Suggested AFO / Orthoses

Richie Brace

Model: G120

Adult Acquired Flatfoot
Model: P2

Overlap Free Motion
Model: A250

Posterior Tibial Tendon Dysfunction

ICD 10 - M76.829

The posterior tibial tendon functions as a large basis of support for the structures of the foot. The posterior tibial tendon attaches the calf muscle to bones within the foot. Dysfunction of the tendon leads to instability of the arch, which is also known as adult acquired flatfoot. Usually, this flatfoot condition is unilateral, but for some people it can develop in both feet.

Posterior tibial tendon dysfunction can be due to acute injuries and falls or poor biomechanics and repetitive use. This condition is more common in women and those past the age of 40.


  • Pain and/or swelling along the inside foot in places near the tendon during early stage progression
  • Increased pain during physical activity and high-impact sports
  • Pain on the outside of ankle during later stage progression
  • Instability of the ankle or the arch of the foot
  • Flattening of the arch
  • Outward rotation of the toes


To confirm a diagnosis, a clinician will perform a physical examination looking for swelling, pain and changes in the morphology of the foot driven by tendon dysfunction.


Most patients can be treated with orthotics, braces and physical therapy. NSAIDs, icing and rest are also likely to alleviate pain. Surgery is a possibility if there’s no reduction in pain and very little repair of the foot after 6 months of treatment with orthotics, braces and physical therapy. Surgical reconstruction is a last resort option since treatment can be quite complex.


When you delve into the anatomy of tibialis posterior you quickly realise that this is a super important muscle!⁣

An anatomical dissection study analysed 41 specimens to determine the course and variation of the tendon attachments.⁣

This study showed that all specimens showed attachment at the navicular. Distal to the navicular, the tendon continues to spread further into several tendon slips. They found between 2-8 insertion points in total:⁣

Navicular (100%)⁣
- Medial cuneiform (80.5%)⁣
- Intermediate cuneiform (19.5%)⁣
- Lateral cuneiform (92.7%)⁣
- Cuboid (46.3%)⁣
- Calcaneus (12.2%)⁣
- Bases of all metatarsals (80.5%)⁣

With that many insertion points on the foot, it’s no wonder we want to make sure that it’s functioning properly. ⁣