Author’s Preferred Method of Treatment

Noncomminuted, displaced fractures that constitute more than 25% of the articular surface or exhibit more than 1 mm of articular step-off are treated operatively. We approach these fractures through a dorsal longitudinal incision that splits the extensor tendon to expose the joint. Two-part articular fractures are usually amenable to fixation with headless screws. Fixation with Kirschner wires, although easier, is less rigid and requires immobilization for 3 to 4 weeks.

Open fractures of a metacarpal head secondary to a clenched fist injury should be presumed to have oral contamination and are treated by formal irrigation and débridement. The wound is generally left open, and internal fixation, if necessary, is delayed until the wound shows no sign of infection.

Comminuted fractures are problematic. Direct fracture fixation with multiple Kirschner wires or cerclage wires can be effective in stabilizing tenuous reductions of these fractures. Unstable reductions may require immobilization for 2 to 3 weeks before range-of-motion exercises are begun. Often these joints need a delayed tenolysis and capsulotomy procedure to improve the functional outcome. If Kirschner wires or cerclage wires fail to stabilize the fracture and maintain the reduction, we prefer immobilization for 2 to 3 weeks with the MP joint flexed 70 degrees, followed by intensive range-of-motion exercises. Skeletal traction or external fixation may be needed if there are associated comminuted fractures of the adjacent base of the proximal phalanx. For open comminuted head fractures, especially fractures with bone loss, prosthetic arthroplasty is a reasonable alternative, but it should not be done under the following circumstances:

• 1.
  

  Fracture of the head of the index finger because shear stresses from pinch predictably result in implant failure

  
  
• 2.
  

  Inadequate soft tissue coverage

  
  
• 3.
  

  Excessive metacarpal bone loss because excessive shortening and instability occur

MP arthrodesis is a salvage procedure and should seldom be done acutely because of the risk of excessive shortening or nonunion.

Closed Reduction of Metacarpal Neck Fractures

Jahss recognized that flexing the MP joint to 90 degrees relaxed the deforming intrinsic muscles and tightened the collateral ligaments, allowing the proximal phalanx to exert a dorsal force on the metacarpal head. He applied a cast in two parts: first immobilizing the proximal metacarpal fragment with the MP flexed, and subsequently pushing dorsally on the flexed proximal interphalangeal (PIP) joint while applying the second part. The Jahss maneuver ( Figure 7.2 ) remains the best technique of closed reduction; however, fingers should never be immobilized in the “Jahss position” (MP and PIP joints flexed 90 degrees) because of the risk of skin necrosis over the dorsum of the PIP joint or permanent PIP stiffness.

A, Jahss maneuver for reduction of metacarpal neck fracture. Arrows indicate direction of pressure application for fracture reduction. B, After reduction, fingers are held in intrinsic-plus (safe) position in ulnar gutter splint with molding as indicated by arrows .

With regard to cast immobilization, Hofmeister and colleagues demonstrated that immobilization of the fifth metacarpal fracture in extension rather than flexion (as in the Jahss maneuver) did not affect fracture healing. However, the extension cast was faster to apply and showed greater improvement of angulation.

Maintenance of closed reduction by percutaneous longitudinal or crossed Kirschner pin fixation of the fractured metacarpal neck is a popular method of treatment for metacarpal neck and shaft fractures. Percutaneous transverse Kirschner wire fixation to the adjacent metacarpal has also been used for these fractures. Percutaneous fixation has the advantage of being minimally invasive, with a decreased likelihood of postoperative swelling and stiffness that may follow ORIF. The disadvantage is that it does not provide rigid fixation and requires some form of external immobilization for to 3 weeks. Galanakis and associates reported excellent functional and anatomic outcomes in treatment of closed metacarpal neck fractures by transverse percutaneous pinning, using two Kirschner wires distally and one proximally. Active flexion-extension exercises of the fingers were started at 1 week after surgery. These investigators reported no fixation failures. Transarticular Kirschner wire fixation may be also used to hold a reduction adequately.

Foucher reported excellent results with the use of “bouquet” osteosynthesis in the management of displaced small finger metacarpal neck fractures ( Figure 7.3 ). The fracture is reduced in closed fashion; a hole is made in the proximal ulnar metaphysis of the metacarpal; and three blunt prebent Kirschner wires are passed antegrade down the medullary canal, across the fracture, and into the subchondral bone of the metacarpal head. This antegrade fixation technique has the advantage of avoiding the fracture site, but it can be technically difficult, and pins can migrate either proximally or distally. Using a similar antegrade intramedullary Kirschner wire fixation technique, Kelsch and Ulrich reported satisfactory 1-year radiographic and functional results in 35 patients. The fractures were immobilized for 2 to 6 weeks, depending on patient compliance.

Technique for antegrade fixation of metacarpal neck fracture with multiple prebent Kirschner wires. Exposure of fracture site is avoided.

