What is Adult-Acquired Flatfoot?
Adult-acquired flatfoot, also known as collapsed arch or posterior tibial tendon dysfunction, is a painful condition that affects the ankles and feet of adults. The condition usually occurs in those over the age of forty and is more common in women than men. The condition is defined by progressive collapse or flattening of the medial arch of the foot. The medial arch of the foot is the most important foot arch. It runs along the inside of the foot. The arch is formed by the tarsal and metatarsal bones and is supported by tendons and ligaments in the foot. It functions as a shock absorber while walking and running. An adult-acquired flatfoot can progress from early stages with pain along the inside of the foot and ankle to advanced deformity and arthritis.
Causes of Adult-Acquired Flatfoot
Adult-acquired flatfoot most commonly occurs as a result of posterior tibial tendon dysfunction. The posterior tibial tendon is one of the crucial supporting structures of the medial arch of the foot. If the posterior tibial tendon becomes overused, inflamed, or torn it can stretch, causing the medial arch of the foot to collapse. It usually develops from cumulative wear and tear of the posterior tibial tendon, rather than a specific incident. Individuals with pre-existing flexible flatfeet, obesity, hypertension, diabetes, and rheumatoid arthritis are more likely to develop this condition. High-impact sports are also a contributory factor.
Symptoms of Adult-Acquired Flatfoot
Individuals with adult-acquired flatfoot commonly experience pain, swelling, and/or deformity at the hindfoot or ankle. When the posterior tibial tendon does not work correctly, a number of changes can occur to the foot and ankle. In early stages, symptoms often include swelling and pain along the posterior tibial tendon behind the inside of the ankle. As the tendon fails over time, deformity of the foot and ankle may occur. This deformity may include:
- Progressive flattening of the arch of the foot
- Outward turning of the heel
- Rotational deformity of the forefoot
- Development of arthritis
- Deformity of the ankle joint
- Tightening of the heel cord
- Difficulty with walking/running
- Inability to bear weight on the affected foot
Diagnosis of Adult-Acquired Flatfoot
The diagnosis of adult-acquired flatfoot is usually made from a combination of physical examination, review of symptoms, and imaging. Your physician will first check your walking pattern, the location of the pain, flexibility of the hindfoot joints, shape of your foot while you are standing with your full weight on your feet, and ask you to try to stand on your heels or tiptoes to see if an arch appears to confirm the diagnosis. X-rays may also be ordered to assess how advanced the problem is.
Treatment for Adult-Acquired Flatfoot
Treatment for adult-acquired flatfoot depends upon the severity of the condition. For phase 1 (you are still able to stand on tiptoes of the affected foot) and phase 2 (your foot and ankle are still flexible rather than stiff and rigid) adult-acquired flatfoot, your physician may recommend some of the following non-surgical treatments:
- Rest, Ice, Compression, Elevation (RICE) Therapy: This involves providing ample rest to the foot by avoiding activities that consistently cause pain such as running or standing for long periods of time, applying ice packs to reduce swelling and pain, use of compression devices such as elasticated support bandage to alleviative symptoms and ease pain and discomfort, and elevating the affected foot to reduce painful swelling.
- Medications: Use of pain-relieving medications such as NSAIDs to help reduce pain and inflammation.
- Shoe modification: Using a well-fitting, supportive shoe to help relieve aching pain caused by flatfoot.
- Physical Therapy: Stretching exercises of the foot to increase mobility, strengthen the tendon, and reduce pain.
- Massage therapy: You may also obtain pain relief in the form of regular massage with 10% ibuprofen gel when painful.
- Orthotic devices: Your surgeon may advise on the use of custom-made orthotic devices that are worn inside the shoes to support the arch of the foot. Long-term use of orthoses may help stop the progression of the deformity and reduce pain without surgery.
Your physician may recommend surgical treatment for phase 3 and 4 adult-acquired flatfoot conditions such as partially torn tendon, serious limitation of foot function, and significant pain and swelling that is nonresponsive to non-surgical treatment.
Surgical treatment procedures may include muscle and ligament lengthening, tendon transfers, removal of the inflamed tendon lining, cutting and realigning bones, placement of implants to realign the foot, and joint fusions. Typically, the early phase with flexible flatfoot condition can generally be treated with ligament and tendon procedures with the addition of osteotomies (cutting/shortening of bone) to realign the foot.
Later phase condition with either arthritis or a rigidly fixed deformity is usually treated with joint fusion procedures. Joint fusions or triple arthrodesis involves fusing or stiffening of the three joints in the back of the foot - the subtalar, talonavicular, and calcaneocuboid joints - to realign the foot and give it a more natural shape. Screws or pins are used to hold the bones in place until they heal. This procedure provides strong correction of severe deformities, leading to increased stability and pain relief; nonetheless, they also lead to a stiffer foot and loss of motion.
Recovery after almost all surgical treatments requires restricted weight-bearing and a defined period of immobilization that can range from several weeks to several months. More involved surgical procedures that include osteotomy, tendon transfer, or fusion may need a longer period of recovery. Usually, individuals do not experience complete improvement until 1 to 2 years after surgery.
