Knee osteoarthritis (KOA) is a very common condition that is a significant cause of disability in older adults, often resulting in knee replacement surgery. There are several contributing factors to KOA, and perhaps one of the most important issues is excessive force exerted on the knee joint by improper biomechanics of the foot and ankle.
In the normal gait or walking cycle, there are two primary phases called the stance phase and the swing phase. As the names imply, the stance phase refers to the entire time the foot is in contact with the ground and the swing phase occurs when the foot is off the ground.
A 2019 systematic review and meta-analysis reported that the forces across the knee are not transmitted equally during walking, with the inside of the knee joint bearing greater loads than the outer knee joint in most individuals. This leads to breakdown of the cartilage faster on the medial side of the joint, which leads to KOA. One identified cause of this is called ankle pronation, which is an excessive rolling-inward of the ankle that occurs during the stance phase. This results in the knee knocking inward, which is technically called external knee adduction moment, or EKAM.
Fortunately, this can be addressed with the use of lateral wedge insoles or shoe inserts that try to minimize or eliminate the ankle pronation aspect that reduces the EKAM and associated excess loading of the medial knee joint.
When assessing a patient, doctors of chiropractic will expand their examination to regions of the body outside of the area of chief complaint as it’s common for dysfunction in one body part to affect another. In this case, we can see that abnormal motion of the ankle can place added stress on the knee, potentially leading to knee replacement. For the patient to achieve an optimal outcome, such issues need to be addressed.
Chiropractic treatment for the KOA patient can include manual therapies to restore proper motion to the affected joints, specific exercises to strengthen weakened muscles, and nutritional recommendations to reduce inflammation. If ankle pronation is suspected to contribute to the patient’s knee condition, then an orthotic insert may also be necessary. As with many musculoskeletal conditions, it’s better to seek care sooner rather than later. The earlier treatment can be provided, the faster and more likely there will be a satisfactory outcome.