Flexible FlatfootIf your foot is flat when you are standing but it rebounds to a normal arch height when you sit, this is known as flexible flatfoot. When it is painful and medical treatment is sought, the ACFAS guideline recommends first using non-invasive treatments including changing or limiting activity and doing stretching exercises. They may prescribe non-steroidal anti-inflammatory medication and custom shoe orthotics. After trying those tactics and the patient still has foot pain, they may resort to surgical interventions.
Adult-Acquired Flatfoot - Fallen ArchesA more serious condition, according to ACFAS, is adult-acquired flatfoot, often cause by posterior tibial tendon dysfunction (PTTD). In this case, the tendon that supports the arch weakens and fails, leading to a rigid flatfoot where the arch stays flat even when you aren't standing. It can lead to a loss of range of motion in the foot and ankle and pain in the arch. The ACFAS clinical guideline recommends that flatfoot caused by PTTD can be treated with custom shoe orthotics, soft casts, walking boots, physical therapy and non-steroidal anti-inflammatory medications. If there is no relief or the condition worsens, then the patient may be referred to surgery.
More: Flat Feet
Press Release "New clinical practice guideline published to treat flat feet in adults." American College of Foot and Ankle Surgeons, March 5, 2005
Gross KD, Felson DT, Niu J, Hunter DJ, Guermazi A, Roemer FW, Dufour AB, Gensure RH, Hannan MT. "Association of flat feet with knee pain and cartilage damage in older adults." Arthritis Care Res (Hoboken). 2011 Jul;63(7):937-44. doi: 10.1002/acr.20431.