As the antegrade intramedullary fixation technique has gained in popularity, multiple studies have compared this technique with traditional Kirschner wire fixation. In a retrospective study of 30 patients with displaced neck fractures of the fifth metacarpal that compared retrograde crossed pinning with antegrade intramedullary fixation, Schadel-Hopfner and colleagues found significantly decreased motion of the MP joint in the retrograde cohort. There was decreased shortening of the metacarpal after antegrade fixation, suggesting that intramedullary fixation was preferable. When comparing antegrade intramedullary pinning with transverse Kirschner wire fixation, Wong and associates found no statistical difference in the effectiveness, functional outcome, or complications, concluding that both methods are comparable in treating small finger metacarpal neck fractures.

Facca and colleagues demonstrated no benefit of locked dorsal plate fixation and immediate motion when compared with intramedullary fixation. Both techniques had a high complication rate (>30%), and the authors concluded that the intramedullary pinning technique should be continued as the fixation standard for displaced fractures of the fifth metacarpal neck.

Open Reduction of Metacarpal Neck Fractures

Malunions of the fifth metacarpal neck rarely result in significant disability. Open reduction is occasionally indicated when manipulation fails to restore acceptable angulatory or rotational alignment. Following reduction, any number of techniques can stabilize the reduction adequately, including wires or tension band or miniplate fixation.

Author’s Preferred Method of Treatment

Most closed metacarpal neck fractures (especially of the ring and small fingers) should be treated nonoperatively. In the absence of pseudoclawing or rotational malalignment, metacarpal neck fractures produce minimal, if any, functional problems despite angulation on the lateral radiograph and shortening in the frontal projection. The term pseudoclawing refers to compensatory hyperextension of the MP joint and flexion of the PIP joint caused by excessive metacarpal neck flexion; the relative metacarpal shortening creates an imbalance between the longer extrinsic extensors and the short intrinsics. If pseudoclawing is not present on attempted digital extension, we prefer to use a functional brace. A forearm-based, dorsal-ulnar gutter splint using thermoplastic material is fabricated such that the wrist is extended 30 degrees, and the proximal phalanges of the ring and small fingers are splinted in approximately 70 degrees of flexion. “Buddy taping” is used to secure the digits to one another. Active range of motion is encouraged. The splint is worn for 2 weeks and is discontinued when pain has resolved.

Reduction of metacarpal neck fractures is clinically indicated when there is pseudoclawing or when there is a rotational deformity. After appropriate anesthesia, a closed manipulation of the metacarpal neck fracture is performed by the Jahss maneuver (see Figure 7.2 ). This maneuver is accomplished by flexing the MP and PIP joints to 90 degrees and exerting upward pressure through the flexed proximal phalanx and simultaneous downward pressure on the metacarpal shaft. Particular attention is paid to correcting any rotational deformity by using the flexed proximal phalanx as a crank. A forearm-based ulnar gutter plaster cast is applied and includes the adjacent, stable finger. The wrist is placed in 30 degrees of extension, the MP joints are maximally flexed, and the PIP joints are held extended (see Figure 7.2, B ).

Radiographs are obtained to check the accuracy of reduction. Angulation greater than 15 degrees is unacceptable for fractures of the index and middle metacarpal necks. Angulation of 30 to 40 degrees is acceptable in the ring finger, and angulation of 50 or 60 degrees is acceptable in the small finger. Patients who use their hands extensively for gripping (e.g., professional athletes, carpenters) may generate discomfort, however, from the flexed metacarpal head of the small finger in their palm. In these patients, we would typically not accept flexion greater than 40 degrees. Immobilization usually can be discontinued after 12 to 14 days, and a program of active range of motion and intermittent splinting is initiated. The patient may return to sports and unrestricted activity at 4 to 6 weeks. Manipulation is not usually worth attempting if the fracture is older than 7 to 10 days.

In fresh metacarpal neck fractures, closed reduction is usually possible; however, reduction may be difficult to maintain because of volar comminution and intrinsic muscle pull. If an acceptable reduction cannot be maintained, we prefer percutaneously inserted crossed Kirschner wires ( Figure 7.4 ) or antegrade intramedullary fixation under fluoroscopic guidance. After closed reduction, the pins are inserted into the nonarticular portion of the metacarpal head and drilled proximally into the metacarpal shaft. Alternatively, two pins can be percutaneously inserted in a transverse fashion from the fractured metacarpal head and fixed to the adjacent intact metacarpal ( Figure 7.5 ). Care should be taken not to induce lateral translation of the fractured metacarpal head.

A, Severely displaced neck fractures of ring and small metacarpals. B, Closed reduction using Jahss maneuver and percutaneous crossed pins.

Percutaneous transverse pinning of displaced metacarpal neck fracture. After closed reduction, significantly angulated metacarpal neck fracture can be held with two percutaneous pins extending into adjacent intact metacarpal.

