Hand Dislocation

Hand dislocation is a common injury in sports and in occupational settings, often appearing to be minor. If the athlete, trainer, or coach has already reduced the dislocation, it appears unimpressive compared with a major knee injury or a shoulder dislocation.

However, hand dislocations have real potential for long-term disability in sports and other areas of life if adequate reduction is not performed, if associated injuries are not identified and appropriately treated or referred, and if potential complications of the injury and its treatment are not foreseen. The judgment of the initial treating physician can be critical in determining the long-term outcome of these injuries.

Many hand dislocations can be effectively treated with closed reduction, traction, or both. Grossly unstable joints and those for which closed reduction has failed typically require surgical intervention. Physical and occupational therapy are key components of treatment throughout. Any long-term complications (usually involving stiffness or instability) that develop must be addressed.

Interphalangeal joints

The bony anatomy of the proximal interphalangeal (PIP) joint consists of medial and lateral condyles on the proximal phalanx, with matching concavities on the associated distal phalanx. The joint has a wide range of motion (ROM) in flexion and extension but is relatively rigid in abduction and adduction; thus, it is a hinge (ginglymus) joint functionally. The bony anatomy of the distal interphalangeal (DIP) joint is similar, but the surrounding soft tissue provides more restriction in flexion.

The extrinsic flexors across both joints are at least 4 times stronger than the extensors, allowing flexion contractures to develop very rapidly, especially with immobilization in flexion. Adequate ROM, especially at the PIP joint, is critical for normal hand function.

The PIP and DIP joints are both supported on all 4 sides by similar soft-tissue structures, which include the volar plate on the palmar side (the integrity of which is essential for a stable reduction), collateral ligaments on the radial and ulnar sides, and the extensor complex (central slip, lateral bands, and hood) dorsally (see the image below). These structures attach to and reinforce the joint capsule. For a dislocation to occur, at least 1, often 2, and sometimes 3 of these structures must be significantly injured.

The volar plate is a roughly triangular structure with its base oriented distally, attaching to the volar base of the middle phalanx with its tip attaching to the distal aspect of the proximal phalanx. The volar plate functions largely in limiting hyperextension. Thus, it is nearly always injured in dorsal dislocations.

The collateral ligaments restrict the joint from opening to varus or valgus stress and are also commonly injured in dorsal dislocation. Injury to the radial collateral ligament is about 6 times more common than injury to the ulnar collateral ligament.

The extensor complex comprises the central slip, which attaches to the base of the middle phalanx; the lateral bands, which run dorsolaterally on each side; and the transverse retinacular ligament, which connects these structures and extends laterally. It helps limit volar movement of the base of the middle phalanx and thus is commonly injured in volar dislocations at the PIP joint, with the middle phalanx either tearing the central slip from its insertion or buttonholing through the transverse retinacular ligament between the central slip and a lateral band.

Metacarpophalangeal joint

The metacarpophalangeal (MCP) joint is thought to be an ellipsoid joint. The head of the metacarpal consists of medial and lateral condyles and is narrower on its dorsal surface than on its palmar surface; it fits into the concavity of the base of the proximal phalanx. The true collateral ligament attaches to a recess created by the junction of the shoulder and head. The collateral ligament is composed of the following 2 parts:

• A dorsally placed cord portion

• A fan-shaped volar portion or accessory collateral ligament, which extends from the metacarpal to the sides of the volar plate

To accomplish flexion and extension at the MCP joint, the anterior and posterior parts of the capsule must be lax. When the joint is extended, the phalanges have considerable lateral play in abduction and adduction; consequently, this joint is not frequently injured. However, if the ligament is torn, dislocation occurs.

The MCP joint of the thumb has radial and ulnar collateral ligaments, which are loose when the joint is extended and tight when flexed. When the joint is extended, the proximal phalanx has the lateral play achieved by the action of the interosseous muscles.

When the thumb is flexed and in a functional position, as in the case of many sports situations (eg, skiing, falls on a gloved hand), the ulnar collateral ligament is the structure at risk and can be ruptured (see Skier’s Thumb). The ulnar collateral ligament can then be displaced so that the adductor aponeurosis is interposed between the ruptured end of the ligament and its site of bony attachment.

