How Wedged Insoles Work

It is true that there is some controversy concerning the effectiveness of wedged insoles for knee arthritis. There are credible publications for and against the benefit. You may have read the Harvard Health article that claims that wedged insoles are just a waste of money. However, all disease conditions require indications in order to have effective treatment. For instance, antibiotics are not a benefit for a virus. The truth is that no publication or study until now has considered whether you or a patient is a candidate who would benefit from the wedged insole. 


How It Works


Wedged insoles are intended to divert the forces from the arthritic side of the knee to the healthy side of the knee. This requires mobility of the knee ligaments and those in the foot and ankle (subtalar joint). The slope of the wedged insole should cause the foot and ankle to turn one way or the other, depending upon how the slope is placed.  If the wedge is higher on the outside then the foot and ankle rotates outward during walking.

How to Tell If Wedged Insoles Will Work For You 

Lanny L. Johnson, M.D. a world recognized orthopedic surgeon, has created a simple test to determine if you or a patient has enough looseness of the knee ligaments and the foot and ankle to have insoles be a benefit. If you or a patient pass this test based on mobility, the wedged insoles will be effective and transfer forces to the healthier side of the knee joint.  See the evidence:

The lateral wedge moves the compliant foot and ankle outward, resulting in a knock knee force at the knee.  If the knee is compliant, the forces are shifted away from the inner side to the outer side. But if the patient’s foot and ankle are stiff, there will be no outward motion and no transfer of forces. Therefore, there is no resultant shift of forces upward toward the knee joint. There is no benefit to wedge insoles if there is no foot, ankle and knee joint compliance. 

Why Wedged Insoles Are Considered “A Waste of Money” 

There are two main reasons why wedged insoles are often thought to be a waste of money. The first is that evidence suggests there is no difference between buying a pricey custom made orthotic vs. an inexpensive store bought insert. This argument makes sense if you are shopping for comfort insoles. Comfort insoles cannot be expected to alleviate pain. The second reason wedged insoles are sometimes thought to be a waste of money is “they don’t work”. The truth is, knee pain is a complicated condition to address. Knee pain may be the result of an injury, such as a ruptured ligament or torn cartilage. Medical conditions — including arthritis, gout and infections — also can cause knee pain. It is important to determine the specific reason for you knee pain, and choose your treatment accordingly. iI you are a candidate for wedged insoles based on the test, it will behoove you to buy specific wedged insoles depending on what kind of pain you have. 

Gel vs Poron insoles

Dr. Lanny’s wedged insoles for arthritic knees are constructed with Poron, an open cell polyurethane foam, which will not flattens regardless of how many times it is stepped on. Its porous nature keeps it springing back into shape after every step. Poron acts like a cushion when it comes to vertical pressure. It also helps stabilize the foot by providing resistance to horizontal pressure as well. Other materials, such as memory foam, are made up of a closed cell material, preventing it from rebounding back into place. This renders memory foam useless for support and gives minimal comfort when used in an insole. 

Gel insoles are a popular and inexpensive choice, but gel insoles do not give you the same support and shock absorption that Poron does. They do not provide any retention or weight shift that is required to alleviate arthritic knee pain. Gel insoles are often deemed to be uncomfortable, and do not stay in place within the shoe. Patients report that gel insoles feel like there is a big lump in their shoes, making it even harder to get around. 

If you or a patient are having trouble with inner knee problems and would like to see if wedged insoles would work for you, click here. Or if you or a patient are having trouble with Outer knee problems and would like to see if wedged insoles would work for you, click here