Polydactyly of the Foot Treatment & Management
- Author: Cara Novick, MD; Chief Editor: Dennis P Grogan, MD more...
Surgical treatment consists of excision of the duplicated digit and reconstruction of any associated abnormalities in the remaining rays (eg, longitudinal epiphyseal bracket).[3, 11, 12, 13] A thorough preoperative examination should be undertaken, including evaluation of radiographs, to formulate an operative plan. Most patients have good-to-excellent results after surgery (see the images below). Careful surgery helps to ensure better cosmetic and functional outcomes.
Most medial digits in preaxial polydactyly and most lateral digits in postaxial polydactyly are usually resected. This allows the foot to be narrow, with a straight medial or lateral border.
In postaxial polydactyly, a racquet-shaped or oval incision is made at the base of the most lateral digit and carried through skin and fascia. Tendons are divided as distally as possible. The capsule of the metatarsophalangeal (MTP) joint is divided, and the digit is disarticulated. Care is taken to remove T or Y extensions of the metatarsal head or to reshape an expanded metatarsal head. The capsule is repaired, the skin closed, and a bandage or cast applied.
Park et al conducted a retrospective study to evaluate the operative treatment of postaxial polydactyly in 27 patients. For excision of the medial toe, dorsal rectangular flap and full-thickness inguinal skin grafting were used; for excision of the lateral toe, a racket-shape incision was used. The investigators concluded that satisfactory functional and cosmetic results were obtained with dorsal rectangular flap and full-thickness inguinal skin grafting for medial toe excision and with the toe selection algorithm that was employed.
In preaxial polydactyly, the medial toe is usually excised. The toe is again removed through disarticulation. Care must be taken to appropriately balance the abductor and adductor hallucis muscles and to minimize hallux varus. Correction of an associated longitudinal bracket epiphysis helps to prevent the development of hallux varus and an excessive short first metatarsal. The capsule is repaired as accurately as possible.
If the more lateral toe is hypoplastic and is excised, the intermetatarsal ligament must be reapproximated. A Kirschner wire (K-wire), in place for 4-6 weeks, may be helpful in maintaining position and avoiding varus deformity. A soft dressing or cast may be used.
In central polydactyly, a dorsal racquet-shaped incision is made at the base of the duplication. The extra digit is excised through disarticulation. The intermetatarsal ligament is reapproximated prior to closure. A cast or orthosis may be useful postoperatively to minimize a residual widened forefoot. A careful plastic skin closure is used in all patients, as cosmesis is a concern.
Osborn et al conducted a retrospective case series review of 22 patients (27 feet) who underwent surgical treatment of central polydactyly using the dorsal and plantar advancement flap technique. Significant narrowing of the forefoot was achieved after surgery. This radiographic narrowing was maintained with growth after a mean follow-up of 8 years. However, persistent clinical widening of the forefoot after surgery was reported in the majority of cases (82%).
The researchers concluded that the dorsal and plantar advancement flap technique provides excellent radiographic and functional outcomes in the treatment of central polydactyly: It successfully narrows the forefoot on radiographs, and this narrowing is maintained with growth over time. They advised that families be made aware that it is common for patients to experience persistent widening of the forefoot relative to normal, despite successful radiographic narrowing after surgery.
A cast or soft dressing is used. If a K-wire is used, it is usually left in place for 4-6 weeks. A walking cast allows the small child to be active and at the same time protects the surgical incision.
The patient must be monitored and evaluated for residual or future deformity.
The most common complication in preaxial polydactyly is hallux varus. This may cause pain and difficulty with shoe wearing, warranting subsequent surgical correction.
Failure to correct a longitudinal bracket epiphysis that may be associated with a duplicate great toe can result in the development of hallux varus. The deformity should be addressed when noted. The bracket can be resected to allow for untethered growth, and the varus can be corrected with capsulorrhaphy and K-wire fixation at the metatarsophalangeal (MTP) joint. Resection and metatarsal osteotomy may occasionally be needed in the older child.
Patients with postaxial polydactyly may have residual angular deformity, including angulation at the MTP joint and bowing of the metatarsal. This is usually not clinically significant.
In patients with central polydactyly, a widened forefoot is a common complication.
All patients are at risk for developing MTP joint subluxation or angular deformity and residual deformities of the metatarsal head. Incomplete excision of elements that are not yet ossified may also lead to future problems or deformity.
Future and Controversies
Accurate understanding of the involved anatomy leads to better clinical results. Radiographs obtained after ossification of the involved bones allow for definitive treatment of the duplicated parts and all associated abnormalities. Recent better appreciation of the longitudinal bracket epiphysis, often seen in the first metatarsal in children with preaxial polydactyly, and descriptions that allow for earlier diagnosis and correction of this abnormality lead to better outcomes.
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