Management of Metacarpal and Phalangeal Fractures in the Athlete

Metacarpal and phalangeal fractures are common injuries in athletes and occur frequently in contact and ball-handling sports. They usually result after direct hits from other players or athletic equipment. The fractures often are minimally displaced and require a short period of immobilization followed by early range of motion for expeditious return to play. Unstable or intra-articular fractures may require operative fixation. Open reduction and internal fixation afford the most stability while allowing for early rehabilitation. Athletes represent a unique population, and treatment of these fractures requires consideration of specific sport, timing of injury, and level of play.

Key points

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Metacarpal and phalangeal fractures are common injuries in athletes and usually result from low-energy, direct hits to the fingers and thumb.
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Contact sports, in particular football, account for most metacarpal and phalangeal fractures.
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Consideration of the degree of injury, the specific sport, the timing of the injury, the level of play, and the athlete’s goals must be made when developing a treatment plan.
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Return to play can be expedited with early fixation, playing casts, and an emphasis on early range of motion.

Introduction

Metacarpal and phalangeal fractures account for 18% and 23%, respectively, of below-elbow fractures in the general population in the United States and are the most common injuries of the upper extremity. In the sporting world, injuries to the hand and wrist account for 2% to 9% of all injuries, with some studies reporting that metacarpal and phalangeal fractures account for 39.2% of all sports-related fractures. These fractures are more likely to occur in male athletes between the ages of 10 years and 40 years. ^, ^, Rates of injuries vary by sport, with higher rates in contact sports and approximately half occurring in football.. ^,

Participation in sports during childhood and adolescence has nearly doubled in the United States in the past 4 decades, leading to a similar increase in sporting injuries. Hand fractures are the most common fractures sustained by children, and hand and wrist injuries account for up to 17% of sporting injuries in children. ^,

Athletes represent a unique population due to the high level of physical demand for function and the potential significant monetary impact injury has on players, whether scholarship opportunity for high school or collegiate athletes or loss of income for elite and professional athletes. Not only are these opportunities at risk in the short term due to loss of playing time from injury recovery but also there is potential risk for long-term functional hand impairment after an athletic career. Because of this, thoughtful consideration of the treatment plan and fixation method is warranted for these fractures. The treating surgeon must take into account the specific sport being played, whether the athlete will finish the season, and the return-to-play time in order to proceed with a plan that is in best interest of the athlete.

Anatomy

The metacarpals form a concave, transverse arch that is fixed proximally via the strong articulations with the distal carpal row at the carpometacarpal (CMC) joints and is more mobile and adaptive distally at the metacarpophalangeal (MCP) joints. ^, There are 4 finger metacarpals and 1 thumb metacarpal. The finger metacarpals articulate with the neighboring metacarpal proximally; they are attached to each other via strong interosseous ligaments and distally via the deep transverse metacarpal ligament ( Fig. 1 ). ^, ^,

The index finger metacarpal is the largest in length and diameter whereas the ring finger metacarpal is the smallest in diameter and the small finger metacarpal is the shortest in length. Furthermore, the index and long finger metacarpals essentially are fixed at the CMC joints whereas the ring and small finger CMC joints allow for 15° to 25° of ring and small finger CMC joints, respectively. This discrepancy in CMC joint stability gives the hand the ability to have a strong grasp while at the same time accommodate different-shaped objects.

The increased mobility of the ring and small finger CMC joints places them at higher risk for fracture and/or dislocation yet also allows for a greater degree of acceptable angulation and displacement after fracture. ^, ^, Additionally, the border (index and small finger) metacarpals are more likely to shorten compared with the long and ring finger because they have fewer soft tissue attachments. ^, ^, ^,

The thumb metacarpal has a pronated position relative to the other metacarpals. It has a unique, saddle articulation with the trapezium featuring 2 biconcave surfaces, giving the thumb the unique motion of opposition as well as motion in the other 2 planes that helps provide 40% of hand function. ^, ^, ^,

The MCP joints consist of the metacarpal head and the base of the proximal phalanx. The metacarpal head has a cam-shaped appearance, with the head volar to the axis of the shaft. This results in the collateral ligaments changing length during range of motion. When the joint is flexed to approximately 90° degrees, the collateral ligaments are taut, firmly stabilizing the joint. This multiaxial condyloid joint provides the fingers significant radioulnar movement when extended and stability when flexed to allow for power pinch and grip. ^, The volar plate is an important soft tissue structure at the MCP joint that prevents joint hyperextension. The volar plates of the nonthumb metacarpals are interconnected via the deep transverse ligament (see Fig. 1 ). ^,

