Fifth-Toe Deformities Treatment & Management

Surgical correction is indicated for chronically painful hard and soft corns in cases where conservative treatment fails. Patients with neuropathy may also choose surgery for prophylaxis against chronic lesions that may lead to ulceration and other morbidity. This has also proved beneficial for treating patients with chronic ulcerations to prevent amputations. ^[12]  Surgical correction is also indicated for progressively painful hammertoes or over- or underlapping toes if conservative treatment fails.

Contraindications for surgery include adequate control with conservative treatment, poor circulation, underlying infection, or any systemic condition that would inhibit healing of the surgical site.

Medical therapy is commonly considered conservative care. Conservative treatment for hard corns and soft corns involves periodic shaving by a healthcare professional using a scalpel or paring device. This is reinforced by regular use of a pumice stone or callus file during or after bathing.

Protective padding can be used over hard corns to decrease shoe irritation, and toe spacers are available to ease pressure on soft corns. To decrease pressure, multiple devices such as gel pads, foam, felt, devices with cutouts to accommodate lesions, and moleskin are available over the counter. Wearing wider shoes is a simple way to decrease pressure placed on hammertoes or other rotational deformities. Modifying and stretching the shoes can accomplish the same goals.

Surgical therapy depends on the type and level of the deformity. One must determine the underlying pathology and the degree of bone and soft-tissue involvement.

Angular deformities can be corrected with a combination of bone cuts and derotational skin incisions. Areas with contracted skin or tendons may require lengthening procedures, tenotomy, or both. ^{[13, 14]}

Hard corns

Hard corns are probably the most common fifth-toe deformities and yield the most options for treatment. These lesions occur most frequently on the dorsum of the proximal interphalangeal (PIP) joint (PIPJ) as a result of a hammertoe deformity or on the dorsolateral aspect of the PIPJ as the result of a hammertoe with varus rotation. Corrective procedures include the following:

• Partial condylectomy
• Exostectomy
• Hemiphalangectomy
• PIPJ arthroplasty with resection of the proximal phalangeal head
• Some combination of the above

A derotational skin plasty is often included for the varus-rotated toe, and a flexor tenotomy or extensor lengthening can be included for a straight hammertoe deformity.

Soft corns

Surgical correction for soft corns involves resection of the appropriate bony prominence. This usually involves a combination of condyles from the fourth and fifth digits. A rotational deformity may also be present in the fifth toe, which should be addressed. Typical surgical options are as follows:

• Resection of the lateral condyle on the base of the fourth toe proximal phalanx and the medial condyle on the head of the fifth toe proximal phalanx
• Resection of the prominent condyles at the lateral aspect of the fourth PIPJ and the medial aspect of the fifth distal interphalangeal (DIP) joint (DIPJ)

Web-space incisions should be avoided to prevent infections and painful scarring. ^[15]

Hammertoe, claw-toe, cockup fifth-toe deformities

Surgical approaches vary, depending on the severity of the deformity. The simplest hammertoe is one that is completely reducible with no bony obstruction to straightening. This is clinically determined by manually straightening the toe. If a very mild deformity is completely reducible, a soft-tissue procedure with proper splinting of the digit may be all that is needed for correction. Examples of these are extensor tendon lengthening, dorsal metatarsophalangeal (MTP) joint (MTPJ) capsulotomy, and flexor-tendon release. ^{[16, 17]}

PIPJ arthroplasty is added to the soft-tissue releases in more advanced cases that are semireducible or nonreducible. Most surgeons favor PIPJ arthroplasty as a primary procedure because it resolves a contracted PIPJ and functionally lengthens the extensor and flexor tendons, decompressing the MTPJ and the DIPJ. After this is performed, the foot is put into a simulated weightbearing position by pushing up on the fifth metatarsal head.

The dorsal contracture at the MTPJ should resolve, and the toe should straighten. If residual contracture at the MTPJ is present, dorsal capsulotomy is performed and lengthening of the extensor tendon should be considered. Arthrodesis is described for correction of hammertoes but should not be performed in the fifth digit; it leaves the toe too straight, and this causes irritation when shoes are worn.

The Ruiz-Mora and syndactylization procedures are commonly described salvage options for severe or recurrent cockup fifth-toe deformities. ^[18] The original Ruiz-Mora procedure involved removing the entire proximal phalanx, which left the toe somewhat shortened and unstable. Janecki described the modification more commonly used today, which calls for a subtotal proximal phalangectomy. ^[19] Patients should be advised that a good deal of shortening occurs, which may not be cosmetically appealing. (See the images below.)

The initial step of the Ruiz-Mora procedure is the removal of an ellipse of skin plantar to the proximal phalanx curving slightly medial at the proximal margin of the incision. The flexor tendons are dissected and retracted to expose the PIPJ. A transverse capsulotomy is performed, the collateral ligaments are released, and a subtotal phalangectomy is performed at the head of the proximal phalanx. If a large portion of the bone is removed, the flexor and extensor tendons are held together with purse-string sutures of 2-0 nonabsorbable material. The skin is closed in such a way as to allow correction of the toe in a plantar-medial direction.

Complications of the Ruiz-Mora procedure include the following:

• Instability of the toe
• Fourth digit hammertoe formation
• Callus formation
• Bunionette deformity

Postoperatively, the patient is allowed to ambulate in a stiff-soled shoe, and the toe is splinted or taped in the corrected position for 6 weeks.

