The posterior tibial tendon runs down the inside of the leg, behind the ankle, and attaches to the underside of the foot. It is the primary dynamic support of the arch — its job is to control pronation and support the foot during the push-off phase of walking and running.
When this tendon becomes overloaded it can develop inflammation, micro-tears and progressive degeneration — a spectrum of injury more accurately described as Posterior Tibial Tendon Dysfunction (PTTD). Without treatment, PTTD can progress from localised tendon pain to acquired flatfoot deformity, where the arch collapses and the condition becomes significantly more complex to manage.
Early intervention is critical. Most cases caught in the early stages respond well to conservative treatment. Advanced stages may require bracing, injection, or surgical referral.
PTTD is classified into stages that guide treatment decisions. Understanding which stage you are at determines the most appropriate approach.
Stage I — Tendinopathy
The tendon is painful and inflamed but still intact and functioning. The arch remains normal. This is the optimal stage to intervene — most cases resolve with conservative treatment.
Stage II — Flexible Flatfoot
The tendon has partially failed, causing progressive arch collapse. The flatfoot deformity is flexible and correctable. Conservative management remains possible but more intensive.
Stage III — Rigid Flatfoot
The arch collapse has become fixed and rigid. Conservative treatment has limited effect at this stage and surgical opinion is typically required.
Overpronation
Excessive inward rolling of the foot places increased tensile load on the posterior tibial tendon with every step, accelerating overload and degeneration.
Training Load Spike
A sudden increase in running, walking, or high-impact activity — particularly on hard surfaces — is a common trigger for acute tendon overload.
Hypermobility
Hypermobile joints increase arch flexibility and reduce the passive stability the tendon must compensate for dynamically.
Calf & Hip Weakness
Weakness in the calf complex and hip stabilisers increases the demand placed on the posterior tibial tendon during single-leg loading activities.
Footwear
Flat, unsupportive footwear reduces arch support and increases the load the tendon must manage during daily activities.
Pain and tenderness along the inner ankle and below the medial malleolus
Swelling on the inside of the ankle or along the tendon
Arch pain or fatigue, particularly after prolonged activity
Difficulty rising onto tiptoe on the affected foot
Progressive flattening of the arch over time
Pain that worsens with walking, running, or standing on uneven surfaces
Diagnosis is primarily clinical. A key diagnostic test is the single-leg heel raise — inability to complete a pain-free single-leg raise is a strong indicator of posterior tibial tendon dysfunction. We also assess foot posture, arch height, pronation pattern, calf strength, and the integrity and pain response of the tendon along its course.
Where the stage of dysfunction needs to be confirmed, or where symptoms are not responding as expected, we can arrange ultrasound or MRI imaging to assess tendon integrity and guide treatment decisions.
Treatment is matched to the stage of the condition. For Stage I and II, conservative management is highly effective when started early. The goal is to reduce tendon load, restore strength, and prevent further arch collapse.
01
Avoid sudden increases in walking or running load — the tendon is sensitive to volume spikes
02
Wear supportive footwear with good arch support — avoid flat, unsupportive shoes and bare feet on hard floors
03
Apply ice to the inner ankle after activity if swollen — 10–15 minutes wrapped in a cloth
04
Complete your prescribed rehabilitation exercises consistently — the tendon responds to progressive loading
6 – 10 weeks
Stage I — Early
Acute tendinopathy caught early typically responds well within 6–10 weeks with consistent rehabilitation and load management.
3 – 6 months
Stage II — Flexible flatfoot
More involved cases with early arch collapse require a longer, more structured programme — typically 3–6 months of active rehabilitation.
Ongoing
Stage III — Advanced
Advanced rigid flatfoot deformity requires specialist orthopaedic input. Conservative management focuses on symptom control and function.
If you have pain or swelling on the inside of the ankle, arch fatigue, or difficulty rising onto your toes, book an assessment promptly. PTTD is a progressive condition — the earlier it is caught, the more effectively it can be managed conservatively.
Do not wait for the arch to collapse. Stage II and III dysfunction is significantly harder to treat and carries a higher risk of requiring surgery. Early diagnosis changes outcomes.
Is this the same as flat feet?
Not exactly. PTTD can cause or worsen flatfoot deformity over time, but many people with flat feet do not have PTTD. The key distinction is whether the posterior tibial tendon is dysfunctional — which is what we assess clinically.
Can I keep running?
In early-stage PTTD, modified activity is often possible with appropriate support and load management. High-impact running is usually reduced during the acute phase. We will guide you on a safe return-to-running plan as the tendon recovers.
Will orthotics fix the problem?
Orthotics are an important part of management — they reduce the load on the tendon and support the arch — but they work best combined with a strengthening programme. Orthotics alone without rehabilitation rarely produce lasting results.
Do I need a scan?
Most cases are diagnosed clinically. Ultrasound or MRI is arranged where the extent of tendon damage needs to be established, symptoms are not improving as expected, or where surgical planning may be needed.
When is surgery considered?
Surgery is considered in Stage III rigid flatfoot or where Stage II has not responded to thorough conservative treatment. We can refer you to experienced orthopaedic surgeons and support you through that process.
Ready to book your assessment?
We'll stage your condition accurately and build a plan to reduce pain, restore strength, and protect your arch long-term.
