Metacarpal neck fractures

INTRODUCTION — Metacarpal fractures are among the most common hand injuries, and frequently present to emergency departments and clinics. Fractures of the metacarpal neck, including so-called "boxer's fractures" (fractures of the fifth metacarpal neck) account for a substantial percentage of all hand fractures.

The presentation, diagnosis, and management of metacarpal neck fractures is reviewed here. A general overview of metacarpal fractures and the management of other types of metacarpal fractures are discussed separately. (See "Overview of metacarpal fractures" and "Metacarpal shaft fractures" and "First (thumb) metacarpal fractures" and "Metacarpal base fractures" and "Metacarpal head fractures".)

EPIDEMIOLOGY — Metacarpal fractures are common injuries that account for 30 to 40 percent of all hand fractures [1]. Metacarpal neck fractures are the most common and are usually due to direct trauma, typically involving young males [2,3]. In younger and older populations, falls are another common mechanism of injury. Metacarpal neck fractures most often involve the fifth and to a lesser degree, the fourth metacarpal neck. Fractures of the fifth metacarpal neck ("boxer's fractures") account for approximately 10 percent of all hand fractures.

CLINICAL ANATOMY — Finger and metacarpal anatomy are reviewed in greater detail separately; items of particular relevance to metacarpal neck fractures are discussed below. (See "Finger and thumb anatomy" and "Overview of metacarpal fractures", section on 'Anatomy'.)

Metacarpals are often described using the numbers one through five. The first metacarpal refers to that associated with the thumb, the second to that associated with the index finger, and so on through the fifth metacarpal.

The heads of the metacarpals are bulbous and "cam" shaped, thereby permitting adduction, abduction, flexion, extension and passive rotation of the fingers. The collateral ligaments join the metacarpal to the proximal phalanx and are taut in flexion, while having some laxity in extension (figure 1). These characteristics have important implications for therapy. During splinting or casting, the metacarpophalangeal (MCP) joints are typically immobilized in flexion to prevent shortening of the collateral ligaments and subsequent loss of motion.

The dorsal and volar interosseous muscles originate from the metacarpal shafts and insert onto the proximal phalanges (figure 2 and figure 3). These muscles serve as primary flexors of the MCP joint. In metacarpal neck (and shaft) fractures, the force exerted by these interosseous muscles predictably causes apex dorsal angulation of the fracture.

The common palmar digital arteries and nerves run parallel with the distal portion of each metacarpal. These structures can be injured in significantly displaced metacarpal neck fractures.

MECHANISM OF INJURY — The usual mechanism of injury with metacarpal neck fractures involves direct trauma to a clenched fist, such as punching a wall or solid object [4-6]. The "roundhouse" punching motion common in street fights (but rare in professional or high level amateur boxing) generally transmits significant force to the fifth metacarpal, resulting in fracture. Experienced boxers rarely sustain this type of fracture, and the term "boxer's fracture" is therefore a misnomer. Among children and older adults, falls onto the hand may cause a metacarpal fracture. However, unlike some other hand and wrist fractures, falls (particularly falls onto an outstretched hand [ie, FOOSH mechanism]) are not common mechanisms for metacarpal neck fractures. In addition to punching, direct blunt force trauma to the dorsum of the hand can cause these fractures.

SYMPTOMS AND EXAMINATION FINDINGS

Presentation and general findings — Patients with a metacarpal neck fracture typically present after sustaining direct trauma to the hand with complaints of pain and/or deformity along the dorsum of the hand overlying the involved metacarpal. The dorsum of the hand is swollen and focal bony tenderness is present over the fractured metacarpal. Significant tenderness or ecchymosis on the palmar (volar) surface is highly suggestive of fracture. The hand should be examined closely for signs of fracture angulation and malalignment, impaired extensor function of the fingers, and loss of skin integrity. Neurovascular status of the affected hand should be assessed.

Fracture angulation — Metacarpal neck fractures almost universally result in dorsal angulation of the apex of the fracture due to the pull of the interosseous muscles. As a result, the metacarpophalangeal (MCP) joint is often depressed, causing loss of the usual knuckle contour. Angulation is determined using a lateral radiograph. (See 'Diagnostic imaging' below.)

