Same-Week Appointments at Balance Foot & Ankle
Three board-certified podiatric surgeons. 950K+ YouTube subscribers. 1,123+ five-star reviews. Howell & Bloomfield Hills, Michigan.
Medically reviewed by Dr. Tom Biernacki, DPM
Board-certified podiatric surgeon | Balance Foot & Ankle
Last reviewed: April 2026
Quick answer: Os trigonum syndrome is posterior ankle pain caused by compression or avulsion of the os trigonum — an accessory bone behind the ankle, present in 7–14% of people. It is common in ballet dancers, soccer players, and gymnasts who repetitively plantarflex the ankle. Most cases respond to injection and activity modification; refractory cases are cured by arthroscopic or open os trigonum excision.
Os Trigonum Syndrome: Symptoms, Diagnosis & Treatment | Podiatrist 2026
If you’re a ballet dancer, gymnast, or soccer player with persistent pain behind your ankle — deep in the back of the joint, worsened by pointing your toe — os trigonum syndrome is at the top of your differential. This often-missed posterior ankle pain syndrome is caused by impingement of an extra bone behind the talus during ankle plantarflexion. At Balance Foot & Ankle, we diagnose it with targeted clinical examination and MRI, and our athletes consistently return to full activity after arthroscopic excision within 6–8 weeks.
What Is the Os Trigonum?
The os trigonum is an accessory ossicle located posterior to the lateral tubercle of the posterior talar process. It develops as a secondary ossification center that appears between ages 8–13 and normally fuses to the talus by age 16–18. When fusion fails to occur, the os trigonum remains as a separate small bone connected to the talus by a fibrocartilaginous synchondrosis.
Alternatively, some patients have a long, prominent posterior talar process (Stieda process) rather than a separate os trigonum — this produces identical symptoms through the same impingement mechanism. Both are encompassed under posterior ankle impingement syndrome (PAIS) or the specific term os trigonum syndrome when the accessory bone is present.
Key takeaway: Os trigonum is present in 7–14% of the population. It is bilateral in approximately 1.4% of the general population. It is a common finding on ankle X-rays — its presence alone does not indicate pathology. Only when symptomatic impingement is confirmed does it become a clinical problem.
Why Does It Become Painful?
Pain arises when the os trigonum is compressed between the posterior tibial plafond and the calcaneus during extreme ankle plantarflexion (pointing the toe). Specific mechanisms:
- Repetitive microimpingement: Ballet dancers (‘pointe’ and ‘demi-pointe’ positions), gymnasts, soccer players (kicking with the foot pointed), downhill runners
- Acute fracture/synchondrosis disruption: Sudden extreme plantarflexion (stepping off a curb, soccer tackle) can acutely fracture the os trigonum or disrupt the synchondrosis
- FHL tendon friction: The flexor hallucis longus (FHL) tendon passes immediately adjacent to the os trigonum in the fibro-osseous tunnel; an enlarged os trigonum can produce stenotic FHL tenosynovitis simultaneously
- Posterior capsule impingement: The posterior ankle capsule is pinched between the os trigonum and the posterior tibial plafond in plantarflexion
Symptoms
- Posterior ankle pain: Deep, aching pain behind the ankle, between the Achilles tendon and the peroneal tendons
- Pain with plantarflexion: Pointing the foot, going up on tiptoe, or any activity requiring extreme ankle plantarflexion reproduces pain
- Tenderness posterior to the ankle: Palpating the posterior ankle between the Achilles and peroneal tendons — the os trigonum area — reproduces pain
- Posterior impingement test: Passive maximum plantarflexion by the examiner reproduces the posterior pain (positive in 90% of cases)
- FHL triggering: In cases with concurrent FHL stenosis, ‘trigger toe’ — catching or triggering of the great toe during flexion-extension — may be present
Diagnosis
- Lateral ankle X-ray: Usually visualizes the os trigonum or prominent Stieda process. Weight-bearing or plantarflexion stress views increase sensitivity.
- MRI: Shows bone marrow edema within the os trigonum and surrounding synchondrosis disruption — confirms active impingement vs. incidental finding. Also evaluates FHL tendon for associated tenosynovitis.
- Diagnostic injection: 2mL local anesthetic injected into the posterior ankle behind the talus — if it eliminates 70-80% of the patient’s pain, os trigonum syndrome is confirmed as the source.
- Ultrasound: Less commonly used but can confirm FHL tenosynovitis and guide injection.
Differential diagnosis: Achilles tendinopathy, FHL tenosynovitis without os trigonum, posterior tibiotalar impingement (soft tissue), tarsal tunnel syndrome, calcaneal stress fracture.
