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Hammer Toes
Nicole Nelson, DO
David Bode, MD
image BASICS
Deformities of digits 2 to 5 (“lesser” digits) of the foot.
DESCRIPTION
  • Plantar flexion deformity of the proximal interphalangeal (PIP) joint with varying degrees of hyperextension of the metatarsophalangeal (MTP) and distal interphalangeal (DIP) joint; primarily in sagittal plane (1)
  • Can be flexible, semirigid, or fixed
    • Flexible: passively correctable to neutral position
    • Semirigid: partially correctable to neutral position
    • Fixed: not correctable to neutral position without intervention
EPIDEMIOLOGY
Most common deformity of lesser digits, typically affecting only one or two toes:
  • Second toe is the most commonly involved.
Incidence
  • Undefined
  • Increases with age, duration of deformity (from flexible to rigid)
Prevalence
  • Predominant sex: female > male (2)
    • Female predominance from 2.5:1 to 9:1, depending on age group
  • Can range from 1% to 20% of population studied
  • Blacks are more often affected than whites (2).
ETIOLOGY AND PATHOPHYSIOLOGY
  • Can be congenital or acquired
  • Biomechanical dysfunction results in loss of function of extensor digitorum longus (EDL) tendon at the PIP joint and the flexor digitorum longus (FDL) tendon at the MTP joint; the intrinsic muscles sublux dorsally as the MTP hyperextends. This results in plantar flexion of the PIP joint and hyperextension of the MTP joint (2).
  • Specific pathomechanics vary by etiology:
    • Toe length discrepancy or narrow footwear toe box induces PIP joint flexion by forcing digit to accommodate shoe.
      • May also lead to MTP joint synovitis secondary to overuse, with elongation of plantar plate and MTP joint hyperextension
    • Rheumatoid arthritis (RA) causes MTP joint destruction and resultant subluxation.
    • Any condition that compromises intra-articular and periarticular tissues, such as second ray longer than first, inflammatory joint disease, neuromuscular conditions, improper-fitting shoes, and trauma (3)
    • Damage to joint capsule, collateral ligaments, or synovia leads to unstable PIP joint or MTP joint.
Genetics
  • Significant heritability rates of 49-90% (4)
  • Specific genetic markers are not identified.
RISK FACTORS
  • Pes cavus, pes planus
  • Hallux valgus
  • Metatarsus adductus
  • Ankle equinus
  • Neuromuscular disease (rare)
  • Trauma; improperly fitted shoes (narrow toe box) and/or tight hosiery
  • Abnormal metatarsal and/or digit length
  • Inflammatory joint disease (e.g., RA)
  • Connective tissue disease
  • Diabetes mellitus
GENERAL PREVENTION
  • Proper fitting of shoes. Use of pressure-dispersive footwear helps reduce pain.
  • Foot orthoses modulate biomechanical dysfunction and muscular imbalance, preventing progression (2).
  • Control of predisposing factors (e.g., inflammatory joint disease) may also slow progression.
COMMONLY ASSOCIATED CONDITIONS
  • Hallux valgus
  • Cavus foot
  • Metatarsus adductus
  • Dorsal callus
image DIAGNOSIS
History and physical exam are typically sufficient for diagnosis of hammer toes. Additional tests are available to exclude other conditions.
PHYSICAL EXAM
  • Note MTP joint hyperextension, PIP joint flexion, and DIP joint extension.
  • Observe any adjacent toe deformities (e.g., hallux valgus, flexion contractures).
  • Assess degree of flexibility and reducibility of deformity in both weight-bearing and non-weightbearing positions (2)[C].
  • Note any hyperkeratosis over the joint, ulcers, clavi (dorsal PIP joint, metatarsal head), adventitious bursa, erythema, or skin breakdown (2)[C].
  • Palpate for pain over dorsal aspect of PIP joint or MTP joint.
  • Drawer test of MTP joint
  • Palpate web spaces to exclude interdigital neuroma.
  • Neurovascular evaluation (e.g., pulses, sensation, muscle bulk)
DIFFERENTIAL DIAGNOSIS
  • Hammer toe: hyperextension of the MTP and DIP joints and plantar flexion of the PIP joint
  • Claw toe: dorsiflexion of MTP joint and plantar flexion of the DIP joint
  • Mallet toe: fixed or flexible deformity of the DIP joint of the toe
  • Overlapping fifth toe
  • Interdigital neuroma
  • Plantar plate rupture
  • Nonspecific synovitis of MTP joint
  • Fracture; exostosis
  • Arthritis (e.g., rheumatoid, psoriatic)
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
  • Not required unless clinically indicated to rule out suspected metabolic or inflammatory arthropathies (2)[C]: rheumatoid factor, antinuclear antibodies (ANA), HLA-B27 serologies for inflammatory disease
  • Weight-bearing x-rays of affected foot in anteroposterior (AP), lateral, and oblique views (2)[C]:
    • AP view superior for assessing MTP subluxation or dislocation
    • Lateral view is best for the evaluation of hammer toe.
Follow-Up Tests & Special Considerations
MRI or bone scan if osteomyelitis is suspected
Diagnostic Procedures/Other
  • Nerve conduction studies or EMG if neurologic disorder is suspected
  • Doppler or plethysmography if impaired circulation and surgery is considered
  • Computerized weight-bearing pressure testing is indicated only in setting of neuromuscular deficiencies.
Test Interpretation
Histologic evaluation is not necessary before treatment.
image TREATMENT
  • Goal of treatment is to relieve symptoms and help patients return to their normal activity level.
  • Surgical and nonsurgical interventions are available.
  • Mild cases may not require treatment.