Rotational alignment — Assessment of rotational alignment is critical to the proper evaluation of all metacarpal fractures. Rotational alignment should be assessed with the MCP joint in flexion. The rotational alignment of the metacarpals can be assessed in two ways:

●With a semi-clenched fist (flexion to 90 degrees at the MCP and proximal interphalangeal [PIP] joints), normal alignment will show convergence of the digits but not necessarily to a single point (picture 1A-B).

●With the MCP joint flexed 90 degrees and the PIP and distal interphalangeal (DIP) joints in full extension, the planes of the fingernails should be aligned in the uninjured hand (picture 2). Alignment can be compared to the contralateral (ie, injured) hand.

Extensor apparatus — The function of the extensor apparatus should be evaluated in patients with metacarpal neck fractures. In a severely angulated fracture, efforts to extend the finger may result in hyperextension at the MCP joint with flexion at the PIP joint (so-called "pseudo-clawing") (figure 4).

Skin integrity — Special attention must be paid to skin integrity near the metacarpal head since this site is particularly prone to injury caused by a tooth during an altercation (sometimes called a "fight bite" (figure 5)). Any evidence of laceration or skin breakdown requires aggressive decontamination to avoid potentially disastrous intraarticular infections. Prophylactic antibiotics appear to be beneficial with hand bites. (See "Human bites: Evaluation and management", section on 'Management'.)

DIAGNOSTIC IMAGING

Plain radiographs — Plain radiographs are performed to establish the diagnosis of metacarpal neck fracture and to determine the degree of fracture angulation. In addition, clinicians facile with ultrasound often perform a bedside ultrasound examination to make the initial diagnosis. Observational studies suggest that ultrasound provides a quick and accurate means for diagnosing metacarpal fractures [7-9].

With plain radiographs, three views of the hand (anteroposterior (AP), lateral, and oblique) adequately display metacarpal neck fractures (image 1A-B and image 2). Measurements of angulation should be performed on the lateral view using the shaft of the metacarpal and a line through the mid-point of the fracture fragment [10]. Use of an oblique view results in an exaggerated measurement of angulation. Angulation is almost universally apex dorsal in metacarpal neck fractures.

Clinicians must remember that the normal head-to-neck angle of the metacarpals is 15 degrees, and angulation references are based upon this baseline. Thus, fracture angulation is equal to the measured angle on the lateral radiograph minus 15 degrees.

No clear consensus is established in the medical literature regarding acceptable degrees of fracture angulation. However, it is clear that the second and third metacarpals tolerate significantly less angulation than the fourth and fifth metacarpals due to their fixed proximal position at the carpometacarpal (CMC) joints.

Historically, a simple "10, 20, 30, 40 rule" was used to determine acceptable angulation [11]. The second metacarpal neck tolerates 10 degrees of angulation, the third 20 degrees, the fourth 30 degrees, and the fifth metacarpal up to 40 degrees of angulation without adversely affecting functional outcome (one small randomized trial and some observational evidence suggest acceptable results for uncomplicated fifth metacarpal neck fractures are achievable with up to 70 degrees of angulation) [12,13]. The degree of fracture angulation that warrants surgical referral is discussed below. (See 'Indications for surgical referral' below.)

Musculoskeletal ultrasound — Ultrasound is well suited for investigating fractures in linear areas of bone such as the diaphyseal and metaphyseal regions of the metacarpals.

Musculoskeletal ultrasound (MSK US) examination of the hand is best performed with the patient seated and the hand resting on an examination table. Examination of the dorsum is performed first, followed by the volar side. A high-frequency transducer of at least 10 mHz is typically used. A small footprint (hockey stick) linear probe (picture 3) makes examination of the hand and metacarpals easier. MSK US examination of the hand and metacarpals involves a standard two-position examination (longitudinal [ie, sagittal] (picture 4) and transverse views). Initially, the probe is placed on the dorsum of the hand at the distal metacarpophalangeal (MCP) joint, and then moved proximally. Images are obtained in the longitudinal and transverse planes. This allows for evaluation of potential joint involvement of a metacarpal fracture. The cortex of each potentially injured metacarpal is examined carefully for any discontinuity in the hyperechoic surface consistent with a fracture (image 3). Cortical discontinuities as small as 1 mm can be identified with high-resolution transducers and may enable visualization of fractures that would be missed with standard radiographs [14]. Occasionally, hematoma, edema, or ligamentous disruption may be seen.

