Treatments for knee pain associated with osteoarthritis range from over-the-counter medications to total knee replacement. The recently tested Misha Knee System is designed to help fill the gap between these extremes by acting as an implanted shock absorber.
Made by California-based Moximed, the Misha device looks like a miniature version of the type of shock you might see in a car. Anchored to the inner sides of the femur and tibia bones okay knee joint, includes a steel piston on top that slides in and out of a flexible polymer cylinder underneath.
As the piston compresses the cylinder on the downstroke, the cylinder responds by bulging outward along the sides, absorbing much of the energy that would otherwise go into the joint. As a result, the implant is claimed to reduce peak forces on the knee by over 30% with each step.
According to Moximed, Misha is implanted under the skin through a single incision in an outpatient procedure. Once the device is in place, it does not place any restrictions on the knee’s range of motion or weight bearing capabilities. It also leaves the bones, tendons and cartilage intact, so future alternative treatments are still possible.
Back in 2019—when it was known as Calypso—Misha was implanted in a total of 81 patients with knee pain as part of a multicenter clinical trial led by The Ohio State University Wexner Medical Center. The results of that trial were announced this Thursday (September 22), after test subjects lived with the implant for three years.
According to Ohio State, over 90% of participants had “significant reductions in pain scores and improvement in functional outcomes.” Overall, the device has an 86% success rate, which is said to be better than the success rate for a commonly performed surgical procedure known as a high tibial osteotomy – it involves realigning the knee joint by cutting a wedge of bone from the tibia.
Data from the trial have been submitted to the US Food and Drug Administration and are now undergoing regulatory review. There is no word on when the Misha Knee System may be widely available.
Its impact absorbing function is illustrated in the animation below.
Walking animation with MISHA knee system
sources: The Ohio State University, moximed