Carpometacarpal joint

The bony anatomy of the carpometacarpal (CMC) joint consists of the 5 metacarpal bases that articulate with the trapezoid, trapezium, capitate, and hamate (in that order) from the radial aspect of the hand to its ulnar aspect. The CMC joint is a relatively fixed joint segment because of the articular congruity of the joint surfaces, with the metacarpal bases acting like concave receptacles to the distal carpal row, and because of the strong interosseous and extrinsic ligament complex.

The palmar and dorsal ligaments are distinct, with the palmar ligaments being stronger. The scaphoid acts as a link between the proximal and distal carpal rows. The extensor and flexor tendons pass over this articular area but add no strength to the CMC joint because the bases of the metacarpals dislocate dorsally relative to the distal carpal row.

The first CMC joint (also referred to as the first metacarpotrapezoid joint) is a highly mobile saddle joint, with articular surfaces that are reciprocally concavoconvex. The most important soft-tissue support for this first CMC joint is the deep ulnar or anterior oblique ligament, which runs from the volar beak of the metacarpal to the tubercle of the trapezium. This ligament can be ruptured, but it tends to be avulsed with a piece of bone (Bennett fracture-dislocation).

Traumatic force applied to the hand can be transmitted to bone, soft tissue, nerves, and vascular structures. Because the structures of the hand are close to the surface and near each other, injury often results in a combination of fractures, dislocations, and soft tissue injury.

The DIP and PIP joints both have lateral ligaments and a fibrous volar plate. Common dislocations are posterior or lateral. Typical forces resulting in DIP dislocations include a jamming blow to the end of the finger. Forces that commonly lead to PIP joint dislocation include axial loading or hyperextension. Lateral dislocations can result from radial- or ulnar-directed force on the joint.

Dislocations of finger MCP joints are rare and frequently are trapped by the surrounding ligaments, in which case surgical relocation is necessary. MCP or palmar dislocations occur when a hyperextension movement occurs with rotation. The finger is bent back toward the top of the hand and is twisted during the injury. The finger may have been pushed, or compressed, during the injury. MCP dislocations are typically associated with fractures.

In thumb MCP joint dislocations, the mechanism encountered most often is hyperextension that leads to volar dislocations. A significant lateral force can disrupt the collateral ligaments, resulting in instability. Gamekeeper’s (skier’s) thumb often results from a fall onto the hand with the thumb in abduction (as when the hand grips a ski pole).[1]

CMC joint dislocation[2] is not always a high-energy injury. Identification involves careful analysis of subtle findings on radiographs and may require additional radiographic views. Missed diagnosis of carpometacarpal dislocation can result in significant morbidity.

Hand dislocation is caused by the following:

• Sports injuries (usually involving contact sports or a ball forcefully striking the tip of the finger)

• Occupational injuries

• Falls

• Traffic collisions

Sport-specific biomechanics

Dislocations of the PIP and DIP joints of the hand probably occur most commonly in basketball and football. In basketball, the usual mechanisms include being struck by the ball, catching a finger on the rim, or contact with another player. In football, the finger may be caught on a jersey, slapped against a helmet, or crushed between some combination of players, equipment, and the ground. Linemen and defensive players are at highest risk. In both sports, return to play almost always requires that the injury can be splinted stably to allow a power grip.

Dislocations of the MCP and basilar CMC joints occur most commonly with falls on the outstretched hand (so-called FOOSH injury) or the flexed supinated wrist. With this extension vector, the forces are transmitted up through the carpus.

Injuries and dislocations of the thumb, the MCP joint, and the CMC basilar joint commonly occur in falls with the thumb in abduction. Examples of this type of injury include a fall on the gloved hand in baseball or application of an abduction force to a flexed thumb while the hand is grasping an object—as in skiing injuries, when the pole impacts the proximal phalanx tearing the radial collateral ligament. This occurs when the wrist is extended at the time of the injury.

The annual incidence of all types of dislocations in the hand is approximately 67,000 in the United States. Most hand dislocations are sports or occupational injuries, with a lesser number sustained in falls and traffic collisions (sometimes associated with airbag deployment).[3, 4, 5, 6, 7]

Most of these injuries are dislocations at the PIP joint, because the greater ROM of this joint makes it more vulnerable to injury. Of the PIP dislocations, most are dorsal.[8] Volar dislocations of the PIP joint are much less common, more difficult to reduce, and associated with more complications. DIP joint dislocations are also uncommon, almost always dorsal, and often open.