GENERAL MEASURES
Nonsurgical (conservative) treatments include
  • Shoe modifications (wider and/or deeper toe box) to accommodate the deformity and decrease the pressure over osseous prominences. Avoid high-heeled shoes (2)[C].
  • Toe sleeve or orthodigital padding of the hammer toe prominence (5)[C]
  • Hammer toe-straightening orthotics or taping to reduce flexible deformities
  • P.435

  • Débridement of hyperkeratotic lesions can reduce symptoms. Topical keratolytics may be helpful (2)[C].
  • Shoe orthotics mitigate abnormal biomechanics.
  • Physical therapy for stretching and strengthening of the toes helps preserve flexibility.
MEDICATION
For pain relief
First Line
NSAIDs may be helpful in managing symptoms of pain as well as soft tissue and joint inflammation.
ISSUES FOR REFERRAL
If nonsurgical (conservative) treatment is unsuccessful and/or impractical or patient has combined deformity of MTP joint, PIP joint, and/or DIP joint, then patient may be referred to an orthopedic surgeon or surgical podiatrist.
SURGERY/OTHER PROCEDURES
  • Surgical procedures for the correction of hammer toes depend on the degree and flexibility of the contracture(s) and related abnormalities.
  • Surgical interventions for flexible hammer toes include (1, 3, 5, 6)[C]
    • PIP joint arthroplasty (most common)
    • Flexor tendon lengthening/flexor tenotomy
    • Extensor tendon lengthening/tenotomy/MTP joint capsulotomy
    • Flexor to extensor tendon transfer
    • Exostosectomy
    • Implant arthroplasty
  • Surgical interventions for semirigid/rigid hammer toes include (1,3,5)[C]
    • PIP joint resection arthroplasty or arthrodesis
    • Girdlestone-Taylor flexor-to-extensor transfer
    • Metatarsal shortening (Weil osteotomy)
    • Exostosectomy
    • Diaphysectomy of the proximal phalanx (less common)
    • Middle phalangectomy (less common)
    • Soft tissue releases/lengthening
  • Procedures may be performed as isolated operations or in conjunction with other procedures.
  • Contraindications for surgery: active infection, inadequate vascular supply, and desire for cosmesis alone
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
  • Obtain radiographs immediately following surgery or at the first postoperative visit; subsequent x-rays as needed.
  • Full weight-bearing in a postoperative (surgical) shoe or other device based on the procedure(s) performed and the individual patient
  • Elevate the foot to minimize swelling.
  • Return to regular shoe wear after pain is controlled, swelling has subsided, and wounds have healed.
  • Role and efficacy of postoperative physical therapy (3 times a week for 2 to 3 weeks) unclear
Patient Monitoring
In the absence of complications, the patient should be seen initially within the 1st week following the procedure(s). Frequency of subsequent visits is determined based on the procedure(s) performed and the postoperative course.
PATIENT EDUCATION
  • Patients should be aware of mild to moderate swelling and plantar foot discomfort that may persist for many (1 to 6) months after surgery and may limit footwear options until resolved.
  • MTP joint and PIP joint may remain stiff for extended periods of time.
  • “Molding” of the operative toe (assuming the contours of adjacent toes) is common.
  • Encourage patients to wear shoes of adequate size with “roomy” (rounded or squared) toe box.
PROGNOSIS
  • Nonoperative (conservative) treatment usually alleviates pain; however, the deformity may progress.
  • Surgical treatment of flexible hammer toe deformity reliably corrects the deformity and alleviates pain. Recurrence and progression are common, especially if the patient continues to wear ill-fitting shoes.
  • Surgical treatment of fixed hammer toe deformity provides reliable deformity correction and pain relief. Recurrence is uncommon.
REFERENCES
1. Shirzad K, Kiesau CD, DeOrio JK, et al. Lesser toe deformities. J Am Acad Orthop Surg. 2011;19(8): 505-514.
2. Thomas JL, Blitch EL IV, Chaney DM, et al. Diagnosis and treatment of forefoot disorders. Section 1: digital deformities. J Foot Ankle Surg. 2009;48(3):418.e1-418.e9.
3. Zelen CM, Young NJ. Digital arthrodesis. Clin Podiatr Med Surg. 2013;30(3):271-282.
4. Hannan MT, Menz HB, Jordan JM, et al. High heritability of hallux valgus and lesser toe deformities in adult men and women. Arthritis Care Res (Hoboken). 2013;65(9):1515-1521.
5. Smith BW, Coughlin MJ. Disorders of the lesser toes. Sports Med Arthrosc. 2009;17(3):167-174.
6. Kwon JY, De Asla RJ. The use of flexor to extensor transfers for the correction of the flexible hammer toe deformity. Foot Ankle Clin. 2011;16(4): 573-582.
Additional Reading
&NA;
  • Marx RC, Mizel MS. What's new in foot and ankle surgery. J Bone Joint Surg Am. 2013;95(10): 951-957.
  • Miller JM, Blacklidge DK, Ferdowsian V, et al. Chevron arthrodesis of the interphalangeal joint for hammertoe correction. J Foot Ankle Surg. 2010;49(2):194-196.
See Also
&NA;
Algorithm: Foot Pain
Codes
&NA;
ICD10
  • M20.40 Other hammer toe(s) (acquired), unspecified foot
  • M20.41 Other hammer toe(s) (acquired), right foot
  • M20.42 Other hammer toe(s) (acquired), left foot
Clinical Pearls
&NA;
  • Hammer toe is a plantar flexion deformity of the PIP joint.
  • Initial management of hammer toe deformity is conservative. Consider surgery if pain persists or the deformity worsens.
  • Properly fitting footwear helps minimize recurrence. Patients should be aware of mild to moderate swelling and plantar foot discomfort that may persist for months after surgery and may limit footwear options until resolved.