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THUMB METACARPAL PEDIATRIC FRACTURE

Introduction

Fracture Nomenclature for Thumb Metacarpal Pediatric Fracture

Hand Surgery Resource’s Diagnostic Guides describe fractures by the anatomical name of the fractured bone and then characterize the fracture by the Acronym:

In addition, anatomically named fractures are often also identified by specific eponyms or other special features.

For the Thumb Metacarpal Pediatric Fracture, the historical and specifically named fractures include:

Salter-Harris III and IV thumb metacarpal base fracture/Type D fracture

Salter-Harris II metacarpal base fracture/Types B and C fracture

By selecting the name (diagnosis), you will be linked to the introduction section of this Diagnostic Guide dedicated to the selected fracture eponym.

Fractures of the hand are the most common type of fracture sustained by children, and fractures of the metacarpals account for 10-39% of all pediatric hand fractures. While the incidence of pediatric thumb metacarpal fractures is not well established, some estimates are as high as 21%. Of these, fractures of the thumb metacarpal base are the most common. In children, fractures and fracture-dislocations are more common than true dislocations because the thumb metacarpal bone is weaker than its associated ligaments. Pediatric thumb metacarpal fractures are also less common than their adult counterparts and differ from adult hand fractures owing primarily to the presence of physes. In the growing child, the growth plate is the weakest part of the thumb metacarpal and is frequently involved when this bone is fractured.  Most pediatric thumb metacarpal fractures are isolated, simple, closed, and stable injuries, and can be effectively managed conservatively.  Surgical intervention may be necessary when closed reduction fails or is likely to fail.1-6

Definitions

  • A pediatric thumb metacarpal fracture is a disruption of the mechanical integrity of the thumb metacarpal.
  • A pediatric thumb metacarpal fracture produces a discontinuity in the thumb metacarpal contours that can be complete or incomplete.
  • A pediatric thumb metacarpal fracture is caused by direct forces that exceed the breaking point of the bone or the epiphyseal plate. 

Hand Surgery Resource’s Fracture Description and Characterization Acronym

SPORADIC

S – Stability; P – Pattern; O – Open; R – Rotation; A – Angulation; D – Displacement; I – Intra-articular; C – Closed

S - Stability (stable or unstable)

  • Universally accepted definitions of clinical fracture stability is not well defined in the hand surgery literature.7-9
  • A stable fracture fragment pattern is generally nondisplaced or minimally displaced. It does not require reduction, and the fracture fragment’s alignment is maintained with simple splinting. Stabile fractures maintain anatomical alignment after a simple closed reduction and splinting. Some authors add that stable fractures remain aligned, even when adjacent joints are put through a partial range of motion (ROM).
  • Unstable fractures will not remain anatomically or nearly anatomically aligned after a successful closed reduction and simple splinting. Typically unstable pediatric thumb metacarpal fractures have significant deformity with comminution, displacement, angulation, and/or shortening.
  • The vast majority of pediatric thumb metacarpal fractures are minimally displaced, stable fractures.  This is due to the thick periosteal covering and ability of the bone to plastically deform affording a great deal of stability in incomplete fractures.10
    • Unlike the phalanges, the metacarpals are relatively protected by their position within the hand and by the stout soft tissues which surround them.1
  • Fractures of the border metacarpals generally tend to be less stable and more difficult to control than those of the central metacarpals.  Intra-articular metacarpal base fractures are relatively stable.11-1  This stability is primarily due to the osseous architecture of the carpometacarpal (CMC) joints and the interosseous, dorsal and volar CMC ligaments which provide additional stability.13
  • In children, even displaced fractures are often easily reduced closed and remain stable following reduction.14
  • However, displaced Salter-Harris types III and IV fractures of the pediatric metacarpal thumb are inherently unstable, intra-articular injuries that typically require closed or open treatment to restore the physeal and articular alignment.4,5  Metaphyseal and Salter-Harris II metacarpal base fractures with a radial metaphyseal fragment also tend to be unstable, while Salter-Harris II fractures with an ulnar metaphyseal fragment are typically stable.4
  • Similar to two opposing saddles with perpendicular transverse axes, the stability of the thumb CMC joint in power pinch and power grasp motions depends on the joint’s two prime stabilizers. Mechanical instability of this joint is an important factor that may lead to osteoarthritis.15