In addition to PIP and DIP joint dislocations, MCP and CMC joint dislocations also occur, though less frequently.[4, 9, 10] The MCP joint of the 4 fingers usually dislocates posteriorly (simple type) but can, on rare occasions, become entrapped between the palmar fascia and the palmar plate and become irreducibly dislocated.[11] CMC joint dislocation is a disabling injury, which is usually dorsal and may be associated with fractures of the bases of the metacarpals.

Transcarpal fractures in children are rare, but the emergency physician must be cognizant that they do occur.

Anatomic restoration of dislocated joints is imperative for achieving good long-term outcomes. Accurate and stable reduction, early fixation, and initiation of ROM exercise are very important. Dislocations can lead to osteoarthritis, compression neuropathies, and carpal tunnel syndrome. Additional disability from chondrolysis, carpal instability, and traumatic arthritis can also occur.

Median or ulnar neuropathy can occur from direct nerve compression or increased pressure within the median or ulnar nerve canals.[12] Evaluation of the patient’s nerve status is especially important in the early evaluation of carpal dislocations.[13] Grip strength must be tested before and after reduction.

The prognosis is good for simple PIP dislocations and most DIP dislocations, as well as for volar dislocations with the central slip intact (rotatory subluxations). Frequently, some loss of ROM occurs, but with adequate rehabilitation, a functional range can be maintained.

The prognosis is fair for volar dislocations with avulsion of the central slip if the diagnosis is made at the time of initial evaluation and proper treatment initiated; however, the prognosis is fair to poor for dorsal fracture-dislocations.

The prognosis is poor for any dislocation that is incompletely reduced for more than a few days and is very poor for a dorsal fracture-dislocation or a volar dislocation with central slip injury if the diagnosis is not made and appropriate treatment instituted early in the course of the injury.

The prognosis is good in most MCP joint and CMC joint dislocations that are treated early. Delay in diagnosis and treatment may progressively worsen the prognosis. Long-term sequelae of hand dislocations with injury to the joint surface include instability, ankylosis, and arthrosis.

All athletes in high-risk sports should know to have significant finger injuries evaluated and treated by the team physician or trainer at the time they occur. This helps to avoid some of the morbidity from fracture-dislocations, boutonniere injuries, and incompletely reduced dislocations. In addition, all athletes who sustain these injuries should be made aware of the importance of timely follow-up, of the expected duration of immobilization, and of the rehabilitation plan, goals, and timetable.

For patient education resources, see Broken Hand, Broken Finger, and Hand Injuries.

As with any hand injury, the history of a patient with a suspected hand dislocation should begin with determining the patient’s age; handedness; sex; and type of participation in sports, hobbies, or occupation, because these affect both the presentation of the injury and the goals of treatment.

The patient most likely presents with a history of trauma leading to finger deformity. The clinician should inquire about whether other injuries took place to rule out the presence of any life-threatening injury. The time at which the event occurred should be determined, as should the conditions surrounding it (these are particularly important if there is a question about whether an associated wound is contaminated or clean).

Because the dislocation is often reduced by the patient or others involved at the scene, it is important to elicit the mechanism of injury (eg, hyperextension, axial loading, torsion, radial or ulnar stress, or a direct blow) and assess the resultant deformity.

Although in many cases, the patient is unable to clearly describe the mechanism of injury, description of the deformity as either volar or dorsal is still valuable because the associated injuries and the appropriate treatment of these 2 types of deformity differ significantly. The exact location of pain can be helpful in localizing the injury, but this is more precisely defined by tenderness on physical examination.

Most carpal trauma occurs as a result of fall-on-outstretched-hand (FOOSH) injury, such as might occur in any sport or accident. When the resultant vector is primarily one of ulnar deviation and intercarpal supination, ligamentous disruption and carpal dislocations tend to result. This mechanism can be observed in glove-side injuries in baseball fielders or hockey goalies.

Once the mechanism of injury has been translated into forces, loads, rotations, extensions, reductions, joint deformities, and related forces that caused the dislocation, the clinician can use this knowledge to manage the local or obvious deformity as well as any distal or occult injuries. For example, the metacarpophalangeal (MCP) joint may appear dislocated, but fractures are typically associated with MCP dislocations because rotational and compressive forces are involved. Hence, radiographs are required before any reduction attempt.[14]

The past medical and surgical history should focus on previous injuries to the hand, presence of fixation devices, and underlying conditions that may affect healing (eg, ligamentous laxity).

With significant injury to the digits, a comprehensive examination may be hindered by pain. A thorough visual inspection of the hand and fingers is the first required step. Inspect for deformity, skin color, skin temperature, skin integrity, and swelling. Distal digital sensation should be checked early and often.

