Hammer/Claw/Mallet Toe
Robyn Fean
Jonathan Drezner
BasicsDescription
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Mallet toe is a flexion contracture of the DIP joint with normal alignment of the MTP and PIP joints. The 2nd toe is most commonly affected
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Hammer toe is a plantar flexion contracture of the proximal interphalangeal (PIP) joint. Passive extension of the metatarsophalangeal (MTP) joint is common. The distal interphalangeal (DIP) joint is neutral or slightly extended. The 2nd toe is most commonly affected.
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Claw toe is an extension contracture of the MTP joint with a flexion contracture of the PIP joint and sometimes the DIP joint. Claw toe usually results from weakness in the intrinsic muscles of the foot secondary to a neurologic condition and commonly affects multiple toes.
Epidemiology
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Hammer, claw, and mallet toes are the most common deformities of the lesser toes.
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Incidence increases with age.
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Predominant gender: Female > Males (∼9:1).
Risk Factors
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Hammer and mallet toe deformities are usually the result of long-term use of poorly fitting and constricting footwear.
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Abnormally long ray or digital length
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Pressure or deforming force from adjacent digits (ie, hallux valgus)
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Inflammatory joint disease
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Pes cavus may indicate an associated neuromuscular disorder.
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Claw toes are found in associated neurologic conditions such as peripheral neuropathies (diabetes and alcoholism), Charcot-Marie-Tooth disease, cerebral palsy, muscular dystrophy, and spinal cord tumors.
General Prevention
Avoidance of constrictive footwear.
Etiology
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Long-term use of poorly fitting and constricting footwear
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Idiopathic
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Congenital anatomic dysfunction
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Trauma
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Inflammatory arthropathy
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Neuromuscular dysfunction resulting in weakness in intrinsic muscle function
DiagnosisHistory
Painful callus formation over the dorsal aspect of the PIP or DIP joint (from rubbing against the undersurface of the shoe). Callus formation also may take place at the tip of the toe (1)[C].
Physical Exam
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Hammer toe:
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Painful callus over the dorsal aspect of the PIP joint (from rubbing against the undersurface of the shoe) is most common.
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Secondary metatarsalgia with plantar keratosis (callus) under the metatarsal head may occur if MTP joint subluxation is present.
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Claw toe: Painful callus formation over the dorsal PIP joint, beneath the metatarsal head, or on the end of the toe
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Mallet toe: Painful callus at the tip of the toe
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Physical examination:
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Patients should be evaluated both standing and non–weight bearing. (In hammer toe deformities, extension of the MTP joint is common in the standing position but may largely resolve when non–weight bearing.)
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Toes should be passively stretched to determine if the deformity is flexible (reducible to neutral position), semirigid (partially reducible), or rigid (nonreducible). A flexible hammer or claw toe deformity may appear to resolve when passively bringing the ankle from dorsiflexion to plantarflexion.
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Inspection for the presence of calluses, ulcers, adventitious bursa, infection, and interdigital maceration
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Calluses are common on the dorsum of the PIP joint and under the metatarsal head (hammer and claw toes) or on the tip of the toe (hammer, claw, and mallet toes).
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Dorsal dislocation of the proximal phalanx onto the metatarsal head may occur in advanced cases.
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A crossover deformity of the 2nd toe resting on top of the great toe may exist with medial subluxation of the 2nd MTP joint.
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Diagnostic Tests & Interpretation
Imaging
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Radiographs typically are unnecessary for conservative management in most cases.
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Weight-bearing anteroposterior (AP) radiographs are helpful to assess for the presence of MTP joint subluxation or dislocation.
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Lateral radiographs best confirm the deformity.
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Advanced imaging (bone scan or MRI) may be indicated when ulceration is present and osteomyelitis is suspected.
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Electromyography and nerve conduction studies may be useful to evaluate for peripheral neuropathies in claw toe deformities.
