Chapter 209. Hammer Toe

A 44-year-old woman presented with pain in the ball of her left foot on weight-bearing. She works as a nurse and walks most of her 12-hour shift. Two months ago she noticed a new deformity of the second digit of her left foot (Figure 209-1). Her second digit was contracted with a nonreducible proximal interphalangeal joint and reducible metatarsophalangeal (MTP) joint. Her x-ray is seen in Figure 209-2.

She was referred to a podiatrist who diagnosed an acute isolated hammer-toe deformity. At the time of surgery a plantar plate rupture at the MTP joint was found. The podiatrist fused her proximal interphalangeal (PIP) joint and released her extensor tendon and dorsal capsule at the MTP joint to reduce the deformity. She began protective ambulation in a surgical shoe on postoperative day 3. An internal fixation wire, which was used to fixate the fusion site, was removed in 4 weeks. She returned to work and her regular activities within 6 weeks of the operation.

Hammer-toe deformity is a flexion contracture in the PIP joint of a pedal digit, resulting in plantar flexion of the middle phalanx at the PIP joint with dorsal angulation of the proximal phalanx at the MTP joint. Hammer toes are associated with imbalance of soft-tissue structures around the joints in the digits and are often progressive. Surgical correction is required when deformity interferes with function.

• Hammer toe, claw toe, and mallet toe describe similar digital ­contractures.
• Claw toe refers to progression of hammer toe to include extension of the MTP joint along with flexion in the PIP joint.
• Mallet toe has a digital contracture at the distal interphalangeal (DIP) joint.

Hammer-toe deformity is the most common digital deformity, and it can affect up to 60% of adults. The second digit is most commonly affected.1

A hammer toe is caused by multiple factors:

• Genetic and hereditary factors.
• Abnormal biomechanics (cavus or high-arch foot, flatfoot deformity, loss of intrinsic muscle function, and hypermobile first ray).
• Long metatarsal and/or digit.
• Systemic arthritidis.
• Neuromuscular diseases such as Charcot-Marie-Tooth disease (Figure 209-3).
• Ill-fitting shoes.
• Trauma.
• Iatrogenic causes.

• High-arch foot type (cavus foot).
• Flatfeet.
• Bunion deformity (Figure 209-4).

The diagnosis of hammer-toe deformity is made clinically and ­radiographically.

• Pain and deformity in 1 or more of the lesser toes.
• Dorsiflexed proximal phalanx at the MTP joint and plantarflexed middle phalanx at the PIP joint of a lesser digit.
• Callus formation at the dorsal aspect of the PIP joint and/or distal aspect of the digit.
• Edema and tenderness on the plantar aspect of the lesser MTP joint(s).
• Associated signs—Cavus foot deformity, flatfoot deformity, bunion deformity, transverse deformity of the digits, decreased ankle dorsiflexion, and bowstringing of the extensor and/or flexor tendons.
• Evaluation of the digit in weight-bearing and non-weight-bearing conditions helps assess reducibility and rigidity of the deformity. In the case of predislocation syndrome (acute rupture or tear of the MTP joint capsule or plantar plate), the deformity may not be appreciated unless the foot is evaluated in the weight-bearing position.2

Obtain weight-bearing plain radiographs in dorsoplantar, lateral, and medial oblique views (Figure 209-2).

• Dorsal angulation and/or translation of the proximal phalanx on the metatarsal head with plantar angulation of the middle phalanx (lateral view).
• Degenerative changes in the digital joints and dislocation in the MTP joint.
• Transverse deformity and abnormal metatarsal length (dorsoplantar view).

Pain and swelling in the digit may be caused by the following:

• Gout or pseudogout presents with acute pain with signs of inflammation, and prior history of gout/pseudogout. Joint aspiration may be performed to rule out septic joint (see Chapter 100, Gout).
• Rheumatoid arthritis presents with pain, inflammation, and loss of range of motion and is often symmetrical. Radiographic evidence of other small foot joint involvement usually is evident (see Chapter 97, Rheumatoid Arthritis).
• Septic joint presents with acute pain, loss of range of motion, and systemic signs and symptoms of infectious process.
• Fractured toe caused by sudden trauma.
• Neuroma in the intermetatarsal space (Morton neuroma) with compression of the intermetatarsal nerves—Numbness and cramping of the innervated toes are the most common symptoms.

Conservative measures and surgical treatment may be used to correct this condition. Note that a neglected hammer-toe deformity could result in ulceration in a patient with diabetes.

Nonpharmacologic

• Change shoes.
• Pad shoes to limit shearing force. A crest pad can be used to prevent painful callus formation at the distal tip of the digit (Figure 209-5).
• Splinting can be used in an early flexible hammer toe.
• Custom-made orthoses are helpful to slow down progression of the deformity if it is caused by biomechanical factors.
• Rest, NSAIDs, and ice help an inflamed joint and/or shoe irritation.

Surgical Treatment

• Consider surgical referral to a foot specialist to correct the deformity.
• Percutaneous tenotomy and/or capsulotomy are used for mild, flexible deformities.
• Resectional arthroplasty at the PIP joint may be beneficial for a more rigid deformity.
• Shortening osteotomy of the metatarsal is indicated in the deformities resulting from the long metatarsal.
• Arthrodesis (fusion) of the PIP joint and/or flexor tendon transfer is indicated for a severe deformity (Figure 209-6).
• Adjunctive procedures (e.g., correction of bunion, cavus foot, ­flatfoot deformities, and ankle equinus) may be necessary for a good long-term outcome.

• Proper shoes with an adequate toe box and heel counter prevent excessive contracture of the digits.
• Controlling associated deformities, such as bunion and flatfoot deformities via orthotic management can prevent progression of hammer-toe deformity.

• The prognosis worsens as the deformity progresses.
• Function and quality of life can be affected in severe debilitating deformity. Surgical correction provides good prognosis in such patients.

Periodic debridement of the calluses developed from the deformity may be sufficient in many of the patients if the deformity is not progressive. Serial plain radiographs can be obtained to follow the progression of the deformity and arthritic changes in the first MTP joint. In a high-risk, immunocompromised, neuropathic patient, prophylactic surgical correction of the deformity may be indicated.

Explain to patients that conservative measures may prevent progression of the deformity and provide temporary relief, but that surgical management is necessary to correct the deformity. Surgical treatment can require up to 4 to 6 weeks of non-weight-bearing status postoperatively in severe deformities. A less-involved surgical approach to correct a mild deformity can allow a patient to walk on the same day as the surgery. In many cases, fixation with a pin, small screw, or implant is necessary to correct the deformity.

Patient Resource

• MedlinePlus. Hammer Toe—http://www.nlm.nih.gov/medlineplus/ency/article/001235.htm.

Provider Resource

• Medscape. Hammertoe Deformity—http://emedicine.medscape.com/article/1235341.