The two most common reasons, from my experience, why people get orthotics is for over-pronation (aka flat feet) or over-supination (aka high arches). I think it’s best to briefly describe the patterns seen in the knees and low back with people who have flat feet and high arches.
When people have flat feet, their feet are typically very mobile. They may frequently get Plantarfasciitis and/or foot and ankles sprains. However, the pattern that occurs with over-pronation is the tendency for the knees to buckle inward (knock-kneed) and for the lower back to arch too much. Inward buckling of the knees causes a torque that could lead to meniscus tears and problems with the patella. Overarching of the low back typically leads to muscular spasms and possibly arthritic conditions and tightening of the lumbar joints.
People who fit into this category can benefit from orthotics that help to control the over-pronation so the ankles stay more “neutral.” In effect, the knees and lumbar will hopefully stay more neutral as well. Combining the proper orthotic along with stabilization training, gluteal strengthening, and improved flexibility in particular areas of the hips and lower leg provide the best combination of treatment for people in this category.
When people have high arches, their feet are typically very rigid and absorbing shock forces is one of the major problems. Plantarfasciitis and ankle sprains can certainly be seen among people in this category, but pain in the lateral lower leg (Peroneal muscles) or lateral thigh (ITB) is extremely common. The knees and legs often appear more “bowl legged” and the lower back may appear flattened. From my experience, lumbar disc problems are more common among people in this category, however, disc problems can certainly occur among people of either category.
People with high arches can benefit from orthotics that help fill the space under the foot so that pressure is more evenly distributed under the foot, as well as orthotics that provide some cushioning to assist with shock absorption. Patients usually see optimal outcomes when the proper orthotics are combined with joint mobilization of the foot and ankle, as well as techniques to improve the mobility of the soft tissues in the lateral leg.
I hope you found this information helpful in understanding the potential positive impact of orthotics and how foot and ankle dysfunction can add to someone’s knee and/or low back pain. If you or anyone you know has a specific questions on this information, please feel free to reach out through email at info.JLPT@gmail.com or phone at (646) 455-1312.