Flexor Digitorum Longus Tendon Transfer



Flexor Digitorum Longus Tendon Transfer


Annette D. Filiatrault

John A. Ruch

Steven A. Weiskopf



Complex digital deformities and metatarsophalangeal joint (MTPJ) instability encompass a wide range of pathology including crossover toe, severe hammer toe, subluxed or dislocated toe, metatarsalgia, capsulitis/synovitis, and plantar plate insufficiency or rupture. The surgical treatment of these problems requires a sequential process of correction, which may include proximal interphalangeal arthrodesis, soft tissue rebalancing, tendon transfers, plantar plate repair, or metatarsal osteotomy. The controversy that persists in the current day literature as to which procedures are the most appropriate for each deformity only highlights the fact that no one procedure has become the gold standard or fits every patient and deformity. The flexor digitorum longus (FDL) tendon transfer is a common and popular method of reestablishing mechanical stability to a deranged MTPJ with resultant digital deformity. It offers the advantage of changing the deforming force of the FDL to one of active stabilization and plantarflexion of the proximal phalanx at the MTPJ. It may also resist transverse plane forces by imparting both an active and passive stabilizing effect to the digit.

The transfer of the FDL for correction of digital deformities dates back to the early 1900s with Trethowan (1) referencing its use in 1925. Girdlestone used the procedure years before Taylor described it in 1951 as the transfer of the long and short flexor tendons to the extensor expansion, which became known as the Girdlestone-Taylor procedure (2,3). Parrish modified the procedure to include splitting the flexor tendon longitudinally and suturing the ends to themselves and to the dorsal extensor tendon expansion; it is this modification that most closely predates the surgical technique outlined in this chapter (4). Additional variations in the technique have been described by several authors and are discussed in a later subsection.




SURGICAL TECHNIQUE

The procedure (5) begins with a dorsolinear incision from the metatarsal neck across the MTPJ and ending at the middle phalanx, staying central over these structures to avoid laceration of the neurovascular bundles. The incision may be curved slightly over the MTPJ depending on the deformity. Anatomic dissection is performed at the subcutaneous level, coagulating any crossing tributaries as needed for hemostasis, until the deep fascia is exposed at the proximal interphalangeal joint (PIPJ) and extending this dissection over the long extensor tendon and capsule over the MTPJ. The PIPJ is disarticulated with a transverse tenotomy/capsulotomy at the joint level and is prepared for arthrodesis or arthroplasty. Next, a sequential release of the MTPJ is preformed when required. The extensor digitorum longus and brevis tendons are noted at the MTPJ level, and the extensor hood is released along the medial and lateral aspects of the combined extensor apparatus at that level. The extensor tendon complex should be left intact at the middle one-third area of the proximal phalanx. A Z-plasty lengthening of the extensor complex is performed by making a longitudinal incision between the digitorum longus and brevis tendons (Fig. 16.2A) and then transecting the long tendon distally at the
point where it joins the extensor brevis tendon and the brevis tendon proximal to the MTPJ (Fig. 16.2B). The tendon ends are retracted and an MTPJ release is performed sometimes including use of a McGlamry metatarsal elevator to release plantar adhesions.






Figure 16.1 A: Severe second digit hammer toe deformity with deformity in all three planes. There is sagittal contracture at the MTPJ and PIPJ, transverse medial deviation, and varus frontal plane rotation of the toe. B: The second toe is seen dorsally subluxed at the MTPJ. C: The gun-barrel sign on a dorsal-plantar radiograph indicating severe sagittal place deformity.

There are varied ways to harvest and transfer the FDL to the dorsal aspect of the proximal phalanx. In the author’s approach, dorsal transfer of the FDL at the level of the PIPJ, the FDL is isolated from the FDB, and the FDL is longitudinally split into two slips. The two slips are delivered dorsal around each side of the proximal phalangeal shaft and are secured superiorly under physiologic tension.

Prior to isolating the FDL tendon at the PIPJ, the proximal phalanx is prepared for transfer by making an incision through the deep fascial attachments along the inferior surface of the proximal phalanx. A freer elevator is passed along the inferior surface of the proximal phalanx, between the periosteum and flexor tendons, creating a plane for easy transfer (Fig. 16.2C). The inferior fibers of the extensor sling are incised along the elevator medially and laterally (Fig. 16.2D and E).

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Jul 26, 2016 | Posted by in MUSCULOSKELETAL MEDICINE | Comments Off on Flexor Digitorum Longus Tendon Transfer

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