Os Trigonum Syndrome Treatment
Conservative Treatment
- Activity modification: Eliminate activities requiring extreme plantarflexion (pointe work, kicking) during the acute phase
- Immobilization: Short leg walking boot or cast for 4–6 weeks for acute synchondrosis disruption or during a significant flare
- NSAIDs: Anti-inflammatory medications reduce synovitis in the posterior ankle
- Corticosteroid injection: Ultrasound-guided injection into the posterior ankle space adjacent to the os trigonum provides 2–6 months relief in most patients and confirms the diagnosis simultaneously
- Physical therapy: Posterior ankle stretching, calf flexibility work, proprioception training
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Surgical Treatment
When conservative treatment fails (usually after 3–6 months), os trigonum excision is the definitive treatment:
- Arthroscopic excision: Two posterior ankle portals allow visualization and excision of the os trigonum using a small shaver/burr. Concurrent FHL tenosynovitis is released in the same procedure. Minimal soft tissue disruption, rapid recovery.
- Open excision: A small posterolateral incision allows direct visualization and excision — used when arthroscopic access is limited by os trigonum size or adhesions.
- Results: 85–92% good/excellent outcomes. Return to dance or sport at 6–8 weeks post-arthroscopy, 8–12 weeks post-open.
Warning: When to See a Podiatrist for Os Trigonum Syndrome
- Posterior ankle pain during activities requiring pointing the foot
- An athlete (dancer, gymnast, soccer player) with persistent deep ankle pain
- Pain behind the ankle with tiptoe walking or downhill running
- Confirmed os trigonum on X-ray with matching symptoms
- Triggering of the great toe with ankle motion (FHL involvement)
Frequently Asked Questions
Can os trigonum syndrome heal without surgery?
Yes — 50–70% of patients with os trigonum syndrome improve sufficiently with conservative treatment to return to their sport or activities. For recreational athletes or patients with mild impingement, activity modification, injection, and physical therapy often provide durable relief. Surgery is reserved for athletes who cannot modify their activity demands or for refractory cases.
How quickly can dancers return to full pointe work after os trigonum surgery?
After arthroscopic excision, most dancers return to full pointe work in 6–8 weeks. After open excision, return takes 8–12 weeks. Return timelines are individualized — flexibility, pre-operative conditioning, and rehabilitation compliance affect recovery. Most professional dancers undergo arthroscopic excision during the off-season to minimize missed performance time.
Is os trigonum removal necessary?
Os trigonum removal is necessary only when conservative treatment has genuinely failed and the patient’s activity level is significantly limited. Many people have an os trigonum on X-ray with no symptoms — for them, no treatment of any kind is needed.
What causes os trigonum to become painful suddenly?
An acute flare is usually triggered by a sudden extreme ankle plantarflexion movement — stepping off a curb wrong, a soccer tackle, or a new training load increase in a dancer. This can acutely disrupt the synchondrosis between the os trigonum and talus, producing an acute fracture-like pain pattern on top of any baseline irritation.
Can os trigonum syndrome come back after surgery?
True recurrence after complete excision is rare (< 5%). Residual symptoms occasionally occur if the excision was incomplete or if the FHL tenosynovitis component was not addressed. A second operation is rarely required.
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Sources
- Shepherd FJ. A hitherto undescribed fracture of the astragalus. J Anat Physiol. 1882;17:79-81.
- Mouhsine E, et al. Endoscopic versus open resection of os trigonum in posterior ankle impingement. Orthopedics. 2010;33(8):572.
- Willits K, et al. Endoscopic versus open resection of os trigonum: a prospective comparison. Foot Ankle Int. 2012;33(4):286-291.
- Zwiers R, et al. Posterior ankle impingement syndrome: a systematic review and meta-analysis. J Foot Ankle Surg. 2018;57(1):87-93.
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.
- The Pinnacle Full length insoles for men & women provide maximum cushioning, from high activity to moderate support. The PowerStep arch support shape provides stability to the foot and ankle, helping to relieve foot pain.
- When you spend all day on your feet, every step counts. PowerStep insoles are a podiatrist-recommended orthotic to help relieve & prevent foot pain related to athletes, runners, Plantar Fasciitis, heel spurs & other common foot, ankle & knee injuries
- The Pinnacle plantar fasciitis insoles offer superior heel cushioning and arch support. The dual-layer cushioning is designed to reduce stress and fatigue, while PowerStep premium arch support is designed for plantar fasciitis relief.
- The PowerStep Pinnacle arch support inserts for men & women can be worn in a variety of shoe types such as; athletic, walking, running, work & some casual shoes. Orthotic Inserts are ordered by shoe size, no trimming required.
- Made in the USA & backed by a 30-day money-back guarantee. PowerStep orthotic inserts for men & women are designed for shoes where the factory insole can be removed. HSA & FSA Eligible
✓ 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.
- Full Length Support - Our ProTech orthotic insoles support pronation, arch pain, heel pain, plantar fasciitis, and heel spurs.
- Your Go To Inserts - These orthotics for plantar fasciitis provide full length, total contact support for a number of common foot issues
- Easily Fix Your Arches - Standard, semi-rigid arch support that fits most shoes including, work boots, dress shoes and sneakers.
- Enhanced Comfort - Our ProTech orthotic inserts have maximum cushioning featuring ShockAbsorb Premium Foam heel support cushion to increased protection.