Distal to the metacarpals are the proximal phalanges. The base of the proximal phalanx has insertion sites for the collateral ligaments of the MCP joint as well as a groove on the volar aspect for the flexor tendon sheath. The diaphysis is oval in shape and the head is bicondylar and broader volarly. The interossei insert onto the proximal phalanx whereas the central slip and terminal extensor tendon insert onto the middle phalanx and distal phalanx, respectively. ^, The pull from the interossei flexes the proximal fragment in proximal phalanx fractures, whereas the extensor mechanism extends the distal fragment and remaining finger, accounting for the apex volar angulation exhibited by most fractures of the proximal phalanx ( Fig. 2 ).

Unlike the MCP joint, the proximal interphalangeal (PIP) joint allows mainly for flexion and extension; however, the slight asymmetry of the proximal phalanx condyles allows for a few degrees of rotation of the fingers with flexion. ^, In addition to the stability from the bony articulation, the PIP joint has strong collateral ligaments that are taut throughout range of motion and a thick volar plate as well as the flexor and extensor tendons that contribute to stability. ^, The articular surface of the middle phalanx is biconcave with an intercondylar ridge, creating stability for the PIP joint. ^, Fractures of the middle phalanx have a less predictable angulation as the flexor digitorum superficialis (FDS) inserts onto the middle phalanx, countering the pull of the central slip. ^, ^, If the fracture is proximal to the FDS insertion, the resulting deformity is apex dorsal as the FDS pulls the distal fragment into flexion and central slip extends the proximal fragment. If the fracture is distal to the FDS insertion, then the FDS flexes the proximal fragment and the extensor mechanism extends the distal fragment ( Fig. 3 ). ^,

The distal phalanx base has tubercles that are the attachment sites for the collateral ligaments of the distal interphalangeal (DIP) joint. The distal phalanx is protected by the nail plate, which acts as a splint to prevent deformity with fracture. ^,

The classification of metacarpal and phalangeal fractures is best described by the name of the bone, the location of the fracture, the type of fracture, and whether the fracture is angulated, translated, rotated, or shortened ( Fig. 4 ).

Mechanism of injury

In a review of the National High School Sports-Related Injury Surveillance Study of hand and wrist injuries over an 11-year period, the most frequent mechanism of injury was contact with another player (40.9%), followed by contact with sporting equipment, and, in football, 60% of metacarpal injuries occurred in player-to-player contact. In the adult literature, injuries to the metacarpals and phalanges from athletic endeavors occurred from falls, direct hits, or a crush mechanism. ^, ^,

Consideration must be made to the specific sport being played because this may influence the location and type of fracture. For example, skiers are more likely to fracture the bones of the first ray whereas football players are more likely to fracture a bone of the fifth ray. Weiss and Hastings reported on 28 patients with unicondylar fractures of the proximal phalanx and found the most common mechanism of injury was during ball-handling sports. Less commonly reported are stress fractures of the upper extremity; however, there are case series reporting metacarpal stress fractures in racket sport athletes and epiphyseal stress fractures of the phalanges in rock climbers.

Evaluation and management

The initial management of hand and finger injuries may be performed first by an athletic trainer or sideline physician. The hand and fingers should be evaluated for any wounds suggestive of an open fracture, which require treatment more promptly than a closed injury. Gross deformities, like apparent shortening or loss of normal knuckle contour, should clue the treating provider that a fracture or dislocation may have occurred. This may be confirmed by crepitus and/or instability felt by palpation if tolerated. Not all fractures result in gross deformity; thus, careful examination of the hand and fingers for rotational deformity is necessary to avoid potential misalignment of the hand and fingers. ^,

If a dislocation is suspected or confirmed radiographically, joint reduction should be prioritized, followed by splint immobilization. The same is true for displaced extra-articular fractures. When immobilized, athletes are encouraged to mobilize the uninjured fingers as well as the shoulder, elbow, and wrist to prevent stiffness. Care should be taken if using ice for pain and swelling of the fingers to prevent vasospasm and potential vascular compromise.

