Medically Reviewed | Dr. Tom Biernacki, DPM | Board-Certified Podiatric Surgeon | Balance Foot & Ankle, Michigan
Quick Answer: What causes pain from an accessory bone in the foot?
What Are Accessory Bones in the Foot?
Accessory bones are small extra bones present at birth as anatomical variants — bones that failed to fuse with the primary bone during development. They’re far more common than most people realize: approximately 10–25% of the population has at least one accessory bone in the foot or ankle, most of which are completely painless and incidentally discovered on X-rays taken for other reasons.
The most clinically significant accessory bones are the os tibiale externum (also called accessory navicular — on the inner midfoot), the os trigonum (behind the ankle), the os peroneum (near the base of the 5th metatarsal and cuboid), and the os vesalianum (near the 5th metatarsal base). Each sits adjacent to a specific tendon or joint and can become painful when that area is stressed or traumatized.
Pain from an accessory bone typically follows one of three patterns: gradual onset with increased activity (especially in adolescents), acute onset after a twisting ankle injury (the accessory bone’s cartilaginous connection is disrupted), or chronic mechanical irritation from shoe pressure directly over the bony prominence.
Os Tibiale Externum (Accessory Navicular): Most Common
The os tibiale externum (accessory navicular) is present in approximately 10–14% of the population and is the most common symptomatic accessory bone in the foot. It sits on the inner side of the navicular bone, where the posterior tibial tendon attaches. The prominence it creates is often visible as a bump on the inner midfoot.
Symptoms include medial midfoot pain with activity, a visible and tender bony prominence on the inner foot, flat foot appearance (because the tibialis posterior tendon inserts on the accessory bone rather than the navicular itself, the arch pull is less effective), and pain with palpation directly over the bump.
Conservative treatment includes activity modification, arch support orthotics (which reduce tibialis posterior tension), ice, anti-inflammatory medication, and sometimes a short period of immobilization in a boot during acute flares. If conservative care fails after 3–6 months, surgical excision of the accessory navicular (Kidner procedure) with tibialis posterior tendon reattachment is very effective.
Os Trigonum: The Dancer’s Accessory Bone
The os trigonum is present in approximately 7–25% of the population and sits behind the ankle joint, adjacent to the posterior talus. It’s typically asymptomatic unless the foot is repeatedly forced into extreme plantarflexion (pointing down) — which explains why it disproportionately affects ballet dancers, gymnasts, soccer players, and swimmers.
Os trigonum syndrome presents as posterior ankle pain with plantarflexion — pain at the back of the ankle when pointing the foot. It can mimic Achilles tendon pain but is located more deeply and is reproduced by passive forced plantarflexion.
Conservative treatment includes activity modification, physical therapy, cortisone injection into the posterior ankle joint, and footwear modification. For dancers and athletes who can’t avoid forced plantarflexion, surgical excision of the os trigonum — now commonly performed arthroscopically — provides excellent relief with quick return to activity.
Dr. Tom's Product Recommendations
PowerStep Pinnacle Insoles
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Essential for accessory navicular syndrome — provides arch support that reduces tibialis posterior tendon load, directly addressing the mechanism of pain.
Dr. Tom says: “PowerStep arch support is my first recommendation for accessory navicular pain. It reduces the biomechanical stress on the os tibiale externum significantly.”
Accessory navicular, medial foot pain, tibialis posterior tendon support
Post-surgical immobilization period — use boot/cast as directed
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Doctor Hoy’s Natural Pain Relief Gel
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Topical analgesic for accessory bone pain flares. Apply directly over the painful prominence for localized relief.
Dr. Tom says: “Doctor Hoy’s provides effective topical relief for the localized pain over an accessory navicular or os trigonum without the need for oral medications.”
Accessory bone prominence pain, activity-related flares, post-activity soreness
Open skin or bursitis with skin breakdown
Disclosure: We earn a commission at no extra cost to you.
