K-wire Fixation, Intraosseous Wiring, Tension Band Wiring

4 K-wire Fixation, Intraosseous Wiring, Tension Band Wiring

Lindsay Muir, Anuj Mishra, Zafar Naqui

Abstract

We have at our disposal ever more sophisticated plate and screw systems for use in the treatment of hand fractures. While the most modern of these are excellent, there are still circumstances where the use of more traditional methods may offer an advantage. It is important for the hand surgeon to have a mastery of all methods, in order to be able to tailor the implant to the situation. Whereas plates and screws can achieve rigid fixation, Kirschner’s wires (K-wires) and cerclage techniques may cause less soft tissue injury and stripping and should not be forgotten about in an understandable urge to achieve impressive postoperative X-rays.

This chapter considers the role of intraosseous wiring and K-wires in the management of hand fractures. It will examine techniques and applications in intraosseous wiring. It will review the history and theory of K-wiring and various applications for the technique. It will also outline some of the potential complications.

Keywords: hand, fracture, K-wire, cerclage wire, intraosseous wire

4.1 Intraosseous and Cerclage Wiring

Intraosseous wire can be used alone or as an adjunct to K-wire fixation. The advantages include that it requires minimal exposure, is less prominent than screws and plates, and decreases the risk of adhesions to overlying tendons. The technique is most frequently used for transverse phalangeal and metacarpal fractures and in digital replantation.

Different intraosseous wire configurations have been proposed. Lister’s loop was initially described in 1978 where a single interosseous wire is used with a K-wire.1 Double interosseous wire has been used in parallel and perpendicular configurations (90–90 wiring) for transverse metacarpal/phalangeal fractures, replantations, and arthrodesis ( Fig. 4.1). More recently, a “theta” (θ) configuration has been described which is similar to Lister’s loop ( Fig. 4.1).²

4.1.1 Metacarpal and Phalangeal Fractures

Cerclage (circumferential) wiring with 24-gauge stainless steel wire can be successfully used for oblique and spiral metacarpal shaft fractures. The technique was originally described to include scoring of the cortical bone with a side-cutting burr so that wire migration would not occur (Lister 1978). In a series of 100 cases, Lister achieved a 100% union rate in the case of transverse fractures. Overall, 83.2% of the maximum attainable total active range of motion (TAM) was achieved in the 100 cases.

Fig. 4.1 (a, b) “Theta loop” wiring, which is similar to Lister’s wire technique. In this case, for a distal interphalangeal arthrodesis following a chain saw injury. In this case, the soft bone meant that the ideal placement of the wire 3- to 4-mm away from the bone ends was not achievable.

Gingrass et al 3 achieved six excellent or good results in seven metacarpal fractures treated by double 26-gauge interosseous wires placed in a dorsal–volar direction. A single Kirschner pin was added in five of seven cases to augment stability. These authors suggest that intraosseous wiring without supplemental K-wire fixation is generally unsuitable for metacarpal shaft fractures because wire loosening and subsequent loss of reduction are real possibilities.

Gropper et al⁴ used cerclage wires for the management of metacarpal shaft oblique and spiral fractures. All 21 metacarpal fractures were followed up until the patient was ready to return to work, which occurred an average of 7 weeks after surgery. Seventeen patients had no restriction of range of motion (ROM), with normal anatomical restoration of the metacarpal. Three patients lost 15 degrees of total active finger motion, and one had an extension lag of 10 degrees at the metacarpophalangeal (MCP) joint.

Al-Qattan⁵ reported treatment of 36 metacarpal shaft fractures with intraosseous loop wire fixation alone. In contrast to Gingrass, he concluded that intraosseous wiring without K-wire fixation is rigid enough for immediate postoperative finger mobilization. Of 36 patients, 34 regained full ROM. Al-Qattan suggested, however, the use of supplementary K-wires if the fracture is comminuted.

