level, and health. In a total knee replacement, parts of the femur, tibia, and patella are replaced with a mix of materials to reduce wear on the implant. 

One limitation of a traditional implant is that doctors aren’t able to tell if a patient is overexerting themselves and wearing down the implant too quickly. Implants may loosen and detach from the bone. Components can wear out and release debris, causing inflammation. Wear and tear can cause the knee to break. By the time these symptoms develop and the implant requires replacement, the damage has already been done.

How are smart, self-powered knee implants different?

A smart, self-powered knee implant has sensors that can monitor how much pressure is being put on the implant, giving doctors a clearer understanding of the patient’s regular activity and how it might be negatively affecting it. Doctors can then gauge the best level of activity for each patient.

While these sensors solve the problem of “how much is too much” activity, another problem arose. Powering the sensors with a battery that needed periodic replacement would defeat the purpose of a smart knee implant. To solve this new problem, researchers from Binghamton University worked on a new energy harvesting mechanism that wouldn’t rely on batteries. Instead, the patient’s motion generates “triboelectric energy,” or energy collected from friction during motion. When a patient walks, microsurface friction coming into contact with each other powers the sensors. Researchers also calculated that a smart knee implant requires 4.6 microwatts of energy to power itself. Luckily, the act of walking generates around 6 microwatts by the average person.
Knee replacement surgery is the most common joint replacement procedure, and the expected number of procedures continue to rise. About 3.5 million procedures a year are expected by the year 2030. With evolving technology like smart, self-powered knee implants, the number of replacement procedures may decrease. Patients can enjoy an improved quality of life with determined levels of safe activity with a smart knee implant.

Orthopedic Corner | Leon Mead MD Orthopedic Doctor | 730 Goodlette Road North, Suite 201  Naples Florida 34102 | Phone: (239) 262-1119