✅ Pros / Benefits
- Most accessory bones are asymptomatic — no treatment needed
- Conservative care resolves symptoms in majority of cases
- Surgical excision is safe and effective when conservative care fails
- Arthroscopic surgery for os trigonum allows quick recovery
❌ Cons / Risks
- Often misdiagnosed as ankle sprain or other conditions
- Conservative care may require 3–6 months of patience
- Surgery requires 4–8 weeks recovery
- Re-excision occasionally needed if fibrous tissue regrows
Dr. Tom Biernacki’s Recommendation
Accessory navicular syndrome is something I see frequently, particularly in teenage athletes and active adults. The good news is that most patients do very well with orthotics and activity modification. For those who don’t — and especially active patients who can’t live with the activity restrictions — surgical removal of the accessory bone is a straightforward procedure with excellent results.
— Dr. Tom Biernacki, DPM | Board-Certified Podiatric Surgeon | Balance Foot & Ankle
Frequently Asked Questions
Is an accessory bone the same as a fracture?
No. Accessory bones are present from birth and have smooth, rounded edges on X-ray. Fractures have irregular, jagged edges and are associated with a specific injury event.
Do accessory bones in the foot need surgery?
Most don’t. The majority are asymptomatic and require no treatment. Symptomatic accessory bones that fail conservative care are candidates for surgical excision.
Can an accessory navicular cause flat feet?
Yes. If the posterior tibial tendon inserts on the accessory navicular rather than the main navicular, the arch-pulling effect is reduced, contributing to a flat foot appearance.
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📞 (810) 206-1402 Book Online →When Shoes Aren’t Enough — Dr. Tom’s Top 9 Orthotics
About 30% of patients I see for foot pain need MORE than a great shoe — they need a structured insole. Below: my complete 2026 orthotic ranking with pros, cons, and the specific patient I’d give each one to.
★ DR. TOM’S COMPLETE 2026 ORTHOTIC RANKING
9 Best Prefab Orthotics by Use Case
PowerStep, CURREX, Spenco, Vionic, and Tread Labs — every orthotic I’ve fitted to thousands of patients across both Michigan offices. Each card includes pros, cons, and the specific patient I’d give it to. Real Amazon ratings, review counts, and prices below.
Best All-Purpose Orthotic for Most Patients
Semi-rigid arch shell + dual-layer cushion + deep heel cup. The orthotic I’ve fitted to more patients than any other for 15 years. APMA-accepted. Trim-to-fit design works in athletic shoes, casual shoes, and most work boots.
✓ Pros
- Semi-rigid arch shell provides true biomechanical correction
- Deep heel cup centers the heel and reduces lateral instability
- Dual-layer cushion (top + bottom) lasts 9-12 months daily wear
- Available in 8 sizes for precise fit
- APMA-accepted and clinically validated
- APMA-accepted with superior cushioning versus rigid alternatives
✗ Cons
- Too thick for most dress shoes (use ProTech Slim instead)
- Some break-in period required (3-7 days for arch tolerance)
- Not enough correction for severe pes planus or rigid pes cavus
Dr. Tom’s Recommendation: If a patient has run-of-the-mill plantar fasciitis, mild flat feet, or arch fatigue, this is the first orthotic I try. Better value than most premium alternatives for 90% of patients, which is why it’s the first orthotic I reach for in the clinic. Sub-$50 typically.
Maximum Motion Control · Flat Feet & Severe Over-Pronation
PowerStep’s most aggressive stability orthotic. Adds a 2°-7° medial heel post on top of the standard PowerStep platform — designed specifically for flat-footed patients and severe pronators who need real corrective force.
✓ Pros
- 2°-7° medial heel post adds aggressive pronation control
- Same trusted PowerStep arch shell, more correction
- Built specifically for flat-foot biomechanics
- Excellent for posterior tibial tendon dysfunction (PTTD)
- Removable top cover for cleaning
✗ Cons
- Too aggressive for neutral-arch patients
- Needs longer break-in (10-14 days) due to stronger correction
- Adds 2-3 mm of stack height — won’t fit slim dress shoes
Dr. Tom’s Recommendation: When a patient comes in with significant flat feet AND symptoms (heel pain, arch pain, knee pain), the Original PowerStep isn’t aggressive enough. The Maxx is what gets prescribed. About 25% of my flat-footed patients end up here.
