Flat Feet (Adult)
Flat feet in adulthood often develop gradually, and unlike flexible flat feet in children, adult-onset flat feet frequently point to an underlying issue that’s worth investigating.
At Emerald Hill Podiatry, we assess how and why your arch has changed, then treat the cause — whether that’s supporting the foot as it is, or addressing a developing tendon or joint problem before it progresses further.
What It Means to Have Flat Feet
Flat feet (pes planus) describes a foot where the arch has flattened, sitting lower than normal or disappearing entirely when standing. This can present as a flexible flat foot, where the arch is visible off the ground but flattens under weight, or a rigid flat foot, where the arch stays flat regardless of position.
Some adults have had flat feet their whole lives without issue, a well-tolerated foot type rather than a condition. What we’re more focused on is adult-acquired flat foot, where a previously normal arch has flattened over time, most often linked to a specific underlying cause and needing a different approach than feet that have simply always been flat.
The Common Culprit Behind Adult Flat Feet
The most common driver is posterior tibial tendon dysfunction (PTTD). The posterior tibial tendon runs along the inside of the ankle and is one of the main structures supporting the arch.
When it weakens, becomes inflamed, or degenerates from repetitive strain, it can no longer hold the arch up, and the foot gradually collapses inward.
Other contributing factors include:
- Ageing and cumulative wear on tendons and ligaments
- Excess body weight, adding ongoing load to arch-supporting structures
- Previous injury, such as an ankle fracture or significant sprain
- Inflammatory joint conditions such as rheumatoid arthritis
- Prolonged high-impact activity without adequate support
- Diabetes, associated with a higher risk of tendon and joint changes
The Signs to Watch For
- A visible change in foot shape, or shoes wearing unevenly along the inside edge
- Pain and swelling along the inside of the ankle
- Aching or fatigue in the arch or ankle after standing or walking
- Difficulty or pain standing on your toes
- The foot rolling inward, with the heel tilting outward when viewed from behind
- Discomfort that worsens through the day and improves with rest
When to See a Podiatrist
You should see a podiatrist if:
Your arch or foot shape has changed over recent months or years
Pain or swelling along the inside of your ankle
Standing or walking has become noticeably more tiring or uncomfortable
You have diabetes or reduced sensation and notice any change in foot shape
Existing flat feet have started feeling painful or unstable when they previously didn't
Catching adult-acquired flat foot early generally leads to a far better outcome than addressing it once significant collapse has occurred.
Get Your Arch Properly Assessed
Reassess Your Step with Emerald Hill
Treatment depends heavily on what’s driving your flat feet and how far it’s progressed, a longstanding, well-tolerated flexible flat foot is managed very differently from an early-stage tendon problem. Options include:
- Custom Orthotics — provides arch support to reduce strain on the posterior tibial tendon, easing pain and slowing further progression
- Biomechanical Gait Assessment — identifies the degree of arch collapse and any compensations elsewhere in your gait, informing orthotics, footwear, and bracing decisions
- Shockwave Therapy (ESWT) — stimulates blood flow and supports tendon repair where chronic inflammation or degenerative changes are present
- EMTT — supports deeper tissue regeneration, often paired with ESWT for persistent tendon-related cases
What to Expect at Your Assessment
Your podiatrist reviews when you first noticed changes to your foot shape, examines arch flexibility and tendon tenderness, and observes your gait to assess the degree of arch collapse. Imaging such as X-ray, ultrasound, or MRI may be used for more advanced cases. From there, you’ll be walked through a treatment plan suited to your stage, with ongoing review since flat feet, particularly PTTD-related cases, benefit from regular reassessment.