In a series of 19 cases of midshaft oblique or spiral metacarpal fractures showed that cerclage wire fixation can be sufficient without scoring of bone or finger immobilization.⁶

Immediate postoperative mobilization is key to regaining the full ROM in all hand fracture patients. A review of fixation techniques of metacarpal shaft fractures found that regardless of the method of internal fixation, the majority of the patients regain a full ROM, provided a protocol of immediate postoperative mobilization is used.⁵

In long oblique or spiral fractures, lag screws have traditionally been used. Al-Qattan and Al-Zahrani⁷ have described the use of intraosseous and/or cerclage dental wires for primary use or as a salvage because of the problems encountered with lag screws. The use of dental loop wires has not gained popularity because it is not believed to be rigid, based on several in vitro biomechanical studies which showed the superior stability of lag screws for long oblique and spiral metacarpal fractures.^5,8–11 The use of the combination of intraosseous and cerclage dental loop wires was described by Al-Qattan.¹¹ He highlighted the different roles for each technique. The intraosseous wire, although unicortical, prevents axial migration (shortening) at the fracture site, which is known to occur in long oblique/spiral metacarpal shaft fractures. It also aligns the fragments exactly and thus avoids any rotational problems, and prevents the migration of the cerclage wires, which compress the fracture site.

Al-Qattan and Al-Zahrani⁷ performed a prospective study of 15 cases of long oblique or spiral fractures of proximal phalanx which were treated with cerclage wires. All fractures united. Full movement (> 260 degrees) was achieved in 12 patients. Fixed flexion deformity of 5 to 15 degrees at the proximal interphalangeal joint (PIPJ) occurred in three cases. One prominent wire was removed. No infection, complex regional pain syndrome (CRPS), loss of fracture position, wire migration, or extrusion occurred. An average return to work of 8 weeks (7–11) was achieved.

Al-Qattan¹¹ showed better results with open reduction and interosseous wires when compared with closed reduction and K-wire in 78 industrial injuries with displaced unstable transverse fractures of the proximal phalanges. Forty fractures were treated with closed reduction and K-wiring that crossed the MCP joint, 38 with open reduction and interosseous loop wire fixation, 10 patients in each group were compound.

All fractures were united. Final range of movement (total active movement, TAM) was graded as excellent (> 240 degrees), good (220–239 degrees), fair (180–219 degrees), poor (< 180 degrees). For intraosseous wires, the results were excellent in 39%, good in 42%, fair in 8%, and poor in 11%. For K-wires, the results were excellent in 13%, good in 50%, fair in 25%, and poor in 13%. Thus, movement was better for intraosseous wires (19% fair and poor against 38% for K-wires). Return to work was 15 (12–30) weeks for K-wires, 14 (11–26) for interosseous wires. Complications for K-wires were fracture redisplacement in 2 cases, CRPS in 1, rotational malalignment in 1, infection in 2, and wire migration in 5, versus 3, 0, 0, 0, and 1, respectively, for intraosseous wires.

Thomas et al² treated 10 patients with open transverse fractures of the proximal phalanx, with a Lister loop and oblique K-wire (they named this “theta fixation”) ( Fig. 4.1). All fractures were united. Patient outcomes were assessed with the Belsky score, with 90% excellent, and 10% good results. Radiological union was achieved in 6.1 weeks. All patients returned to their preaccident employment at a mean of 11.3 weeks.

4.1.2 Fracture Dislocation around Joints

Comminuted fractures around joints are problematic. Direct fracture fixation with multiple K-wires or cerclage wires can be effective in stabilizing tenuous reductions of these fractures. Weiss 12 used cerclage wiring for PIPJ fracture dislocations. Twelve patients were treated by the volar cerclage wiring technique ( Fig. 4.2).

Fig. 4.2 Cerclage wiring for a fracture of the base of the middle phalanx.

At an average follow-up examination of 2.1 years, 11 of 12 patients were noted to have no radiological degenerative joint changes, with only 1 patient having evidence of early volar articular surface beaking. Average final active arc of motion at the PIPJ was 89 degrees (range 72–109 degrees). The average extension loss at the PIPJ was 8 degrees (range 0–16 degrees). There were no complications involving implant failure, irritation, or infection. The advantage of this technique was to avoid fracture fragment stripping, stable restoration of the articular surface, and palmar buttress of the middle phalanx at the PIPJ. Aladin and Davis 13 compared this technique with other open reduction and internal fixation techniques and did not show good results. Patients treated by cerclage wire fixation reported more cold intolerance and had a significantly larger fixed flexion deformity (median 30 degrees, range 18–38 degrees) and a smaller arc of motion (median 48 degrees, range 45–60 degrees) at the PIPJ, despite having the best radiological outcomes.