If open reduction is necessary, we prefer crossed Kirschner pins. Alternatively, a dorsal tension band wire with a supplemental Kirschner pin or a laterally applied minicondylar plate ( Figure 7.6 ) can be applied. Plate application requires more dissection, however, which may result in tendon adherence and MP stiffness, and should be used as a last resort. Plates require intracapsular positioning and may interfere with tendon gliding and collateral ligament function, all of which can adversely affect MP joint mobility.

Laterally applied 2-mm minicondylar plate for stabilization of metacarpal neck fracture. A, Anteroposterior view. B, Lateral view.

Postoperatively, the operated digit is immobilized in an intrinsic-plus position for 5 to 7 days. Radiographs are taken to verify hardware position and fracture alignment, and, if satisfactory, protected active range-of-motion exercises are initiated after internal fixation. Immobilization in an ulnar gutter splint is usually maintained for 2 to 3 weeks after percutaneous pin fixation. If MP joint transarticular pins have been placed, immobilization is maintained until the pins are removed at 3 weeks postoperatively. Edema control with an elastic garment is also recommended.

Closed Reduction and Plaster Immobilization

Closed reduction with plaster immobilization works well for most metacarpal shaft fractures, and overtreatment is to be avoided. Many metacarpal fractures are inherently stable and may be treated with minimal or no immobilization. In athletes, Rettig and associates reported that 82% of the fractures were minimally displaced or nondisplaced, and the average time lost from practice or competition was 13.7 days. Burkhalter advocated closed treatment for fractures that showed no rotational malalignment on clinical examination. He used a short-arm cast with the wrist in 30 to 40 degrees of extension and added a dorsal extension block to hold the MP joints flexed 80 to 90 degrees and the interphalangeal (IP) joints extended. Composite active MP and IP flexion was initiated, and the cast was maintained for 4 weeks.

When the PIP joints are extended in this splint, the hand assumes the intrinsic-plus or clam-digger position ( Figure 7.7 ). This position limits joint contractures and maintains the intrinsics in a relaxed position. In a retrospective study examining 263 patients, Tavassoli and coworkers compared three different casting techniques for metacarpal neck or shaft fractures and found that positioning the MP joints in flexion or extension or the IP joints free or immobilized resulted in no difference in motion, grip strength, or fracture alignment. They recommended immobilizing the MP joints in extension and allowing full motion of the IP joints. A recent study performed by Westbrook and colleagues in Britain examined the functional and aesthetic outcomes of operative and nonoperative treatment of little finger metacarpal fractures in 262 patients. The authors concluded that up to 40 degrees of flexion of the metacarpal shaft can be safely managed nonoperatively, although the patient must be warned that a visible deformity is possible.

A and B, Clam-digger cast for metacarpal shaft fracture. Wrist is extended 30 degrees, MP joints are flexed 80 to 90 degrees, and IP joints are extended. Active range of motion is encouraged, and supplemental “buddy taping” can help control rotation.

Closed Reduction and Percutaneous Pinning

Antegrade or retrograde percutaneous pinning can be successfully employed as above; if cut and bent outside the skin, short-term immobilization is necessary. Buried intramedullary Kirschner wire fixation for unstable metacarpal fractures has been advocated and is greatly facilitated by the use of image intensification. Using an awl, a cortical window is made at the ulnar base of the fifth metacarpal 1 cm distal to the CMC joint. Three or four prebent (≈30 degrees) 0.9-mm pins are inserted and buried within the medullary canal ( Figure 7.8 ).

Intramedullary pins are inserted in antegrade fashion through multiple drill holes. Technique is facilitated by fluoroscopy. A, Fifth metacarpal shaft fracture. B, Antegrade pin insertion. C, Pins cut so that they are buried within medullary canal.

Open Reduction

A small percentage of metacarpal fractures were irreducible by closed manipulation or percutaneous pinning and require open reduction. Absolute indications for open reduction include the following:

• 1.
  

  Open fractures are associated with bone loss, contamination, or soft tissue injury.

  
  
• 2.
  

  Multiple fractures: In such cases, the stabilizing effect of the adjacent metacarpals is lost.

  
  
• 3.
  

  Unstable fractures: Fractures of the border metacarpals tend to be more unstable and more difficult to control than fractures of the central metacarpals because of the lack of support for soft tissue on both sides.

  
  
• 4.
  

  Malalignment: Rotational malalignment is unacceptable and is characteristically seen in spiral and oblique fractures. When correction of a rotational deformity by closed techniques or percutaneous pinning is unsatisfactory, open reduction is indicated.

Techniques of Open Reduction.

See eTable 7.1 .

Kirschner Wires.

