Knee osteoarthritis usually starts with small trade-offs. You take the elevator instead of the stairs. You skip the second lap around the block. Over time, the things that used to feel automatic start to feel like decisions.
Treatment often begins with physical therapy, medication, injections and activity changes. Those help many people, but not everyone gets enough relief. That leaves a common problem: the pain is limiting daily life, but knee replacement still feels like too big a step.
A device called the MISHA Knee System is built for that middle ground, and newly published five-year results give a clearer picture of how it holds up over time.
Image: MISHA Knee System / Moximed
How the implant works
The MISHA Knee System is an FDA-cleared implantable shock absorber for people with osteoarthritis on the inner, or medial, side of the knee. That inner compartment carries a large share of the load every time you take a step, which is part of why it wears down.
Instead of replacing the joint, the implant is placed along the inner side of the knee and moves with it. Moximed, the company that makes it, says the device takes on about 30% of the peak force on the knee with every walking step. The idea is straightforward: lighten the load on the painful part of the knee while leaving the natural joint in place.
It is designed for people who have not gotten enough relief from non-surgical care and who are not ready for, or not candidates for, knee replacement.
Image: MISHA Knee System size comparison / Moximed
The five-year evidence
The new findings, published in the Journal of Bone and Joint Surgery, followed 81 patients for five years after they received the implant. On average, these patients had lived with symptoms for more than four years, their arthritis ranged from early to severe, and all of them had already tried non-surgical treatment without enough relief.
At five years:
- 96% had a clinically meaningful improvement in pain
- 86% had a clinically meaningful improvement in function
- 90% had not moved on to knee replacement, partial or total, or to high tibial osteotomy, a procedure that shifts weight away from the damaged part of the knee
Researchers counted an improvement as clinically meaningful when a patient’s score on a standard knee questionnaire rose by at least 20%, and by at least 10 points, compared with before surgery. In everyday terms, better function can mean walking farther, moving with more confidence, or getting back to activities that pain had ruled out.
Getting back on your feet
Recovery looks quick for many patients. David Flanigan, MD, an orthopedic surgeon at The Ohio State University and a study investigator, reported that patients returned to full weight bearing within days of surgery and had no activity restrictions afterward. Recovery still varies from person to person, and your surgeon will set a plan based on your health and your goals.
As with any knee surgery, there are risks. The side effects reported in the study were mostly mild to moderate, such as knee pain, a catching or pulling sensation, trouble with certain activities, infection, and scarring. Most resolved without further problems, and in certain instances the implant was removed.
Image: MISHA Knee System / Moximed
Is it right for you?
The MISHA Knee System treats one specific problem: osteoarthritis in the medial compartment of the knee. It is not a fix for every kind of knee pain or every type of arthritis. An orthopedic specialist can look at where your arthritis sits, review what you have already tried, and tell you whether a joint-sparing option makes sense for your situation.
For the right patient, the five-year data suggest an implanted shock absorber may be a way to ease pain, move better, and hold off on replacing the knee.
This article is for general information and is not medical advice. Talk with a qualified healthcare professional about your symptoms and treatment options.