Three views, posteroanterior, lateral, and oblique, of the injured finger and hand should be obtained for any suspected fracture. Oblique views of the hand allow for better visualization of the metacarpals and CMC joints due to the overlap of the metacarpals. ^, In addition to oblique views, there are specific views to better evaluate particular areas. A Brewerton view provides the best visualization of the MCP joints. The MCP joints are flexed 60° and the x-ray beam is directed 75° to the cassette. To adequately image the thumb, a Robert’s view should be performed to get a true anteroposterior (AP) of the thumb. This is achieved with the arm in full pronation and the dorsum of the thumb on the x-ray cassette. A true lateral of the thumb is achieved with the hand pronated 30° and the beam angled 15° distally ( Fig. 5 ).

Three-dimensional imaging, such as computed tomography (CT), usually is not necessary for simple or nondisplaced fractures; however, CT can be helpful for surgical planning for intra-articular or highly comminuted fractures. Magnetic resonance imaging and ultrasonography rarely are indicated for acute fractures of the metacarpals and phalanges.

Fractures

Metacarpal Fractures

Metacarpal fractures can be divided into base, shaft, neck, and head. Each metacarpal tolerates a different degree of angulation and displacement based on its location due to the increasing mobility of the CMC joint from radial to ulnar. Given this, the ring and small finger metacarpals can tolerate more angulation and displacement, whereas the index and long finger tolerate less.

In general, most metacarpal fractures are stable and can be treated successfully nonoperatively. This can be accomplished by buddy taping or splinting. Metacarpal neck fractures often can be successfully reduced via the Jahss maneuver ( Fig. 6 ) and then immobilized. Traditionally, metacarpal fractures were immobilized in the intrinsic plus position with the MCP joints in flexion and interphalangeal (IP) joint in extension to prevent contracture of the collateral ligaments. A randomized controlled trial by Hofmeister and colleagues, however, compared ulnar gutter casting of small finger metacarpal fractures with the MCP joint in neutral or flexion for 4 weeks in a young, active population and found no difference in range of motion, grip strength or aesthetics. ^, Additionally, another prospective study evaluated the difference between 3 different immobilization techniques—with the MCP joints in flexion with free IP joint motion, with the MCP joints in extension and full IP joint motion permitted, and with the MCP joints in flexion and the IP joints in extension without joint motion permitted—and found no difference at 9 weeks in range of motion, fracture reduction, and grip strength. ^,

Unstable fractures that demonstrate displacement or malalignment or are angulated more than accepted parameters should undergo operative treatment. In a cadaveric study, Strauch and colleagues reported that for every 2 mm of metacarpal shortening, an average of 7° of extensor lag was demonstrated. Furthermore, metacarpal shortening leads to altered interosseous muscle anatomy resulting in changed force ratios and, thus, reduced grasp and grip strength. ^, In general, greater than 10° to 20° of angulation in the index finger and 40° in the small finger results in undesirable fingertip overlap and is an indication for operative treatment. ^, ^, ^,

A unique consideration for operative fixation of metacarpal fractures in athletes is return to play. Although a fracture may not meet operative criteria by radiographic parameters, surgical fixation may offer a more rapid recovery and minimize lost playing time. Similarly, operative management may lessen the immobilization requirements and allow for a sooner return to play. These decisions are specific to the sport, position, and time of season.

Metacarpal head

Metacarpal head fractures are best treated by headless compression screws via a dorsal, extensor-splitting approach. Hand drilling can be useful to prevent further shearing or comminution of the fragments. Head fractures require anatomic reduction and rigid fixation due to their intra-articular nature. Intra-articular head fractures that cannot be fixed in this manner pose a challenge in the athlete because the alternative treatment methods, arthrodesis and arthroplasty, can jeopardize an athlete’s career.

Metacarpal neck and shaft

There are multiple methods of operative fixation for metacarpal neck and shaft fractures. Percutaneous Kirschner (K)-wire fixation is a minimally invasive treatment option that provides fixation in multiple planes with cross-pinning in a retrograde fashion through the collateral recesses of the metacarpal head ( Fig. 7 ). Furthermore, the K-wire can be fixed to an intact, adjacent metacarpal for further stability. This does not provide rigid fixation, however, and thus requires a period of protected, immobilization, delaying athletes’ return to play. There is a risk of pin tract infection from the exposed pins; however, this can be prevented by burying the pins under the skin whenever possible.