Kirschner wires may be used in nearly any fracture pattern ( Figure 7.9 ). Pin fixation is technically easy, requires minimal dissection, and is universally available. Pin configurations can be either single or multiple and may be crossed, transverse, longitudinal (intramedullary), or in combination. They can be used to supplement other forms of fracture fixation and can be used as a “bailout” if more complicated fixation has failed. Kirschner wires are not rigid; may loosen or even migrate; and, if improperly inserted, may distract fracture fragments. Pin track infections may develop secondary to skin irritation or loosening, and pin protrusion may make therapy and splinting awkward. Botte and associates reviewed a series of 422 Kirschner wires placed in the hand and wrist and reported an 18% complication rate.

Techniques for Kirschner pin fixation of metacarpal shaft fractures. A, Transverse pins may be inserted percutaneously or open. B, Retrograde intramedullary fixation. Pin can be backed out so that they do not remain in MP joint. C, Crossed pins ( left ) and supplemental 25-gauge stainless steel wire (composite wiring) ( right ).

For longitudinal fixation, the pin can be drilled in antegrade fashion from the fractured end out the dorsal radial aspect of the metacarpal head. After reduction, the pin can be drilled in a retrograde fashion back down the shaft through the reduced fracture. Antegrade drilling of the proximal fragment through the fracture site is also possible with the wrist acutely flexed. Retrograde pins can also be introduced directly into the metacarpal head on either side of the extensor tendon and driven down the metacarpal shaft to engage subchondral bone at the CMC joint. Transarticular pins are generally bent outside the skin and left in place for 3 weeks. One or more supplemental transverse pins are generally recommended for unstable or transverse fractures in border digits when using this technique.

Composite (Tension Band) Wiring.

Composite wiring for metacarpal fractures is a combination of Kirschner wires (0.035-inch or 0.045-inch diameter) and monofilament stainless steel wire (24-gauge or 26-gauge). The stainless steel wire is inserted as a tension band through a small transverse drill hole in the distal fragment and crossed around the Kirschner wires at the bone interface proximally (see Figure 7.9, C ). Composite wiring provides additional stability and fracture compression and superior strength, stiffness, and approximation compared with crossed Kirschner wires alone. Little, if any, additional dissection is necessary. The technique is rigid enough to permit early motion. The technique is contraindicated when there is bone loss, comminution, or osteopenia.

Cerclage and Interosseous Wiring.

Cerclage (circumferential) wiring with 24-gauge stainless steel wire can be successfully employed for oblique and spiral metacarpal shaft fractures (see Figure 7.38 ), but the technique is not widely popular. The technique was originally described to include scoring of the cortical bone with a side-cutting bur so that wire migration would not occur. Al-Qattan and Al-Lazzam showed that cerclage wire fixation can be sufficient without scoring of bone or finger immobilization for midshaft oblique or spiral fractures in 19 cases.

Gingrass and colleagues 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 interosseous wiring done without supplemental Kirschner pin fixation is generally unsuitable for metacarpal shaft fractures because wire loosening and subsequent loss of reduction are real possibilities. In contrast, Al-Qattan reported treatment of 36 metacarpal shaft fractures with interosseous loop wire fixation alone and concluded that interosseous wiring without Kirschner wire fixation is rigid enough for immediate postoperative finger mobilization. Of 36 patients, 34 regained full range of motion. It is prudent to use supplementary Kirschner wires if the fracture is comminuted or if bone is missing.

Intramedullary Fixation.

Open reduction and intramedullary fixation are applicable for transverse fractures, are easy to perform, and allow early active motion ( Figure 7.10 ). There are no exposed pins, and secondary removal is unnecessary. In 1981, Grundberg reported one nonunion in 27 metacarpals treated by open reduction and permanent intramedullary fixation with a large Steinmann pin. Potential disadvantages include rotational instability, pin migration, and occasional fracture distraction. The technique is not recommended for spiral or long oblique fractures.

Intramedullary fixation. A, Displaced open metacarpal shaft fractures. B, Clinical appearance of dorsum of hand. C, Intramedullary Steinmann pin fixation. Pin in ring metacarpal extends into carpus for more secure fixation.

The technique involves determining the diameter of the medullary canal using a smooth Steinmann pin and drilling one size larger. Next, the pin is introduced into the proximal fragment (blunt end first to avoid penetration of the subchondral bone) and cut so that it protrudes 1.5 cm. The fracture is distracted, and the pin is introduced into the distal fragment. Finally, the fracture is impacted to achieve rotational stability.

When segmental bone loss is present and the soft tissue sleeve is largely intact, locked intramedullary fixation with rods or plates with bone grafting is recommended. In this situation, the rod or plate acts as an internal spacer while the defect is bridged with corticocancellous autogenous bone graft. One or more supplementary Kirschner wires may be necessary.

Interfragmentary Compression Screws.

Interfragmentary compression screws provide stable fixation and are primarily indicated for long oblique and spiral shaft fractures ( Figure 7.11 ). Interfragmentary screw fixation is stable enough to allow early active range of motion. To ensure success, the fracture length must be a minimum of twice the bone diameter. The fracture is reduced by manipulating it into alignment and holding the reduction with provisional Kirschner wires or a fracture reduction forceps, followed by placement of two or three interfragmentary compression screws (see Figure 7.11 ). A dorsal miniplate can be applied to neutralize the fracture if stability of the fracture is questionable.