P - Pattern

  • Thumb metacarpal head fractures can occur in oblique, transverse, or comminuted patterns.  This type of fracture is rare because the longitudinally directed force that produces them is usually transferred to the proximal metaphysis or thumb CMC joint.11,16  Pediatric thumb metacarpal head fractures are usually epiphyseal, intra-articular injuries that result from direct injury and affect one or both condyles of the metacarpal head, with or without displacement. Interrupting the normal articular surfaces of the metacarpophalangeal (MP) joint increases the chances of arthritis developing if left untreated.5,11,16,17  MP joint effusion and limited motion in the absence of a more obvious metacarpal neck fracture may suggest a pediatric thumb metacarpal head fracture.4
  • Thumb metacarpal neck fractures are also rare and tend to result from direct injury. 1,5
  • Thumb metacarpal shaft fractures are usually transverse, oblique, spiral, or comminuted, with or without shortening.3  Pediatric thumb metacarpal shaft fractures are more common than those of the head and neck, and are managed similarly to shaft fractures in the other metacarpals.1  These injuries tend to occur in older children, and the pattern usually yields clues to the pathologic forces that caused the fracture, and indicates the mechanism of reduction.1
  • Thumb metacarpal base is the most common site of fracture in the pediatric thumb metacarpal. These are typically high-energy injuries that may or may not involve the physis—which is located at the proximal end of the bone near the CMC joint. Pediatric thumb metacarpal base fractures are generally subdivided and managed based on their location, physeal involvement, and intra-articular extension.4,5
  1. Type A: fractures occurring between the physis and the junction of the proximal and middle thirds of the bone, and the fracture line usually is oriented in a transverse direction or slightly oblique to the shaft.  The fracture is often angulated in an apex radial direction and ulnar impaction may be present.1,5
  2. Type B: Salter-Harris II fractures with a metaphyseal fragment on the ulnar side.  These fractures are more common than type C fractures.  The shaft fragment is adducted secondary to the adductor pollicis and pulled in a proximal direction by the abductor pollicis longus (APL).  This pattern resembles an adult Bennett’s fracture with respect to the deforming forces, but there is no intra-articular extension.1,5
  3. Type C: Salter-Harris II fractures with a metaphyseal fragment on the lateral side and are less common than type B fractures.  Has a reverse pattern, in which the proximal metacarpal shaft is displaced in a medial direction.  Often result from substantial trauma and are not reducible by closed manipulation.1,5
  4. Type D: Salter-Harris III and IV fractures that involve the joint surface and most closely resembles an adult Bennett’s fracture.  The deforming forces are similar to the adult Bennett’s and type B fractures with subsequent adduction and proximal migration of the base-shaft fragment, but the intra-articular component of the fracture permits the base-shaft fragment to subluxate laterally at the CMC joint.1,5

O - Open

  • A thumb metadcarpal fracture is open when a wound connects the external environment to the fracture site. The wound provides a pathway for bacteria to reach and infect the fracture site. As a result, there is always a risk for chronic osteomyelitis. Therefore, open fractures of pediatric thumb metacarpal require antibiotics with urgent surgical irrigation and wound debridement.7,18,19
  • Open pediatric thumb metacarpal shaft fractures may require an external fixator to prevent shortening and to allow soft tissue healing.11

R - Rotation

  • Pediatric thumb metacarpal fracture deformity can be caused by rotation of the distal fragment on the proximal fragment.
  • Degree of malrotation of the fracture fragments can be used to describe the fracture deformity.
  • Oblique and spiral pediatric thumb metacarpal shaft fractures are usually the result of torsional forces and can cause rotational malalignment. These fractures may also angulate or shorten.4,11
  • The planes of motion of the thumb are different from those of the rest of the hand. Malrotation is therefore more challenging to judge in the physical examination.  The perpendicular relationship of the thumb’s nail plate to those of the other digits provides a good guide.  The thumb metacarpal fracture with malrotation is tolerated better than a similar malrotation in the fingers.1
  • Unlike the other metacarpals, extra-articular fractures of the thumb metacarpal base can also tolerate moderate malunion in rotation.  Example: type A fractures are often angulated in an apex-lateral direction.1,5

A - Angulation (fracture fragments in relationship to one another)

  • Angulation is measured in degrees after identifying the direction of the apex of the angulation.
  • The surrounding soft tissue attachments and muscles determine the direction of deforming forces for extra- and intra-articular thumb metacarpal fractures.  Extra-articular fractures become angulated dorsally owing to extension of the metacarpal base by the APL and flexion of the distal shaft by thenar muscles.20  Salter-Harris II fractures usually have the shaft fragment angulated laterally and slightly proximally from the pull of the APL.1
  • Given the large ROM of the thumb, higher degrees of angulation are well tolerated, since the deformity can be compensated for without functional deficit; however, the amount of residual angulation considered acceptable in basilar metacarpal fractures is still a matter of some debate.1,21  Because the motion at the adjacent CMC joint is multiplanar and the fractures are near or involve the physis, the remodeling potential is great.  Malangulation ≤20° remodels quite predictably, and even angulation of 30° appears to exhibit significant remodeling, but the improvement in radiographic appearance is less predictable.1

D - Displacement (Contour)

  • Displaced thumb metacarpal fracture disrupted cortical contours
  • With nondisplaced fractures the fracture line defines one or several fracture fragment fragments; however, the external cortical contours are not significantly disrupted
  • In type C fractures, the shaft displacement is ulnarly.1,5
  • Isolated thumb CMC joint dislocations almost always displace dorsally, although volar displacement is also possible.22

I - Intra-articular involvement

  • Thumb metacarpal intra-articular fractures have a fracture line which enters a joint.
  • A pediatric thumb metacarpal fracture can have fragment involvement with its respective MP or CMC joint.
  • If a fracture line enters a joint but does not displace the articular surface of the joint, then it is unlikely that this fracture will predispose to posttraumatic osteoarthritis. If the articular surface is separated or there is a step-off in the articular surface.  Then there is a risk of posttraumatic osteoarthritis.
  • Salter-Harris III and IV thumb metacarpal base fractures are intra-articular injuries that are inherently unstable.4
  • Differentiating between extra- and intra-articular fractures is crucial for planning an appropriate treatment protocol for pediatric thumb metacarpal fractures.  Intra-articular thumb metacarpal base fractures, like those of the little metacarpal base, lack ligamentous support and are therefore prone to subluxation.16

C - Closed

  • Closed thumb metacarpal fractures have no associated wounds; the external environment has no connection to the fracture site or any of the fracture fragments.7-9

Pediatric thumb metacarpal fractures: named fractures, fractures with eponyms, and other special fractures

 

