Arches of the Hand

The hand is composed of two arches: one of these is transverse and corresponds with the metacarpophalangeal (MCP) joints; the other is longitudinal and is aligned along the third digital ray. These two arches of the palm give the hand its cupped shape, which facilitates prehension. The second and third metacarpals are fixed to the second carpal row, whereas the first, fourth and fifth metacarpals are mobile and contribute to cupping of the hand and improved prehension.

The fixed second and third metacarpals do not tolerate angulation well, and all therapeutic options must be considered to restore their anatomy. The fourth and fifth metacarpals, however, tolerate angulation better owing to both their carpometacarpal (CMC) mobility and the possibility of hyperextension of the MCPs.

Hand grip strength is retained if the metacarpal arch is restored. It is hence desirable to reduce oblique and spiral fractures so as to reestablish the length and axis of the metacarpals. Meunier has shown that a metacarpal shortening of just 2 mm results in an 8% loss in the intrinsic functional strength. He determined the loss to be 55% when the shortening was of the order of 10 mm. Low noted a decrease in extrinsic function starting with 3 mm of shortening and a variation of 30 degrees in the angle.

The digits are articulated around the MCPs, which have an active flexion of 90 degrees. The proximal interphalangeal (PIP) joint and distal interphalangeal (DIP) joint flex to 100 degrees and 70 degrees, respectively.

Each digital chain can achieve this function only if its metacarpal and phalangeal lengths match with Fibonacci’s numerical series (0, 1, 1, 2, 3, 5, 8, 13, 21 …). Thus the length of the first phalanx is the sum of that of the middle and distal phalanxes. This highlights the need for a treatment that accurately restores the length of each component of the skeleton. In this context Strauch noted a loss of 7 degrees of extension for every 2 mm of skeletal shortening.

Although they appear parallel in extension, the long digital chains converge toward the scaphoid tubercle upon flexion. The occurrence of a rotational malalignment by more than 5 degrees has an adverse impact on function, particularly if there is scissoring. The thumb retains its key functions as long as the trapeziometacarpal (TMC) joint is free and the first commissure has not been compromised by any contracture. Furthermore, it can tolerate a certain degree of stiffness of the MCP and IP joints.

Mechanisms of Deformity

These have been well described and analyzed by McNealy and Lichtenstein.

Metacarpal Fractures

The action of the flexor tendons and interosseous muscles results in palmar flexion of the distal bone fragment and dorsal opening of the fracture site. This deformation is even more pronounced with regard to metacarpal neck fractures ( Fig. 7.1 ).

The distal metacarpal fragment angulates palmarly under the combined action of the interosseous muscles and the flexor tendons. 1, Extensor tendon; 2, interosseous muscles; 3 and 4, flexor tendons.

The interosseous muscles also induce an axial rotation of the distal fragment. The second and third metacarpals have a tendency to pronate (ulnar rotation), whereas the fourth and fifth metacarpals have a tendency to supinate (radial rotation). These deformities may go unnoticed when the fingers are in extension. Only placing the digits in flexion will reveal the deformity, which manifests itself as an overlap of the fractured finger with its neighbor ( Fig. 7.2 ).

Overlap of Index Finger on Middle Finger.

Consequence of insufficient rotational reduction of the fracture.

All attempts to reduce a fracture must ensure that they restore the convergence of the fingers toward the scaphoid tubercle.

Through their contractile power the interosseous muscles shorten metacarpals that have long oblique or spiral fractures.

With a Bennett fracture the first metacarpal is displaced upward and outward through the action of the abductor pollicis longus and thenar muscles ( Fig. 7.3 ).

With a Bennett fracture the first metacarpal is displaced dorsally and proximally by the action of the abductor pollicis longus (1). The same mechanism is found with joint fractures of the base of the fifth metacarpal under the action of the extensor carpi ulnaris (2).

A fracture at the base of the fifth metacarpal triggers the same phenomena through the action of the extensor carpi ulnaris (see Fig. 7.3 ).

Direct and axial traumas to the metacarpals of the digits generate fractures and dislocations at their base. The palmar bone fragment remains associated with the carpal bone. Through the action of the radial wrist extensors, the second and third metacarpals become dislocated in an upward and proximal direction, thereby generating a dorsal bulge like the “back of a dinner fork,” although this is often masked by edema and a hematoma.

