Toe Posture Disorders (Hammer, Claw, and Mallet Toes)

Populations and Risk Factors

• Prevalence increases with age — estimated 2–20% of the general population, rising significantly after age 60
• Women affected more commonly than men (approximately 4–5:1 ratio), primarily attributed to narrow-toe-box footwear and high heels that force the toes into flexed positions chronically
• Individuals with a second toe longer than the great toe (Morton's foot type) — the longer toe is crowded in footwear, predisposing to hammertoe deformity
• Diabetes mellitus — motor neuropathy causes intrinsic foot muscle atrophy, allowing extrinsic flexor dominance and progressive clawing; sensory neuropathy means the deformity may progress painlessly until ulceration occurs
• Charcot-Marie-Tooth disease and other hereditary motor-sensory neuropathies — intrinsic muscle wasting produces the characteristic bilateral claw toe pattern
• Rheumatoid arthritis — MTP joint destruction and synovitis weaken the plantar plate and allow dorsal subluxation of the proximal phalanx
• Pes cavus (high arch) — the rigid, supinated foot concentrates pressure on the metatarsal heads and predisposes to claw toe deformity through intrinsic muscle shortening
• Pes planus (flat foot) — excessive pronation alters the force vectors through the MTP joints
• Hallux valgus — as the great toe deviates laterally, the 2nd toe loses its lateral buttress and may develop hammertoe or crossover deformity
• Poorly fitting footwear (narrow toe boxes, high heels, shoes too short) — the single most modifiable risk factor

Causes and Pathophysiology

Intrinsic-Extrinsic Muscle Imbalance

• Normal toe alignment depends on a balance between the intrinsic muscles (lumbricals and interossei, which flex the MTP joint and extend the IP joints through their insertion into the extensor expansion) and the extrinsic muscles (extensor digitorum longus, which extends the MTP, and flexor digitorum longus/brevis, which flex the IP joints). When the intrinsic muscles weaken or atrophy, the extrinsic muscles act unopposed.
• The imbalance cascade: intrinsic muscle weakness or denervation → loss of MTP flexion and IP extension control → the extensor digitorum longus hyperextends the MTP joint unopposed → the flexor digitorum longus and brevis flex the IP joints unopposed → the proximal phalanx subluxes dorsally on the metatarsal head → the plantar plate stretches and attenuates → the deformity becomes self-reinforcing as the tendons bowstring across the deformed joints.
• Footwear contribution: narrow toe boxes physically force the toes into flexed positions. High heels increase forefoot loading and shift body weight forward, overloading the MTP joints and exacerbating the flexor-extensor imbalance. Chronic footwear-induced positioning creates adaptive shortening of the flexor tendons and joint capsules.

Deformity Types

• Hammertoe: flexion contracture at the PIP joint with hyperextension at the MTP joint; the DIP may be neutral or slightly flexed. Most commonly affects the 2nd toe. The dorsal PIP prominence rubs against footwear, producing dorsal corns. Classified as flexible (passively correctable) or rigid (fixed).
• Claw toe: flexion contractures at both the PIP and DIP joints with MTP hyperextension. Affects multiple toes simultaneously (unlike hammertoe, which is often a single-toe deformity). The characteristic "clawed" appearance results from global intrinsic muscle failure — this is why claw toes are a neurological warning sign. Dorsal IP prominences and plantar metatarsal head pressure produce both dorsal corns and plantar calluses.
• Mallet toe: isolated flexion contracture at the DIP joint only; the PIP and MTP are uninvolved. Typically affects the 2nd or 3rd toe. The flexed DIP tip presses against the shoe sole or ground, producing a distal tip callus or nail deformity. Less functionally significant than hammertoe or claw toe but can produce persistent distal toe pain.

Plantar Plate and MTP Joint Dysfunction

• The plantar plate is a fibrocartilaginous structure on the plantar surface of each MTP joint that provides static stability against dorsal subluxation of the proximal phalanx. In toe posture disorders, chronic MTP hyperextension stretches and attenuates the plantar plate, leading to progressive dorsal subluxation — the proximal phalanx rides up on the metatarsal head, concentrating weight-bearing pressure on the metatarsal head rather than distributing it across the toe pad.
• This plantar plate failure is why clients develop metatarsal head calluses and metatarsalgia — the deformed toe no longer participates in weight-bearing and load distribution during push-off. The metatarsal heads bear the load directly against the ground, producing pressure-induced callus and deep tissue pain.