Salter-Harris III and IV thumb metacarpal base fracture/Type D fracture

  • Type D fractures are Salter-Harris III and IV thumb metacarpal base fractures that involve the joint surface.1,5
    • These injuries closely resemble the adult Bennett’s fracture, however, whether or not to use eponyms like “children’s Bennett’s fracture” is a matter of debate, with detractors claiming that doing so is unhelpful for establishing management strategies.1,4
    • A type D fracture is an inherently unstable, two-part intra-articular avulsion fracture-dislocation.  As in adults, the volar oblique ligament holds the volar lip of the epiphysis in place in children.2,4
    • The most common mechanism of injury is a fall that axially loads a flexed thumb metacarpal. This causes the thumb metacarpal to dislocate radially and dorsally, taking most of the articular surface with it, and leaving the ulnar "beak" attached to the strong ulnar-volar ligament.2,23
  • Supination of the thumb is considered an important element in the mechanism of this injury.23
  • An isolated dislocation of the thumb CMC joint without a fracture can also result from a direct blow, but these injuries are extremely rare because the stress transmitted to the joint is mainly dissipated through the adjacent physis of the metacarpal.2,23

Imaging

  • In addition to standard radiographic views, Bett’s and Robert’s views are typically required to visualize type D fractures.9
    • A Kapandji view can be difficult in pediatric patients because of incomplete ossification of the thumb metacarpal base.15
  • Ultrasonography and CT scan are alternative imaging techniques that may occasionally be necessary in certain cases.  However, given the higher dose of radiation, CT is not recommended in the pediatric population unless absolutely necessary.11,15

Treatment

  • There is some controversy regarding the optimal treatment for these injuries, but most authors agree that the treatment principles are similar to those for adult Bennett’s fractures. Therefore, displaced type D fractures generally require closed or open treatment to restore their physeal and articular alignment because they are unstable.5,23
  • Closed reduction and cast immobilization that utilizes longitudinal traction, thumb metacarpal base adduction, and pronation of the thumb ray should be attempted and may be sufficient to achieve fracture reduction.5,23  Direct pressure along the thumb metacarpal base may help push the shaft towards the avulsion component of the fracture.5
    • Cast immobilization should then be used for 4-6 weeks and checked by X-ray every week.23
  • Closed reduction and percutaneous pin fixation (CRPP) is typically reserved for rare cases in which conservative treatment fails early.5,15,23
    • After reduction is verified, percutaneous K-wires are drilled through the thumb metacarpal and into the index metacarpal and/or carpus to hold the position.5
    • Percutaneous K-wire fixation can be performed with one transarticular pin or with two intermetacarpal K-wires.  Double pinning may prevent rotation and pin breakage.15
  • Open reduction and internal fixation (ORIF) is typically required for irreducible type D fractures and/or for recurrent thumb CMC joint dislocation.5,15
    • The preferred approach is volar, using a gently curved incision overlying the thumb CMC joint along the glabrous border of the skin.5
    • The thumb CMC joint is isolated, opened, and exposed to reveal the articular surface, and provisional reduction is achieved under direct visualization. Subsequently, internal fixation is performed using K-wires or mini-screws.  An effort should be made to not cross physis with screw threads as this can disrupt the physis and subsequent growth.1,5
    • Additional percutaneous K-wire fixation between the thumb and index metacarpal is often performed to protect the fracture fixation.5
    • Ligament repair or reconstruction may also be needed prevent late recurrence of thumb CMC joint dislocation or chronic instability.15
  • Whatever the type of treatment for thumb CMC joint reduction, it seems important to combine intermetacarpal or K-wire pinning with 4-6 weeks of immobilization in a gauntlet cast, especially in pediatric trauma cases with restless young patients.15

Complications

  • Instability
  • First web space contracture
  • Pin loosening/pin tract infection
  • Nonunion
  • Malunion
  • Aseptic necrosis
  • Stiffening
  • Posttraumatic osteoarthritis

Outcomes

  • Pediatric patients with thumb CMC joint dislocation treated on the day of injury who demonstrate post-reduction stability have good results after conservative treatment.23

 

Salter-Harris II metacarpal base fracture/Types B and C fracture

  • Types B and C injuries are Salter-Harris II fractures at the thumb metacarpal base.5
    • The majority of these injuries are type B, which have a metaphyseal flare on the medial side and the shaft fragment angulated laterally and slightly proximally from the pull of the APL. The adductor pollicis may also adduct the shaft.
    • The less common type C injury has the reverse pattern, with the metaphyseal fragment on the lateral side and the shaft displacement medial. This injury may result from more significant trauma and is usually is more difficult to treat by closed methods.1

Imaging

  • In addition to standard radiographs, it may be helpful to supplement with a hyperpronated view of the thumb that accentuates the detail at the thumb CMC joint.
    • Biplanar views of the thumb are also a must, as type B fractures often appear well reduced in the lateral view of the thumb but are significantly displaced on the anteroposterior (AP) view.1

Treatment

  • Simple closed reduction is challenging for types B and C fractures, as the mobility of the metacarpal base and swelling make reduction attempts more problematic. Treatment varies based on the amount of displacement and degree of periosteal disruption.5
    • Mild angulation of <20° can be treated by cast application without reduction.
    • Moderate angulation is treated with closed reduction and immobilization using a short arm thumb spica splint or cast.
  • Repeat radiograph evaluation should be obtained 5-7 days later to check the reduction.5
    • Recurrent angulation requires repeat reduction and percutaneous pin fixation, while severe angulation is usually combined with shaft displacement and warrants CRPP.
    • CRPP is also preferred if closed reduction is attainable but the reduction is unstable.
  • There are multiple options for pin configuration, including direct fixation across the fracture, pinning across the reduced CMC joint, or pinning between the thumb and index metacarpals.5
  • Irreducible type B and C fractures typically require ORIF.5
    • Type C fractures can be particularly difficult to manage, as they are often more widely displaced and may include a distal fragment buttonholed through the thick periosteum.1  Closed reduction may be attempted for these injuries, but the threshold to progress to ORIF is low, as comminution, soft tissue interposition, or transperiosteal buttonholing may prevent reduction. In these cases, ORIF is performed to extricate the offending structure, followed by pin fixation to maintain alignment.5

