Sesamoiditis: Causes, Diagnosis & Treatment | Podiatrist Howell MI

What Are the Sesamoid Bones?

If you have ever felt a tender, pea-sized area of pain directly under the ball of your foot at the base of the big toe, you have encountered the sesamoids. The sesamoid bones are two small, oval bones embedded within the flexor hallucis brevis tendon — one medial (tibial sesamoid) and one lateral (fibular sesamoid) — sitting just beneath the first metatarsal head. Unlike most bones, which articulate with other bones at synovial joints, sesamoids are embedded in tendons and serve a mechanical purpose: they act as pulleys, increasing the mechanical advantage of the flexor hallucis brevis and absorbing up to three times body weight during the push-off phase of gait.

This high mechanical load makes the sesamoids disproportionately vulnerable to cumulative stress. In our clinic at Balance Foot & Ankle, we see sesamoid injuries most commonly in dancers (the “ballet dancer’s heel”), distance runners, basketball players, and anyone who spends prolonged time in high heels or on hard surfaces. The medial (tibial) sesamoid bears more load and is injured far more frequently than the lateral.

Types of Sesamoid Injury

Not all sesamoid pain is the same. Distinguishing between these entities changes management significantly.

• Sesamoiditis (inflammation): Cumulative overuse producing peritendinous inflammation around the sesamoids without structural bone damage. The most common presentation. Responds well to conservative offloading and activity modification.
• Acute sesamoid fracture: A traumatic break from a sudden hyperextension injury (landing from a jump, stubbing the toe) or a direct crushing force. Identified on X-ray; MRI confirms non-displaced fractures invisible on plain film.
• Stress fracture: Gradual accumulation of microdamage in runners or dancers — a progressive rather than sudden onset. Bone edema on MRI is the key diagnostic finding when plain X-rays are normal.
• Bipartite sesamoid: A developmental variant in which the sesamoid failed to fuse during growth, producing two segments with a smooth, corticated interface. Present in roughly 10% of the population, usually bilateral and asymptomatic. Distinguishing a bipartite sesamoid from an acute fracture is critical — bipartite edges are rounded and smooth; fracture edges are irregular and sharp. Bilateral X-rays help (a contralateral bipartite sesamoid confirms the variant).
• Avascular necrosis (AVN): Loss of blood supply to the sesamoid producing progressive bone death. Rare, but seen in patients with diabetes, chronic steroid use, or following prolonged immobilization. MRI shows dark signal on T1 with surrounding edema on T2. May ultimately require surgical excision.
• Chondromalacia: Softening and degeneration of the sesamoid’s cartilaginous articulating surface — essentially arthritis of the sesamoid-metatarsal articulation. Produces chronic, deep aching rather than the sharp pain of acute injury.

Symptoms and Physical Examination

Sesamoiditis produces a characteristic symptom pattern: plantar forefoot pain at the first MTP joint that is aggravated by push-off (the toe-off phase of gait), going up stairs, wearing high heels, or walking barefoot on hard floors. The pain is localized — patients can often point to the exact spot — and is reproduced by palpating directly over the affected sesamoid on the plantar surface of the foot. Dorsiflexion of the great toe (loading the flexor hallucis brevis) reproduces the pain and distinguishes sesamoiditis from hallux rigidus (dorsal MTP pain) and gout (diffuse MTP swelling and warmth).

In acute fractures, swelling and bruising under the first metatarsal head may be visible. In chronic sesamoiditis, the examination is often surprisingly benign except for the point tenderness — a mismatch between reported pain severity and examination findings is characteristic.

What Sesamoiditis Actually Feels Like

Almost everyone describes it the same way before they know what it is: a stone in the shoe that will not come out. The pain sits directly under the ball of the big toe, in a spot you can cover with a fingertip, and it feels like standing on something small and hard that has been left under the foot.

That single description is diagnostically useful, because most other forefoot pain does not feel like that. Nerve pain burns or radiates into the toes. Joint arthritis feels stiff and grinding at the joint itself rather than beneath it. A neuroma often produces numbness or the sense of a sock bunched under the foot. Sesamoiditis is pressure, and it is precisely located.

When it hurts, and when it does not

The pain is loading pain. It appears at the moment the heel leaves the ground and body weight rolls forward onto the big toe, which is why the same foot can feel almost normal standing still and unbearable walking. People notice it going up stairs, pushing off to cross a road, or rising onto the toes to reach something.

Surfaces and shoes change it more than activity does. Barefoot on tile or hardwood is usually the worst. Thin, flexible soles, minimalist trainers and heels all concentrate load onto exactly the wrong spot. A cushioned, stiff-soled shoe can make the same foot feel dramatically better within a few steps, and that swing is itself a clue.