Differential Diagnosis
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Hammer toe (flexion of the PIP joint)
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Claw toe (extension of the MTP joint and flexion of the PIP and DIP joints)
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Mallet toe (flexion of the DIP joint)
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Hard corn (keratosis over the lateral aspect of the 5th toe)
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Interdigital (soft) corn (keratosis and maceration resulting from pressure between 2 adjacent toes)
P.287
Treatment-
Long-term treatment
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Acute treatment:
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Shoes with a roomy toe box are recommended to accommodate the deformity (an elevated toe box may eliminate dorsal pressure on the PIP joint).
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High-heeled shoes should be avoided.
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Passive manual stretching and strengthening exercises for the intrinsic foot muscles (laying a towel flat on the floor and using the toes to crumple it beneath the foot) may be helpful for flexible deformities.
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Débridement of hyperkeratotic lesions and home use of a pumice stone may reduce painful calluses.
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Foam pads used over the callosity or a cushioned toecap to protect the end of the toe may reduce symptoms.
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Metatarsal pads placed proximal to the MTP joint may reduce pressure on the metatarsal heads.
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Taping the toe in a corrected position may stabilize a subluxed MTP joint.
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Medication
First Line
NSAIDs may be appropriate to relieve pain and inflammation
Additional Treatment
General Measures
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Shoes with a roomy toe box are recommended to accommodate the deformity (an elevated toe box may eliminate dorsal pressure on the PIP or DIP joint) (2)[C].
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High-heeled shoe should be avoided (2)[C].
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Foam pads used over the callosity or a cushioned toe cap to protect the end of the toe may reduce symptoms.
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Metatarsal pads placed proximal to the MTP joint may reduce pressure on the metatarsal heads.
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A toe crest placed beneath the toes may be used to diminish pressure on the tip of the toe (2)[C].
Surgery/Other Procedures
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Surgery is indicated when nonoperative treatment is unsuccessful in relieving symptoms (2)[C].
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Flexible hammer/claw toes may be repaired with flexor and extensor percutaneous tenotomies (3)[C].
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Rigid deformities require a capsulotomy or treatment with arthroplasty (joint resection) or arthrodesis (joint fusion) (3)[C].
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Flexible mallet toes may be treated with percutaneous release of the flexor digitorum longus tendon (4)[C].
Ongoing CareFollow-Up Recommendations
Referral for surgical consideration is recommended when conservative treatment has not adequately relieved symptoms.
Prognosis
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Surgery usually can be avoided if conservative treatment is started early.
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When needed, surgery can be very effective in alleviating pain and improving the deformity.
Complications
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Toe and toenail deformity
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Chronic pain/metatarsalgia
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If surgery is performed, persistent numbness of the toe and surrounding areas may occur as a result of nerve injury.
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Malalignment of the digits may occur after surgery.
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Flexor digitorum longus tendon transfer results in the inability to actively flex the affected toe.
References
1. DeLee JC, Drez D. Orthopaedic sports medicine. Philadelphia: WB Saunders, 1994.
2. Coughlin MJ. Lesser-toe abnormalities. J Bone Joint Surg-Am. 2002;84:1446–1469.
3. Migues A, Campaner G, Slullitel G, et al. Minimally invasive surgery in hallux valgus and digital deformities. Orthopedics. 2007;30:523–526.
4. Coughlin MJ. Operative repair of the mallet toe deformity. Foot Ankle Int. 1995;16:109–116.
Additional Reading
Bade H, Tsikaras P, Koebke J. Pathomorphology of the hammer toe. Foot Ankle Surg. 1998;4:139–143.
Barakat MJ, Gargan MF. Deformities of the lesser toes. How should we describe them? The Foot. 2006;16:16–18.
Hammer toe syndrome. American College of Foot and Ankle Surgeons. J Foot Ankle Surg. 1999;38:166–178.
Snider RK, ed. Essentials of musculoskeletal care. Chicago: American Academy of Orthopaedic Surgeons, 1997.
CodesICD9
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735.4 Other hammer toe (acquired)
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735.5 Claw toe (acquired)
Clinical Pearls
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The distinction between hammer toe and claw toe deformities can be difficult because both have flexion contractures of the PIP joint.
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However, in claw toe, deformities of multiple toes are involved, and there is always an extension deformity of the MTP joint and often a flexion contracture of the DIP joint.