Fixation of spiral metacarpal fracture with 2.7-mm lag screws. A, A 2-mm bicortical hole is drilled. B, Near hole is countersunk to accept truncated screw head and distribute compression. C, Screw length is determined with depth gauge. D, Precision use of the 2.7-mm tap is critical, as failure to engage the far cortical drill hole can disrupt fracture reduction. Most modern screws are self-tapping. E, The near (gliding) hole is overdrilled with a 2.7-mm drill bit. F, Insertion of screw, engaging far hole and compressing the fracture.

To optimally resist axial and torsion loading, the screw should be placed in a plane bisecting the fracture plane and longitudinal axis. In large patients, at least two 2.7-mm screws are necessary, and in smaller individuals three 2.4-mm or 2-mm screws are necessary. To avoid fragmentation, the screw hole should be a minimum of two screw diameters from the fracture margin.

Interfragmentary screw fixation (2.7-mm) of a metacarpal fracture involves six sequential steps (see Figure 7.11 ). There is little tolerance for technical error with this technique; if the screw is inserted through the near cortex and is misdirected such that it strikes the endosteal surface of the far cortex, the fracture is distracted, and the reduction lost. Any resistance to screw tightening should alert the surgeon to stop and redirect the screw.

Plate Fixation.

Dorsal metacarpal plating with or without an interfragmentary screw provides more stable fixation than crossed Kirschner wires, an interosseous wire loop alone, or an interosseous wire with a Kirschner pin. The amount of strength required for stable fixation in the clinical setting has not been determined; fixation should be customized to the particular fracture.

Page and Stern reported multiple complications of metacarpal fracture plating, however, including malunion, nonunion, and stiffness (articular and tendon adhesions). Complications were more frequent when there was associated bone loss, soft tissue injury, and open fractures. Fusetti and colleagues assessed 81 patients treated with plate fixation and reported complications in 28 (35%). Complications included difficulty with fracture healing (15%), stiffness (10%), plate loosening or breakage (8%), complex regional pain syndrome, and infection. In another study, Fusetti and Della Santa reported significant correlation between a transverse fracture pattern and nonunions when treated with plate fixation.

Most implants are made of either stainless steel or titanium. Although titanium is more expensive, some advantages of titanium include generally lower incidence of corrosion and allergic reactions, ease of contouring, and a modulus of elasticity that approaches that of bone. Some studies have shown, however, that use of titanium plates may still lead to significant corrosion and release of metal debris. No clinical difference in outcomes has been shown with the use of titanium implants. Great care must be taken when using titanium implants; screws may break, especially when being removed, and plates can break if excessively contoured before application.

Successful use of small titanium maxillofacial plates has been reported. Screws are self-tapping, and diameters range from 0.8 to 1.7 mm. Because the plates are low profile (≈1 mm), the periosteum can often be closed over the plate to reduce adhesion formation. Fracture stabilization was adequate to allow early mobilization with a low incidence (3%) of hardware failure or plate breakage in a series of 36 patients treated for metacarpal and phalangeal fractures after acute and complex hand injury.

Bioabsorbable plates and screws are not widely used in the United States, and clear advantages of such plates over metal implants have not been demonstrated.

Although infrequently used in the United States, bioabsorbable implants are commonly used in Europe. Biomechanical testing in cadaveric metacarpal and phalangeal bone shows that the implants provide fixation stability that is comparable to that of metal implants. Bioabsorbable platings resulted in higher torsional rigidity than 1.7-mm titanium plating and in failure torque comparable with 2.3-mm titanium plating. The advantage of absorbable plates is that removal is unnecessary.

The first-generation bioabsorbable implants in the 1990s consisted mostly of polyglycolic acid, which led to a noninfectious inflammatory response 7 to 30 weeks after fracture fixation in 5% to 25% of cases. A newer generation of bioabsorbable implants using poly-L-lactide implants is now being evaluated. Dumont and coworkers used this new plate in 12 patients (14 fractures) with displaced, unstable metacarpal fractures. The plates were molded and placed laterally on the bone to reduce irritation to the extensor tendon. Lag screws were used as needed. At 26 weeks, the authors found that 25% of the patients had keloid formation and soft tissue swelling. Swelling resolved after 6 months. It is unclear whether the new generation of bioabsorbable implants diminishes the inflammatory response.

External Fixation.

The advantages of external fixation were enumerated by Schuind and coworkers : “There is respect of bone biology.” Fracture fragments are not stripped of periosteal blood supply and further devascularized. External fixators are adjustable, and there is adequate stability to permit early mobilization. When there has been concomitant soft tissue injury, external fixation permits ready access to the wound for débridement and for reconstruction of tendons, nerves, and blood vessels.

