LESSER TOE DISORDERS

Each of the lesser toes consists of three phalanges, the
proximal, middle, and distal phalanx. In the case of the fifth toe,
sometimes the middle and distal phalanx fail to separate (7).
Barriers to deformities include the medial and lateral collateral
ligaments of the metatarsophalangeal (MP) joints, as well as of the
proximal and distal interphalangeal joints. The plantar plate helps to
passively return the MP joints to a neutral position when the joints
are dorsiflexed during ambulation.

Active motion of the joints of the lesser toes is accomplished with both the intrinsic and the extrinsic musculature (11).
Dorsiflexion of the MP joint is accomplished by the extensor digitorum
longus tendon, whereas flexion of that joint is accomplished by the
intrinsic lumbrical and interossei musculature. The interossei attach
to the dorsal hood over the proximal phalanx, and through this they
work to act as extensors of the proximal and distal interphalangeal
joints. The proximal interphalangeal (PIP) joint is plantar flexed by
the flexor digitorum brevis, and the distal interphalangeal joint is
plantar flexed by the flexor digitorum longus (FDL) tendon. Because the
strength of the extrinsics is significantly greater than that of the
intrinsics, deformities are most commonly that of dorsiflexion at the
MP joint and plantar flexion at the proximal and distal interphalangeal
joints.

The etiology of a flexible hammer toe
is often a tight FDL tendon; if the deformity persists for a sufficient
duration, it can become fixed. A disproportionately long lesser toe or
a shoe with a tight toe box can also cause a fixed hammer-toe
deformity. Further causes of hammer-toe deformity can be poor shoe wear
or the formation of a hallux

valgus deformity, which can push the second toe into a “hammered” or overlapped position.

A rigid hammer toe is defined as a fixed flexion deformity of the PIP joint (10). This deformity can cause symptoms over the dorsum of the PIP joint where the toe rubs against the top of the toe box (Fig. 113.1),
or at the tip of the toe where the toe hits the sole of the shoe. If
the hammer toe produces sufficient distal migration of the plantar
fatty cushion, pain under the metatarsal head can result. Shoe
modifications, including extradepth shoes, soft insoles, and metatarsal
pads, can help to alleviate symptoms.

Evaluation of the entire foot for related deformities,
such as a tight FDL tendon or a hallux valgus deformity, is important
prior to any surgical treatment. A hallux valgus deformity can reduce
the space lateral to the hallux, which prevents reduction of a second
toe into a reduced position. If this condition exists, a hallux valgus
repair should be strongly considered as a concomitant surgical
procedure.

A flexible hammer-toe deformity can decrease or be
completely eliminated with plantar flexion of the MP joint or of the
ankle. These deformities are usually caused by tightness of the FDL
tendon. Treat a flexible hammer toe with a Girdlestone-Taylor (11)
flexor tendon transfer if surgery is indicated. This transfer, often
combined with the release of deforming forces at the MP joint, can
produce satisfactory results. An arthroplasty of the PIP joint is
sometimes combined with the tendon transfer if there is some element of
a fixed component.

Deformities or pain at the MP joint can exist along with a hammer toe (5,8,9,13).
These usually consist of a fixed dorsiflexion deformity, although
subluxation or dislocation of the joint can occur. Mild dorsiflexion
deformities often can be treated with extensor tenotomy. Should the
deformity be of such a magnitude that this treatment is not sufficient,
however, an open release of the joint capsule may be necessary. An open
extensor tenotomy and capsulotomy will correct many subluxation
deformities, although it is important to ensure release of the medial
and lateral collateral ligaments also. Take care to avoid injury to the
neurovascular bundles on either side of the joint. After correcting the
soft-tissue deforming forces, hold the toe in a neutral position and
insert an intermedullary K-wire of at least 0.062 inches in diameter.
Protect the foot with a wooden postoperative shoe until the pin is
removed, 2–3 weeks after surgery.

When a severe deformity is present, a soft-tissue
procedure is often not adequate, and an arthroplasty of the MP joint is
necessary. Decompression of the joint will allow its reduction, and the
conversion of a diarthrodial joint to a fibrous joint will provide
stability.

A significant hallux valgus deformity can cause pressure
on the second toe and lead to dorsal subluxation or dislocation of the
second toe, placing the great toe adjacent to the third toe (1,2,3 and 4).
This results in attenuation of the second MP joint’s fibular collateral
ligament, and possibly even the formation of a rent in it. The tibial
collateral ligament can sometimes contract. As the deformity
progresses, dorsal subluxation and possibly dislocation of the second
MP joint can occur.

Evaluate instability of the joint using the anterior drawer sign of the lesser MP joint, as described by Thompson and Hamilton (13).
Grasp the proximal phalanx of the lesser toe between the thumb and
index finger and stabilize the metatarsal with the other hand. Then
manipulate the toe in a vertical fashion. If instability exists, there
is subluxation at the MP joint, and pain may exist.

Nonsurgical treatment includes taping the second toe in a reduced position or using open-toed or extra-depth shoes.

A claw toe is a deformity of the MP joint that occurs
together with a flexion deformity of either the proximal or distal
interphalangeal joints. The PIP joint is involved much more frequently
than the distal interphalangeal joint in a claw-toe deformity. When
evaluating a claw toe, examine both the MP and the involved
interphalangeal joint to determine whether the involved deformity is
fixed or flexible at each joint. In addition, carefully evaluate the
hallux for a valgus deformity, which could prevent reduction of the
second toe into its normal position. If there is a hallux valgus
deformity that might interfere with the second toe, correct it
simultaneously.

Mallet toe is a flexion deformity of the distal interphalangeal joint. It often causes pain because the tip of the toe

rubs on the inner sole of the shoe. Mallet toe is usually a fixed deformity and is less common than hammer toe.

A hard corn is a thickened area of skin usually found on the dorsolateral aspect of the fifth toe (Fig. 113.6). The thickened skin is a hyperkeratotic reaction to the increased

pressure between the distal condyle of the proximal phalanx of the
fifth toe and the side of the shoe. Nonsurgical treatment for this
problem consists of protecting the skin with a donut device made of
soft material. In addition to this, wider, roomy shoes that minimize or
eliminate a confined toe box are also quite effective. Shaving of the
keratotic lesion can also help alleviate symptoms. If surgery is
necessary, the underlying principle is to remove the offending condyle
to relieve pressure on the skin.

A soft corn is a thickening of the skin between two lesser toes (Fig. 113.9).
This hyperkeratotic skin reaction is caused by excess pressure in the
web space between the toes, often caused by a constricted toe box. The
moisture present in the region between the toes results in the
maceration of the keratotic lesion. The location of the corn is usually
at the area where one bony prominence is pushed into the adjoining toe.

To treat, prescribe open-toed shoes or a wide toe box, and place a soft material such as lamb’s wool between the

toes. If this is not satisfactory, removal of the offending condyle can
resolve the problem. If there is any question as to which is the
offending condyle, identify it by placing a small lead marker over the
soft corn, and obtain a radiograph (Fig. 113.10). This condyle may be on the toe with the lesion or on the adjacent digit.