4.1.3 Surgical Technique

Intraosseous wires (25- or 26-gauge/0.35–0.45 mm) are useful for the fixation of unstable transverse phalangeal/metacarpal shaft fractures. The holes for the wire should ideally be drilled at least 3 to 4 mm from the fracture edge so that the wire does not cut out when it is being tightened. Kinking of the wire should be avoided because tightening becomes impossible. Additional fixation with an oblique K-wire may provide additional stability, particularly in the phalangeal diaphysis, where the bending moment is greatest (Lister’s loop) ( Fig. 4.3).¹

4.2 K-wire Fixation

4.2.1 History

K-wire fixation has long been a principle method of fracture stabilization. Initially described by Kirschner for the application of traction in 1909, it was first used for fracture fixation by Otto Loewe in 1932. Bunnell first described the use of K-wires for transfixation of joints in the hand in the 1940s.14 The small size of the bones of the hand with their small soft tissue envelopes coupled with the need for early mobilization of the fingers have ensured that K-wire fixation for hand fractures remain a central part of the surgeon’s armamentarium.

4.2.2 Wire Design

K-wires are thin, smooth, and made of stainless steel or nitinol (nickel titanium). Their diameter is typically between 0.9 and 1.5 mm.15 Larger diameter implants are referred to as “pins” and are too big for the hand and wrist. The end of the wire can be either diamond (two faced) or a trocar tip which has three faces ( Fig. 4.4).

The trocar tip has been found to have the highest pullout force immediately after drilling, requiring the most torque to penetrate the bone during insertion; it does, however, generate the most heat.^16,17 Therefore, a trocar tip inserted at low speed is recommended for the strongest fixation in bone. Screw tipped or threaded wires have not been shown to have superior grip power but are less strong and have largely therefore been abandoned. Wires can be single or double ended. Double-ended wires can be passed through back and forth, but care needs to be taken to avoid injury to the surgeon.

Fig. 4.3 (a–c) Leddy and Packer type Vb flexor digitorum profundus avulsion fixed with cerclage wire and longitudinal K- wire.

Fig. 4.4 Diamond (left) and trocar (right) K-wire tips.

4.2.3 Indications

K-wires may be used effectively for many varied indications, including extra- and intra-articular fractures, joint dislocation, closed and open fractures, definitive or temporary intraoperative fixation, as well as being uses for guiding other implants. While wires can be used to pull fragments together, they can also be used to maintain a joint space between two bones. The management of specific injuries are dealt with later in this chapter. The advantages of K-wires over other techniques include their low cost, ready availability, versatility in many different fracture configurations, the requirement for only minimal dissection, and percutaneous insertion. Compared to other fracture implants, there is little implant load, which is an important consideration for the bones of the carpus and hand. It is often said that K-wires are also easy to insert and while this is true from a purely conceptual perspective, the efficient use of this technique to hold a fracture, while avoiding osteonecrosis and soft tissue injury requires skill and experience.

4.2.4 Technique: General Principles of K-wire Fixation at the MHC

We prefer to perform the procedure under local or regional anesthesia. Patients often watch the image intensifier; this helps them understand what has been done and the postoperative rehabilitation can be clearly reinforced to the patient. The role of intravenous antibiotics has not been defined.18 A tourniquet is applied but is seldom inflated; it is preferable to allow some bleeding to help mitigate the heat generated from the wire insertion.

Most metacarpal and phalangeal fractures are amenable to smooth K-wires of between 1 and 1.3 mm in diameter, the smaller sizes being used more distally. Wires smaller than 1 mm have significantly less stiffness. For the carpus, we prefer using 1.25-mm wires.

Fractures should initially be reduced, if possible, closed, if not, then open with care taken to address any rotational deformity of the fingers, which is usually poorly tolerated. Intra-articular fractures may require open reduction, as any articular step of more than 1 mm should be avoided.

K-wires should be placed with as few passes as possible to minimize soft tissue trauma and osteonecrosis. It is helpful to take an X-ray with the fluoroscan while placing the wire over the hand in the position you will aim to drive the wire. The entry point and direction of the wire can then be marked on the skin. Plan in advance where you will place the other wire(s) and allow for this before inserting your first wire ( Fig. 4.5).

Ideally, the wire should be inserted perpendicular to the fracture site. Planning these steps cannot be overemphasized in reducing the number of unnecessary passages of the wire. This is especially of importance in the tubular metacarpal and phalangeal bones, which have a narrow diameter, and where repeated passage of wires can lead to osteonecrosis, loss of cortex, and weakening of the bone.