Phalangeal Fractures

Proximal Diaphyseal Fractures

Through the action of the interosseous muscles the proximal fragment flexes, whereas the distal fragment is placed in extension by the action of the lateral bands of the extensor apparatus. This results in a recurvatum with palmar opening of the fracture site ( Fig. 7.4 ).

Through the action of the interosseous muscles, the proximal fragment of a diaphyseal fracture of the first phalanx angulates palmarly.

Lateral tilting of the distal fragment is more clinically obvious; it depends on the nature of the injury and pattern of the fracture. On the other hand, axial rotation is common but can only be diagnosed clinically or by radiography with the finger in a flexed position.

Middle Diaphyseal Fractures

When the fracture is proximal to the superficial flexor tendon insertion, the proximal fragment is pulled into extension by the central slip of the extensor tendon and the distal fragment is flexed by the action of the superficial flexor. The deforming forces create an open dorsal angulation ( Fig. 7.5 ). When the fracture is distal to the superficial flexor tendon insertion, the proximal fragment moves with flexion and the distal fragment in extension. This creates an open palmar angulation ( Fig. 7.6 ).

Fracture of the middle phalanx situated proximal to the FDS insertion (2) develops an open dorsal angulation. 1, FDP.

Fracture of the middle phalanx distal to the FDS insertion develops an open palmar angulation.

Consolidation Time Frames

These are typically from 3–5 weeks for metacarpal and epiphyseal fractures, 5–7 weeks for diaphyseal fractures of the proximal phalanx, 7–10 weeks for the middle phalanx, and 3–4 weeks for fractures of the distal phalanx. Open fixation doubles these times. Finally, additional factors come into play, such as the extent, the mechanism, the energy of the injury-causing trauma and the presence of associated injuries (eg, joint involvement, soft tissue contusion, comminution of the site, neurovascular pedicle injuries). Just like the quality of the reduction and fixation, the patient’s age, their metabolic state and possible tobacco use also affect the prognosis.

Clinical Examination

Hand deformities resulting from one or more skeletal fractures are not always readily apparent because they may remain hidden by edema or hematomas. Although a recurvatum deformity of the phalanges can be readily diagnosed, oblique or spiral fractures are often not apparent on a finger in extension. It is through careful flexing of the finger that a rotatory malalignment can be seen. Flexion of the MCP joints reveals the metacarpal arch. In the case of a fracture of the metacarpal neck, the knuckle becomes less prominent, and if there is much angulation, the head can be felt in the palm of the hand at the distal palmar crease. This can be a hindrance with physical labor, especially when gripping. The clinical examination must always be completed by an assessment of the tendon apparatus and neurovascular pedicles.

Radiologic Examination

The radiologic examination of a fracture must be performed carefully and should not be limited to a single posteroanterior (PA) and lateral view of the hand.

For the metacarpals, angled exposures at 45 and 60 degrees allow for resolution of the bone overlaps that occur with a lateral view ( Fig. 7.7 ). Anomalies of the metacarpal rays are searched for on the PA exposures, with any shortening arousing suspicion if there is no obvious injury. Despite the overlap, an entirely side-on view is very useful to assess interfragment separation in the case of a long oblique fracture to rule out an associated CMC dislocation. The latter are often difficult to see on PA and oblique exposures (see Chapter 6 ).

Oblique views of the second and fifth metacarpals by positioning the hand at 30 degrees of pronation (A) and supination (B).

For the thumb we use the Kapandji views :

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  Static PA views ( Fig. 7.8 ): the forearm and hand rest on their ulnar side, with the hand in semipronation, the wrist at 15 degrees of extension, the coronal plane of the thumb parallel with the table. The adjacent digit is inclined obliquely in a vertical position at a proximal angle of 30 degrees and centered on the MCP joint.

  
  

  
  

  
  

  

  
  

  
  

  PA Views of Thumb Column According to Kapandji.

  
  

  (a) Static exposure. (b) Dynamic exposure in adduction. (c) Dynamic exposure in abduction.

  
  
  
  
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  Static lateral views ( Fig. 7.9 ): the wrist is in ulnar inclination and in 20 degrees of extension, the thumb aligned with the radial side of the forearm, the hand in pronation. The thumb and forearm rest on their radial side, the fingers flexed so as to lift the metacarpal off the surface of the table by 30 degrees. The beam is vertical and centered on the MCP joint.