Complications

  • Post-operative infection
  • Intra-articular incongruity
  • Pain
  • Impaired ROM
  • Nonunion
  • Malunion
  • Aseptic necrosis
  • Stiffening
  • Instability
  • Posttraumatic osteoarthritis

Related Anatomy

  • The pediatric thumb metacarpal consists of a distal head that articulates at the MP joint with the proximal phalanx, a supportive neck, a narrow diaphyseal shaft, a proximal metaphysis, and a base that articulates at the thumb CMC joint with the trapezium. The thumb CMC joint is a double saddle that is concave in one direction and convex on the other. It moves in flexion/extension, abduction/adduction, and pronation/supination planes, but this greater range of motion results in less inherent stability.20,22,24  In children and adolescents, the physeal plate is located at the proximal end of the thumb metacarpal, which is weaker than the surrounding mature bone. There are also some normal bony variations that may occur:1,4
  • A pseudoepiphysis is a persistent expression of the distal epiphysis of the thumb metacarpal, which does not contribute to growth, appears earlier than the proximal epiphysis, and fuses to the metacarpal by age 6 or 7. Pseudoepiphyses are easily be confused with thumb metacarpal fractures, and clinicians therefore must be aware of them.5
  • A double epiphysis is an active growth plate present on both ends of the metacarpal. It is usually seen in children with a congenital difference, and its presence does not affect the overall length of the thumb ray. Fractures can occur through a double epiphysis.5
  • Ligaments associated with the pediatric thumb metacarpal include the posterior oblique ligament, the dorsal central ligament, the dorsoradial ligament, the first intermetacarpal ligament, and the volar anterior oblique (beak) ligament, which inserts at the thumb metacarpal base and opposes the action of the APL.5,20,24
  • Tendons associated with the thumb metacarpal include the APL tendon, which has a broad-based insertion onto the epiphysis and metaphysis of the thumb metacarpal, and the opponens pollicis tendon, which inserts on the anterior and lateral surfaces of the thumb metacarpal shaft.20

Incidence and Related injuries/conditions

  • Hand fractures are a common problem in the pediatric population, with a reported incidence of 24.2 hand fractures per 100,000 children each year.17
    • Together, metacarpal and phalangeal fractures account for 21% of all pediatric fractures, with the phalanges being fractured more commonly than the metacarpals in this population.2,25
  • This distribution is also found in the thumb, as one study found that of 42 thumb fractures, the majority occurred in the proximal phalanx (52%) followed by the metacarpal (31%).26
  • Metacarpal fractures account for 10-39% of all pediatric hand fractures.27-30
    • The little finger metacarpal is consistently found to be the most commonly injured metacarpal bone, representing 54-80% of these injuries.6,29-31
    • According to other studies, the incidence of thumb metacarpal fractures ranges from 4-21%.6,31,32
  • In one study on fracture distribution within the thumb metacarpal, of 10 fractures, 80% occurred in the base, 10% in the shaft and 10% in the neck/head.6
  • Pediatric metacarpal fractures are most common between ages 13-16, with a median age of 15.29,31  The incidence of thumb fractures in particular increases significantly after the age of 10, and it becomes the second most commonly injured digit after the little finger in adolescence.20  The majority of these pediatric metacarpal fractures (~68%) occur in boys.26  Sports-related injury is the most common mechanism of injury, with most pediatric metacarpal fractures occurring at school (44%) and at the playground or sporting venues (32%).31

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ICD-10 Codes

  • THUMB METACARPAL FRACTURE

    Diagnostic Guide Name

    THUMB METACARPAL FRACTURE

    ICD 10 Diagnosis, Single Code, Left Code, Right Code and Bilateral Code

    DIAGNOSISSINGLE CODE ONLYLEFTRIGHTBILATERAL (If Available)
    BENNETT'S FRACTURE (UNDER THUMB METACARPAL FRACTURE) S62.212_S62.211_ 

    Instructions (ICD 10 CM 2020, U.S. Version)

    THE APPROPRIATE SEVENTH CHARACTER IS TO BE ADDED TO EACH CODE FROM CATEGORY S62
     Closed Fractures
    Initial EncounterA
    Subsequent Routine HealingD
    Subsequent Delayed HealingG
    Subsequent NonunionK
    Subsequent MalunionP
    SequelaS

    ICD-10 Reference

    Reproduced from the International statistical classification of diseases and related health problems, 10th revision, Fifth edition, 2016. Geneva, World Health Organization, 2016 https://apps.who.int/iris/handle/10665/246208

Symptoms
History of trauma
Fracture pain and deformity
Swelling and ecchymosis, mainly in the thenar eminence
Impaired active thumb ROM
Typical History

A typical patient is a 14-year-old, left-handed girl who suffered a serious fall from a horse in an equestrian competition. During the competition, the horse failed to complete a jump over an obstacle, and the girl tumbled forward, landing on her outstretched left hand with a flexed fist. The impact of this fall axially loaded her thumb metacarpal, fracturing its base and causing the thumb CMC joint to displace radially and dorsally. There were no open wounds. The girl experienced severe pain, swelling, and tenderness at the base of the thumb after the injury, which led her directly to the emergency department for appropriate treatment.

