M21.4

Clinical Causes: Tendon dysfunction, especially involving the posterior tibial tendon, which supports the arch Obesity, increasing stress on the foot's structures Chronic arthritis, such as rheumatoid arthritis, leading to joint damage Trauma or injury to the foot or ankle Ligament deterioration or dislocation Neuromuscular diseases affecting foot muscle control Age-related weakening of foot-supporting structures

Key Symptoms: Flattened arch visible when standing Pain along the inner side of the foot and ankle Swelling in the medial (inner) ankle area Muscle fatigue after prolonged activity Difficulty standing on tiptoe In some cases, discomfort worsens with activity and improves with rest Balance issues or difficulty walking

Diagnosis Path: Diagnosing acquired flat foot involves a physical examination and medical history review. A healthcare provider may observe the foot from different angles and assess the arch during standing and sitting positions. Imaging tests such as X-rays can help evaluate the structure of the foot bones and the severity of the arch collapse. Sometimes, additional imaging like MRI or ultrasound may be used to evaluate the condition of tendons and soft tissues, particularly the posterior tibial tendon. The diagnosis aims to determine the underlying cause and the extent of deformity.

Treatment Protocols: Management of acquired flat foot depends on severity and underlying causes. Common options include: - **Conservative treatments:** - Custom orthotic devices or shoe inserts to support the arch - Physical therapy focused on strengthening foot and leg muscles - Use of anti-inflammatory medications or ice to reduce inflammation - Weight management to reduce stress on the foot - **Surgical options:** - Tendon repair or transfer if tendons are damaged - Osteotomy procedures to realign the bones - Fusion of joints to stabilize the foot Treatment aims to relieve pain, improve foot function, and prevent progression of deformity. The choice of therapy is individualized based on symptoms and functional limitations.