Syndactylization of the fifth toe to the fourth is generally reserved as a salvage procedure or to resolve a painfully fibrosed web-space lesion secondary to long-standing soft corns. Syndactylization provides excellent stability for an unstable or flail fifth toe. ^[20] With this procedure, the skin incisions on the fourth and fifth toes should be mirror images of each other. A good technique is to scribe the initial incision on the fifth digit with a surgical pen and then press the two digits together where they are to be joined. The ink is transferred to the fourth digit in the precise area where the incision should be placed.

The island of tissue created with the incision is carefully dissected to remove only the skin and to leave the subcutaneous tissue intact. Meticulous hemostasis is practiced, and a needle-tipped electrocautery device should be used for precision. Bone work and isolated tendon balancing can be performed through the open sulcus if needed. The skin is closed by placing all of the sutures throughout the site prior to tying the knots. This allows easier and more accurate passage of the needle through the skin margins of the toes. Sutures are left in for 1 extra week (total, 3 weeks), and the digits are splinted for an additional 2-3 weeks.

Underlapping and overlapping fifth-toe deformities

Many procedures have been described for the correction of an overlapping fifth toe. The deformities range from moderate to more severe, and the procedure chosen should address the existing contractures. The surgical treatment often includes the following:

• Lengthening of the contracted skin and tendon and release of the tight capsular structures
• Resection of redundant skin and soft tissue

Osseous contractures, if present, also must be addressed by means of ostectomy, arthroplasty, or both.

The images below illustrate one technique for correcting a painful overlapping fifth-toe deformity. Schuh et al described their experiences with the Butler technique. ^[21]  Simoes et al also found the Butler arthroplasty to be effective for an overriding fifth toe. ^[22]

The DuVries procedure is indicated for correcting a mildly overlapping fifth toe. The area over the fourth interspace is longitudinally incised from the base of the toe to just proximal to the fifth metatarsal head. The MTPJ contractures are released via medial capsulotomy and release of the medial collateral ligament. The extensor digitorum longus (EDL) tendon is then released or lengthened to achieve the final release. The toe is placed into an overcorrected plantar and lateral position, and the skin is closed in this orientation. Dog-ears are removed when they occur.

Wilson described a modification to the procedure incorporating a V-Y skin advancement to lengthen the contracted skin dorsomedially. ^[23] Similar releases of the capsule and tendon are performed through the V-Y incision to complete the procedure. The authors use a Z-plasty advancement technique to lengthen the contracted skin dorsomedially. This affords greater lengthening potential, and the results are more cosmetically appealing than would be the case without the modification. PIPJ arthroplasty with appropriate capsule balancing completes the procedure, resulting in an excellent correction.

Lapidus described using a tendon transfer to correct severely overlapping fifth toes. ^[24] He transferred the EDL under the MTPJ and into the abductor digiti quinti. Other modifications have been described, including transfer of the EDL into the metatarsal neck, Z-plasty, dorsal capsulotomy with plantar capsulorrhaphy, and PIPJ arthroplasty. When possible, extensive dissection should be avoided because the toes tend to become postoperatively edematous, leading to pain and difficulty fitting shoes.

Underlapping fifth toes typically have a contracted plantar MTPJ capsule and flexor digitorum longus (FDL) with an attenuated EDL and a redundant dorsal MTPJ capsule. Underlapping fifth toes are usually flexible deformities in the pediatric population; tenotomy at the FDL and the flexor digitorum brevis (FDB) with appropriate splinting typically offers good results. However, as with the other conditions mentioned, the degree of deformity must be accounted for, and the appropriate adjunct procedures should be performed.

The Thompson technique is widely used and offers good results. ^{[25, 26]} Thompson described a Z-type incision over the proximal phalanx with the distal limb laterally oriented and the proximal limb medially oriented. Dissection extends to the PIPJ, where the head of the proximal phalanx is freed of soft-tissue attachments and resected using a microsagittal saw. The amount of head resection depends on the severity of the deformity, but care should be taken not to remove too much because this makes the toe unstable.

The soft tissue is appropriately augmented, the toe is derotated, and the flexor and extensor tendons are held together with purse-string sutures by using 2-0 nonabsorbable material. In less severe deformities, the purse-string suture can be left out and the capsule simply closed in a standard fashion. Adding a Kirschner wire (K-wire) across the PIPJ for 3-4 weeks or splinting with dressings for the same period can provide stability.

Finally, the Z-incision is reversed and closed with 4-0 nylon. A variation of the Thompson procedure involves a derotational skin plasty by creating a tissue island with a converging semielliptical incision over the PIPJ oriented from distal-dorsal-medial to proximal-plantar-lateral. As with the other procedures, the patient is allowed to ambulate in a postoperative shoe and is gradually transitioned to a roomy athletic-style shoe. The toe should be splinted in the corrected position for 6 weeks.

The most common complication involving fifth-toe procedures is the development of a flail toe. Other potential problems include vascular embarrassment, undercorrection, recurrence, and prolonged edema. Meticulous dissection and tissue handling are the best defenses against vascular problems or prolonged edema. Proper planning should decrease the chance of recurrence or undercorrection.