  
  

  
  

  
  

  

  
  

  
  

  Lateral Views of Thumb Column According to Kapandji.

  
  

  (a) Static exposure. (b) Dynamic exposure in flexion. (c) Dynamic exposure in extension.

  
  
  
  
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  Dynamic exposures assume the same positions as for static ones, with the thumb in hyperabduction, then in hyperadduction for the PA exposure, then in hyperflexion and hyperextension for the lateral view.

The Brewerton scale, originally for assessment of erosive injuries encountered at the head of the metacarpals with rheumatoid arthritis, is equally of great relevance for assessing traumatic MCP joint injuries. The hand is placed with its dorsum on the radiographic cassette, with the MCP joints bent to 65 degrees and the digit at an inclination of 15 degrees toward the ulnar side of the hand ( Fig. 7.10 ).

For a Brewerton view, the MCPs are placed at 65 degrees of flexion and the x-ray beam is tilted by 15 degrees ulnarly. Such an exposure allows detection of MCP fractures but is also useful for the diagnosis of fractures of the base of the fourth and fifth metacarpals.

Functional Treatment

Functional treatment relies on immediate and careful mobilization. Weeks, de La Caffinière and Mansat observed that one-quarter of cases of finger stiffness are due to a hand fracture. Early, if not immediate, mobilization is the best way to combat edema and joint stiffness and to preserve tendon gliding. The best dynamic orthosis to promote mobilization while also protecting against excessive movement is achieved by buddying the injured finger with its neighbor with Elastoplast or Velcro bands that hold them together ( Fig. 7.11 ).

The best dynamic orthosis ensuring a rapid functional outcome involves placing the finger with a stabilized fracture in syndactyly with an uninjured adjacent digit. Two Velcro bands are attached to proximal and middle phalanges.

Splinting

Splinting with or without prior reduction requires immobilization in a position that minimizes hand stiffness. Immobilization with a splint is a necessity for fractures that are deemed to be unstable, although this results in stiffness in numerous joints. Too many fingers are assigned to tongue depressors, which should never have left the otorhinolaryngology setting.

Attention must therefore always be given to the immobilized position, also referred to as the safe position, because it prevents joint stiffness by keeping the collateral ligaments stretched. This is the intrinsic-plus position, with the wrist in extension at 20 degrees, the MCP joints flexed between 40 and 60 degrees and the IPs in extension or very slight flexion (15 degrees at the most). The various positions of immobilization are derived from this basic position.

Immobilization follows the principle of stabilization of the injured segment and the adjacent joints.

Use of Orthoses Made From Thermoplastic Materials

Use of orthoses made from thermoplastic materials is preferable because they are customized to fit the injured person’s anatomy, thereby leaving the uninjured fingers and joints free so as to limit stiffness. These orthoses can be altered successively to match reduction in edema or resized if progress with the consolidation allows additional digital segments to be freed ( Figs. 7.12 and 7.13 ).

(a) Static splinting for metacarpal fractures. The wrist is stabilized in 20 degrees of extension, the MCP joints in 40–60 degrees of flexion. The dorsal flap ends in line with the head of the proximal phalanx and the palmar flap at the middle. (b) The fractured finger is placed in syndactyly with the adjacent finger to promote active flexion of the PIP and DIP joints.

(a, b) Static splinting of a fracture of the first metacarpal. The MCP joint is held in 20 degrees of flexion, the TMC joint in abduction and antepulsion.

As a general rule, 3 weeks are sufficient to stabilize the fracture site. Beyond this time frame, active rehabilitation with use of a dynamic orthosis will allow for functional restoration. From 3–6 weeks are required to regain mobility in a sector, beyond which manual labor is allowed.

Nonoperative management should not be seen as withholding more advanced therapies, and the choice of a suitable method is paramount if a favorable outcome is to be expected. Indeed, the majority of hand fractures are amenable to nonoperative treatment.

Percutaneous Fixation With Wires and Screws

Percutaneous fixation with wires and screws is recommended when reduction can be achieved by external means. The closed approach avoids devascularization, limits injuries at the surgical site and preserves the hematoma and its valuable growth factors. It is indicated for cases of simple displaced fractures, and the conferred stability often allows early mobilization.