Inspection for deformity

The following deformities may be observed:

• Hyperextension - This is typical of dorsal proximal interphalangeal (PIP) joint dislocations, indicating damage to the volar plate

• Angulation - This may be radial or ulnar, indicating damage to one or both of the collateral ligaments

• Rotation - This is common in rotatory subluxation, which is a subtype of volar dislocation rather than a separate class of injury; it is best noted by looking at the nails, which should all lie in the same plane (the nail of an injured digit will be rotated out of the plane occupied by the others)

• Displacement of the more distal phalanx - This is volar in volar dislocations and dorsal or dorsolateral in dorsal dislocations; it may be obscured by swelling or may be subtle in partially reduced dislocations with entrapped soft tissue

Assessment of skin

The skin of the fingers is tightly stretched over the underlying structures and adherent to them, especially on the volar aspect and toward the fingertip. This makes the interphalangeal joints more prone to open dislocations than many other joints in the body. Accordingly, it is important to check for any breaks in the skin.

Any skin defect in the area of a joint must be presumed to represent an open dislocation with direct communication to the joint and potential contamination by bacterial flora. This flora can be destructive to articular cartilage and, therefore, may necessitate intravenous (IV) antibiotics and consultation with a hand surgeon for irrigation and debridement. One should be suspicious of an open injury in a patient presenting with a laceration over a joint even without deformity, because the patient may have reduced the jammed finger before the examination.

Sensation examination

Sensation examination includes testing for the following:

• Ability to distinguish light touch from deep pressure

• Ability to distinguish sharp from dull

• Ability to detect 2 points separated by 5 mm

• Ability to detect temperature variation

Because the presence of pain can limit the examination, rapid pain relief should be considered. The patient can be made pain-free or the pain made tolerable before manipulation of the hand or digit. Benefits of examination with anesthesia include improved assessment of range of motion (ROM) and digit stability. Digital block with a local anesthetic is quick and efficacious intervention. However, the clinician must have a working protocol with the hand specialist. In some cases, the hand specialist may want to examine the digit before giving the anesthetic.

Reducing the patient’s pain is a priority, but this priority must not be allowed to outweigh the need to perform a very thorough and well-documented neurovascular examination. The emergency physician and the hand specialist must establish some guidelines for eliminating the patient’s pain without compromising the examination and documentation for the provider who will have to provide ultimate follow-up, rehabilitation, and occupational guidelines.

Findings associated with specific dislocations

Dislocations of the thumb MCP joint may be simple or complex. In simple dislocations, the phalanx sits perpendicular to the metacarpal, and the volar plate is not trapped. In complex dislocations, the phalanx is positioned parallel to the metacarpal, with the volar plate trapped in the joint. Gamekeeper’s (skier’s) thumb presents with pain and tenderness on the ulnar aspect of the thumb around the MCP joint.[15]  The extent of associated laxity depends on the amount of disruption and the ability of the examiner to stress the joint.

Dislocations of the finger MCP joints also may be simple or complex. Simple dislocations can be identified as the base of the phalanx sits on the dorsum of the head of the metacarpal at a right angle. A complex dislocation (see the images below) may reveal a dimple on the palmar surface, and the digit may appear shortened and deviated to the ulnar side.

Simple dorsal dislocations of the PIP joints of the fingers may include volar plate disruption. The middle phalanx is often perpendicular to the distal aspect of the proximal phalanx. With lateral dislocation, the digit often is deviated to the ulnar side. Open dislocations of the distal interphalangeal (DIP) joints of the fingers are common because of the strong support of the skin and periarticular structures.

Evaluation after reduction

After reduction, the point of maximum tenderness, active ROM, stability to gentle passive stress should be checked. If the injury is to the thumb, testing specific to the thumb may be warranted.

Point of maximum tenderness

The point of maximum tenderness may not be easy to determine but helps to define damaged structures. The following locations are associated with specific injuries:

• Lateral – Injury to collateral ligaments (radial, ulnar, or both)

• Volar – Injury to volar plate

• Dorsal (base of middle phalanx) – Injury to central slip

Active range of motion

Active ROM (AROM) may be difficult to test if the patient is experiencing significant pain. Digital block (after neurologic examination) may be necessary for an accurate determination of ROM (see the image below).