Altered Toe-Off Mechanics and Ascending Chain

• Normal toe-off in gait requires the toes to remain in contact with the ground during push-off, distributing propulsive forces and activating the windlass mechanism (great toe dorsiflexion tensions the plantar fascia, raising the arch). When the lesser toes are clawed or hammered, they cannot contact the ground during push-off — the MTP hyperextension lifts the toe pads off the weight-bearing surface.
• Loss of effective toe-off reduces gait efficiency, shortens stride length, and transfers propulsive loading to the remaining functional toes (often the great toe) and the metatarsal heads. If the great toe is also deformed (hallux valgus), the entire forefoot push-off mechanism is compromised.
• Plantar fascial restrictions: the chronic MTP hyperextension pre-tensions the plantar fascia through the windlass mechanism at rest, which may produce plantar fascial irritation and contribute to plantar fasciitis.
• Ascending chain effects: altered toe-off → compensatory ankle and knee mechanics to maintain gait velocity → hip compensation → potential pelvic and lumbar asymmetry. The effects are less dramatic than in major structural foot disorders (pes planus/cavus) but are cumulative, particularly when multiple toes are affected.

Signs and Symptoms

Hammertoe

• Visible PIP flexion deformity with MTP hyperextension, most commonly 2nd toe
• Dorsal corn or callus over the PIP prominence (friction from shoe dorsal contact)
• Pain at the PIP joint with footwear pressure
• Plantarward pressure under the corresponding metatarsal head (metatarsalgia)
• Flexible early → rigid late; the deformity may be passively correctable initially but becomes fixed as capsular contracture develops

Claw Toe

• All IP joints (PIP and DIP) flexed with MTP hyperextended — affects multiple toes, often bilaterally
• Dorsal corns over the PIP prominences AND plantar calluses under the metatarsal heads (dual pressure pattern)
• More functionally disabling than hammertoe — multiple toes are unable to participate in push-off
• Neurological association: bilateral, progressive, symmetric claw toes suggest intrinsic muscle denervation — screen for diabetic neuropathy (stocking-glove sensory loss, diminished reflexes), Charcot-Marie-Tooth (distal muscle wasting, "inverted champagne bottle" legs, pes cavus), or other neuromuscular conditions

Mallet Toe

• Isolated DIP flexion; PIP and MTP uninvolved
• Distal tip callus or nail deformity from end-bearing pressure (the flexed DIP tip presses into the shoe sole)
• Less gait disruption than hammertoe or claw toe — the MTP joint functions normally
• Typically 2nd or 3rd toe

Common Across All Types

• Pain where deformed joints rub against footwear (dorsal, distal, or plantar depending on type)
• Metatarsalgia — pain and callus under the metatarsal heads from concentrated weight-bearing
• Impaired push-off phase of gait; reduced walking speed and endurance
• Difficulty fitting shoes; preference for open-toed or extra-depth footwear
• Ascending compensatory pain in the knee, hip, and low back (cumulative, especially with multiple deformed toes)

Assessment Profile

Subjective Presentation

• Chief complaint: "My toes are curling and I can't straighten them"; "the tops of my toes hurt in my shoes"; "I have painful corns that keep coming back"; "the ball of my foot hurts when I walk" (metatarsalgia); "my toes look clawed — my doctor said it's from my diabetes"
• Pain quality: Sharp, burning pain at the dorsal PIP prominences from shoe friction; deep ache under the metatarsal heads from plantar pressure; distal tip pain in mallet toe; corns and calluses may produce sharp, localized pain when pressed
• Onset: Usually gradual over months to years; may be accelerated by change in footwear or progressive neurological disease. In diabetic neuropathy, the deformity may progress painlessly — the client may not notice the clawing until ulceration or skin breakdown occurs. Post-hallux valgus development, the 2nd toe may rapidly develop hammertoe as it loses its lateral buttress
• Aggravating factors: Enclosed footwear (especially narrow toe boxes and high heels), prolonged walking, standing, running; activities requiring push-off; pressure on corns and calluses
• Easing factors: Open-toed or wide-toe-box footwear, toe pads, corn pads, metatarsal pads (redistribute pressure proximal to the metatarsal heads), rest, warm foot soaks
• Red flags: Diabetic client with progressive clawing and loss of sensation — risk of painless ulceration over pressure points; ensure regular podiatric surveillance. Rapidly progressive bilateral clawing with distal weakness and sensory loss in the feet → suspect peripheral neuropathy (diabetic or hereditary); refer for neurological evaluation