Conversely, this method is also suitable for highly comminuted fractures, for which access to perform a direct fixation has little chance of success. The aim is then to restore the length and proper rotation of the injured segment, even if this arrangement will not always allow for immediate mobilization. Furthermore, it will allow stabilization of a fracture for which the contused or injured adjacent covering does not allow for open fixation ( Fig. 7.14 ).

(a) Comminuted proximal phalanx fracture of the index and middle fingers. (b) Fixation by transcutaneous cannulated screws (Biotech-Ortho). (c) Outcome after 2 months.

Axial and Cross-Wiring

Pratt and Von Saal proposed the use of Kirschner wires for hand surgery. They are preferably introduced from the dorsolateral side of the finger, while avoiding damaging or blocking the extensor apparatus ( Fig. 7.15 ). Depending on the size of the bone, the Kirschner wires are 1.0 or 1.2 mm and are introduced with a powerful driver at a slow rotational speed to avoid heating and burning of the cortical bone. The use of wires must avoid fixing uninjured joints, and it is preferable to perform oblique wiring through the lateral surfaces of the metacarpal and phalangeal heads. A single wire is insufficient to stabilize the fracture site and can act as a rotational axis. The second wire must be introduced from the opposite side so as to form a crossed assembly. It is best to manually maintain axial compression of the fracture site at the time of introduction so as to avoid creating a physical separation of the bone at the fracture site.

(a, b) Fractures of the proximal phalanges from the middle to the little fingers: fixation by cross-wiring of the phalanxes.

When wiring of an unstable fracture proves to be difficult, it is prudent to introduce a temporary axial wire that will restore the alignment. Once the two crossed wires are in place the assembly is strong enough to remove the axial wire. This assembly, referred to as an “Eiffel Tower,” was proposed by Tubiana and assists the surgeon with his or her effort while also protecting the injured individual from a malunion ( Fig. 7.16 ). Wires in the vicinity of joints impede capsular-ligament movement, and the risk of neurovascular pedicle injuries is not insignificant. Furthermore, the rate of sepsis, pseudarthrosis and/or malunions remains relatively high (25.3%).

Closed Fixation by K-Wires.

Known as an “Eiffel Tower,” the assembly according to Tubiana reduction is initiated by alignment of the skeleton using an axial wire (1). Two oblique wires are introduced through the tuberosities of the neck (2). During these maneuvers it is best to maintain compression on the fracture site to avoid diastasis. In the end the axial wire is removed (3).

Intramedullary Wiring of Metacarpals and Phalanges

This is based on the principle of elastic fixation promoted by Hackethal and Ender. For extraarticular fractures of the base of the first metacarpal, Kapandji has proposed a crossed ascending double wiring whereby the wires are introduced through the lateral surfaces of the first metacarpal head ( Figs. 7.17 and 7.18 ). A similar technique can be used for the intermediate phalanges by following the three-point support by elastic stable intramedullary nailing (ESIN) of Métaizeau. For the fifth metacarpal, Foucher uses multiple intramedullary wires introduced through a cortical window at the base of the fifth metacarpal ( Fig. 7.19 ).

Principle of Reduction and Stabilization by Percutaneous Wiring of Closed Fractures Proximal to First Metacarpal According to Kapandji

Kapandji Technique.

(a) The entry hole for the wire is made using an awl, transversely at first (1) and then obliquely (2). (b) The first wire (with a rounded tip) is introduced up to the fracture site (1), then after reduction and compression it is pushed up to the base of the first metacarpal (2). (c) The second external wire (3) is introduced in the same manner.

(a, b) Bouquet technique according to Foucher for a fracture of the neck of the fifth metacarpal.

Transverse Metacarpal Wires ( Fig. 7.20 )

In 1973 Lamb published his experience with transverse wiring of unstable metacarpal fractures. He thereby paid homage to a little known old idea of Berkmann and Myles. The healthy metacarpal constitutes a “biological” external fixator, allowing stabilization at the fractured digit while maintaining its length and its axis. Furlong used this to stabilize unstable fractures of the fifth metacarpal neck (see Fig. 7.20, [2] ). James (see Fig. 7.20, [1] ) also recommended it for the treatment of unstable metacarpal fractures. This method is starting to be developed to treat metacarpal fracture-dislocations and to maintain the length of the metacarpal when there is bone loss ( Fig. 7.21 ; also see Fig. 7.20, [3] ). It is the best way to neutralize the palmar flexion stresses exerted by the interosseous muscles on one or more distal fragments of fractured metacarpals. Johnson proposed single transverse wiring to treat Bennett fractures (see Fig. 7.20, [4] ). In the same way, Iselin uses two divergent wires to better stabilize the first metacarpal and prevent retraction of the first commissure.