The examiner must test full active extension of the PIP joint against resistance. In a PIP joint injury, inability to perform this motion with preservation of passive ROM (PROM) is diagnostic of a rupture of the central slip of the extensor tendon. This injury must be splinted in extension to avoid development of a boutonniere deformity (see the images below).

The joint should stay reduced throughout the ROM examination. Instability or redislocation, usually in extension, necessitates extension block splinting at an angle that preserves the reduction.

If both AROM and PROM are reduced, this is consistent with entrapment of a soft-tissue structure (eg, volar plate, collateral ligament, flexor or extensor tendon) in the joint and persistent subluxation. This requires a further attempt at closed reduction. If this is unsuccessful, open reduction is urgently indicated.

Stability to gentle passive stress

Different forms of passive stress are employed to evaluate stability. Hyperextension tests the volar plate. Ulnar deviation tests the radial collateral ligament. Radial deviation tests the ulnar collateral ligament. If the joint opens up 20° or more with minimal resistance, this is consistent with a complete collateral ligament tear.

Forceful passive testing for stability must be avoided, because it can convert a partial tear to a complete one; furthermore, instability of any of these structures to passive stress is unlikely to change the management of an injury that is stable with AROM. The one potential exception to this general rule is complete rupture of the radial collateral ligament of the index finger PIP joint in a young, active patient. This injury is often surgically repaired, primarily because stability at this joint (required for a normal pinch grip) is more important than ROM.

Dorsal deformities can be observed in both MCP-joint and CMC-joint dislocations. Because of swelling, clinical identification of these dislocations is sometimes hard. Bony prominences at the joints of maximum tenderness may be the most common physical findings.

After reduction, the stability of the MCP joint should be checked by means of radial and ulnar deviation with the joint in flexion to determine the functional stability of the radial and ulnar collateral ligaments. The MCP joint should be put through an ROM examination to assess its stability.

After reduction of carpometacarpal (CMC) dislocations, evaluation of hand ROM in dorsal and palmar flexion should be carried out to determine the intrinsic stability of the CMC joint.

Assessment specific to thumb

Physical examination testing specific to the thumb is indicated in some cases. In addition to AROM, testing of the thumb includes flexion of the MCP joint with radial and ulnar stress testing in extension and flexion and contralateral side-to-side comparison. Increased laxity with pain to palpation suggests an ulnar collateral ligament injury, such as gamekeeper’s (skier’s) thumb (see the images below).

Entrapment of the ulnar collateral ligament in the aponeurosis (Stener lesion) prevents healing and may necessitate surgical intervention (see the images below).

Joint stiffness, flexion deformity, hyperextension and instability may develop from the dislocation or damaged periarticular structures or from immobilization during treatment. Boutonniere deformity may result from an undiagnosed or untreated central slip injury associated with volar PIP dislocation. Overly forceful attempts at reduction may result in phalangeal fractures.[16] Associated intra-articular fractures may predispose to degenerative joint disease (DJD).

Laboratory studies are not typically necessary for the patient with an isolated interphalangeal joint dislocation. However, if management of the dislocation requires open reduction, general anesthesia, or anesthetic limb block, then preoperative laboratory studies may facilitate patient care. On occasion, therapeutic drug levels, cardiac studies, coagulation studies, or preoperative microbial studies may be required if the dislocation involves an open joint or concurrent soft tissue contamination.

Edema, tenderness, or deformity at a joint or along the digit should prompt radiographic evaluation. Findings can be subtle; pain out of proportion to radiographic findings should heighten the physician’s suspicion for significant injury.

If radiographs are obtained and no identifiable fracture is visible, yet the patient remains in a significant amount of discomfort, an occult fracture may be present. Proper splinting and urgent referral may be indicated.

A child or adolescent with open growth plates who remains in pain even though radiographs reveal no fracture may have a growth plate injury. Proper splinting and urgent referral may be indicated.

The following views should be taken:

• Anteroposterior

• Lateral (to check the lateral radiograph for joint congruency or rotation)

• Oblique

• Stress views can be examined if ligamentous laxity is documented or suspected. (see image below)

  Radiograph displaying a stress test of a torn ulnar collateral ligament.

