Tibialis Posterior Tendinopathy (PTTD)
Tibialis posterior tendon
dysfunction (PTTD), also known as posterior tibial tendonitis, is the most common cause of an acquired flat foot in adults. It develops gradually rather than from a single injury, which is why it’s often mistaken for general ankle ache or “getting older” until the arch has already started to change shape. At RS Podiatry Clinic in Hampton-in-Arden, we see this regularly in patients from Solihull, Meriden, Coventry and the wider region. Early, accurate assessment makes a genuine difference to how well it responds to treatment.
What's actually happening
The tibialis posterior tendon runs behind the inside of the ankle and attaches mainly onto the navicular bone, where it supports the arch and helps lock the foot into a stable position as you push off through each step. When the tendon is overloaded over time, whether through age-related degeneration, being carried on an already low or over-pronated arch, body weight, or inflammatory joint conditions, it begins to fail structurally rather than snap suddenly. As the tendon lengthens and weakens, the arch loses its support, which increases the load on the tendon further. It’s a self-feeding cycle, which is why PTTD tends to progress rather than plateau if it isn’t addressed.
How PTTD tends to present
In the earlier stages, patients usually notice pain and swelling along the inside of the ankle, worse with walking, standing, or stairs, while the arch itself may still look relatively normal. As it progresses, the arch visibly flattens, the heel rolls outward, and in some cases the front of the foot drifts outward too. Pain can also shift to the outside of the ankle as the altered heel position causes impingement in that area. One of the simplest things we check is whether you can rise onto one leg on tiptoes without difficulty; struggling to do so on the affected side is a reliable sign that the tendon isn’t doing its job properly.
Why proper assessment matters
Because PTTD sits on a spectrum from mild tenosynovitis to a fixed, deformed foot, treatment depends heavily on which stage you’re at, and that’s not something that can be judged from symptoms alone. We start with a full biomechanical and gait assessment, using RS Footscan pressure analysis where relevant to;
- Understand how you’re loading the foot
- How flexible or fixed any arch change already is
- What’s driving the problem in your case specifically
Where there’s diagnostic uncertainty, or the tendon’s condition will change the management plan, ultrasound imaging may be arranged. We’ll also ask about the pattern and history of your symptoms, because a sudden onset after a specific incident, or joint symptoms elsewhere in the body, point toward a different problem and a different plan.
How we treat PTTD at RS Podiatry
For most patients, particularly in the earlier stages, treatment centres on taking load off the tendon while it’s irritable, supporting the arch mechanically so the tendon isn’t managing that load alone, and then rebuilding the tendon’s capacity through targeted, staged exercise.
Custom orthotics, built from your Footscan data, reduce the pronation forces the tendon has to resist with every step, and they’re one of the better-supported interventions for stage I and II PTTD. Alongside this, we prescribe rehabilitation and exercise programmes that progressively load the tibialis posterior and surrounding muscles once symptoms allow, following similar principles to tendon rehab elsewhere in the body. Laser therapy can be a useful adjunct for calming pain and swelling in an acutely irritable tendon. Footwear advice matters more here than in most conditions we see, since a shoe that lets the midfoot collapse works against everything else the plan is trying to achieve.
Where the tendon and joint alignment have become more structurally compromised, more supportive bracing may be needed, and we’ll have an honest conversation with you about whether a surgical opinion should form part of the plan. We would rather tell you that clearly than suggest a boot and some exercises will resolve a foot that has already changed shape.
PTTD often overlaps with, or gets confused with, flat feet and over-pronation generally, as well as other causes of heel and ankle pain, so a proper differential assessment is part of getting the plan right from the outset rather than treating the arch in isolation.
Benefits of specialist podiatry assessment
If your arch has changed shape, you’ve got a persistent ache on the inside of your ankle, or one side struggles noticeably more than the other on a heel raise, it’s worth having it looked at rather than waiting to see if it settles. Book a musculoskeletal assessment at RS Podiatry Clinic in Hampton-in-Arden, and we’ll tell you plainly what’s going on and what the right next step looks like.