Indications for Transverse Metacarpal Wires.

1, Unstable fracture; 2, fracture of the neck; 3, support of bone substance loss; 4, Bennett fracture treated by divergent wiring (M. Iselin).

(a, b) Bone loss from the second, third and fourth metacarpals supported by transverse wires and inclusion of a tissue cement spacer. (c, d) The second phase of the surgery consists of coverage using a posterior interosseous flap and inclusion of an iliac graft fixed by a plate. (e) Outcome after consolidation.

Treatment by Rigid Open Fixation

Treatment by rigid open fixation requires specific equipment. Following a period of great enthusiasm that was prompted by the emergence of AO devices, many users pointed out that the bulky size of the implants—the screws and plates in particular—injured the extensor apparatus when applied to the dorsum of the metacarpals and phalangeals. In 1974 Heim and Pfeiffer, who were the initial proponents of this method, observed that treatment of the phalangeals with such implants ultimately yielded mostly unsatisfactory outcomes, while the surgery could prove very difficult in and of itself. Biomechanical studies have now established that the stresses placed on the digital chain during extension and flexion motion are minimal. Based on these measurements, Foucher and Merle have developed Osteo, which is a miniaturized apposition device that has now been reproduced by the majority of manufacturers of such biomechanical items. Stryker Leibinger ( Fig. 7.22 ) and DePuy Synthes have developed a wide range of screws and plates. In practice, screws of 1.1, 1.2, 1.5, 1.7, 2.0, and 2.3 mm in diameter and straight “L” and “T”-shaped plates with thicknesses of 0.55 and 1 mm cover the various fixation requirements that are typically encountered. These sectionable plates are sufficiently malleable to be custom designed and applied as close as possible to the bone ( Fig. 7.23 ).

Miniaturized Sets for Fixation (Stryker Leibinger).

The self-tapping titanium cortical screws (1.2, 1.7, 2.3 mm in diameter) facilitate fixation of small fragments.

(a) Sectionable plates (straight [top], L-shaped [bottom left] and T-shaped [bottom right]) fixed by 1.2- and 1.7-mm screws allow most fixations to be tackled. (b) Indications. 1. Fractures of the thumb column: Bennett by cannulated screw. Joint fracture of the base of proximal metaphyseal fracture: screws + wires. 2. Long or spiral oblique fractures: ulnar screw fixation. 3. Fracture of the base of the distal phalanx: screw fixation. 4. Metadiaphyseal fracture, proximal-middle: fixation by lateral plate. 5. Bicondyle fracture: fixation by a lateral L-shaped plate. 6. Unicondyle fracture: fixation by a screw and an antirotational Kirschner wire.

Osteosynthesis of the hand conforms with the biomechanical principles laid out by the AO and with conventional assemblies. Primary stability and contact are key parameters. Direct screw fixation with compression perpendicular to the fracture line is used on long oblique or spiral fractures. Short oblique or spiral fractures call for a compressive interfragment screw fixation with a neutralizing plate in apposition. Complex fractures combine screw fixation, plates and cerclage wiring to align the intermediate fragments on the plate.

The plates are preferably installed on the dorsolateral sides of the phalangeals to avoid tendon adhesions ( Fig. 7.24 ). Full dorsal application of the device leads to exposure to a double risk of adhesion of the extensor to the plate and catching of a flexor tendon by a protruding screw. On the metacarpals, the implantation is lateral on the distal part and more dorsal at the level of the median and proximal diaphysis; this is to counter strong stresses during flexion. In the last few years, bioengi­neering has allowed for the use of locking screws with these miniplates. This simplifies the treatment of highly comminuted injuries and multifragmented epiphyseal plates while offering increased stability that allows early mobilization.

(a-c) Dorsolateral L-shaped plate on a spiral fracture of the fifth metacarpal.

