Hammer Toe Causes 2026: Why Toes Curl and Buckle | Podiatrist

I see hammertoes in patients across a 60-year age range — from competitive runners in their 30s whose toes have buckled from tight race shoes to 70-year-olds who’ve worn narrow dress shoes their entire career. What strikes me every time is how preventable the progression is when caught early, and how predictable the surgical results are when it isn’t. The deformity looks like a simple structural problem, but it has a specific biomechanical cause that, once understood, points directly to the right treatment. This article covers exactly that — what causes a hammertoe, why it progresses, and what stage requires what intervention.

What Is a Hammertoe

A hammertoe is a flexion deformity of the proximal interphalangeal (PIP) joint — the middle knuckle of a lesser toe (2nd through 5th). Instead of lying flat, the toe bends downward at this joint while the tip (distal interphalangeal joint) often bends further down or remains extended. The toe takes on a shape resembling a hammer or an upside-down V when viewed from the side. This position causes the PIP joint to rub against the top of the shoe, producing a painful corn, and sometimes forces the metatarsal head down to produce a plantar callus underneath. Hammertoes almost exclusively affect the lesser toes — the 2nd toe is the most common, followed by the 3rd and 4th.

The deformity affects an estimated 2–20% of the population depending on how it’s defined, with prevalence increasing steeply with age. Women are 2–3 times more likely than men to develop hammertoes, almost certainly because of high heel and narrow toe box shoe exposure. Hammertoes account for approximately 20% of all foot surgery performed by podiatric surgeons in the United States.

Hammertoe vs. Mallet Toe vs. Claw Toe: Understanding the Differences

These three terms are frequently used interchangeably but describe distinct deformities with different anatomical causes. Knowing the difference guides treatment selection.

The critical distinction between hammertoe and claw toe is the metatarsophalangeal (MTP) joint. In hammertoe, the MTP is usually neutral or only mildly involved. In claw toe, the MTP is hyperextended — the toe is pulled up at its base while bent sharply at the PIP and DIP. Claw toes almost always indicate a systemic or neurological problem (diabetes, Charcot-Marie-Tooth disease, rheumatoid arthritis, alcoholic neuropathy) rather than a shoe fit problem. Any patient presenting with claw toes should be evaluated for underlying neurological or inflammatory disease.

The Root Cause: Muscle-Tendon Imbalance

Understanding why hammertoe develops requires understanding how the toe stays straight in the first place. Two opposing systems control lesser toe position: the extrinsic system (long tendons from the leg — flexor digitorum longus/FDL and extensor digitorum longus/EDL) and the intrinsic system (small muscles within the foot — lumbricals and interossei). In a balanced foot, the intrinsics stabilize the MTP joint in slight flexion and assist toe extension, effectively counterbalancing the FDL’s strong pull on the PIP and DIP joints. The result is a straight, flat toe that makes even ground contact.

When the intrinsics lose power — whether from nerve damage, muscle atrophy, or positional disadvantage — the FDL wins unopposed. It flexes the PIP joint with each step, and over months to years, this repeated unresisted pull causes the joint capsule and tendons to shorten and the joint to remodel into a permanently bent position. This is the universal mechanism behind all hammertoe formation, regardless of the triggering cause. Everything that causes hammertoe does so by disrupting this balance — either by weakening the intrinsics or by creating a mechanical situation that forces the FDL to fire harder than it should.

Specific Causes of Hammertoe

1. Shoes That Are Too Short or Too Narrow

This is the most modifiable and most common cause. When the toe box is too short, the toe tip hits the end of the shoe and must bend to fit — the PIP joint flexes against the upper repeatedly with every step. Over months and years of this repeated compression, the flexor tendons adaptively shorten, the joint capsule contracts, and the deformity becomes structural rather than positional. High heels compound this by simultaneously forcing the toes forward into the toe box (reducing effective toe box length by a full shoe size at 3-inch heels) and loading the forefoot at an angle that increases FDL tension relative to the intrinsics. This is why hammertoe is dramatically more common in women and in cultures where fashion footwear is worn daily for decades.

In our clinic, we ask patients to bring their most-worn shoes to their first visit. The wear pattern, depth of the toe box, and whether the toes leave imprints in the insole tell us more than almost anything else about the footwear contribution. The “thumb test” — there should be a thumb’s width between the longest toe and the end of the shoe — is simple and reliable. An estimated 60–80% of Americans wear shoes that are too short, making this the single highest-yield intervention for early hammertoe prevention.

2. Hallux Valgus (Bunion) Pushing the 2nd Toe

The 2nd toe is the most common site of hammertoe for two reasons: it is anatomically the longest in many people, and it is the first toe crowded when a hallux valgus deformity develops. As the big toe progressively drifts laterally toward the 2nd toe, it applies a constant medial force on the 2nd digit — pushing it upward and eventually buckling it at the PIP joint into a hammertoe position. The 2nd MTP joint capsule stretches and the 2nd toe can subluxate (partially dislocate) on top of the big toe in severe cases. In our practice, we routinely see severe 2nd hammertoes as direct consequences of long-standing hallux valgus — addressing only the hammertoe without correcting the bunion reliably leads to recurrence.