Studies of MSK US report sensitivities of 90 to 91 percent and specificities of 97 to 98 percent for hand fractures [7,8]. However, while ultrasound can be effective for diagnosing metacarpal fractures, plain radiographs may still be needed to determine angulation and rotation.

DIAGNOSIS — The definitive diagnosis of a metacarpal neck fracture is made by diagnostic imaging, usually a plain radiograph, but some clinicians use ultrasound to make the initial diagnosis. A history of direct trauma to the hand, most often a punch thrown against a stationary object by a young male, and findings of swelling along the dorsum of the hand, accompanied by focal bony tenderness at the distal metacarpal, suggest the presence of a fracture.

DIFFERENTIAL DIAGNOSIS — The injuries most commonly mistaken for a metacarpal neck fracture include hand contusion and metacarpal-phalangeal dislocation.

Hand contusion — A contusion of the hand sustained from direct trauma can present in similar fashion to a fracture, with significant pain, swelling of the dorsum of the hand, and bony tenderness. However, contusions are more often the result of a direct blow rather than force sustained by a clenched fist striking an object. In addition, fractures may have appreciable step-off on palpation whereas contusions will not. Often, imaging is warranted to distinguish between contusion and metacarpal fracture.

Metacarpal phalangeal dislocation — Dislocation at the metacarpal-phalangeal joint presents with obvious deformity, pain, and impaired flexion and extension at the metacarpophalangeal (MCP) joint. This can generally be distinguished from a metacarpal fracture based on:

●Mechanism – MCP dislocation is typically be caused by pulling or twisting that exerts a sudden lateral, anterior, or posterior force to the phalanx. In contrast, a metacarpal neck fracture is typically caused by direct force from a clenched fist striking an object or a direct blow to the metacarpal.

●Examination – Loss of congruity at the articulation of distal metacarpal and proximal phalanx is palpable following dislocation. Diagnostic imaging (eg, plain radiograph) readily distinguishes dislocation from fracture and is warranted at presentation and/or after reduction of the dislocation.

INDICATIONS FOR SURGICAL REFERRAL

The major indications for referral to a hand surgeon can be summarized as follows:

●Immediate surgical consultation is needed for open metacarpal neck fractures (laceration extends to bone) and injuries associated with major neurovascular impairment. Such injuries are uncommon.

●Complex metacarpal neck fractures that are unstable and not amenable to conservative management, such as severely comminuted fractures and fractures with any rotational component, should be referred to a hand surgeon. (See 'Rotational alignment' above.)

●Metacarpal neck fractures with significant angulation as described immediately below should be referred to a hand surgeon. (See 'Diagnostic imaging' above.)

Limited angulation alone is functionally well tolerated in many metacarpal neck fractures. The traditional "10, 20, 30, 40 rule" can be used to determine the tolerability of fracture angulation, with the important exception of the fifth metacarpal. Cadaveric studies looking at the effect of different degrees of fracture angulation upon biomechanics suggest that any fracture angle greater than 30 degrees impairs motor function [15-17]. Therefore, offering referral to a hand surgeon for fourth and fifth metacarpal neck fractures with angulation >30 degrees is reasonable. Our practice is to refer fourth metacarpal fractures with >30 degrees angulation and discuss referral for all fifth metacarpal fractures >30 degrees (we tend to refer fifth metacarpal fractures with angulation >40 degrees).

Remember that the normal metacarpal head-to-neck angle is 15 degrees. Thus, fracture angulation is equal to the measured angle on the lateral radiograph minus 15 degrees.

Fractures angulated beyond acceptable levels are managed with closed reduction and immobilization or operative fixation to restore more normal alignment (image 4). Hand surgery referral should be obtained for such injuries if the primary care clinician is inexperienced in metacarpal fracture management. Referral is also necessary when adequate fracture reduction cannot be maintained.

Hand surgery consultation should be obtained for individuals whose occupations or hobbies require a great deal of fine motor movement or gripping of the hand (eg, musicians, craftsmen, seamstresses, baseball players). In addition, some patients may prefer less angulation for cosmetic reasons. Injury of the dominant hand and patient request are acceptable reasons for referral.

MANAGEMENT

Initial treatment — The following discussion describes the initial therapeutic approach in patients who do not require immediate fracture reduction or surgical referral as described in the previous section. Initial therapy typically consists of a splint, since swelling often prevents optimal casting. Splinting is used in the initial immobilization of, and sometimes is the definitive treatment for, metacarpal fractures [1,18]. A detailed description of the techniques for applying splints is presented separately. (See "Basic techniques for splinting of musculoskeletal injuries".)

