Definition

Mallet toe refers to an abnormal flexion deformity at the distal interphalangeal (DIP) joint ( Fig. 89.1 ). Typically, the metatarsophalangeal and proximal interphalangeal joints are aligned in neutral position without extension or flexion. The most commonly affected toe is the longest toe, usually the second. The deformity may be fixed (rigid), semirigid, or flexible; it may occur unilaterally or bilaterally, and it may be acquired or hereditary. The cause of mallet toe is not clear, but is associated with trauma, arthritis, genetics, and neuromuscular and metabolic diseases. High-heeled shoes and shoes with a narrow toe box may aggravate the deformity; it is present symptomatically more in women. There is some observational evidence to suggest that a toe significantly longer than adjacent toes is at increased risk for development of deformities (mallet toe, hammer toe, claw toe). The incidence of a mallet toe deformity is much less common than that of a hammer toe deformity at almost 1:10. Clinically, the difference between mallet toe, hammer toe, and claw toe is that hammertoe involves flexion at the PIP, while mallet toe involves only the DIP. Hammer toes are typically more problematic compared with mallet toe deformity. Claw toe involves flexion deformity at both DIP and PIP.

Mallet toe ( arrow indicates usual area of hyperkeratosis or ulcer formation).

From Maguire S. Mallet toe. In: Frontera WR, Silver JK, Rizzo TD Jr, eds. Essentials of Physical Medicine and Rehabilitation, 2nd ed. Philadelphia: WB Saunders; 2008.

Symptoms

Patients typically complain of pain or tenderness in the area of the dorsal DIP joint or distal aspect of the toe, most commonly when wearing shoes, particularly with a narrow or low toe box. The symptoms are also worse during weight-bearing activities, such as running. Patients may also have complaints of toenail deformities, which eventually may become painful. A painful corn or clavus may develop on either the dorsal aspect of the DIP joint (as a result of shoe irritation) or the distal aspect of the toe.

Physical Examination

The degree of DIP joint flexion should be evaluated, both weight bearing and non–weight bearing. Passive range of motion should be determined to evaluate whether the deformity is flexible, rigid, or semi-rigid, which will influence treatment options. One should inspect for erythema or cutaneous lesions (corns) on both the dorsal and distal aspects of the toe. Corns may progress to ulcers with subsequent superficial or deep infection, especially in the diabetic population with neuropathy. If the patient has peripheral arterial disease, ulceration may lead to necrosis and possible toe loss.

Swelling, increased temperature, or erythema might indicate inflammatory arthritis or joint infection. The patient’s footwear should be examined to determine sufficient or insufficient toe box height to accommodate the deformity. Traditional neurologic and vascular examinations generally reveal no abnormal findings in uncomplicated mallet toe conditions.

Functional Limitations

Functional limitation in ambulation occurs most often as the result of pain, particularly with wearing of closed shoes and with weight-bearing activities. Walking may be limited, and high-impact activities such as running may be altogether too painful. Both men and women may complain that they are unable to wear fashionable shoes (dress and high heeled) required for their work environment. Painless deformity generally neither causes functional limitations nor requires treatment.