External Fixation in the Hand

William H. Seitz Jr

INTRODUCTION

Miniaturization of external fixation apparatus, applications, and techniques has evolved to afford hand surgeons a unique and useful tool to treat a variety of difficult conditions that they face on a regular basis. Principles as applied to the hand are similar to those applied across segments of the entire limb and long bones; however, the complexities of the hand including tendon gliding, multiple small joint interactions, fine neurologic structures, and limited space for skeletal targeting all require technical expertise and careful planning and execution of the process. The techniques of applying miniature external fixation in the hand have application in acute trauma, in posttrauma reconstruction and staged management of infections, in burn reconstruction, in deformity correction, and in congenital hand surgery (1,2,3,4,5,6,7,8,9,10).

This chapter will review the indications, contraindications, perioperative preparation, surgical technique, “pearls and pitfalls,” postoperative management, potential complications, and their management with an overview of expected results.

INDICATIONS

Acute trauma
- Unstable intra-articular fractures (CMC, MP, PIP joints)
- Unstable segmental fractures (pathologies unknown)
- Open fractures (gunshot wounds)
- Crush injuries
- Soft-tissue loss
Posttrauma reconstruction
- Malunion/nonunion
- Arthritis
- Instability
- Contracture
- Deformity
- Amputation
Burn reconstruction
- Contracture
- Deformity
- Amputation
Congenital hand deformity
- Symbrachydactyly
- Transverse terminal arrest
- Hypoplastic thumb
- Complex syndactyly (Apert’s syndrome)
- Radial clubhand
- Contractures

Acute Trauma

In the setting of acute trauma, indications for external fixation can include unstable intra-articular fractures involving the proximal interphalangeal (PIP), metacarpophalangeal (MP), and carpometacarpal (CMC) joints (Fig. 10-1; Video 10-1). They may also include unstable segmental fractures with or without bone loss, open fractures, crush injuries, or injuries with soft-tissue loss (skin, tendon, and muscle injury) (Fig. 10-2; Video 10-2). Some contaminated wounds may present

indications for external fixation to be used as a spanning apparatus until definitive internal fixation can be performed pending wound care, debridement, and resolution of potential infection (Fig. 10-3; Video 10-3). Areas of traumatic or burn loss of skin and subcutaneous tissue can be bridged and position maintained pending adequate coverage (Fig. 10-4; Video 10-4). Combinations of joint, tendon, burn, and soft-tissue injury may also be managed by means of dynamic fixation, which allows some degree of tendon excursion avoiding adhesions and contractures during the early healing phases (Fig. 10-5; Video 10-5) (4,11).

FIGURE 10-1 Miniaturized external fixation can provide a wide area of application throughout the hand. This includes stabilization of fractures and dislocations across the CMC joints (A,B). Applications across fractures and dislocations of the MP joint (C,D) and across the PIP joint (E,F) where fractures and/or fracture dislocations may be well stabilized by a combination of external fixation and limited internal fixation.

FIGURE 10-2 Open fractures with comminution and surrounding soft-tissue injury (A-D), gunshot wounds with bone loss (E,F), and in certain cases of tumor with pathologic fracture requiring grafting and spanning stabilization (G-J).

FIGURE 10-2 (Continued)

FIGURE 10-3 In the face of severe open trauma with loss of soft tissue and bone and potential contamination/infection, a complex external fixation system can be designed to allow for debridement, soft tissue revascularization, and allow access for wound care to allow secondary reconstruction once the environment has been declared viable.

External fixation utilizes the principles of “ligamentotaxis” whereby the soft-tissue envelope is tensioned around the skeletal architecture to both mold the fragments into place and provide tension on the tendinous, muscular, and ligamentous structures providing a physiologic environment
so as to minimize contracture and adhesions. The principle, however, does not ensure fine fragment realignment in the face of intra-articular fractures and therefore may need to be augmented by means of fine fragment realignment using various forms of internal fixation, intercalary support, or subchondral support in the face of loss of bone stock through bone grafting (Fig. 10-6; Video 10-6) (5,8,9,10).

FIGURE 10-4 In the face of severe burns with loss of substance (A-C), soft-tissue coverage is obtained when external fixation can be used to both stretch contracted soft tissues and perform callotasis lengthening of the remaining skeletal parts (D-F) and ultimately functional digital prehension (G-I).

FIGURE 10-4 (Continued)

Posttraumatic Reconstruction

The outcome of trauma may result in malunion or nonunion, posttraumatic arthritis, joint instability, contracture, or amputation.

Indications for use of external fixation in posttraumatic reconstruction include providing stable fixation for realignment and osteotomy; compression arthrodesis, which leaves no long-term hardware in place; transarticular stabilization in conjunction with ligament reconstruction; slow distraction of severe contractures; and distraction lengthening of an amputated thumb or multiple digits (11,12,13,14,15,16) (Figs. 10-7A and 10-8; Videos 10-7 and 10-8).

FIGURE 10-5 Custom additions to external fixation include hinges, which can be centered over the center of rotation of a joint as seen clinically (A-C), and in postoperative video showing dynamic excursion of an MP joint, which has been reconstructed due to severe capsular and ulnar collateral ligament rupture.

FIGURE 10-6 Periarticular fractures frequently require fine fragment approximation using augmentation techniques with K-wires, screw fixation, and bone grafting (A-E). Successful management of these periarticular fractures provides an excellent functional outcome (F,G).

FIGURE 10-7 External fixation can also be used to control rotational and angular realignment in conjunction with osteotomy of deformity such as seen in this child having undergone prior complex syndactyly release who has significant functional malalignment of the central two fingers (A). A planned rotational angular correction can be seen based on the alignment of the fixator pins inserted before osteotomy and following realignment (B). Similar correction is performed in the shortened and deformed ring finger (C). Final alignment with restoration of normal cascade is seen in (D) and (E). Once the fixator is aligned, compression can be achieved across the fixator to enhance healing of the osteotomy, much as it can in an arthrodesis. (F) through (K) demonstrate surgical technique of exposure, denuding the articular surfaces, and compression arthrodesis of a thumb MP joint with good early function during the healing phase (L).

FIGURE 10-7 (Continued)

FIGURE 10-8 Distraction lengthening can provide both stabilization and creation of elongated functional length digits once soft-tissue coverage has been achieved (A-D). During the process of distraction lengthening and consolidation of the new bone that is forming in the distraction gap functional hand use is learned, guided by our hand therapists (E-H).

FIGURE 10-8 (Continued)

In all these cases, the external fixation apparatus acts as a stable bridge or self-limited traction system, which is quite sturdy and supports the complexities of multiple joint control through the interaction of extrinsic and intrinsic musculotendinous excursion across the injured area allowing joint mobility of adjacent articulations and ligamentous flexibility. It is indicated in conditions where other alternative forms of fixation may not provide ideal stability (K-wires, interfragmentary screws, plate and screw fixation, and intramedullary fixation).

Burn and Congenital Hand Reconstruction

In patients who are born with congenital hand differences, such as symbrachydactyly, transverse terminal arrest, hypoplastic thumbs, or complex syndactyly with failure of formation of parts, external fixation techniques can be utilized applying the techniques of callotasis or distraction lengthening to elongate small digital remnants to form functional digits for purposes of sensate prehension (Fig. 10-9; Video 10-9) (12,16,17,18

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