What is flat feet or a low arch?
If you have flat feet, the arch on the inside of your feet is flattened. Flat feet or low arches usually doesn't cause a problem. However, flat feet can contribute to problems in your feet, ankles and knees. Simple corrective devices, such as low arch orthotics, are available to help prevent complications of flat feet.

• A flat look to one or both of your feet
• Uneven shoe wear and collapse of your shoe toward the inside of your flat foot
• Lower leg pain or weakness
• Pain on the inside of your ankle
• Swelling along the inside of your ankle
• Foot pain

Lax ligaments can cause flat feet, as can conditions present at birth (congenital) that affect the foot.

Arches can also fall over time. Years of wear and tear can weaken the posterior tibial tendon, which runs along the inside of your ankle, from above your ankle to your arch. The posterior tibial tendon is the main support structure for the arch. An overload to this tendon can cause inflammation of the tendon (tendonitis) and even tearing of the tendon. Once the tendon is damaged the foot's arch loses support and can flatten.

You may lose support in your arches due to:

• Ongoing stresses in your feet. One of these stresses may be long-term wearing of high heels, which can affect your Achilles tendon and change the mechanics of your ankles. Compensation by the posterior tibial tendon may eventually cause it to break down and your arches to fall.
• Obesity
• Traumatic injury to your foot or ankle
• Rheumatoid arthritis
• Diabetes

• Inflammation and pain in the ligaments in the soles of your feet (plantar fasciitis)
• Achilles tendonitis and posterior tibial tendinitis
• Shin splints
• Stress fractures in your lower leg
• Bunions
• Calluses
• Because flat feet can affect your body's alignment, the condition may also lead to pain in your ankles, knees and hips.