Positive Tests, Exams or Signs
Work-up Options
Images (X-Ray, MRI, etc.)
Thumb Metacarpal Pediatric Fracture X-rays
  • Fracture of the pediatric thumb metacarpal Salter II Lateral (1) and less evident AP fracture line (1) with accessory growth plate visible (2)
    Fracture of the pediatric thumb metacarpal Salter II Lateral (1) and less evident AP fracture line (1) with accessory growth plate visible (2)
Treatment Options
Treatment Goals
  • When treating closed pediatric thumb metacarpal fractures, the treating surgeon has 4 basic goals:7,19
    1. A hand with a normal appearance. The X-ray may not need to be perfect, but the metacarpal should have no obvious deformity (ie, the thumb metacarpal looks normal!)
    2. Avoid stiffness by maintaining a normal functional ROM (ie, the thumb metacarpal works!)
    3. The metacarpal is not painful (ie, the thumb metacarpal does not hurt!)
    4. Congruent joint surface with none-to-minimal joint surface irregularities (ie, the thumb CMC joint does not develop early posttraumatic arthritis!)
  • For open fractures, fracture care should minimize the risk for infection and osteomyelitis.
Conservative
  • The management principles of pediatric thumb metacarpal fractures are generally quite similar to those of other metacarpals. Given the large ROM of the thumb, higher degrees of angulation are well tolerated.21
    • Treatment plans must consider the location of the fracture and the status of the joint surface.  Children have a tremendous capacity to remodel extra-articular fractures, especially in the thumb metacarpal.5
  • Most pediatric thumb metacarpal fractures are isolated, simple, closed, and stable injuries that can be treated nonsurgically. The thick periosteal covering can be a powerful tool for reduction in children, and the ability of the bone to plastically deform affords a great deal of stability in incomplete fractures.9,10,33
    • Typical fractures that are closed, nondisplaced, and minimally angulated without significant malrotation can be managed with closed reduction and immobilization with plaster, fiberglass, or custom splint.1,9,10,33
    • Even pediatric thumb metacarpal fractures that require a reduction to correct fracture-related deformity usually can be held in anatomic or near-anatomic alignment with a splint without surgical fixation.2,16
  • The majority of type A fractures can be effectively managed with closed reduction and cast application.5
    • A brief period of cast immobilization (3-5 days) may be needed to alleviate swelling before closed reduction can be performed.5
    • Type A and B fractures can be reduced under adequate conscious sedation supplemented by radial and medial nerve blocks.1
    • The maneuver for reduction consists of volar-directed pressure exerted over the apex of the fracture, with counterpressure applied to the metacarpal head.1,5
    • Residual angulation from 20-30° is acceptable—depending on the age of the child and clinical appearance of the thumb—due to the universal thumb CMC joint motion and potential for remodelling.5
    • Increased soft tissue present in the thenar eminence may make maintenance of fracture reduction in a spica cast alone difficult.4
  • Closed reduction requires immobilization for 4-6 weeks, depending on the age of the child, fracture severity, and degree of soft tissue damage.5
Operative
  • Surgical treatment of pediatric thumb metacarpal fractures must always be an individualized therapeutic decision. However, surgical metacarpal fracture care is most frequently recommended when:
    1. Closed reduction fails or the simple splint or cast immobilization does not maintain the reduction. For these irreducible or unstable fractures, operative treatment is recommended to achieve the 4 treatment goals of fracture care.
    2. There is a significantly displaced base of the metacarpal fracture involving the CMC joint. Surgical fracture care is often required in these cases.
    3. There is an open metacarpal fracture, which requires surgical care in the form of irrigation and debridement to prevent chronic infection.
  • Pediatric thumb metacarpal head fractures often have articular involvement, and thus are best treated surgically in most cases.1,4,11,16,33  When fixation is required, the decision between pins, screws, and plates depends on the size and number of fracture fragments.  It is rare that plates and screws are needed for pediatric fractures.  Large, 2-part fractures are amenable to fixation with small screws, while a minicondylar plate is useful in sagittal and coronal patterns and head fractures with proximal metaphyseal extension.  Highly comminuted head fractures are problematic, but fare better with CRPP than ORIF because of the risk for avascular necrosis. Direct fracture fixation with multiple K-wires or cerclage wires can be effective in stabilizing tenuous reductions of these fractures.11,16  If a displaced intra-articular pediatric thumb metacarpal head fracture is left untreated, the child may be at higher risk for developing osteoarthritis.17
  • Pediatric thumb metacarpal neck fractures that are irreducible, open, or intra-articular, and those with any malrotation or unacceptable angulation require surgical reduction and fixation.  Some children near skeletal maturity have metacarpal neck fractures that are difficult to reduce or maintain, and CRPP or ORIF may be considered.1  Delayed presentation of metacarpal neck fractures occurs commonly, and closed reduction techniques may be ineffective if the fracture is more than 10 days old.  ORIF may be needed if CRPP cannot accomplish the reduction, but these fractures are difficult to plate due to limited bone for distal fixation.  Dissection may further compromise physeal blood supply. Therefore, even though it may guarantee anatomic restoration, ORIF is rarely indicated.1,3,11
  • Complex thumb metacarpal shaft fractures in the distal aspect of the bone with soft tissue interposition may also require surgical fixation.1  Surgical options for fracture fixation include CRPP, intramedullary fixation, tension band wiring, cerclage and interosseous wiring, K-wires, interfragmentary compression screws, plate fixation, and external fixation.11,16  CRPP is indicated for unstable type A fractures.5  Lag screws may provide strong fixation in long oblique fractures and allow for early motion but should only be used when the fracture length is at least two times the width of the metacarpal.33  ORIF for thumb metacarpal shaft fractures is rarely indicated in children, but may be needed for irreducible type A fractures.
  • For long spiral oblique fractures, interfragmentary screws can be an excellent option.
  • For a severely comminuted fracture, especially if there is bone loss, plate fixation can be used.1
  • [For pediatric thumb metacarpal base fracture treatment recommendations, see special sections above.]
  • Regardless of the surgical method used, careful manipulation of and around the physis is extremely important, and excessive tissue stripping at this level must be avoided.
    • The smallest diameter non-threaded wire that effectively holds the fragments should be used, and implant choices must be individualized to the fracture pattern and to the patient’s size. Smooth wires, tension bands, and mini screws are preferred over larger implants in children. For most fractures requiring fixation, smooth wires are the implant of choice.1

