Sesamoiditis
Sesamoiditis is a general term used to describe inflammation of the sesamoid bones — two small bones that sit underneath the big toe joint at the ball of the foot. Understanding exactly which structure is injured is the key to targeting treatment, setting realistic expectations, and getting you back to activity as quickly as possible.
Written and reviewed by Peter Charles, Sports Podiatrist — Shoes Feet Gear, Bardon Brisbane
What Are the Sesamoid Bones and Why Do They Get Injured?
The sesamoid bones work like a kneecap for the big toe. They sit inside the flexor hallucis longus tendon — the tendon that controls the big toe — and help it function efficiently as it crosses the big toe joint. What makes these bones particularly vulnerable is their location: all of your body weight is bearing down on top of them while simultaneously bending and pushing off at the same time.
This combination of compression from body weight and tension from movement creates enormous force through a very small area. For some people, too much bending force during push-off, or too much impact from the ground, is enough to cause inflammation in or around these bones.
Signs & Symptoms
Sesamoiditis typically presents as pain directly under the ball of the foot, at the base of the big toe. The pain is usually well-localised — patients can often point to the exact spot with one finger. Common features include:
- Pain on push-off — the most consistent symptom; pain that peaks as the heel rises and the big toe bends back during walking or running
- Pain with forefoot loading — standing on tiptoe, climbing stairs, or squatting often reproduces symptoms
- Swelling and tenderness — localised swelling under the big toe joint, with direct tenderness on pressing the sesamoid area from below
- Stiffness in the big toe — reduced range of motion, particularly bending the toe upward, due to pain and soft tissue tightening
- Gradual or sudden onset — symptoms may build slowly over weeks with increasing activity, or appear more acutely after a change in footwear, surface, or training load
- Aggravation with running — particularly forefoot running styles or running on hard surfaces; symptoms often worsen as a run progresses
If you are experiencing pain in this area that is not settling, see our guide to forefoot and foot pain or book in for an assessment — early diagnosis makes a significant difference to recovery time.
Which Specific Structure Is Injured? Why It Matters
Most clinicians treat sesamoiditis as a single condition, but the specific anatomy that is injured makes a significant difference to treatment approach, prognosis, and return-to-sport timelines. There are several distinct structures that can be involved:
- The flexor hallucis longus tendon itself — responds well to strengthening, stretching, and offloading
- The cartilage surface the sesamoid slides along — responds well to pressure offloading and reducing the tension pulling the sesamoid down against the joint surface
- The adventitial bursa above the sesamoid — inflammation here can settle relatively quickly with cushioning and offloading alone
- The small ligaments holding the sesamoid in place — particularly vulnerable in sports involving side-to-side movement and twisting, where the sesamoid is pulled sideways and the stabilising ligaments are damaged
- The sesamoid bone itself (stress reaction / bone oedema) — the most serious presentation; these are slow to recover and can become long-term problems if not managed correctly. Learn more about stress reactions and bone stress injuries.
MRI showing adventitial bursitis overlying the sesamoid — fluid signal in the bursa above the bone. This presentation typically responds well to cushioning and offloading. Image: Shoes Feet Gear.
Mild, superficial inflammation recovers quickly and return to sport can be rapid. When inflammation is deeper into the bone itself — behaving like a stress reaction — recovery is significantly slower and requires careful management.
Avascular Necrosis — The Serious Complication
When inflammation reaches the bone proper, a critical complication becomes possible. The sesamoid bones are very small, and their blood supply can be precarious. When the bone is under sustained duress, the blood supply can become compromised — the bone weakens, deteriorates, and effectively begins to disintegrate. This is called avascular necrosis.
The result is a damaged, malformed bone that can be extremely difficult to manage as a chronic condition. This is why early, accurate diagnosis and appropriate load management matters — not just for recovery speed, but to prevent a manageable condition from becoming a permanent structural problem.
Who Is Most at Risk?
High arch feet are the most common foot type we see with sesamoiditis. In a high arch foot, the big toe sits lower than the rest of the forefoot. This is a genetic, inherited foot structure — and when walking or running, rather than striking on the outside of the foot and smoothly rolling through to push off, the big toe impacts the ground first and takes the full force of loading.
Two mechanisms compound this problem in high arch feet:
- Impact loading — the big toe strikes the ground directly, creating a large impact force through the sesamoids with every step
- Windlass compression — as the big toe lifts and tightens the flexor tendon and plantar fascia, it pulls the sesamoid hard down against the cartilage surface and limits how freely the toe can bend. This creates significant compression at exactly the point where bending force is highest
Other contributing factors include forefoot running style, hard training surfaces, and footwear with insufficient forefoot cushioning or protection.
Treatment — From Acute Offloading to Return to Sport
Treatment centres on two priorities: protecting the sesamoid from further loading while it recovers, and correcting the underlying mechanics that caused the problem in the first place.
Acute Management — Stopping the Bending Force
In severe cases, we go straight to a CAM walker (moon boot). Keeping the foot completely still and preventing the toe from bending back dramatically reduces the compression and bending force through the sesamoid. Special padding inside the boot keeps body weight off the bone itself. This approach works far better than crutches for most patients.
For milder cases, or when transitioning out of a CAM walker, stiff footwear achieves a similar result. Current running shoe designs with a thick forefoot and aggressive rockers are excellent for this — they significantly reduce bending force through the forefoot. For casual wear, platform-style shoes with a thick, stiff forefoot offer similar protection.