Treatment by External Fixation

Treatment by external fixation is not often used in the hand. It is essentially restricted to multitissue injuries of the thumb column and for PIP joint fractures. In 1974 Crockett suggested the use of an external construct to fix digital arthrodeses with Kirschner wires that are joined together with acrylic resin. Scott and Mulligan and then adherents of Vilain’s teachings specified their indication in complex traumas of the hand and in osteoarthritis ( Fig. 7.25 ). In 1973 Allieu adapted Hoffmann’s external fixator for the hand, and they recommended assembly in a single section with transfixing wires for the thumb column.

Open comminuted fracture of proximal phalanx of little finger treated by a cemented external fixator known as a “Beaubourg.”

In terms of the digits, to retain full joint movement it is best to use oblique dorsal wires joined together by small tie rods. Hoffmann’s minifixator allows such assemblies on the digital chain, and it is compatible with mobilization. Its use remains tenuous, however, when the wires are anchored in small juxtaarticular bone fragments. This necessitates reliance on the adjacent skeleton and on the bridging of intact joints. The use of this must remain restricted to complex traumas of the thumb column when the loss of bone and skin cannot be treated in an emergency ( Fig. 7.26 ). For the first metacarpal the Orthofix Pennig Minifixator allows stabilization by a “minirail” system or ready-for-use articulated device, but its size limits its use almost entirely to the thumb.

(a, b) Orthofix minifixator stabilizing bone loss from the first metacarpal. (c) The cutaneous cover is provided by a posterior interosseous flap covering the tissue cement spacer. (d) Iliac crest graft fixed in place. (e, f) Functional outcome after 6 months.

More recently, dynamic external fixation processes with varying degrees of complexity have emerged that allow joint distraction mobilization. These devices are suitable mainly for smashed PIP joints, with entities as described by Suzuki or the Ligamentotaxor (Arex) developed by Pélissier ( Fig. 7.27 ; also see Fig. 7.50 ).

(a, b) Use of the Ligamentotaxor to treat a comminuted joint fracture of the middle phalanx. (c) Consolidation and remodeling of the fracture after 6 weeks. (d, e) Functional outcome after 5 months.

Temporary Fixation

Temporary fixation is useful for severe multitissue injuries or with major loss of bone. A minimal fixation is performed in light of the frequent contamination of these injuries. It relies on wires and individual screws to reassemble an epiphyseal plate, along with a wire cerclage that makes a multifragmented diaphysis look like a bundle of wood. The length and axis of the digital chain are maintained in neutral by an external fixator or by interposition of a spacer that may be cemented in and equipped with wires. Once there is no risk of infection and there is adequate soft tissue coverage, the spacer is replaced by a corticocancellous graft or a more stable fixation (see Figs. 7.21 and 7.26 ).

Distal Phalanx Injuries

Fractures of the distal phalanx are the most common and most often affect the thumb and the middle finger. The diagnosis is strictly by PA and lateral x-rays. Schneider distinguishes between fractures of the tuft, the diaphysis and the base.

Tuft Fractures

Tuft fractures are the result of crushing that may or may not be associated with avulsion injuries or loss of pulp and nail. These comminuted fractures result in multiple small fragments that are minimally displaced and do not warrant fixation.

Closed Tuft Fractures

Closed fractures of the tuft are associated with a very painful subungual hematoma that is treated by perforation of the fingernail using a small drill bit, a trocar or a red-hot paper clip (see Chapter 13 , Fig. 13.5a ). This indication only concerns new and painful hematomas that affect the entire nail. Treatment of these fractures is functional by encouraging immediate mobilization, since the tuft is not engaged by tendon contraction. Efforts to desensitize the pulp are necessary to reintegrate the digit’s function.

Open Tuft Fractures

Open tuft fractures are often associated with a loss of distal pulp tissue (see Chapter 9 ) and soft tissue contusion. If the injury is substantial, administration of an oral antibiotic for 5 days is advisable following debridement of the wound. Treatment involves surgery with debridement of tissues likely to undergo necrosis and of small bone fragments that may become sequestra. It is best to limit phalangeal shortening to avoid development of a hook nail. When the fragments are still linked by the phalangeal periosteum and the palmar fibrous partitions, placement of a small 0.8-mm wire or an intradermic needle for 15 days to 3 weeks will restore stability and alignment of the phalanx. If the fracture is longitudinal, cerclage with PDS 4-0 improves interfragment contact and limits the risk of a split phalanx. Coverage of these injuries is achieved by a straightforward suture of the nail bed using Monocryl 6-0 (see Chapter 13 , Fig. 13.4 ) and by a cutaneous suture or by creating a local flap in the pulp area.