Low-Profile · Fits Dress Shoes & Narrow Casuals
3 mm slim profile with podiatrist-designed tri-planar arch technology. Engineered specifically to fit inside dress shoes, oxfords, loafers, and women’s flats without crowding the toe box. Vionic was founded by an Australian podiatrist.
✓ Pros
- 3 mm slim profile (vs 7-10 mm for standard orthotics)
- Tri-planar arch technology adds support without bulk
- Built-in deep heel cup despite slim design
- Fits dress shoes WITHOUT having to remove the factory insole
- Trim-to-fit · APMA-accepted
✗ Cons
- Less arch support than full-volume orthotics
- Top cover wears faster than thicker alternatives
- Not enough correction for severe foot deformities
Dr. Tom’s Recommendation: My default when a patient says ‘I need orthotics but I have to wear dress shoes for work.’ Slim enough to fit in oxfords and pumps without the heel sliding out. The single highest-impact change you can make for office workers with foot pain.
Built-In Metatarsal Pad · Morton’s Neuroma · Ball-of-Foot Pain
Standard Pinnacle orthotic with a built-in metatarsal pad positioned proximal to the metatarsal heads — the exact location that offloads neuromas and metatarsalgia. No need for separate met pads or pad placement guesswork.
✓ Pros
- Built-in met pad eliminates DIY pad placement errors
- Specifically designed for Morton’s neuroma + metatarsalgia
- Same trusted PowerStep arch + heel cup platform
- Top cover protects sensitive forefoot skin
- Faster relief than orthotics + add-on met pads
✗ Cons
- Met pad position is fixed (can’t fine-tune individual placement)
- Some patients with very small or very large feet need custom
- Slightly thicker than the standard Pinnacle
Dr. Tom’s Recommendation: If a patient has Morton’s neuroma, sesamoiditis, or generalized ball-of-foot pain (metatarsalgia), this saves a clinic visit and a prescription. The built-in pad placement is anatomically correct for 80% of feet. Way better than DIY met pads.
Adaptive Dynamic Arch · Athletic & Daily Wear
Currex’s flagship adaptive arch technology — the orthotic flexes with your gait instead of fighting it. Different stiffness zones along the length give you targeted support at the heel, midfoot, and forefoot. Available in three arch heights (low/medium/high).
✓ Pros
- Dynamic flex zones adapt to natural gait cycle
- Three arch heights ensure precise fit
- Lighter than rigid orthotics (no ‘heavy foot’ feel)
- Excellent for runners and athletic walkers
- European podiatric design (German engineering)
✗ Cons
- More expensive than PowerStep Original ($55-65 typically)
- Less aggressive correction than Pinnacle Maxx for severe cases
- Three arch heights means you must self-select correctly
Dr. Tom’s Recommendation: I started recommending Currex three years ago for runners who said PowerStep felt ‘too rigid.’ The dynamic flex zones respect natural gait. Best for active patients who walk 8K+ steps daily and don’t need maximum motion control.
Running-Specific · Heel Strike + Forefoot Strike Compatible
Currex’s purpose-built running orthotic. The midfoot flex zone is positioned for runner’s gait mechanics, with a flared heel cushion for heel strikers and a forefoot rocker for midfoot/forefoot strikers. Tested on 1000+ runners during product development.
✓ Pros
- Designed by German biomechanics lab specifically for runners
- Dynamic arch flexes with running gait (not static like PowerStep)
- Three arch heights (low/medium/high)
- Reduces overuse injury risk in mid-distance runners
- Lightweight (no impact on cadence)
✗ Cons
- Premium price ($60-75)
- Not aggressive enough for severe over-pronators (use Pinnacle Maxx)
- Runner-specific design = less ideal for daily walking shoes
Dr. Tom’s Recommendation: If a patient runs 20+ miles per week and has plantar fasciitis or shin splints, this is the orthotic I prescribe. The dynamic flex zones respect running biomechanics in a way that no rigid PowerStep can match. Pricier but worth it for serious runners.