An ulnar gutter splint is used to immobilize fractures of the fourth and fifth metacarpal necks (picture 5 and figure 6). The appropriate position for initial immobilization is 70 to 90 degrees of flexion at the metacarpophalangeal (MCP) joint, slight flexion at the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints, and mild wrist extension. A similar splint applied to the radial side of the hand with an opening to accommodate the thumb is used for fractures of the second and third metacarpal necks.

The application of ice to the injured area, elevation of the affected hand above the level of the heart, and appropriate analgesia are indicated during the first 48 to 72 hours. (See "General principles of acute fracture management".)

Closed reduction — Acute reduction is indicated if there is pseudo-clawing as evidenced by hyperextension at the MCP joint and flexion at the PIP joint with attempted extension of the finger (figure 4). Reduction is also needed for significantly angulated fourth or fifth metacarpal fractures. Acceptable degrees of angulation amenable to splinting without reduction are described in greater detail above. (See 'Indications for surgical referral' above.)

There are several methods for reducing a metacarpal neck fracture; the following is our preferred approach.

Anesthesia — Typically, effective anesthesia is quickly obtained with a hematoma block. The placement of a hematoma block for metacarpal fractures is described separately (see "Metacarpal shaft fractures", section on 'Anesthesia'). Another effective option for anesthesia is an ulnar nerve block at the wrist, which is described separately. (See "Upper extremity nerve blocks: Techniques", section on 'Ulnar nerve block'.)

Reduction — Once adequate anesthesia is confirmed, use the 90-90 method to reduce the fracture (figure 7 and picture 6). Begin by flexing the MCP, PIP, and DIP joints all to 90 degrees. Next, direct pressure axially through the flexed PIP joint, thereby creating a dorsal force on the distal fracture fragment. Simultaneously, apply a volar force over the fracture site until you sense that an anatomic reduction has been achieved. Then immobilize the fracture with a Burkhalter-type splint (picture 7) or an ulnar gutter splint (picture 5). Post-reduction radiographs are imperative to ensure adequate reduction and alignment.

Delayed presentation — It is not uncommon for patients with metacarpal neck fractures, particularly ones involving the fifth metacarpal, to present for evaluation two weeks or longer after their injury. This may be due to denial or possibly embarrassment about the circumstances of the injury. In cases of delayed presentation, important factors to consider when deciding on appropriate management include:

●Hand function

●Level of pain

●Extent of bony healing (as determined with diagnostic imaging)

Often, after three weeks or longer pain is minimal and function is intact, even with significantly angulated fractures. These patients are often comfortable with continuing conservative care. However, if function is impaired in any way, pain remains problematic, or angulation is unacceptable, referral to a hand surgeon is indicated. (See 'Indications for surgical referral' above.)

FOLLOW-UP CARE

General follow-up — Patients with significantly angulated second (>10 degrees) or third (>20 degrees) metacarpal neck fractures should be seen again within three to five days, while fourth and fifth metacarpal fractures should be seen within one week. Repeat plain radiographs are indicated to look for evidence of worsened angulation, loss of reduction, or malrotation. The patient should be referred to a hand surgeon if any of these complications develop. Follow-up studies should be obtained at two-week intervals from that point forward until radiographic healing (callus and consolidation on plain radiograph) and clinical healing (nontender over fracture site) are present. (See 'Indications for surgical referral' above.)

The definitive treatment for metacarpal neck fractures differs from other fractures in that a splint (noncircumferential immobilization) can be used for the entire duration of immobilization. For other metacarpal fractures (eg, head, shaft, or base), a splint is used for the first few days to permit swelling to diminish. A short arm cast (SAC) is then applied and used for the remaining period of immobilization. (See "Overview of metacarpal fractures".)

In minimally displaced fourth and fifth metacarpal neck fractures and nondisplaced second and third metacarpal neck fractures, simple immobilization for three to four weeks in a gutter or Burkhalter-type splint provides definitive treatment (picture 7). The splint should be worn continuously, and it is important to maintain at least 70 degrees of flexion at the metacarpophalangeal (MCP) joints to avoid stiffening of the MCP collateral ligaments [19-21].

