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Health condition · Clinically reviewed

Accessory navicular, a symptomatic normal variant — orthoses, injection and Kidner procedure.

An accessory ossicle on the medial navicular. Present in up to 15% of the population; only some become symptomatic. Modern stratified care: orthoses and immobilisation for symptomatic types II and III; Kidner procedure for refractory cases.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Every claim is checked against BOFAS, NICE MSK guidance and specialist society standards you can see at the end.

  • 03

    Current for 2026

    Reflects current UK guidance on orthoses, image-guided injection and the modified Kidner procedure.

Key facts

Accessory navicular at a glance.

The essentials, in plain English — what an accessory navicular is, why some become symptomatic, and what the evidence says actually helps.

  • Definition

    An accessory navicular is an accessory ossicle on the medial aspect of the navicular bone — a normal anatomical variant, not a disease.

  • How common

    Present in up to 15% of the population; the majority remain asymptomatic through life.

  • Classification

    The Geist classification describes three types (I–III) based on size, shape and relationship to the navicular.

  • Which type hurts

    Type II is most commonly symptomatic — a synchondrosis with the navicular that can become inflamed or mobile.

  • Tendon relationship

    The ossicle sits adjacent to the tibialis posterior insertion, so symptoms often overlap with PT tendon problems.

  • When surgery is needed

    A modified Kidner procedure — excision with tibialis posterior tendon advancement — is used for refractory cases.

Why this guide matters

A normal variant that only sometimes hurts.

Most accessory naviculars are silent. When they do become symptomatic, a stratified plan — footwear, orthoses, injection, then surgery — settles the vast majority.

  • Not every accessory navicular is a problem

    Up to 15% of people have one and never know — imaging findings alone do not warrant treatment.

  • Type matters

    Geist Type II ossicles — with a synchondrosis to the navicular — are the ones most likely to cause pain.

  • Kidner when things stall

    A modified Kidner procedure is the surgical gold standard for refractory cases — excision plus PT tendon advancement.

How the diagnosis is made

From painful midfoot to a clear plan.

The steps a UK GP or podiatrist will normally follow, in order — so you know what to expect and why.

  1. 01

    Recognising

    Symptom and activity history

    Medial midfoot pain, aggravated by activity, tight footwear or a coexisting flat foot — the story usually points the way.

  2. 02

    Recognising

    Palpation of medial navicular

    A tender bony prominence over the medial navicular is the classic finding — often with local swelling.

  3. 03

    Recognising

    Weight-bearing X-ray of foot

    A standing AP and oblique X-ray confirms the ossicle, classifies it by Geist type and assesses associated flat foot.

  4. 04

    Confirming

    MRI foot

    Reserved for uncertain or refractory cases — shows bone marrow oedema across the synchondrosis and assesses the tibialis posterior tendon.

  5. 05

    Confirming

    Assess coexisting flat foot

    A pes planus deformity often coexists and changes the treatment plan — arch support and PT tendon rehab become central.

  6. 06

    Managing

    Assess PT tendon function

    Single-heel-rise test and resisted inversion — weakness or pain suggests coexisting tibialis posterior dysfunction.

  7. 07

    Managing

    Foot & ankle surgery consultation

    For refractory pain, mobile Type II ossicles or coexisting PT tendon dysfunction — Kidner procedure discussion.

Typical timeline: 2–4 weeks from first appointment to a settled plan.

Symptoms

What a symptomatic accessory navicular actually feels like.

The pattern is more telling than any single symptom — medial midfoot pain, a bony prominence and aggravation by tight shoes or activity.

  • Medial midfoot pain

    A localised ache over the inside of the midfoot, worse with activity and tight shoes — the most common presenting symptom.

  • Local swelling

    Soft-tissue swelling directly over the medial navicular, sometimes with warmth after activity.

  • Bony prominence

    A visible or palpable bony bump on the inside of the foot — the ossicle itself, tender to touch.

  • Coexisting PT tendon symptoms

    Pain along the tibialis posterior tendon and weakness on heel rise — because the ossicle sits at its insertion.

  • Coexisting flat foot

    A dropped medial arch (pes planus) commonly accompanies a symptomatic accessory navicular and drives symptoms.

  • Aggravated by tight shoes

    Narrow or stiff footwear presses directly on the ossicle — a reliable trigger for symptom flares.

  • Recurrent symptoms

    Episodes of medial midfoot pain that come and go with activity, footwear changes or prolonged standing.

  • Red flag

    Acute painful ossicle after trauma with tibialis posterior tendon rupture — urgent foot and ankle surgical review.

Treatment

How a symptomatic accessory navicular is treated in the UK.

A staged approach — footwear, orthoses and physiotherapy first, then image-guided injection, with the modified Kidner procedure reserved for refractory disease.

  • Wider / softer footwear

    Room in the toe box and soft uppers stop shoes pressing on the ossicle — often the fastest way to settle symptoms.

  • Medial arch support orthosis

    A supportive orthosis with a medial arch post offloads the ossicle and the tibialis posterior tendon.

  • Boot immobilisation for acute flare

    A walking boot for 2–4 weeks in a genuine flare rests the synchondrosis and settles bone marrow oedema.