How it starts, and why people wait

It builds. Unlike a fracture or a turf-toe injury there is usually no single moment to point to, which is one reason people delay: there was no accident, so it does not feel like an injury. It begins as an ache after a long day, becomes discomfort during ordinary walking over weeks, and in the untreated case eventually aches at rest and at night.

There is often very little to see. Mild swelling at most, sometimes none, rarely bruising or redness. A foot that looks entirely normal but hurts to stand on is characteristic, and the mismatch between how bad it feels and how unremarkable it looks is a large part of why sesamoiditis gets dismissed, by patients and sometimes by clinicians.

Two things should change the timeline. Pain that persists at rest or wakes you at night, and pain that does not ease at all after two or three weeks of genuinely staying off it, both point away from simple inflammation and toward a stress fracture or one of the other problems in the section below.

Diagnosis

Standard weight-bearing foot X-rays in AP, lateral, and axial (sesamoid) views are the starting point. The axial sesamoid view is critical — it visualizes the sesamoid-metatarsal joint directly and is frequently omitted in non-specialist settings, leading to missed diagnoses. MRI is obtained for any sesamoid injury with normal X-rays or when stress fracture, AVN, or chondromalacia needs confirmation. Bone scan with SPECT imaging remains a sensitive alternative when MRI is unavailable. Ultrasound is useful for peritendinous fluid and soft-tissue swelling but cannot assess intrinsic bone pathology.

Differential diagnosis includes: hallux rigidus (dorsal, not plantar, MTP pain; stiffness), gout (acute onset, exquisitely tender diffuse MTP inflammation, responds to colchicine), plantar plate tear (pain at second MTP, not first), and bursitis of the first MTP (more diffuse, medial swelling). Getting sesamoiditis distinguished from a bipartite sesamoid is the single most important diagnostic question — unnecessary surgery on a bipartite variant can produce severe morbidity.

What Gets Mistaken for Sesamoiditis

Sesamoiditis is a diagnosis of pattern, not of a single test, and several other problems produce pain in almost the same spot. In practice this is where most of the delay comes from: people are treated for sesamoiditis for months when the actual problem was one of the conditions below, and the treatment for several of them is meaningfully different.

Two features do most of the sorting. Where exactly the tenderness sits when you press one finger on the bone, and what the pain does at rest. True sesamoiditis is tender directly under one of the two small bones beneath the big toe joint, hurts most on push-off, and settles substantially when you stay off it.

What it may actually be	What points to it instead
Sesamoid stress fracture	Pain that does not settle with rest, night ache, and tenderness that stays sharp and pinpoint rather than diffuse. Often normal on early X-ray, which is why a negative film does not close the question.
Bipartite sesamoid (a normal two-part variant)	Seen on X-ray in a minority of people, most often the medial sesamoid, and frequently on both feet. Smooth rounded sclerotic edges, rather than the sharp irregular edges of a break. It is a normal variant, not an injury, and mistaking it for a fracture is how people end up in unnecessary surgery.
Turf toe (plantar plate and capsule injury)	A clear hyperextension event rather than a gradual build-up. Swelling and pain around the whole joint, pain on pulling the toe upward, sometimes bruising.
Hallux rigidus (first MTP arthritis)	Pain at the joint rather than under it, a stiff or grinding toe, a bump on top of the joint, and pain provoked by bending the toe up rather than by pressing underneath.
Gout	Rapid onset over hours, often waking you at night, with a red, hot, exquisitely tender joint. Even a bedsheet is uncomfortable. This is the one to identify quickly, because it is treated pharmacologically.
Avascular necrosis of the sesamoid	Suspected when well-run conservative treatment simply does not work over months, with imaging showing fragmentation or increasing density in the bone.
Flexor hallucis longus tendinopathy	Pain reproduced by bending the big toe down against resistance, and tenderness tracking further back along the tendon rather than staying under the sesamoid.
Morton’s neuroma or metatarsalgia	Pain sitting further out toward the middle of the forefoot, often burning or with numbness into the toes, rather than localised under the big toe joint.

The two worth ruling out early are gout, because the treatment is entirely different and delay is unnecessary suffering, and stress fracture, because continuing to load a partly broken sesamoid is how a manageable problem becomes a surgical one.

If you have been treating this as sesamoiditis for more than six to eight weeks with no real change, the working diagnosis deserves review rather than more of the same treatment. That usually means repeat imaging, and sometimes advanced imaging, rather than another insole.

We go into several of these separately: sesamoid fracture versus a bipartite sesamoid, sesamoiditis versus gout, sesamoiditis versus metatarsalgia and Morton’s neuroma, and hallux rigidus.