3. Second Toe Longer Than the First (Greek Foot)

A 2nd toe longer than the 1st occurs in approximately 22% of the population and significantly increases hammertoe risk. The longer toe simply has more toe to fit into a fixed shoe length, requiring more flexion to accommodate. Even in correctly fitted shoes, a disproportionately long 2nd toe is mechanically disadvantaged — it bears more ground contact force during push-off than shorter adjacent toes, increasing FDL tension. Patients with this foot type (sometimes called “Greek foot” or “index plus minus” type) need shoes that fit the longest toe, not the 1st toe — a detail that surprises many patients who have been buying shoes sized to their hallux their entire life.

4. Neuromuscular Conditions (Intrinsic Minus Foot)

Any condition that damages the intrinsic foot muscles or their nerve supply creates the biomechanical imbalance described above. Diabetic peripheral neuropathy damages the intrinsic motor nerves early, often producing claw toe deformities before the patient has significant sensory symptoms. Charcot-Marie-Tooth disease (hereditary motor and sensory neuropathy) causes progressive intrinsic wasting and is a classic cause of severe hammertoe and claw toe in young adults. Rheumatoid arthritis destroys the MTP joint architecture and displaces the intrinsic tendons, eliminating their stabilizing effect. Alcoholic neuropathy, Guillain-Barré syndrome, and lumbar nerve root compression (particularly L5–S1 affecting intrinsic innervation) can all contribute.

In any patient under 50 with progressive hammertoe deformities affecting multiple toes bilaterally, neuromuscular evaluation is warranted — the shoes are rarely the sole explanation when multiple toes are affected symmetrically in both feet.

5. Flat Foot (Overpronation) and Intrinsic Disadvantage

Overpronation — the foot rolling inward and the arch collapsing during gait — places the intrinsic muscles at a mechanical disadvantage. The lumbrical muscles, which originate from the FDL tendons and must maintain tension to stabilize the MTP joint, lose their optimal fiber length and force-generating capacity when the foot is excessively pronated. The result is a relative intrinsic insufficiency even without nerve damage — the intrinsics are anatomically intact but functionally weakened by position. Over years, this creates the same FDL-dominant imbalance that produces hammertoe. Patients with flat feet and hammertoes benefit substantially from functional orthotics that restore normal arch position and improve intrinsic muscle efficiency.

6. Previous Trauma or Surgery

Lacerations or crush injuries involving the dorsum of the foot can sever extensor tendons or damage the dorsal hood mechanism — the complex soft tissue structure that coordinates MTP extension. Without extensor function, the FDL again wins unopposed, producing a posture-specific hammertoe deformity. Previous hammertoe surgery that results in excessive soft tissue shortening or pin fixation complications can also produce a fixed deformity. Compartment syndrome of the foot following high-energy trauma leads to intrinsic muscle death and subsequent claw toe deformity across multiple toes.

Hammertoe Risk Factors

Flexible vs. Rigid Hammertoe: Why the Distinction Is Everything

The most important clinical assessment in any hammertoe patient is determining whether the deformity is flexible or rigid. In a flexible hammertoe, the PIP joint can be passively straightened — the toe is bent but not yet locked. The tendons are shortened and the joint capsule is tight, but the joint surfaces are still normal. Conservative treatment can be highly effective at this stage. In a rigid hammertoe, passive correction is impossible — the joint has remodeled, articular cartilage has been lost, and the periarticular soft tissues have contracted to the point that the deformity is structural. No amount of splinting, stretching, or shoe widening will straighten it. Surgery is the only option for a symptomatic rigid hammertoe.

The transition from flexible to rigid happens gradually over years. Patients often notice the toe getting harder to straighten when they grasp it manually — the window for conservative treatment is closing. This is why we emphasize evaluation and intervention at the flexible stage, before surgery becomes the only answer.

Symptoms and Complications of Hammertoe

Hammertoe produces predictable symptoms based on which surfaces of the toe are under pressure. The prominent PIP joint rubs against the top of the shoe, producing a painful hard corn (heloma durum) — a thickened central plug of keratin that can become acutely inflamed when the overlying bursa swells. The plantar metatarsal head, now pushed downward by the buckled toe, develops a callus from increased weight-bearing. The tip of the toe, which also contacts the floor when the toe is sufficiently bent, may develop an end-of-toe callus. In severe deformities, the 2nd toe crosses over or under the hallux, producing crossover toe syndrome with MTP joint instability, pain with every step, and difficulty wearing any closed-toe shoes.

In diabetic patients with peripheral neuropathy, all of these pressure points can ulcerate without the patient noticing pain — a diabetic foot ulcer under a hammertoe callus or over a PIP joint corn represents a serious limb-threatening complication requiring urgent podiatric evaluation.

