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photos by Sydney Foot and Ankle Surgeon Damien Lafferty

An astute podiatrist referred this patient to me recently with a history of treatment for supposed posterior tibial tendon dysfunction (PTTD). The patient has been symptomatic on the medial navicular region radiating slightly proximal. She had been treated for PTTD for many months, including rest, orthotics and physiotherapy with no poor results by another previous practitioner. On X-ray and ultrasound, it was noted there was NO tenosynovitis, NO intra-substance tear and NO tendinopathy in the length of the tendon.

What was noted was a large type 2 accessory navicular with associated insertional tendonosis. The patient’s main symptoms were directly on the prominence of the accessory navicular. Tests for PTTD or as it is better named Adult Acquired Flatfoot were negative, with resupination of the rearfoot occurring on toe stance. The patient, as the referring podiatrist has noted, was suffering from irritation of the syndesmosis where the accessory bone inserts onto the navicular, with some associated insertional tendonosis.

A large accessory navicular can decrease the effectiveness of the pull of the tendon, exaggerating excess pronation and creating a cycle of poor mechanics and hard to control symptoms. The radiographs show Meary’s angle is increased as is the uncovering of the talonavicular joint, which are just two of the measurements of excess pronation/pes planus/flat feet.

This is a huge topic and could cover many hours of discussion, however, my reason for this post is to shine a light on the proper assessment of the adult acquired flat foot. If the patient decides to move to surgery, it is much more straightforward and very different surgery to a later stage adult acquired flat foot (PTTD). I have discussed removing the accessory navicular, trimming the medial hypertrophied navicular and inserting a HyProCure, with platelet-rich plasma (PRP) injected into the insertional point after suturing. This is relatively quick surgery with small incisions and again relatively quick recuperation. No fusions, no medial calcaneal slide procedures and no extended recuperation.

If you have any specific questions or would like to discuss similar cases, feel free to contact me.

Also read:
Accessory navicular with pes planus
Post-operative pes planus/flat feet/excess pronation
Pes planus
Hyperpronation cure

(This content is intended for healthcare professionals only)