What is Adult-Acquired Flatfoot?
Adult-acquired flatfoot, also known as posterior tibial tendon dysfunction (PTTD), is a progressive condition where the arch of the foot gradually collapses. Unlike congenital flatfoot, which is present from birth, this type develops later in life. The foot’s arch is supported by a complex network of tendons, ligaments, and bones that work together as a natural shock absorber. When this support system weakens, the arch can flatten, causing the foot to lengthen and widen.
Primary Causes of Collapsing Arches
Several factors contribute to the gradual flattening of the feet in adulthood:
- Aging: As we get older, the tendons and ligaments throughout our body lose elasticity and can stretch out. The posterior tibial tendon, which is the primary stabilizer for the arch, is particularly susceptible to this wear and tear over time.
- Posterior Tibial Tendon Dysfunction (PTTD): This is the most common cause of adult-acquired flatfoot. The posterior tibial tendon connects the calf muscle to the bones on the inside of the foot and ankle. When this tendon becomes inflamed or torn due to overuse or degeneration, it can no longer support the arch, causing it to collapse.
- Obesity and Weight Gain: Extra body weight puts excessive and prolonged stress on the feet, including the arches. This constant pressure can cause ligaments to stretch and weaken, leading to the arch's collapse.
- Pregnancy: Hormonal changes during pregnancy, specifically the increased production of elastin and relaxin, can cause ligaments to loosen, including those in the feet. This, combined with the added body weight, can lead to fallen arches.
- Medical Conditions: Certain inflammatory diseases, such as rheumatoid arthritis, can attack and damage the connective tissues in the foot. Neurological conditions, like diabetes-related neuropathy (Charcot foot), can cause nerve damage and bone deterioration that lead to arch collapse.
- Injury and Trauma: A foot or ankle injury, such as a fracture or sprain, can damage the ligaments and tendons that support the arch. If not treated and healed properly, this can lead to a gradual flattening of the foot over time.
Symptoms and Stages of Acquired Flatfoot
Adult-acquired flatfoot can present with a variety of symptoms that can progress through different stages.
- Stage 1: Pain and swelling are present along the posterior tibial tendon, but there is no noticeable collapse of the arch.
- Stage 2: The arch begins to flatten, and the foot may appear to roll inward. The foot is still flexible and can be manually corrected by a doctor.
- Stage 3: The foot becomes rigid, and the deformity can no longer be corrected. Arthritis may develop in the foot joints.
- Stage 4: The deformity extends to the ankle joint, causing additional pain and alignment issues.
Symptoms can also include fatigue in the feet and legs, pain spreading to the lower leg or outer foot, and an inability to stand on tiptoes on the affected foot.
Treatment Options for Acquired Flatfoot
Treatment depends on the cause and severity of the condition. For less severe cases, non-surgical options are often successful.
- Orthotic devices or bracing: Over-the-counter or custom-made inserts can provide arch support, reposition the foot, and relieve pain. In more advanced cases, an ankle brace or walking boot may be necessary for immobilization.
- Physical therapy: Stretching and strengthening exercises can help rehabilitate weakened tendons and muscles.
- Medication: Nonsteroidal anti-inflammatory drugs (NSAIDs) can be used to manage pain and inflammation.
- Activity modification: Limiting high-impact activities like running and jumping and choosing low-impact alternatives can reduce stress on the feet.
- Weight management: For overweight individuals, losing weight can significantly reduce the pressure on the feet and slow the progression of the deformity.
- Surgery: If conservative treatments fail or the condition is severe, surgical reconstruction may be necessary to correct the deformity, repair tendons, or fuse bones.
Comparison Table: Flexible vs. Rigid Flatfoot
| Feature | Flexible Flatfoot (Common in children, sometimes continues to adulthood) | Rigid Flatfoot (Develops in adulthood, often due to injury or disease) |
|---|---|---|
| Arch Appearance | Visible when sitting or standing on tiptoes; disappears when standing. | No arch visible at any time, whether sitting or standing. |
| Foot Movement | The foot is still flexible and can be manipulated by a professional. | The foot is stiff and difficult to move from side to side. |
| Cause | Can be hereditary or due to loose ligaments in childhood that don't tighten. | Most commonly caused by damage to the posterior tibial tendon, arthritis, or trauma. |
| Progression | Often improves with age but can worsen if supportive tissues stretch. | Appears in adulthood and tends to worsen over time, especially if untreated. |
| Treatment Focus | Primarily conservative with arch supports, stretching, and physical therapy. | Treatment may start with conservative methods but more often requires bracing or surgery. |
Conclusion
Feet getting flatter is a common and often gradual process, but it's important to understand the underlying causes to seek the right treatment, especially if you experience pain or changes in your walking pattern. Conditions like posterior tibial tendon dysfunction are a major culprit, often exacerbated by factors such as aging, weight gain, and past injuries. For those with noticeable arch collapse or persistent discomfort, a podiatric evaluation is recommended to prevent further progression and manage symptoms effectively with orthotics, physical therapy, or other interventions. Timely and appropriate care can help maintain mobility and reduce pain associated with acquired flatfoot.