Cavus Foot & High-Arch Patients
Polyurethane base with a deeper heel cup and higher arch profile than PowerStep — built for cavus (high-arched) feet that need maximum cushion and support. The 5-zone cushioning system addresses the unique pressure points of high-arch feet.
✓ Pros
- Deeper heel cup centers the heel for cavus foot stability
- Higher arch profile fills the void under high arches
- 5-zone cushioning addresses cavus foot pressure points
- Polyurethane base lasts 12+ months
- Available in Wide width
✗ Cons
- Too tall/aggressive for normal or low arches
- Won’t fit slim dress shoes
- Pricier than PowerStep Original
- Some patients find the arch height uncomfortable initially
Dr. Tom’s Recommendation: Cavus foot patients are often misdiagnosed and given low-arch orthotics — that makes everything worse. Spenco’s Total Support has the arch profile that high-arch feet actually need. About 15% of my patients have cavus feet; this is what they wear.
Cushion Layer · Standing All Day · Gel Pressure Relief
NOT a true biomechanical orthotic — this is a cushion insole. But for patients who want gel pressure relief instead of arch correction (or to add ON TOP of factory insoles in work boots), this is the best gel option on Amazon.
✓ Pros
- Genuine gel cushioning (not foam pretending to be gel)
- Targeted gel waves under heel and ball of foot
- Trim-to-fit · works in most shoe types
- Sub-$15 price (most affordable option in this list)
- Massaging texture is genuinely soothing
✗ Cons
- ZERO arch support — this is cushion only
- Won’t fix plantar fasciitis or flat-foot issues
- Compresses faster than PowerStep (4-6 months)
- Top cover wears through in high-mileage applications
Dr. Tom’s Recommendation: I recommend these to patients who tell me ‘I just want my feet to stop hurting at the end of my shift’ and who don’t have a biomechanical issue. Construction workers, factory workers, retail. Pure cushion does the job for them.
Tight-Fitting Shoes · Cycling Shoes · Hockey Skates
Tread Labs Pace insole with firm orthotic arch support for flat feet and plantar fasciitis relief. The replaceable top cover design makes it one of the most durable picks in this guide — backed by a million-mile guarantee and recommended for tight-fitting athletic footwear.
✓ Pros
- Firm orthotic arch support shell (podiatrist-grade)
- Slim profile fits tight athletic footwear
- Lasts 12+ months daily wear
- Excellent for cycling shoes specifically
- Built-in odor-control treatment
✗ Cons
- Premium price ($45-55)
- Less cushion than PowerStep equivalents
- Not as aggressive correction as Pinnacle Maxx for flat feet
- The signature ‘heel cup feel’ takes 1-2 weeks to adapt to
Dr. Tom’s Recommendation: If you’re a cyclist with foot numbness, hot spots, or knee pain — this is the orthotic. The stabilizer cap solves cycling-specific biomechanical issues that no other orthotic addresses. Worth the premium for athletes.
None of these solving your foot pain?
Some patients (about 30%) need custom-molded prescription orthotics. We make 3D-scanned custom orthotics in our Howell and Bloomfield Hills offices — specifically built for your foot mechanics.
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Dr. Tom Biernacki, DPM is a double board-certified podiatrist and foot & ankle surgeon at Balance Foot & Ankle Specialists in Southeast Michigan. With over a decade of clinical experience, he specializes in heel pain, bunions, diabetic foot care, sports injuries, and minimally invasive surgery. Dr. Biernacki is a member of the APMA and ACFAS, and his patient education content on MichiganFootDoctors.com and YouTube has reached over one million views.
- Plantar Fasciitis: Diagnosis and Conservative Management (PubMed)
- Plantar Fasciitis (APMA)
- Diagnosis and Treatment of Plantar Fasciitis (PubMed / AAFP)
- Heel Pain (APMA)
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