Post-treatment Management

  • The care and precautions related to immobilization devices for pediatric thumb metacarpal fractures must be carefully reviewed with the patient. Patients and parents should be educated regarding care and precautions. Patients should know that pain, especially increasing pain, numbness, tingling, skin irritation, splint loosening, or excessive splint tightness are red flags and should be reported to the surgeon or his team.
  • Pain should be managed with properly fitting splints, reassurance, elevation, ice in the initial post-fracture period, and mild pain medications. Patients should be encouraged to discontinue pain medication as soon as possible. Opioid use should be kept to an absolute minimum.
  • After cast removal in 4-6 weeks, instructions should be given to the patient and parents regarding a home-exercise program that includes range of motion and strengthening exercises, as well as activity return recommendations. In active children and young athletes, a light splint may be used for protection for an additional few weeks.
  • Patients should be instructed to carefully exercise all joints in the injured hand that do not require immobilization. Patients usually can exercise on their own; however, signs of generalized finger or hand stiffness are indications for referral to hand therapy.  Formal hand therapy is typically only indicated in rare circumstances, such as complicated fractures, multiple trauma, or failure to achieve desired functional results in an appropriate time period.  If corrective splinting is to be used, the child and caregivers must be comfortable with its application and use.1,5
  • Joint mobilization is contingent on fracture location and stability.  Early mobilization after rigid fixation in children is controversial, and the stability of the fixation and reliability of the patient are important considerations.5  Thumb metacarpal fractures that involve the distal shaft, neck, and head treated nonsurgically have a greater tendency for secondary displacement, and aggressive rehabilitation should be delayed for 3-4 weekster injury.  Thumb metacarpal base and proximal shaft fractures are immobilized in an intrinsic plus splint with IP joints free to start active and passive range of motion exercises.
  • Gentle active motion at the MP level is allowed in the most proximal stable fractures.
  • Passive MP mobilization is added when there are signs of clinical union, typically at 5-6 weeks after injury. Strengthening exercises are added at 8 weeks.16  A mature adolescent can be allowed early-protected motion beginning 5-7 days after surgery. A removable splint is used for protection between exercise sessions until union between 4-6 weeks.5
  • Attention should be focused on the thumb’s IP joint in all phases of rehab. If there is some limitation of movement at the CMC joint due to the primary pathology, additional motion may be required from the adjacent articulations.1
  • If an infection does occur, management should focus on eradicating sepsis with thorough debridement, appropriate antibiotics (eg, cephalosporin, penicillin), and fracture stabilization, followed by obtaining fracture union and regaining a functional extremity.11
Treatment Photos and Diagrams
  • Thumb Metacarpal Pediatric Fracture treated successfully in splint and cast. Note callus with remodeling (arrow).
    Thumb Metacarpal Pediatric Fracture treated successfully in splint and cast. Note callus with remodeling (arrow).
Complications
  • Most children’s hand fractures heal without complications.1
  • In contrast to adults, stiffness is possible, but not as much of a concern in the pediatric population. Stiffness may occur after prolonged immobilization or delayed rehabilitation, but is usually transient, and formal therapy is rarely needed.3,14  It is preferable to have a fracture union with mild stiffness rather than a nonunion with excessive motion in pediatrics.5
  • Malunion may occur in substantially displaced thumb metacarpal neck fractures and some open, severe, or unstable thumb metacarpal fractures.3  If malunion does occur in a thumb metacarpal fracture, basilar osteotomy and fixation can restore the relationship needed for improved function.1
  • Nonunion is a rare complication of thumb metacarpal fractures, but is more common in transverse fracture patterns.16,33  Bone grafting and rigid fixation can be performed if the nonunion is recalcitrant.1
  • Avascular necrosis of the metacarpal head can occur after some fractures and is influenced by the direct injury and also by the intracapsular pressure caused by the contained hematoma.1
  • Osteonecrosis has also been reported in some pediatric patients who sustain metacarpal head fractures.4
  • Physeal closure and joint incongruity may also occur in pediatric fractures that involve the physes, but these complications are rare. 5
  • After crush injuries or open fractures, there may be shortening and associated soft tissue problems, such as tendon adhesions, poor skin coverage, and neurologic deficit.11
  • Complications of not treating intra-articular metacarpal base fractures include weakness of grip strength and of wrist extension, decreased range of motion, posttraumatic osteoarthritis, tendon rupture, unstable metacarpal boss, and poor appearance.13