Progression of fractures to pseudarthrosis is common. The presence of a painful distal bone fragment may warrant renewed surgery to excise it or to perform an intermediate graft in the case of a split phalanx ( Fig. 7.28 ). In the exceptional case of a painful and unstable pseudarthrosis, regrowth of the nail will have to be complete before undertaking a surgical intervention, because the fingernail has a major stabilizing effect.

(a) Bifid nonconsolidated tuft fracture. (b) Pseudarthrosis treatment by insertion of a graft.

Diaphyseal Fractures

Diaphyseal fractures are divided into the more common transverse fractures and longitudinal fractures. The presence of a displacement or an open fracture determines the specifics of the treatment.

Nondisplaced Closed Fractures

Closed or nondisplaced fractures are amenable to immediate mobilization or splinting depending on the patient’s requirements and the location of the fracture line relative to the fingernail. Mobilization is preferable for longitudinal injuries and with the most distal transverse diaphyseal fractures, provided the patient is not required to perform manual labor. In this case a dorsal splint must be worn nightly for 3–4 weeks to act as an analgesic and shock absorber ( Fig. 7.29 ). The same splint must be worn continuously for 3–4 weeks if the patient engages in strenuous physical activities or if the pain is substantial and the fracture line is situated in the middle or distal third of the diaphysis. In this case the fingernail cannot be considered to be a substitute for a splint.

Immobilization of Nondisplaced Diaphyseal Fracture of Distal Phalanx by Dorsal Splint

Displaced Closed Fractures

Displaced closed fractures are to be treated surgically when bone contact is insufficient or the dorsal cortex exhibits a separation that will lead to ungual dystrophy. Fixation is achieved by percutaneous wiring with wires, preferably divergent, following manual axial compression of the site. The wires are introduced 1–2 mm under the distal edge of the nail under fluoroscopic control. The DIP joint is not immobilized by the fixation ( Fig. 7.30 ). If the fracture is juxtaepiphyseal, however, the hold of the wires can be tenuous, and performing a temporary arthrodesis will provide the stability required for consolidation while also facilitating mobilization of the PIP joint. The wires may be countersunk to reduce the risk of infection and perturbation of the distal pulp, because a delay in consolidation cannot be ruled out.

(a) Unstable diaphyseal fracture of the distal phalanx. (b, c) Reduction and stabilization by two divergent wires.

Displaced Open Fractures

Open fractures, whether displaced or not, require antibiotic therapy and irrigation of the fracture site. Osteosynthesis is then performed with two 0.8- or 1.0-mm wires introduced through the fracture site in opposite directions. The first wire is axial, the second oblique, traversing the fracture site, which is maintained in compression on the axis of the first wire. The nail bed is sutured by a slow-absorption monofilament running stitch. The nail is not routinely replaced, because it has mainly an analgesic role and this could also lead to a secondary infection (see Chapter 13 , Fig. 13.3 ).

Foucher describes a technique for reducing the nail with a needle and using it to brace the fracture in distal diaphyseal injuries (see Chapter 13 , Fig. 13.6c and 13.7 ). A longitudinal fracture can be reduced and stabilized by cerclage with doubled PDS 4-0 and sutured laterally according to the Nice knot technique. With injuries from thick-bladed cutting tools the fracture is accompanied by loss of bone that is treated initially by interposition of a cement spacer stabilized by an axial wire. Once healing has occurred and infection has been avoided, a second surgery will replace the spacer with a corticocancellous bone graft taken from the radius ( Fig. 7.31 ).

(a) Open fracture with loss of bone. (b) Placement of a cement spacer. (c) A bone graft stabilized by two divergent wires. (d) Final outcome.

Seymour’s Juxtaepiphyseal Fracture

Seymour’s juxtaepiphyseal fracture is a transverse extraarticular fracture of Salter type I or II, affecting the growth cartilage of the distal phalanx. This fracture results from trauma by hyperflexion of the phalanx. It often involves an open fracture of the growth cartilage, with avulsion or rupture of the ungual matrix. A Seymour fracture presents clinically as a mallet finger, because the extensor tendon inserts on the proximal epiphysis, whereas the deep flexor tendon inserts on the distal fragment. This results in angulation with dorsal protrusion of the fracture ( Fig. 7.32 ). It is imperative that PA and lateral radiographic images are taken of the injured finger.