  • NSAIDs

    A short course of anti-inflammatories can help with an acute flare, alongside footwear and load modification.

  • Physiotherapy (PT tendon)

    Targeted tibialis posterior loading and calf stretching — particularly important where PT dysfunction coexists.

  • Ultrasound-guided injection

    Image-guided steroid to the symptomatic synchondrosis can settle refractory pain and delay or avoid surgery.

  • Simple ossicle excision

    Removal of the accessory bone alone — appropriate where the tibialis posterior tendon is intact and functioning well.

  • Modified Kidner procedure (excision + PT tendon advancement)

    The gold-standard surgical option for refractory Type II ossicles — excision with tibialis posterior tendon advancement.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, podiatrist or foot and ankle team knows your history and can tell you which parts apply to you. If in doubt, get seen.

  • British Orthopaedic Foot and Ankle Society (BOFAS). Patient information and clinical standards.

  • NICE. Musculoskeletal guidance — assessment and management of foot pain.

  • Royal College of Podiatry. Guidance on midfoot pain and orthotic prescription.

  • American Orthopaedic Foot & Ankle Society (AOFAS). Accessory navicular clinical resources.

Red flags

When medial foot pain is not just the ossicle.

Most symptomatic accessory naviculars settle with conservative care. These are the situations where something more serious needs to be considered.

  • Acute PT tendon rupture with symptomatic ossicle

    Sudden loss of arch height, pain and inability to heel-rise with a known accessory navicular — urgent surgical review.

  • Post-op PT dysfunction

    New weakness or loss of arch height after Kidner surgery — contact the surgical team promptly.

  • Post-op non-union

    Persistent pain months after excision or Kidner procedure may reflect non-union — imaging and orthopaedic review.

  • Post-op wound complication

    Increasing redness, discharge, warmth or fever at the surgical site — same-day surgical review.

  • Recurrent symptoms

    Symptoms returning after settling — reassess footwear, orthoses and consider re-imaging.

  • Failed conservative therapy

    Ongoing pain despite 3–6 months of footwear change, orthoses and physiotherapy — foot and ankle surgery referral.

  • Adult acquired flat foot with symptomatic ossicle

    A collapsing arch with a symptomatic accessory navicular changes the plan — reconstructive surgery may be needed.

  • Missed medial malleolus injury

    Acute medial ankle pain attributed to the ossicle can mask a medial malleolus fracture — image if trauma-related.

  • Post-op tendon retear

    Sudden pain and loss of function after Kidner surgery may reflect a retear of the advanced tendon — surgical review.

Living with it

A quiet variant, manageable day to day.

Four things that make the biggest difference — footwear, orthoses, tendon rehab and patient review.

A quiet reminder

Consistency beats intensity, every time.

Small, steady changes — kept up for months — do more than a heroic week that does not last.

  1. 01 Footwear

    Choose forgiving shoes

    Wide toe box, soft uppers and a supportive arch — the single biggest day-to-day lever for a symptomatic accessory navicular.

  2. 02 Orthoses

    Use your arch support

    A medial arch orthosis takes load off the ossicle and the tibialis posterior tendon — wear it consistently, not just on bad days.

  3. 03 Rehab

    Look after the PT tendon

    Tibialis posterior strengthening and calf stretching protect the tendon that shares real estate with the ossicle.

  4. 04 Reviews

    Reassess in weeks, not days

    Give footwear and orthoses 6–12 weeks before deciding they have not worked — then consider injection or surgical review.

Frequently asked

Everything we get asked about the accessory navicular.

Quick answers on orthoses, injection, the Kidner procedure and when to seek help.

  • What is an accessory navicular?

    It is an accessory ossicle — an extra small bone — on the medial (inner) side of the navicular bone in the midfoot. It is a normal anatomical variant, present in up to 15% of the population, and most people who have one never know.

  • Why has mine started to hurt?

    Symptoms usually come from irritation of the synchondrosis (the cartilage bridge between the ossicle and the navicular), pressure from tight shoes, or coexisting problems with the tibialis posterior tendon or a flat foot. A Type II ossicle is the type most likely to become symptomatic.

  • Do I need surgery?

    Usually not. Most symptomatic accessory naviculars settle with wider softer footwear, a medial arch support orthosis, physiotherapy, and — if needed — a short course of NSAIDs or an image-guided steroid injection. Surgery is reserved for refractory cases.

  • What is the Kidner procedure?

    It is the classic surgical treatment for a symptomatic accessory navicular — excision of the ossicle combined with advancement and reattachment of the tibialis posterior tendon. The modified Kidner procedure is the current gold standard for refractory Type II cases.

  • Will it come back after surgery?

    Recurrence of the bony ossicle itself does not happen — it has been removed. But persistent or recurrent symptoms can occur, particularly if a coexisting flat foot or tibialis posterior tendon dysfunction was not fully addressed at the time of surgery.

  • What is the red flag I should not ignore?

    A sudden loss of arch height, severe medial foot pain and inability to heel-rise — particularly after trauma — can reflect an acute tibialis posterior tendon rupture, and needs urgent foot and ankle surgical review.

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