The surgeon should become familiar with diagnosing the pathomechanics of the contracted digit to fully appreciate the deforming forces that must be addressed intraoperatively. A thorough understanding of the functional anatomy of the lesser digits will also assist the surgeon in understanding the deformity. McGlamry et al (1) discuss this extensively. The surgeon also needs to be able to identify the plane(s) in which the deformity is occurring. Digital deformities have varying components in the sagittal, transverse, and frontal planes, all of which will need to be addressed intraoperatively.

This chapter focuses on the commonly encountered hammer toe (most commonly digits 2, 3, or 4), with contracture predominantly in the sagittal plane at the PIPJ and MTPJ and occasionally the transverse plane at the MTPJ. The choice between arthroplasty, arthrodesis, and soft tissue rebalancing is not clearly defined. In the authors’ experience, arthroplasty of the central digits can lead to painful instability, toe drift/malalignment, and residual deformity. Arthrodesis of the PIPJ has proved over the years to provide reliable stability and predictable results.

Utilizing techniques of anatomic dissection, adequate hemostasis can be achieved. Tourniquets, while acceptable, may pose time restraints on the surgeon as well as cause pain to the patient, necessitating more intravenous sedation or even general or spinal anesthesia (3). To aid in hemostasis, surgeons often employ a local anesthetic with epinephrine in a concentration of 1:200,000. Epinephrine, if used appropriately, has been shown to be safe in digital surgery (4,5 and 6). The use of epinephrine should be avoided or used cautiously in patients with a history of Raynaud disease or phenomenon, peripheral arterial disease, or other conditions that may involve vascular compromise.

Figure 14.1A represents a deformity of the second digit that demonstrates contraction in the sagittal plane at both the PIPJ and the MTPJ as well as medial deviation at the MTPJ in the transverse plane. Incision placement for this digital deformity runs along the midline of the digit. This places the incision and subsequent vertical dissection between the neurovascular structures of the digit. Landmarks for the incision include the distal interphalangeal joint (DIPJ), PIPJ, and MTPJ. The proximal aspect of the incision overlies the metatarsal shaft (Fig. 14.1B)

A “controlled depth” incision allows the edges of the skin to retract and expose superficial vessels (Fig. 14.2A). Superficial vessels that cross the incision may be clamped and cauterized (Fig. 14.2B). A significant vessel consistently encountered in the incision proximal to the metatarsal phalangeal joint is a portion of the distal venous arch. This transverse structure is usually isolated, clamped, and ligated (Fig. 14.2C).

Tissue plane dissection or separation of the superficial fascia from the deep fascia usually begins at the level of the PIPJ, where the subcutaneous tissue is the thinnest. A side-to-side brushing technique begins with the edge of the knife at the midline of the incision and sweeps medially and laterally around the contours of the interphalangeal joint. Neurovascular structures are preserved and protected in the subcutaneous layer, which is separated from the surface of the fascia that encircles the digit (Fig. 14.3A). This plane of dissection may be extended proximally to the level of the MTPJ. A surgical sponge is used to peel the subcutaneous layer away from the deep fascia or extensor hood apparatus at the level of the MTPJ (Fig. 14.3B). This blunt dissection technique clearly defines the separation of the superficial fascia from the deep fascia around the medial and lateral aspects of the metatarsal phalangeal joint (Fig. 14.3C). The blunt end of the knife handle can be used to extend this dissection plane around the medial and lateral aspects of the MTPJ down to the level of the deep transverse intermetatarsal ligament (Fig. 14.3D).

Attention is directed back to the PIPJ to begin disarticulation of the joint. Figure 14.4A shows the trifurcation of the extensor apparatus at the level of the PIPJ. Disarticulation of the PIPJ is initiated with a transverse incision across the dorsal aspect of the head of the proximal phalanx transecting the extensor trifurcation (Fig. 14.4B). The capsular incision is extended around the contour of the medial and lateral



condyles of the head of the proximal phalanx to section the collateral ligaments (Fig. 14.4C-F). When degloving the head of the proximal phalanx, attempt should be made to keep the collaterals intact with dorsal pouch under the extensor tendon (Fig. 14.4G). This will aid in closure over the arthrodesis site, assisting in stabilization and helping to minimize postoperative edema. Figure 14.4H demonstrates proximal reflection of the extensor tendon apparatus and collateral ligaments exposing the articular surface of the head of the proximal phalanx. Distal reflection of the extensor tendon demonstrates the articular surface of the base of the middle phalanx.