Seymour Fracture.

Through the action of the extensor tendon, the proximal fragment is displaced in extension while the distal fragment bends through the action of the deep flexor.

With closed fractures that can readily be reduced, proper treatment is ensured by the wearing of a splint for 4 weeks.

Surgery is required when the reduction is incomplete due to confinement of the ungual matrix. Removal of the nail allows access to the fracture and matrix release. After cleaning the fracture site, fixation is ensured by a 0.8-mm axial wire. The nail matrix and its bed are sutured with Monocryl 6-0. The nail is put back to serve as a guide for healing of the matrix. Complications are the same as for all growth cartilage fractures. Premature epiphyseal arrest may occur following the trauma or a secondary infection.

Diaphyseal distal phalanx fractures can develop into pseudarthrosis, particularly when the severity of the injury is underestimated and the splinting is inadequate. This can result in perpetuation of an interfragmentary gap. Usually the fibrous tissue of the pseudarthrosis and the dorsal stabilization by the fingernail ensure a reasonable functional outcome. When there is a painful instability, surgery is performed when the nail has regrown. Following freshening of the bone ends and the possible addition of a bone graft, stabilization is achieved by a compressive screw or two 0.8- or 1.0-mm Kirschner wires. If the bone quality is poor, Merle has proposed performing an intramedullary bone bilboquet taken from the ulnar crest.

Intraarticular Fractures of the Base of the Distal Phalanx

Intraarticular fractures of the base of the distal phalanx are frequently encountered with ball sports. Avulsion injuries, corresponding with bony mallet fingers and jersey fingers, are different from injuries with an axial component.

Mallet Fingers

Approximately 30% of mallet fingers are fractures of the base of the distal phalanx, versus 70% of tendon injuries. Mallet finger injuries have been classified by Doyle (see Chapter 11 ), but the Wehbe and Schneider classification describes mallet fractures more specifically ( Table 7.1 ). Indications for treatment are controversial. A dorsal splint is generally recommended, and this yields satisfactory results for injuries without subluxation and affecting less than a third of the joint surface. Beyond a third, or when there is DIP joint subluxation, surgery is the rule because functional outcomes and physical appearances are unpredictable with nonoperative treatment. Giddins emphasizes the importance of the stability of interfragment contact (which can be tested by taking a radiography image in hyperextension) and the presence of subluxation. The technique of Ishiguro, improved by Hofmeister with the DIP joint blocked in extension, is the protocol of choice for injuries with small fragments (see Chapter 11 , Fig. 11.13c-g ). When the fragment is of a bigger size, we prefer direct percutaneous interfragment screw fixation or placement of a plate (see Chapter 11 , Fig. 11.13h ).

TABLE 7.1

Classification of Joint Fractures of the Distal Phalanx According to Wehbe and Schneider

Type	Description
I	No distal interphalangeal joint subluxation
II	Distal interphalangeal joint subluxation
III	Epiphyseal injury
Subtype
A	<1/3 joint surface
B	1/3–2/3
C	>2/3

 

Jersey Finger Injuries

Modified Leddy-Packer type 3, 4 and 5 jersey finger injuries involve a fracture of the base of the distal phalanx. The main issue to be addressed in this situation is reconstruction of the flexor apparatus (see Chapter 10 , Table 10.1 and Fig. 10.9 ).

Hyperextension Injuries

With injuries due to hyperextension or that have an axial compression component, a T-shaped or a Y-shaped fracture is seen at the base of the distal phalanx. Horiuchi has shown that when the axial trauma is applied to a flexed IP joint, there is a dorsal dislocation of the phalanx with a palmar fracture. In the case of hyperextension of the DIP joint the deformation is the opposite, with a palmar dislocation of the phalanx and a dorsal fracture ( Fig. 7.33 ). Treatment of these fractures, which are usually displaced, requires surgery to restore joint alignment. The treatment can be performed by closed reduction or by percutaneous screw fixation. In the case of incomplete reduction, directly accessing the fracture site is necessary for fixation by screw fixation or by a hook plate. In cases involving very unstable injuries, it is prudent to add an arthrodesis wire.

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