  • Chronic osteomyelitis in the metacarpal is rare but can occur in open fractures, especially in diabetic patients and those with a compromised immune system.
Outcomes
  • Most outcomes for pediatric thumb metacarpal fractures are very good, as these injuries typically heal and thumb motion eventually returns to near normal.5,7,15,19,23 Fortunately, the complications noted above are very rare, and significant stiffness can usually be avoided with appropriate immobilization that allows unaffected joints and bones to stay mobile.  These outcomes are predominantly positive because of the remodeling capabilities of fractures near or involving the physis, as well as the multiplanar thumb CMC joint, which is tolerant in of slight malunion. In addition, residual deformity along the thumb metacarpal is better tolerated than the fingers, because digital scissoring is not a potential problem.5
  • In one study, 30 children underwent closed reduction and spica cast application for thumb metacarpal base fractures with fracture displacement and angulation >30° or >1 mm of metaphyseal-epiphyseal displacement.  50% of the patients with metaphyseal thumb metacarpal base fractures and 50% of those with type C fractures had displacement, but no displacement occurred in the patients with type B fractures.  The unstable, displaced fractures were found to benefit from pin fixation, while those that were undisplaced were effectively managed with closed reduction and spica cast application alone.35
Key Educational Points
  • Pediatric thumb metacarpal fractures can usually be treated without surgery.7,19
  • Pediatric thumb metacarpal fractures must be immobilized before radiographic fracture healing is complete to avoid stiffneess.  Therefore, immobilization for more than 4 weeks is rarely needed.11  In most cases, signs of clinical union will be present at 4 weeks after a closed metacarpal fracture. Although the fracture has not yet radiographically united, transitioning the patient to a removable splint and initiation of rehabilitation at this time can minimize stiffness.16
  • Underlying pathological conditions such as bone tumors—like enchodromas—and osteoporosis should be expected in fractures that occur from trivial trauma.
  • The functional needs of each patient must be considered when recommending treatment for thumb metacarpal fractures.
  • Angular deformity—especially in the plane of joint motion—reliably remodels in young children, while malrotation does not reliably do so and should be addressed with reduction and fixation as necessary.4
  • Routine X-rays AP and lateral views are always necessary, and oblique views may be added to further assess fracture configuration and displacement.  Because the thumb is rotated 90° to the palm, AP and lateral radiographs should be directed at the thumb and not the fingers.5
  • Special X-ray views include Robert’s, Bett’s, hyperpronated, and biplanar views of the thumb may also be needed.1,16,21
  • CT scan may be necessary when a radiograph is inconclusive, and possibly with a thumb CMC fracture-dislocation, multiple CMC dislocations, complex metacarpal head fractures, and/or intra-articular fractures to assess joint displacement.4,33,34
  • The metacarpal physes typically remain open until age ~16.5 in males and 14.5 in females, and knowledge of these growth centers is important because iatrogenic physeal arrest may occur in patients with physeal injuries or those who undergo multiple fracture reduction attempts.25  The physes are particularly vulnerable in younger children when shear forces are applied, stressing the attachments of the chondrocytes at the zone of proliferation.8  Physeal injuries in the hand seldom result in growth arrest independently, but late reduction (>7-10 days) or multiple attempts at reduction can crush and disrupt the layered order of the physis, resulting in an iatrogenic physeal arrest.1,4,10
  • The evaluation of a child’s injured thumb is more difficult than that of an adult—especially infants and toddlers—as the child is frequently non-compliant, scared, and unable to understand instructions. Observation and play must therefore provide clues to the extent of the injury.  An older child can be comforted and relaxed, which allows palpation for areas of maximum tenderness. Stress testing about the MP joint should be gentle to maintain the maximum trust of the child, and the wrinkle test can be used to assess nerve integrity.5
  • The planes of motion of the thumb are also different from those of the rest of the hand, so motion of the thumb in radial and volar abduction should be assessed carefully during examination.  The integrated motion of opposition should be scrutinized. Malrotation is more challenging to judge, but the perpendicular relationship of the thumb’s nail plate to those of the other digits provides a good guide.1
  • A pseudoepiphysis is a persistent expression of the distal epiphysis of the thumb metacarpal, which does not contribute to growth, appears earlier than the proximal epiphysis, and fuses to the metacarpal by age 6 or 7. Pseudoepiphyses are easily be confused with thumb metacarpal fractures, and clinicians therefore must be aware of them.5
References