Hastings identified numerous complications of external fixation, including pin track infection, osteomyelitis, fracture through pin holes after removal, neurovascular injury during insertion, overdistraction with subsequent nonunion, loss of reduction, impairment of tendon gliding and motion, and interference with adjacent digits by the fixator. In weighing the advantages and disadvantages of external fixation, the technique is primarily indicated for severe fractures when anatomic reconstitution of the skeleton is not feasible. Examples include highly comminuted open shaft fractures with or without bone loss; displaced, comminuted articular fractures; and fractures with injury or loss of soft tissue structures. In addition, external fixation can be used to stabilize septic nonunions after débridement.

Author’s Preferred Method of Treatment

Most metacarpal shaft fractures can be managed nonoperatively. Stable fractures that do not require reduction can be treated in a clam-digger cast or thermoplastic splint until the fracture is clinically nontender. The fractured finger is “buddy taped” to an adjacent finger, and immediate finger flexion is initiated.

Transverse shaft fractures are usually easy to reduce, but maintenance of acceptable alignment may be difficult. To achieve reduction, a palmarly directed load is applied to the dorsal apex at the fracture site with a dorsally directed force to the flexed MP joint (see Figure 7.2 ). A well-molded, forearm-based cast extending to the IP joints and holding the MP joints in 60 degrees of flexion is applied. Special attention must be paid to ensure satisfactory rotational alignment. The fracture is monitored with radiographic imaging at weekly intervals, and guarded active range-of-motion exercises can be initiated at 3 to 4 weeks. Marked swelling, which is often present in acute metacarpal shaft fractures, does not preclude manipulation and casting. The cast should be changed at 5 to 7 days when the swelling subsides.

Closed manipulation and percutaneous treatment are indicated when the fracture can be reduced but cannot be maintained in plaster or when concomitant soft tissue injury requires dressing changes and inspection. Fluoroscopy is invaluable to confirm fracture reduction and assist in placement of fixation devices. Reduction can sometimes be facilitated by placing a small incision over the fracture and inserting an elevator to manipulate the fragments. I pin transverse fractures of the fifth or fourth metacarpal to the neighboring intact metacarpal using two parallel transverse pins into the distal fragment and one through the proximal fragment (see Figure 7.9, A ).

Open reduction is indicated for transverse shaft fractures that either are significantly displaced or have residual angulation of more than 10 degrees in the second and third metacarpals, 20 to 30 degrees in the ring metacarpal, and 30 to 40 degrees in the small finger metacarpal. ORIF using Kirschner wires or interfragmentary screws is indicated for most spiral and oblique fractures, particularly if there is evidence of a rotational deformity on physical examination, because fracture reduction is difficult to maintain by closed techniques. ORIF is nearly always indicated when there are multiple metacarpal fractures or when the fracture is open and associated with soft tissue injury or bone loss.

Fracture exposure is accomplished through a longitudinal incision just to one side of the extensor tendon overlying the involved metacarpal. If all four metacarpals require reduction, two longitudinal incisions are used: one between the fourth and fifth metacarpals and one between the second and third metacarpals. Care is taken to preserve cutaneous nerves and the paratenon surrounding the extensor tendons. Occasionally, one of the juncturae tendinum requires division for better fracture visualization; if this is necessary, the junctura should be repaired after fixation. The fracture ends are exposed, and fracture hematoma is removed. Reduction is accomplished by applying longitudinal traction and is maintained with reduction clamps.

Fixation options include Kirschner wires, composite wiring, an intramedullary rod, multiple interfragmentary screws, or a plate and screws. The choice of implant is dictated by the fracture configuration and experience of the surgeon (see eTable 7.1 ).

Kirschner wire fixation can be used for nearly all fracture configurations. Kirschner wire fixation alone is not rigid and may require immobilization postoperatively. If wire placement or fracture alignment is initially unacceptable, reinsertion is a simple matter. Multiple passes with the wires should be avoided, however, because this may lead to thermal necrosis of bone and increase the incidence of pin track infection. In addition, wires may loosen or distract a fracture, and pin track infection may necessitate premature removal.

I prefer K-wire fixation for isolated short oblique and transverse fractures and when possible supplement the pins with composite wiring to increase rigidity of fixation. The pins, when placed percutaneously, are left in place for 3.5 to 4 weeks, and protected range of motion is initiated at the first postoperative visit (5 to 7 days after fixation). Patients should be instructed that if there is drainage, early pin removal may be necessary.

I find intramedullary fixation using precut Steinmann pins or commercially available rods particularly useful for multiple open transverse shaft fractures (see Figure 7.10 ). In this situation, there may be injury to the intrinsic muscles that allows the fracture to be easily distracted, facilitating pin insertion. Intramedullary fixation is easy and takes little time, but rotational stability may be a problem, particularly if the fracture ends fail to interdigitate. If the adjacent metacarpal is not fractured, a transverse wire can be added to control rotation.

