I now have enough information to give a thorough clinical answer. Here is the complete assessment:
Clinical Assessment: Medial Midfoot Pain - 26-year-old Female
Anatomical Location Identified
The patient is pointing to the navicular tuberosity on the medial aspect of the midfoot - the bony prominence where the tibialis posterior tendon primarily inserts. This is a very specific and clinically significant zone.
Top Differential Diagnoses
1. Accessory Navicular Syndrome (Most Likely) ⭐
This is the leading diagnosis given her age, sex, and exact pain location.
What it is: An accessory navicular (os naviculare) is a normal anatomical variant found in up to 12% of the general population. The posterior tibial tendon typically inserts into this accessory bone rather than the main navicular. It is closely associated with flatfoot deformity.
Why it fits this patient:
- Pain is precisely at the medial navicular tuberosity - the exact location of the accessory bone
- Long walking = classic overuse trigger (the tendon pulling on the accessory ossicle during prolonged loading)
- Heel raise pain = the tibialis posterior is maximally active during push-off/heel raise; pain during this motion is a hallmark sign
- Young females are disproportionately affected
- Often associated with a mild pes planus (flat arch)
Key exam finding: Point tenderness directly over the medial navicular prominence; look for a palpable bony bump there. Check arch height (flatfoot association).
Miller's Review of Orthopaedics, 9th Ed — "Symptoms usually include medial arch pain with overuse and tenderness over prominent os."
2. Tibialis Posterior Tendinopathy / Insertional Tendinitis
Pain at the tendon's insertion onto the navicular from repetitive loading. Clinically very similar to accessory navicular syndrome and often coexists.
Discriminating test: Single-leg heel raise test - ask the patient to rise onto the toes on the affected foot alone. In significant tibialis posterior insufficiency, she will be unable to complete this or will report sharp pain at this spot. Given she already reports pain on heel lifting, this tendon is under stress.
Rheumatology 2-Volume Set, Elsevier 2022 - "A useful diagnostic test is to ask the patient to stand on tiptoe using only the affected side. In the presence of TPD, fewer than half of patients will be able to maintain single-limb standing."
3. Navicular Stress Fracture (Must Exclude)
A hairline fracture through the navicular bone - seen in young active females, especially with increased walking/running activity.
- Presents as diffuse midfoot pain, worsening with activity
- Often not visible on plain X-ray early on
- High-risk fracture - carries significant morbidity if missed
- Requires MRI or bone scan to diagnose early
Rheumatology 2-Volume Set - "Stress reactions and stress fractures can arise at sites of high mechanical demand. The navicular and metatarsals are the most common sites of stress fracture...often not visible on plain X-rays, especially in the early stages."
4. Plantar Fasciitis (Less Likely at This Location)
Typically causes heel pain with first steps in the morning, not midfoot tenderness over the navicular. Can be ruled out by the precise location and symptom pattern described.
Recommended Investigations
| Test | Purpose |
|---|
| Weight-bearing X-ray foot (AP, lateral, external oblique/supination view) | Detect accessory navicular, flatfoot, arthritis |
| MRI foot | Gold standard - identifies accessory navicular fibrocartilaginous union, tendon pathology, bone marrow edema (stress reaction/fracture) |
| Ultrasound | Bedside assessment of tibialis posterior tendon thickening or tear |
The external oblique (supination oblique) radiograph is specifically helpful to visualize the accessory navicular.
Management Summary
Conservative (first line - >80% respond):
- Activity modification and relative rest from prolonged walking
- Medial arch orthosis / UCBL orthosis (University of California Biomechanics Laboratory) to support the arch and offload the navicular
- Supportive footwear with good arch support
- NSAIDs for pain/inflammation
- Below-knee cast immobilization for 6 weeks if initial measures fail
- Physiotherapy focusing on tibialis posterior strengthening
Surgical (if conservative fails after 3-6 months):
- Kidner procedure - excision of the accessory navicular with repair and advancement of the posterior tibial tendon onto the native navicular
- Recent evidence (Wang et al., JMNI 2024, PMID 38825998) also supports tibial posterior tendon reconstruction in young athletes with good outcomes
- A 2025 RCT (Pu et al., BMC Musculoskelet Disord, PMID 40382595) showed customized orthoses significantly improve foot morphology and pressure distribution in accessory navicular syndrome
Clinical Bottom Line
This 26-year-old woman with point tenderness at the medial navicular tuberosity, pain on prolonged walking, and pain on heel raise has a classic presentation of accessory navicular syndrome with likely tibialis posterior tendon involvement. A navicular stress fracture must be excluded with imaging.
Next step: Weight-bearing foot X-ray (AP + lateral + external oblique) as first-line imaging. If X-ray is negative and symptoms persist, proceed to MRI.
Disclaimer: This analysis is for clinical reference only. A formal in-person examination and appropriate imaging by a qualified clinician are required before diagnosis or treatment.