Lesser Toe Deformities

Lesser Toe Deformities

J. Benjamin Jackson III, MD, FACS

Thomas B. Bemenderfer, MD, MBA

J. Kent Ellington, MD, MS

Dr. Jackson or an immediate family member serves as a board member, owner, officer, or committee member of the American Orthopaedic Foot and Ankle Society. Dr. Ellington or an immediate family member has received royalties from Arthrex, Inc., BME, and Medline; is a member of a speakers’ bureau or has made paid presentations on behalf of Synthes; serves as a paid consultant to or is an employee of Amniox, Medline, and Synthes; and has stock or stock options held in Medshape. Neither Dr. Bemenderfer nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.


Lesser toe deformities affect the smallest phalanges of the human body but can have a substantial effect on a patient’s daily life by causing pain with ambulation either shod or barefoot. Lesser toe deformities can be caused by trauma, intrinsic muscle imbalance, a neurologic disorder, an inflammatory disorder, an ill-fitting shoe, diabetes, hallux valgus, or a congenital etiology. Population-based studies in Australia and Sweden found that surgical management of these deformities accounted for 28% to 46% of all forefoot procedures.1,2 There are numerous conservative treatment modalities for lesser toe deformities. However, some patients will fail nonsurgical management. There are multiple surgical options that can lead to successful restoration of toe alignment and a decrease in pain and callus formation.

Mallet Toe, Hammer Toe, and Claw Toe

Pathoanatomy and Etiology

An understanding of the anatomy of the lesser toes is important to appreciate the pathologic changes that occur with deformity. The lesser toes serve to distribute pressure and balance the foot. Deformities can lead to pain, callus formation, transfer lesions, and compensatory gait changes. The deformity initially is flexible, but it may become more rigid as it progresses. The terms that are utilized to describe deformities of the lesser toes are often used incorrectly. This can lead to misunderstandings about the exact pathophysiology and treatment.

A mallet toe is defined as an isolated flexion deformity of the distal interphalangeal (DIP) joint. A hammer toe is a flexion deformity of the proximal interphalangeal (PIP) joint, with or without DIP joint involvement. Finally, a claw toe deformity is an extension of the metatarsophalangeal (MTP) joint with flexion of the PIP and DIP joints (Figure 1). Claw toes often are frequently associated with neuromuscular conditions and typically involve multiple lesser toes and both feet. A hammer toe, however, can occur in isolation; the second toe is most commonly affected.3

The static stabilizers of the lesser toes include the plantar plate, joint capsule, plantar aponeurosis, and the proper and accessory collateral ligaments. The dynamic stabilizers include the extrinsic muscles (extensor digitorum longus and flexor digitorum longus [FDL]) and the intrinsic muscles (extensor digitorum brevis and flexor digitorum brevis, lumbricals, and interossei). The FDL tendon inserts on the distal phalanx and flexes the DIP joint. The flexor digitorum brevis tendon inserts on the middle phalanx and flexes the PIP joint. Because there is no direct flexor insertion on the proximal phalanx, the MTP joint in the extended position lacks antagonists, resulting in flexion in the PIP and DIP joints. The extensor digitorum longus tendon divides into three slips over the proximal phalanx (Figure 2); the middle slip inserts onto the base of the middle phalanx, and the medial and lateral slips pass laterally and converge to form the terminal tendon that inserts on the base of the distal phalanx. The transverse metatarsal ligament divides the intrinsic musculature, with the interossei dorsal and the lumbricals

plantar to the ligament. Both muscles are plantar to the MTP joint axis and provide flexion of the MTP joint. The intrinsic muscles pass dorsal to the PIP and DIP joint axes to extend these joints.4 Hammer toe and claw toe deformities occur with simultaneous contracture of the long flexors and extensors of the toe, causing imbalance and overpowering the weaker intrinsic muscles.5

FIGURE 1 Lateral-view schematics showing (A) a mallet toe, (B) a hammer toe, and (C) a claw toe.

FIGURE 2 Schematics showing the anatomy of a lesser toe. A, The dorsal extrinsic and intrinsic musculature. The extensor digitorum longus (EDL) tendon traverses the metatarsophalangeal (MTP) joint dorsally and splits into three parts. The middle slip extends the proximal interphalangeal joint. The lateral and medial slips form the terminal tendon and extend the distal interphalangeal joint (DIP). The tendon extends the MTP joint through the extensor sling, which is composed of medial and lateral fibroaponeurotic bands that originate on each side of the EDL tendon. B, The lateral extrinsic (top) and intrinsic (bottom) musculature. The flexor digitorum longus (FDL) tendon inserts onto the plantar base of the distal phalanx and flexes the DIP joint. The flexor digitorum brevis (FDB) tendon is split by the central FDL tendon into medial and lateral slips that insert onto the plantar base of the middle phalanx; this tendon is responsible for proximal interphalangeal joint flexion.

The MTP joint often is involved in these deformities. It is stabilized by collateral ligaments and the plantar plate. As the deformity progresses, attenuation of the plantar plate leads to subluxation of the proximal phalanx dorsally onto the metatarsal head. The metatarsal fat pad is pulled distally, and the metatarsal head is depressed plantarly, leading to metatarsalgia.

Clinical Evaluation

Patients commonly report pain that is often associated with footwear, as well as callus formation over the PIP joint, corn formation, and pain at the tip of the toe. In addition, the patient may have pain and callosity under the MTP joint. A standing and seated foot examination is imperative. Many deformities cannot be truly appreciated during the seated examination alone. The position of the hallux should be evaluated as a possible contributor to lesser toe deformity. A careful examination of the patient’s neurovascular status is important because a neurologic condition may be the underlying etiology. If surgery is being considered, it is necessary to ensure that tissue perfusion is adequate for successful healing.

Feb 27, 2020 | Posted by in ORTHOPEDIC | Comments Off on Lesser Toe Deformities
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