The usual healing time for metacarpal neck fractures is four to six weeks, which does not appear to be shortened with surgical intervention. There should be evidence of radiographic healing (ie, callus formation around the fracture site) by four weeks (picture 8).

Following immobilization, there is often stiffness at the MCP and proximal interphalangeal (PIP) joints. This is typically alleviated within a few weeks by performing passive and active range of motion exercises with these joints. These can be performed at home. If the patient is unable to regain adequate range of motion after two to three weeks using a home program, formal referral to occupational therapy may be necessary.

When fractures heal completely, approximately 50 percent of the initial deformity correction is typically maintained. Despite adequate reduction, residual cosmetic deformity may persist (loss of dorsal knuckle contour), but function is generally not impaired.

Fifth metacarpal neck fractures — In the United States, many fifth metacarpal neck fractures are managed with an off-the-shelf Galveston splint or a custom orthosis; the latter is typically molded from low-temperature thermoplastic [22]. These devices allow the use of other fingers and movement at the fifth PIP and distal interphalangeal (DIP) joints, while maintaining fracture position. This is particularly helpful in students (due to frequent writing) and older adults. Functional bracing of metacarpal neck fractures is often helpful for patients at high risk of developing joint stiffness (eg, older adults).

Many occupational therapists receive specific training in constructing and fitting custom orthoses to allow greater hand and finger mobility (and often greater comfort) than a plaster splint or cast, while maintaining fracture position.

There a growing body of evidence that more minimalist interventions for managing uncomplicated fifth metacarpal neck fractures yield results comparable with rigid immobilization. Several randomized trials report that buddy taping or the combination of a soft wrap and buddy tape yields comparable outcomes in function and patient satisfaction to more rigid immobilization techniques [23-25]. Several such alternative approaches have been evaluated in small randomized trials:

●A randomized trial of 97 patients compared buddy taping (ring to little finger) with plaster immobilization [25]. Functional outcomes were the same in both groups at 12 weeks, and all secondary outcomes (pain, satisfaction, and a measure of overall health) were comparable except for days of missed work (median of two days missed in plaster group versus zero in buddy tape group).

●A randomized trial of 68 patients with fifth metacarpal neck fractures willing to accept loss of normal knuckle contour reported comparable patient satisfaction scores for those treated with soft wrap and buddy taping versus reduction and casting [24].

●Gutter plaster immobilization was compared with a pressure bandage and immediate mobilization in 40 patients with nonrotated fifth metacarpal neck fractures angulated up to 70 degrees (mean 39 degrees) [13]. No significant differences were noted in outcome variables at 6 or 12 weeks.

●Functional taping allowing more hand and finger motion was compared with plaster immobilization in 50 patients [26]. Earlier functional recovery and greater mobility were noted in taped patients, but long-term results were similar in the two groups.

●Molded bracing was compared with taping/strapping in 73 patients [27]. Molded bracing was associated with less pain and an earlier return to work.

●Closed reduction/splinting was compared with functional treatment in 29 patients [28]. Functional treatment was associated with a slightly earlier return of grip strength and mobility but comparable results at three months.

●No difference in fracture alignment, joint motion, or strength was noted in a study of 81 patients immobilized in one of two types of SACs [29]. One SAC included a volar outrigger while the other was extended to include the PIP joint.

RETURN TO WORK OR SPORT — Return to work should be expected when the patient's metacarpal joint is pain-free, nontender, and has functional range of motion. Risk of reinjury remains high for four to six weeks after completion of immobilization. Thus, return to contact sports or heavy labor prior to this time requires orthotic protection.

COMPLICATIONS — The most common complication of metacarpal fractures is joint stiffness [19]. Decreased grip strength, relative cold intolerance, and displeasure with cosmetic results (loss of knuckle contour) are other potential complications. A more serious but rare complication of metacarpal neck fractures caused by crush injury is compartment syndrome, which is a surgical emergency. In patients with substantial associated soft tissue damage and persistent pain out of proportion to the injury despite appropriate splinting, compartment syndrome may be present [30]. (See "Acute compartment syndrome of the extremities".)

ADDITIONAL INFORMATION — Several UpToDate topics provide additional information about fractures, including the physiology of fracture healing, how to describe radiographs of fractures to consultants, acute and definitive fracture care (including how to make a cast), and the complications associated with fractures. These topics can be accessed using the links below:

●(See "General principles of fracture management: Bone healing and fracture description".)