- Support + Comfort - PowerStep ProTech orthotic insoles are designed with built-in arch support, heel cradle, and a perfect balance of support and comfort. Legitimate PowerStep product packaging is marked with a unique US quality control code. If you are concerned that a PowerStep item is not legitimate, please contact PowerStep customer service.
✓ 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.
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✓ 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.
- PODIATRIST DESIGNED! An effective alternative to expensive custom-made orthotics. Innovative biomechanical THREE-ZONE COMFORT technology delivers deep heel cup stability, forefoot cushioning, and ultimate arch support to prevent excessive pronation caused by flat feet. These essential contact points help to realign positioning of feet, aiding to re-establish your body's natural alignment, from the ground up.
- VIONIC ORTHOTIC INSOLES! These women's and men's shoe inserts offer a convenient, pain-free natural healing solution for many of the common aches and pains associated with poor lower-limb alignment, plantar fasciitis, and arch pain. EVA orthotic with re-enforced, hardened plastic (PE) shell for added motion control and stability. Cushioned shock dot in the heel for added shock absorption. Can be trimmed in forefoot if necessary.
- DESIGNED FOR EVERYDAY USE! Designed to provide greater control in faster paced activities such as running and fast walking. 4 degree rear foot wedge to provide support and control which helps prevent excess pronation. Odor absorbing cover. Contoured around the heel and arch areas to achieve 100% foot contact. Podiatrist Designed, APMA Seal of Acceptance.
- COMFORTABLE TO WEAR! Shoe inserts for women and men contoured around the heel and arch areas to achieve perfect foot contact.
- SIZES AVAILABLE: XS: Women's 4.5 – 6 / Men's 3.5 – 5 S: Women's 6.5 – 8 / Men's 5.5 – 7 M: Women's 8.5 – 10 / Men's 7.5 – 9 L: Women's 10.5 – 12 / Men's 9.5 – 11 XL: Men's 11.5 – 13
✓ 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).
- Signature waffle-inspired rubber outsole for traction and flexibility
✓ 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.
- Provides continuous support of the Plantar Fascia by gently stretching the fascia tissue.
- Compression zones promote circulation, reduce impact vibration, boost recovery and strengthen feet.
- Lightweight, seamless design with extra cushioning provides support while still being comfortable.
- Supports the heel/arch and overall foot structure while stabilizing the tendon for better performance
- Made from high quality materials, the socks are moisture wicking and breathable.
✓ 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.
- The first generation of Protalus's M-100 Insole
- Patented Alignment Technology: The M-100 features a deep heel cup and contoured arch to correct overpronation and promote better posture, stability, and joint health throughout your body.
- Comfortable Insoles: The patented stress relief replacement shoe insoles increase comfort and relieve plantar fasciitis and anti-fatigue.
- Improves Alignment: The shoe insoles help improve alignment and reduce pain in the feet, ideal for low and high arches.
✓ 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.
- ✶ALLEVIATES HEEL PAIN – Tuli’s Heavy Duty Heel Cups provide heel pain relief caused by plantar fasciitis, Sever’s disease, excessive pronation, Achilles tendonitis, etc. Ideal for those on their feet for most of the day or those looking for added comfort.
- ✶PODIATRIST PREFERRED – In an independent study conducted by M3 Global Research, podiatrists chose Tuli’s as the clear winner of recommended heel cup brands.
- ✶SHOCK-ABSORBING DESIGN – The multi-cell, multi-layer design absorbs shock and impact energy, mimicking the natural shock-absorbing system of your feet. As you walk or run, the design reduces the stress on your feet.
- ✶DOCTOR RECOMMENDED & APMA ACCEPTED – Tuli’s Heel Cups were designed by a leading podiatrist and have the honor of being accepted by the American Podiatric Medical Association.
- ✶FITS MOST LACE-UP SHOES – Best used in spacious lace-up shoes like athletic shoes / sneakers.
✓ 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.
- Plantar Fasciitis Relief, Every Step – Firm arch support helps relieve heel and arch pain from plantar fasciitis and supports flat feet and overpronation for better alignment and all-day comfort.
- Clinical-Grade Biomechanics – Tread Labs 26-33 ARCHitecture delivers orthotic-level stability—custom-orthotic feel without the prescription.
- Dialed Fit for Any Shoe – Four arch heights (low, medium, high, extra-high) and an easy 3-step sizing guide make selection simple for work boots, sneakers, and everyday shoes—great for standing all day.
- Built to Last a Million Miles – Durable, recyclable arch supports with our Million-Mile Guarantee; replaceable top covers keep insoles fresh and cost-effective. Unlike foam that flattens, Pace is engineered to last.
- Trusted Expertise – Designed by Mark Paigen (founder of Chaco). Premium arch support inserts for men and women backed by decades of footwear innovation.
✓ 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.
Schedule a Custom Orthotic Fitting →FSA/HSA eligible · Most insurance accepted · (810) 206-1402
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)