Observation

• Local inspection: Identify the specific deformity type by joint involvement — PIP flexion only (hammertoe), PIP + DIP flexion (claw toe), DIP flexion only (mallet toe); check all toes bilaterally. Note dorsal corns (over PIP/DIP prominences), plantar calluses (under metatarsal heads), distal tip calluses (mallet toe). Check for associated hallux valgus, skin breakdown, ulceration (diabetic), erythema, or open sores over pressure points. Assess the foot overall: arch type (pes cavus predisposes), forefoot width, intrinsic muscle wasting (visible concavity in the interosseous spaces on the dorsal foot indicates atrophy)
• Posture: Bilateral foot assessment — arch height, calcaneal alignment, hallux position. Note intrinsic muscle wasting (dorsal interosseous concavity). Ascending chain: assess the effects of altered push-off mechanics on tibial rotation, knee alignment, hip rotation, and pelvic levelness
• Gait: Reduced toe contact during push-off (toes lift off the ground rather than pressing into it); shortened stride; compensatory ankle plantarflexion to assist push-off; possible forefoot slapping; clients with severe clawing may walk on the metatarsal heads rather than through the normal heel-to-toe progression

Palpation

• Tone: Flexor digitorum longus and flexor digitorum brevis hypertonic (the extrinsic flexors maintaining the deformity); extensor digitorum longus may be hypertonic from compensatory MTP hyperextension; lumbricals and interossei may be atrophied and non-palpable in neurological cases; flexor hallucis longus may be hypertonic if compensating for lost lesser toe push-off; gastrocnemius-soleus hypertonicity may be present if calf shortness contributes to forefoot overloading
• Tenderness: Dorsal PIP and DIP prominences tender from shoe friction and corn formation; plantar metatarsal heads tender from concentrated weight-bearing (the "ballpoint pen" sign — point tenderness under each metatarsal head); plantar fascia may be tender if chronic MTP hyperextension pre-tensions the fascia; calluses themselves may be painless but the deep tissue beneath is tender
• Temperature: Usually normal; warmth over a corn or callus may indicate secondary infection — particularly critical in diabetic clients where infection risk is elevated and healing is impaired; warmth at an MTP joint suggests active synovitis (rheumatoid arthritis)
• Tissue quality: Thickened, fibrotic flexor tendons on the plantar surface of the toes; capsular contracture palpable at the PIP joint in rigid deformities; calluses (dorsal, plantar, distal) represent tissue adaptation to chronic pressure; intrinsic foot muscles may feel atrophied and "flat" with loss of normal muscular bulk in the web spaces; plantar fat pad may be displaced proximally from the metatarsal heads (loss of natural cushioning)

Motion Assessment

• AROM: Attempt active toe extension — inability to straighten the PIP (hammertoe, claw toe) or DIP (mallet toe, claw toe) indicates the deformity. Active toe wiggling and spreading may be reduced or absent. Active MTP flexion against resistance (the "paper grip test" — attempt to grip a piece of paper between the toes and the ground) tests intrinsic foot muscle function
• PROM / end-feel: This is the critical assessment — it distinguishes flexible (correctable) from rigid (fixed) deformities. Passively extend the PIP: if it corrects to neutral with a soft tissue end-feel, the deformity is flexible and responds well to manual therapy and splinting. If it does not correct or meets a hard/bony end-feel, the deformity is rigid and requires surgical consideration for correction. Passively flex the MTP while extending the IP joints: if the toes straighten when the MTP is plantarflexed, the extrinsic muscles are the dominant deforming force
• Resisted testing: Resisted toe flexion tests extrinsic flexor strength (typically strong — these muscles are not weak, they are dominant). Resisted toe extension may be weak if the intrinsic muscles are denervated. The paper grip test (resisted toe MTP flexion with IP extension) specifically tests intrinsic muscle function — inability to perform this motion confirms intrinsic muscle failure

Special Test Cluster

For clients with diabetes or suspected neurological disease presenting with bilateral progressive claw toes: perform a full lower extremity neurological screen (L4–S1 myotomes, Achilles reflex, vibration sense at the great toe, monofilament testing). Neurological claw toes require a different management approach than mechanical toe deformities.

Differential Diagnoses