●(See "General principles of fracture management: Fracture patterns and description in children".)

●(See "General principles of definitive fracture management".)

●(See "General principles of acute fracture management".)

●(See "General principles of fracture management: Early and late complications".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Fractures of the skull, face, and upper extremity in adults" and "Society guideline links: Acute pain management".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the fifth to sixth grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topic (see "Patient education: Hand fracture (The Basics)")

SUMMARY AND RECOMMENDATIONS

Epidemiology and mechanism of injury – Metacarpal neck fractures are common. They usually result from a direct blow to the hand or from striking an object with a clenched fist. Fifth (little finger) metacarpal neck fractures, sometimes called "boxer's fractures," are most common. (See 'Epidemiology' above and 'Mechanism of injury' above.)

Clinical presentation and physical examination – Patients typically present after sustaining hand trauma with complaints of pain and/or deformity along the dorsum of the hand overlying the involved metacarpal. The dorsum of the hand is swollen and focal bony tenderness is present over the fractured metacarpal. Significant tenderness or ecchymosis on the palmar surface is highly suggestive of fracture. (See 'Symptoms and examination findings' above.)

Examine the hand closely for signs of fracture angulation, rotation, and malalignment, as well as impaired extensor function of the fingers and loss of skin integrity. Metacarpal neck fractures almost universally cause dorsal angulation of the fracture apex, which often causes loss of the usual knuckle contour. Assessment of fracture angulation (using plain radiographs) and malrotation (using physical examination) are described in the text. (See 'Clinical anatomy' above and 'Symptoms and examination findings' above and 'Diagnostic imaging' above.)

Diagnostic imaging and diagnosis – Definitive diagnosis of metacarpal neck fractures is made with plain radiographs; skilled operators may use ultrasound for initial diagnosis. Fractures are readily distinguished from the two common alternative diagnoses – hand contusion and metacarpal-phalangeal dislocation – with imaging. (See 'Diagnostic imaging' above and 'Diagnosis' above and 'Differential diagnosis' above.)

Indications for surgical referral – The major indications for referral to a hand surgeon can be summarized as follows:

●Open metacarpal neck fractures (laceration extends to bone) and injuries associated with major neurovascular impairment. Such injuries are uncommon but require immediate surgical consultation.

●Complex metacarpal neck fractures not amenable to conservative management, such as severely comminuted fractures and fractures with any rotational component.

●Metacarpal neck fractures with significant angulation. (See 'Indications for surgical referral' above.)

Acceptable fracture angulation and indications for reduction – Second (index finger) and third (middle finger) metacarpal neck fractures do not tolerate significant angulation. Angulation >10 degrees at the second metacarpal and >20 degrees at the third metacarpal warrant reduction or referral. Angulation is determined using a lateral radiograph and must account for the normal metacarpal head-to-neck angle of 15 degrees. (See 'Indications for surgical referral' above and 'Diagnostic imaging' above.)

Fourth and fifth metacarpal neck fractures tolerate greater angulation (up to 30 degrees). Most of these fractures result in good functional results even with significant angulation. Our preferred method for reducing metacarpal neck fractures is described in the text. (See 'Closed reduction' above.)

Pseudo-clawing (metacarpophalangeal [MCP] joint hyperextension and proximal interphalangeal [PIP] joint flexion with attempted extension of the finger) mandates fracture reduction or referral. (See 'Extensor apparatus' above.)

Management of lacerations at fracture site – Lacerations at the site of trauma ("fight bites") are common and predispose to infection. Any evidence of laceration or skin breakdown requires aggressive decontamination to avoid potentially disastrous intraarticular infections. Prophylactic antibiotics appear to be beneficial with hand bites. (See 'Skin integrity' above and "Human bites: Evaluation and management", section on 'Management'.)

Fracture immobilization and follow-up – In addition to standard fracture care, initial management of metacarpal neck fractures typically consists of immobilization in an ulnar gutter splint for fourth and fifth metacarpal neck fractures, or a radial side splint for fractures of the second and third metacarpal neck. Functional bracing with custom or off-the shelf orthoses are effective and commonly used in the definitive management of metacarpal neck fractures. Follow-up care and imaging varies according to the type of fracture and is described in the text. (See 'Follow-up care' above.)