During initial contact or heel strike, the ankle rolls inward, causing excessive pronation or flattening of the foot. This action forces the big toe (instead of the ball of foot and all toes) to do all the work to push off the ground. When the ankle overpronates, this causes the tibia (shin bone) to rotate and the femur (thigh bone) to adduct (move toward the mid-line of the body), causing internal rotation or knee valgus (knock-kneed).
In adults, the most common reason for the onset of Over-Pronation is a condition known as Post Tibial Tendonitis. This condition develops from repetitive stress on the main supporting tendon (Posterior Tibial Tendon) of the foot arch. As the body ages, ligaments and muscles can weaken. When this occurs the job of providing the majority of the support required by the foot arch is placed upon this tendon. Unfortunately, this tendon cannot bear the weight of this burden for too long. Eventually it fatigues under the added strain and in doing so the foot arch becomes progressively lower over a period of time.
Common conditions seen with overpronation include heel pain or plantar fasciitis, achilles tendonopathy, hallus valgus and or bunions, patellofemoral pain syndrome, Iliotibial band pain syndrome, low back pain, shin splints, stress fractures in the foot or lower leg.
When you overpronate your foot rolls inwards causing the lower leg to rotate inwards too. It’s thought that this increases stress on the soft tissues of the lower leg causing pain and inflammation, or more commonly known as shin splints.
Non Surgical Treatment
Not all over pronation is treated. Although, when it appears to be a causitive factor that is contributing to pain,or development of structural deformities, there are various degrees of treatment.In some cases specific shoes may be all that is required. In other cases, paddings or strapping, are prescribed and where necessary orthotic therapy. A podiatric assesment would be advised to asses this.
Hyperpronation can only be properly corrected by internally stabilizing the ankle bone on the hindfoot bones. Several options are available. Extra-Osseous TaloTarsal Stabilization (EOTTS) There are two types of EOTTS procedures. Both are minimally invasive with no cutting or screwing into bone, and therefore have relatively short recovery times. Both are fully reversible should complications arise, such as intolerance to the correction or prolonged pain. However, the risks/benefits and potential candidates vary. Subtalar Arthroereisis. An implant is pushed into the foot to block the excessive motion of the ankle bone. Generally only used in pediatric patients and in combination with other procedures, such as tendon lengthening. Reported removal rates vary from 38% – 100%, depending on manufacturer. HyProCure Implant. A stent is placed into a naturally occurring space between the ankle bone and the heel bone/midfoot bone. The stent realigns the surfaces of the bones, allowing normal joint function. Generally tolerated in both pediatric and adult patients, with or without adjunct soft tissue procedures. Reported removal rates, published in scientific journals vary from 1%-6%.