Hammertoe Treatment by Stage

Flexible Hammertoe: Conservative Management

When the deformity is still flexible, the priority is eliminating the forces that are driving progression while reducing existing symptoms. Wide toe box shoes with adequate vertical depth are the foundation — there must be room for the toe to exist without being compressed from above or below. Toe spacers (silicone or felt) place gentle dorsiflexion force on the PIP joint to counteract FDL pull during walking. Hammer toe splints or crest pads position the toe flat and offload the metatarsal head simultaneously. Specific toe exercises (towel scrunching, toe-spreading against resistance) strengthen the intrinsic muscles and restore some of the balance that was lost — these work best at the very early flexible stage when the intrinsics still have adequate muscle mass and range.

Rigid Hammertoe: Surgical Options

Surgical correction of a rigid hammertoe addresses the contracted joint through one of several techniques. Proximal interphalangeal joint arthroplasty (PIP arthroplasty) removes a small portion of bone from the PIP joint, allowing the toe to straighten — this is the most common procedure and has a rapid recovery. PIP fusion (arthrodesis) permanently fuses the joint in a straight position — more durable but permanently removes PIP mobility. In deformities with significant MTP involvement (crossover toe, subluxation), additional soft tissue balancing procedures or MTP arthroplasty may be needed. Pin fixation holds the correction during healing; the pin is usually removed at 4–6 weeks. Patient satisfaction for hammertoe surgery is high — approximately 85–90% report significant improvement in pain and cosmetic appearance.

FLAT SOCKS: Reducing Friction on Hammertoe-Prone Feet

Most Common Mistake: Buying Wider Shoes and Thinking That Fixes It

The most common mistake we see in patients with early hammertoe is switching to a wider shoe and assuming they’ve solved the problem. Width is important — a wide toe box prevents lateral compression — but if the shoe isn’t also deep enough (with adequate vertical toe box height), the PIP joint will still rub the upper with every step. A wide EE shoe with a low, shallow toe box is no better than a narrow shoe for dorsal PIP corn prevention. The correct specification is both wide AND deep — a full toe box depth that accommodates the bent toe without contact on the dorsal surface. Therapeutic-depth shoes (extra-depth shoes) provide an additional 3/8 inch of vertical space in the toe box specifically for this purpose and are the footwear standard for managing rigid hammertoes conservatively.

Red Flags: When Hammertoe Requires Urgent Evaluation

Hammertoe Treatment at Balance Foot & Ankle

At Balance Foot & Ankle, Dr. Tom Biernacki provides comprehensive hammertoe evaluation and treatment at our Howell and Bloomfield Hills locations. For flexible deformities, we offer footwear guidance, splinting, orthotic prescription, and corn care. For rigid hammertoes requiring surgery, Dr. Tom Biernacki has performed thousands of forefoot surgical procedures with high patient satisfaction. We provide digital X-ray on-site, same-day assessment for urgent presentations, and coordinate care for diabetic patients requiring routine preventive monitoring. Request your appointment or call (810) 206-1402.

Frequently Asked Questions

Can hammertoe be reversed without surgery?

A flexible hammertoe can be corrected or significantly improved without surgery through footwear modification, toe splinting, and intrinsic strengthening exercises. The window for non-surgical reversal is early — when the PIP joint is still passively correctable. Once the deformity becomes rigid (joint remodeled, passive correction impossible), surgery is the only way to straighten the toe. The earlier conservative treatment begins, the better the outcome. If your toe can still be pushed straight when you hold it, that’s the signal to act now with aggressive conservative measures.

Does hammertoe always need surgery?

No — not at all. Many patients with mild to moderate hammertoe control symptoms effectively for years or indefinitely with proper footwear (wide, deep toe box), padding over the PIP joint, and regular corn care. Surgery is indicated when the deformity is rigid and symptomatic — causing pain that limits activity, producing infected or recurring corns, causing a wound in a diabetic patient, or resulting in crossover toe with MTP instability. Cosmetic surgery for an asymptomatic hammertoe is generally not recommended. The goal is function and pain-free walking, not necessarily a perfectly straight toe.

How long does hammertoe surgery recovery take?

Most patients can walk in a post-operative shoe immediately after hammertoe surgery and return to athletic footwear at 6–8 weeks. The PIP arthroplasty is typically an outpatient procedure under local or regional anesthesia. Swelling in the toes after surgery resolves slowly — expect 3–6 months before the toe looks and feels completely normal. If a pin is used for fixation, it is removed at 4–6 weeks in the office. Most patients return to normal work within 1–2 weeks depending on their job demands. Results in terms of pain relief are excellent — approximately 85–90% of patients report significant improvement.

When should I see a podiatrist for a hammertoe?

See a podiatrist if your hammertoe is causing pain that limits walking or activity, if you have a corn or callus that recurs despite padding, if you have diabetes (any hammertoe in a diabetic patient warrants professional monitoring), if the toe is crossing over an adjacent toe, or if the deformity is progressing — getting harder to push straight, or causing more symptoms over time. Early evaluation preserves the option for conservative treatment. At Balance Foot & Ankle in Howell and Bloomfield Hills MI, same-day appointments are available for acute hammertoe problems. Call (810) 206-1402.

Sources

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