New and Cited Articles

  1. Graham TJ, Waters PM. Fractures and dislocations of the hand and carpus in children. In: Rockwood and Wilkins’ Fractures in Children. Fifth ed. Philadelphia: Lippincott Williams and Wilkins; 2001, pp.  269-341.
  2. Sivit AP, Dupont EP, Sivit CJ. Pediatric hand injuries: essentials you need to know. Emerg Radiol 2014;21(2):197-206. PMID: 24158746
  3. Cornwall R. Finger metacarpal fractures and dislocations in children. Hand Clin 2006;22(1):1-10. PMID: 16504773
  4. Godfrey J, Cornwall R. Pediatric Metacarpal Fractures. Instr Course Lect 2017;66:437-445. PMID: 28594520
  5. Kozin SH. Fractures and dislocations along the pediatric thumb ray. Hand Clin 2006;22(1):19-29. PMID: 16504775
  6. Worlock PH, Stower MJ. The incidence and pattern of hand fractures in children. J Hand Surg Br 1986;11(2):198-200. PMID: 3734557
  7. Cheah AE, Yao J. Hand Fractures: Indications, the Tried and True and New Innovations. J Hand Surg Am 2016;41:712-22. PMID: 27113910
  8. Nesbitt KS, Failla JM, Les C. Assessment of instability factors in adult distal radius fractures. J Hand Surg Am 2004;29:1128-38. PMID: 15576227
  9. Walenkamp MM, Vos LM, Strackee SD, Goslings JC, Schep NW. The Unstable Distal Radius Fracture-How Do We Define It? A Systematic Review. J Wrist Surg 2015;4:307-16. PMID: 26649263
  10. Nellans KW, Chung KC. Pediatric hand fractures. Hand Clin 2013;29(4):569-78. PMID: 24209954
  11. Day CS. Fractures of the Metacarpals and Phalanges. In: Green DP, ed. Green's Operative Hand Surgery. Seventh ed. Philadelphia: Elsevier; 2016, pp. 231-77.
  12. Makino T, Fujioka H, Kokubu T. Neglected fracture dislocation of the second and third carpometacarpal joints: a case report. Hand Surg 2007;12(2):97-100. PMID: 18098361
  13. Bushnell BD, Draeger RW, Crosby CG, Bynum DK. Management of intra-articular metacarpal base fractures of the second through fifth metacarpals. J Hand Surg Am 2008;33(4):573-83. PMID: 18406963
  14. Cornwall R, Ricchetti ET. Pediatric phalanx fractures: unique challenges and pitfalls. Clin Orthop Relat Res 2006;445:146-56. PMID: 16505727
  15. Gaillard J, Fitoussi F. Recurrent posttraumatic trapeziometacarpal joint dislocation in a child: A case report. Hand Surg Rehabil 2016;35(2):139-43. PMID: 27117129
  16. Weinstein LP, Hanel DP. Metacarpal fractures. J Hand Surg Am 2002; 2(4):168–180. Link
  17. Sullivan MA, Cogan CJ, Adkinson JM. Pediatric Hand Injuries. Plast Surg Nurs 2016;36(3):114-20. PMID: 27606586
  18. Ketonis C, Dwyer J, Ilyas AM. Timing of Debridement and Infection Rates in Open Fractures of the Hand: A Systematic Review. Hand (N Y) 2017;12:119-26. PMID: 28344521
  19. Meals C, Meals R. Hand fractures: a review of current treatment strategies. J Hand Surg Am 2013;38:1021-31. PMID: 23618458
  20. Kadow TR, Fowler JR. Thumb Injuries in Athletes. Hand Clin 2017;33(1):161-173. PMID: 27886832
  21. Fufa DT, Goldfarb CA. Fractures of the thumb and finger metacarpals in athletes. Hand Clin 2012;28(3):379-88. PMID: 22883886
  22. Suresh SS, Zaki H, Ahmed A. Isolated Carpo-Metacarpal Dislocation of the Thumb. J Orthop Case Rep 2012;2(1):15-7. PMID: 27298846
  23. Nusem I, Lokiec F, Wientroub S, Ezra E. Isolated dislocation of the thumb carpometacarpal joint in a child. J Pediatr Orthop B 2001;10(2):158-60. PMID: 11360783
  24. Brownlie C, Anderson D. Bennett fracture dislocation - review and management. Aust Fam Physician 2011;40(6):394-6. PMID: 21655486
  25. Abzug JM, Dua K, Bauer AS, et al. Pediatric Phalanx Fractures. J Am Acad Orthop Surg 2016;24(11):e174-e183. PMID: 27755266
  26. Vadivelu R, Dias JJ, Burke FD, Stanton J. Hand injuries in children: a prospective study. J Pediatr Orthop 2006;26(1):29-35. PMID: 16439897
  27. Mahabir RC, Kazemi AR, Cannon WG, Courtemanche DJ. Pediatric hand fractures: a review. Pediatr Emerg Care 2001;17(3):153-6. PMID: 11437136
  28. Hastings H 2nd, Simmons BP. Hand fractures in children. A statistical analysis. Clin Orthop Relat Res 1984;(188):120-30. PMID: 6467708
  29. Rajesh A, Basu AK, Vaidhyanath R, Finlay D. Hand fractures: a study of their site and type in childhood. Clin Radiol 2001;56(8):667-9. PMID: 11467869
  30. Valencia J, Leyva F, Gomez-Bajo GJ. Pediatric hand trauma. Clin Orthop Relat Res 2005;(432):77-86. PMID: 15738807
  31. Chew EM, Chong AK. Hand fractures in children: epidemiology and misdiagnosis in a tertiary referral hospital. J Hand Surg Am 2012;37(8):1684-8. PMID: 22763063
  32. Oak N, Lawton JN. Intra-articular fractures of the hand. Hand Clin 2013;29(4):535-49. PMID: 24209952
  33. Kollitz KM, Hammert WC, Vedder NB, Huang JI. Metacarpal fractures: treatment and complications. Hand (N Y) 2014;9(1):16-23. PMID: 24570632
  34. Soong M, Chase S, George Kasparyan N. Metacarpal fractures in the athlete. Curr Rev Musculoskelet Med 2017;10(1):23-27. PMID: 28185124
  35. Jehanno P, Iselin F, Frajman JM, et al. Fractures of the base of the first metacarpal in children. Role of K-wire stabilisation. Chir Main 1999;18(3):184-90. PMID: 10855318

Reviews

  1. Kozin SH. Fractures and dislocations along the pediatric thumb ray. Hand Clin 2006;22(1):19-29. PMID: 16504775
  2. Cornwall R. Finger metacarpal fractures and dislocations in children. Hand Clin 2006;22(1):1-10. PMID: 16504773

Classics

  1. Worlock PH, Stower MJ. The incidence and pattern of hand fractures in children. J Hand Surg Br 1986;11(2):198-200. PMID: 3734557
  2. Hastings H 2nd, Simmons BP. Hand fractures in children. A statistical analysis. Clin Orthop Relat Res 1984;(188):120-30. PMID: 6467708
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