Spiral and long oblique fractures are well suited for interfragmentary fixation. The fracture length should be at least twice, and preferably three times, the diameter of the bone at the level of the fracture. Reduction is achieved by anatomically interdigitating the proximal and distal apex of the fracture into its corresponding fragment under direct visualization. The reduction is held with two bone clamps, and the screws are inserted. Fixation may be achieved by using two 2.7-mm screws or three 2-mm or 2.4-mm screws. The diameter of the bone and configuration of the fracture may dictate mixing screws of different diameters in the same fracture.

I generally reserve plate and screw fixation for complex situations such as open fractures, multiple metacarpal shaft fractures, or when there is a combination of diaphyseal bony loss or comminution associated with significant soft tissue injury ( Figure 7.12 ). Successful plate application is technically gratifying, provides stable fixation, and maintains length when there has been comminution or bone loss. Plate application is demanding, however, and there is no margin for error. Application requires considerable soft tissue mobilization, and the plates are bulky. Removal is often necessary, and a fracture can occur through a screw hole or at the “original” fracture site. I prefer a 2-mm or 2.4-mm plate that allows screw fixation of at least four cortices, proximal and distal to the fracture, to ensure stable fixation. Supplemental fixation with an interfragmentary screw (for transverse and short oblique fractures) placed either through a hole in the plate or obliquely across the fracture significantly enhances fracture stability. Larger 2.7-mm locking plates are not routinely indicated. Such plates may be indicated in osteopenic bone or for reconstruction of nonunions or malunions. Plate fixation is undesirable if the fracture cannot be covered by local soft tissue or flaps. In such situations, I prefer external fixation.

Plate fixation for metacarpal shaft fractures. A, Shaft fractures of all four metacarpals. B, Fractures were open, and revascularization was required. C, Anteroposterior radiograph showing healed fractures. Plate fixation provided stable framework for microvascular repairs. D, Lateral view.

Whenever possible, after ORIF the periosteum is approximated with an absorbable suture. A forearm-based plaster splint with bulky dressing is applied for 4 to 7 days. Assuming stable reduction, active range of motion is initiated. The wrist is splinted in a slightly extended position. Restoration of full MP flexion may be difficult because of edema, intrinsic muscle injury, and subsequent MP collateral ligament contracture. To maximize MP flexion, elastic garments are worn for edema control, and the IP joints are splinted in extension during MP flexion exercises.

Hardware removal depends on the type of implant. Kirschner wires may be removed 3 to 6 weeks after fixation. The AO-ASIF group recommends screw and plate removal approximately 6 months after fixation. Despite the aforementioned admonitions, I do not routinely remove plates. If the plate is perceived as bulky or is irritating, or if there are restrictive adhesions and a tenolysis and capsulotomy procedure is indicated, I remove the plate. Patients should be informed that refracture may occur after plate removal.

Expected Outcomes: Metacarpal Shaft Fractures

Most metacarpal shaft fractures are inherently stable and can be treated conservatively with acceptable functional outcomes. In a comparison study of three casting techniques, no difference was found in motion, grip strength, or fracture alignment between the treatments. Open reduction and internal fixation can be accomplished using numerous techniques, including Kirschner wire fixation, composite and cerclage wiring, intramedullary fixation, screw fixation, and plate fixation. Kirschner wire fixation has been reported to result in an 18% complication rate. Outcomes of cerclage wiring (although more technically demanding) have generally been positive, with full range of motion reported in 34 of 36 patients. Intramedullary fixation allows for early active motion, with only one nonunion in 27 fractures reported in a single cohort study. Screw fixation also typically results in successful outcomes, especially in long oblique and spiral shaft fractures. Plate fixation shows good to excellent outcomes, but has been associated with a complication rate of 35%. Cerclage wiring, screw fixation, and plate fixation are typically rigid enough to allow for early range of motion. Generally, the least invasive method that can reliably restore and maintain anatomic alignment of metacarpal shaft fractures is preferable for successful outcomes.

Author’s Preferred Method of Treatment: Segmental Loss

Generally, when there is metacarpal bone loss, there are associated soft tissue defects and contamination. After thorough débridement, osseous stability is achieved with an external fixator. Additional débridements are carried out over the next 2 to 5 days until the wound is surgically clean. At that time, a corticocancellous or cancellous bone graft is harvested from the iliac crest and fashioned to fit into the defect. Stabilization is accomplished with an appropriately contoured dorsal plate. When there is bone loss from multiple metacarpals, I prefer to use a monoblock of corticocancellous or pure cancellous graft, rather than individual metacarpal bone reconstruction. Soft tissue coverage is obtained with a regional, distant, or free flap. I prefer staged tendon reconstruction in which silicone rods are inserted at the time of flap coverage and replaced later with free tendon grafts.