Treatment

Treatment is matched to the type and severity of the sesamoid injury. The overarching principle is mechanical offloading — reducing the compressive and tensile forces transmitted through the sesamoid-metatarsal complex during gait.

• Sesamoid offloading orthotic: The cornerstone of conservative management. A custom or semi-custom orthotic with a sesamoid cutout (a relief cavity under the medial sesamoid) removes direct pressure from the injured bone with every step. This single intervention often provides dramatic immediate relief and should be initiated at the first visit.
• Dancer’s pad / J-pad: An adhesive felt or foam padding applied directly to the plantar forefoot, shaped to cushion around (not over) the sesamoid. Effective for acute pain management while an orthotic is being fabricated.
• Footwear modification: Flat, stiff-soled shoes (not high heels, not minimalist barefoot shoes) that minimize push-off dorsiflexion during gait. Rocker-bottom soles are ideal for acute sesamoiditis.
• Activity modification: Eliminating the provocative activity (dance, running, jumping) during the acute healing phase. Cross-training with swimming or cycling maintains fitness without sesamoid loading.
• Immobilization: For acute fractures or severe sesamoiditis, a short-leg walking boot or non-weight-bearing cast for 4–8 weeks reduces mechanical stress to allow bone healing. Stress fractures typically require 6–8 weeks of immobilization.
• Corticosteroid injection: An ultrasound-guided injection into the peritendinous sesamoid region reduces inflammation and provides pain relief for 4–12 weeks. We limit to two injections — aggressive repeated injections can lead to soft-tissue atrophy under the first metatarsal head.
• Physical therapy: Once acute pain is controlled, intrinsic foot muscle strengthening and flexor hallucis longus stretching restore the dynamic support system around the first MTP joint.
• Surgical excision (rare): Sesamoidectomy — removal of the affected sesamoid — is reserved for AVN, nonunion of an acute fracture after prolonged conservative care, or disabling chondromalacia that has failed all conservative measures. The medial sesamoid is excised more commonly than the lateral; excision of both sesamoids simultaneously is contraindicated due to risk of hallux valgus or cock-up toe deformity.

The Most Common Mistake We See

The most common mistake we see with sesamoid injuries is failure to obtain an axial sesamoid X-ray view. Standard AP and lateral foot X-rays frequently miss sesamoid fractures and chondromalacia. Patients arrive having been told their foot X-ray was “normal” when a sesamoid-specific view would have revealed the injury clearly. The second most common mistake is treating a bipartite sesamoid as an acute fracture — leading to unnecessary immobilization or, worse, unwarranted surgical excision. Every sesamoid presentation needs a proper axial view and, when the X-ray is equivocal, an MRI.

The Bottom Line

Sesamoiditis is an overuse injury of two small but mechanically essential bones under the first metatarsal head. Most cases respond well to a sesamoid offloading orthotic, footwear modification, and activity adjustment. The critical steps are obtaining proper X-ray views (including the axial sesamoid view), distinguishing a bipartite variant from a fracture, and using MRI to confirm stress fractures and AVN that plain X-rays miss. Come in early — sesamoid injuries caught and offloaded promptly heal far faster than those that have been walked on aggressively for months.

Related reading: sesamoiditis taping technique · broken big toe · podiatrist-recommended metatarsal pads

Suspect a bruise on the ball of your foot? See our guide: Stone Bruise on the Foot — Michigan podiatrist explains healing timelines and the best at-home and clinical treatment options.

For a complete clinical overview: Foot & Ankle Pain — Complete Guide — all common foot conditions explained by a board-certified podiatrist

Related Sesamoid Resources

• Sesamoiditis Taping Technique — KT tape and rigid taping methods that offload the sesamoids during activity.
• Best Shoes for Top-of-Foot Pain — low-drop, rocker-bottom shoes that reduce forefoot loading for sesamoiditis patients.

Clinical sources

• Conservative Treatment of Sesamoiditis: a systematic literature review with pooled data analysis. PMC
• Sesamoiditis — patient education. AAOS OrthoInfo. AAOS
• Sesamoid injuries. FootCareMD (AOFAS). FootCareMD

More questions patients ask

What is sesamoiditis?

Sesamoiditis is inflammation of the two small sesamoid bones under the big toe joint. It causes pain on the ball of the foot beneath the big toe, especially during push-off when walking or running. Dancers and runners are most affected.

Can sesamoiditis become a stress fracture?

Yes. Chronic sesamoiditis can progress to a sesamoid stress fracture if not properly treated. Persistent pain despite rest warrants imaging (X-ray or MRI) from a podiatrist to rule out fracture and guide appropriate treatment.

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