Very soft, cushioned slides — such as OOFOS slides — can also help by reducing impact and protecting the forefoot during low-load activity.
Offloading — Getting Pressure Off the Bone
Once the right footwear is in place, offloading padding is used to redistribute pressure away from the sesamoid. The goal is that when standing, walking, or returning to running, body weight is not being driven directly into those small bones.
Orthotics — Combining Offloading with Mechanical Correction
Prescription orthotics allow us to combine sesamoid offloading with correction of the underlying foot mechanics. A well-designed orthotic for sesamoiditis will:
- Offload pressure directly from the sesamoid
- Correct forefoot angle to reduce the impact loading pattern of a high arch foot
- Reduce tension in the flexor tendon pulling the sesamoid into compression
- Protect the sesamoid during a graduated return to activity
It is important that recovery continues even as activity is gradually increased. In cases where the bone has oedema, recovery is slow — and having the right orthotic in place is what allows a safe return to sport without re-aggravating the injury. Learn more about our prescription orthotics.
Imaging — What We Use and When
MRI is the definitive imaging for sesamoiditis. It can identify which specific structures are injured and give clear clinical direction — particularly for cases that are not recovering as expected.
T2-weighted MRI: bright signal within the sesamoid confirms active bone oedema — consistent with a stress reaction. Image: Shoes Feet Gear.
T1-weighted MRI: signal loss (dark) within the sesamoid on the same patient — the combination of T2 bright and T1 dark signal is the hallmark of bone oedema and stress reaction. Image: Shoes Feet Gear.
X-ray has a more limited but still useful role:
- Acute fracture — true sesamoid fractures are extremely rare. In clinical practice, the only cases I have seen have involved jumping from a height onto a hard surface, or a heavy object landing directly on the foot. Without a significant traumatic event, an acute fracture is very unlikely.
- Bipartite sesamoid — a sesamoid that naturally develops in two, three, or four pieces is common and can be mistaken for a fracture on X-ray. There are specific radiological signs to distinguish a bipartite sesamoid from a true fracture.
- Stress fracture — X-ray can show signs of gradual bone breakdown from repetitive loading. Learn more about stress reactions and stress fractures.
- Avascular necrosis — in cases where sesamoiditis has been present for several months and bone health has been compromised, X-ray will show the bone has deteriorated, shrunk, or partially dissolved.
MRI showing a bipartite sesamoid — two distinct segments with smooth margins. This is a normal anatomical variant and should not be confused with an acute fracture. Image: Shoes Feet Gear.
Ultrasound can be useful in experienced hands, but the sesamoid structures are very small and technically difficult to image well. For cases that are not settling quickly, we typically progress straight to MRI rather than relying on ultrasound.
Frequently Asked Questions
How do I know if I have sesamoiditis or something more serious?
Pain under the big toe joint that worsens with push-off or forefoot loading is the hallmark of sesamoiditis. If the pain is not settling with rest and basic offloading, or if it has been present for more than a few weeks, imaging is warranted. MRI will clarify whether you are dealing with soft tissue inflammation, a stress reaction in the bone, or early avascular necrosis — each of which has a very different prognosis and management plan.
Can I keep playing sport with sesamoiditis?
It depends on which structure is injured and how inflamed it is. Superficial soft tissue inflammation can often be managed with the right footwear, offloading, and load modification. Bone oedema or a stress reaction in the sesamoid requires a more conservative approach — continuing to load the bone risks progression to avascular necrosis, which is a far more serious and difficult condition to manage. An accurate diagnosis first is essential before making that call.
Why does my sesamoiditis keep coming back?
Recurrence almost always means the underlying foot mechanics have not been addressed. If a high arch foot continues to load the big toe first with every step, the sesamoid will continue to be overloaded regardless of how well the acute episode settles. Prescription orthotics that correct the forefoot angle and offload the sesamoid are the key to preventing recurrence.
Do I need a moon boot for sesamoiditis?
Not always — but for severe or bone-level inflammation, a CAM walker is often the fastest path to recovery. It eliminates bending force through the big toe joint completely, which is very difficult to achieve with footwear and padding alone. For milder cases, stiff footwear with a rocker sole and sesamoid offloading padding can be sufficient.
How long does sesamoiditis take to heal?
Superficial soft tissue inflammation can settle in a few weeks with the right management. Stress reactions in the bone take considerably longer — often three to six months — and require careful load management throughout. Avascular necrosis is a chronic condition that may require long-term orthotic management and, in some cases, specialist referral. Getting an accurate diagnosis early is the single most important factor in determining your recovery timeline.
Is sesamoiditis the same as a sesamoid fracture?
No. True sesamoid fractures are rare and almost always result from significant trauma — a fall from height or a heavy impact directly to the forefoot. Sesamoiditis refers to inflammation of the structures around the sesamoid bones, which can range from mild soft tissue irritation through to bone stress and avascular necrosis. A bipartite sesamoid — where the bone naturally develops in multiple pieces — is commonly mistaken for a fracture on X-ray, but there are clear radiological signs to distinguish the two.
Book an Appointment
If you have pain under the big toe joint that is not settling, the most important first step is an accurate diagnosis. At our Bardon podiatry clinic, we assess foot type, footwear, loading patterns, and the specific structures involved — so treatment is targeted to what is actually injured, not just the general area.
Or call us on (07) 3367 8667.
The information on this page is general in nature and is not a substitute for an individual clinical assessment. If you are experiencing pain, please seek professional advice.