Avulsion Fractures of the Second and Third Metacarpal Bases

Isolated articular fractures of the base of the second and third metacarpals are rare because of the lack of motion in these joints, and there is no consensus regarding optimal treatment. These fractures are usually the result of a fall on a flexed wrist. Avulsion fractures from the dorsal base of the index or middle metacarpals have been successfully managed operatively and nonoperatively. Justification for surgical reattachment includes restoration of the integrity of the extensor carpi radialis longus or brevis, reconstitution of the articular surface of the CMC joint, and elimination of a potentially irritating fragment of dorsal bone.

Fracture-Dislocations of the Ring Finger Carpometacarpal Joint

Ring finger CMC joint dislocations are uncommon, may be associated with a metacarpal fracture, and may be missed at presentation. Isolated ring finger metacarpal fractures should raise the possibility of an associated CMC joint injury and prompt careful examination of various radiographic views. Computed tomography may be helpful to better delineate articular fragments.

Fracture-Dislocations of the Small Finger Carpometacarpal Joint

Articular fractures of the hamate–fifth metacarpal joint are common and are usually associated with proximal and dorsal subluxation of the metacarpal. The hamate articulates with the ring and small metacarpals by two concave facets separated by a ridge. The base of the fifth metacarpal consists of a concave-convex facet that articulates with the hamate and a flat radial facet that articulates with the fourth metacarpal base. Dorsal and palmar intermetacarpal ligaments and an interosseous ligament stabilize the intermetacarpal joint. The injury results from a longitudinally directed force along the fifth metacarpal resulting in proximal and dorsal subluxation of the metacarpal base. The displacement is accentuated by the pull of the extensor carpi ulnaris.

Because the extent of the injury is frequently missed on routine radiographs, Bora and Didizian recommended an anteroposterior view with the forearm pronated 30 degrees from the fully supinated position. A 30-degree pronated lateral view is also helpful to profile the subluxated metacarpal. For difficult visualization or assessment of articular comminution, CT scan is occasionally warranted.

There is no consensus regarding optimal treatment of these fractures. Options run the gamut from closed reduction and cast immobilization to ORIF. Bora and Didizian found that weakness of grip was the major functional disability resulting from inadequate reduction or lost reduction. These authors recommended closed reduction and percutaneous pin fixation of the fifth metacarpal to the fourth metacarpal or carpus for maintenance of reduction.

Petrie and Lamb treated 14 fracture-dislocations of the fifth metacarpal–hamate joint by immediate, unrestricted motion and reviewed them at 4.5 years. Despite persistent metacarpal shortening, incongruity in the articular surface, and widening of the joint, only one patient had enough pain to affect work. These investigators believed that the case for surgical treatment was not strong because arthrodesis of the joint could always be performed for persistent pain. Kjaer-Petersen and colleagues reported that regardless of the method of treatment (closed, percutaneous, or open), 19 of 50 (38%) patients had some symptoms at a median follow-up of 4.3 years. They believed that restoration of the articular surface should be the goal of treatment. Cain and associates noted that fracture-dislocations of the fourth and fifth CMC joints, in association with comminuted dorsal hamate fractures or coronal shear fractures through the hamate, were particularly unstable, and ORIF was uniformly necessary. For single large hamate shear fractures, screw fixation to the body serves to treat the fracture and the dislocation.

Multiple Carpometacarpal Dislocations

Multiple CMC dislocations are high-energy injuries that nearly always require ORIF. Lawlis and Gunther reported on 20 patients, 14 of whom had multiple CMC dislocations. Closed reduction was uniformly unsuccessful because of redislocation or subluxation, and reduction with Kirschner pin fixation was recommended. Open reduction is necessary only if closed reduction is unsuccessful. At 6.5 years’ follow-up, patients with isolated second and third CMC dislocations or concomitant ulnar nerve injury did poorly. Lawlis and Gunther indicated that it was unclear why these patients did poorly compared with patients with dislocations of all four CMC joints. It is possible that these patients had fractures that were unreduced or had recurrent subluxation. Clendenin and Smith reported relief of symptomatic arthritis of the hamate–fifth metacarpal joint when treated by arthrodesis using an iliac crest bone graft.

Author’s Preferred Method of Treatment

Fracture-dislocations of the fifth CMC joint are inherently unstable, and closed reduction and cast immobilization can be risky. Redislocation may not be appreciated because radiographic imaging is difficult as a result of bony overlap and plaster artifact. For unstable fracture-dislocations of the fifth CMC joint, we prefer closed reduction and percutaneous pinning. With appropriate anesthesia, longitudinal traction is applied, and palmar pressure is exerted on the base of the fifth metacarpal. Under image intensification, the fifth metacarpal shaft is pinned into the fourth metacarpal. A second pin can be obliquely directed across the fifth metacarpal–hamate joint ( Figure 7.16 ). When multiple fragments or comminution exists, preoperative CT may be useful.

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