• Postreduction images must follow even the most apparently routine reductions

In rare circumstances, computed tomography (CT) or magnetic resonance imaging (MRI) may be necessary to make a definitive diagnosis.[17]

Radiographs of the affected finger help further define the anatomy of the dislocation, rule out associated fractures, and assess the adequacy of reduction. For dorsal dislocations at the proximal interphalangeal (PIP) joint (see the images below), the initial radiographs are often obtained after reduction because the athlete, trainer, or coach commonly reduces the dislocation at the scene. If the finger is still dislocated when the radiographs are obtained, the middle phalanx may be hyperextended and often deviated to the ulnar side.

In a volar dislocation (see the image below), rotation may be noticeable on the lateral view. The head of the proximal phalanx lies in a different plane from that occupied by the base of the middle phalanx.

Common fractures to look for include avulsions and impacted fractures. Avulsions at the volar base of the middle phalanx (or the distal phalanx, in the case of distal interphalangeal [DIP] joint injury) from the volar plate may not affect the treatment plan if they are small. Larger fractures at this location make the injury a fracture-dislocation, which may be unstable in extension (see the image below).

Avulsions at the dorsal base of the middle phalanx (or the distal phalanx, in the case of DIP joint injury) from the extensor tendon should prompt careful testing of extensor function and probably require splinting in extension; splinting in hyperextension should be avoided. Most central slip injuries, however, involve only soft tissue.

Impacted fractures of the joint surface are often best visualized on a true lateral view, allowing direct comparison of the radial and ulnar articular surfaces.

Key considerations in the radiographic assessment of reduction include the following:

• Congruence of the articular surfaces

• Absence of rotational deformity

• Fractures around the metacarpophalangeal (MCP) and carpometacarpal (CMC) joints

With respect to articular congruence, the head of the more proximal phalanx should form a U shape that fits symmetrically within the U shape of the base of the more distal phalanx. If the joint space is not equal throughout on both views, the examiner should be highly suspicious for persistent subluxation secondary to entrapment of soft-tissue structures within the joint.

A volar PIP dislocation in which the head of the proximal phalanx buttonholes between the central slip and the lateral band has a rotational component. This can be observed on the lateral view, where the radial and ulnar aspects of each joint surface would be superimposed.

To rule out fractures around the MCP and CMC joints, anteroposterior, lateral, and oblique views of the entire hand are indicated (see the images below). In the dorsal dislocation patterns, the oblique or lateral view reveals the dorsal prominence of the affected joint. Common fractures to look for include avulsion-type fractures of the metacarpal bases, associated with the CMC dislocation.

The Breuerton view of the MCP joints may be useful. This view is taken with the fingers flat on the plate, the metacarpals at 65° of inclination to the fingers, and the tube at 15° from the ulnar side of the hand. The Breuerton view demonstrates the MCP bony surface.

Modified lateral views of the metacarpals are sometimes necessary because little of the shaft or head can be observed on a true lateral radiograph of the hand. To study the index and middle finger, the hand should be pronated 30° from the lateral. To study the ring and small fingers, the hand should be supinated 30° from the lateral.

Many hand dislocations can be effectively treated with closed reduction, traction, or both. Some of these injuries become subluxated in extension and require extension block splinting. Grossly unstable joints and those for which closed reduction has failed typically require surgical intervention. Most patients needing surgery for hand dislocation injuries are best served by treatment in the acute phase. Steroid injection may rarely be indicated for a chronically swollen, painful joint in those with a hand dislocation.

Active range-of-motion (AROM) and passive range-of-motion (PROM) exercises are key components of treatment throughout. Ensure early follow-up for reexamination and repeat radiography in questionable cases. Any long-term complications (usually involving stiffness or instability) that develop must be addressed.

Dislocations of the distal interphalangeal (DIP) joint are almost always reducible with longitudinal traction and gentle manipulation in the direction opposite to the deformity. Irreducible dislocations may occur if soft-tissue entrapment develops in the joint or if the patient presents more than a few days out from the injury.[11]

Closed reduction is almost always successful for dorsal proximal interphalangeal (PIP) joint dislocations. Volar dislocations are more problematic, especially if the deformity has a rotational component. For all closed reduction maneuvers, be gentle and limit the number of attempts to 2-3. Irreducible dislocations are usually caused by soft-tissue structures (eg, volar plate, collateral ligament, tendons) trapped in the joint, in which case the patient may need to be referred to a hand surgeon for open reduction (see below).

Most dorsal dislocations of the PIP joint can be easily reduced by placing gentle traction on the finger with the wrist and the metacarpophalangeal (MCP) joints flexed, then pressing the base of the middle phalanx in a volar direction while holding the proximal phalanx steady. In a sports setting, the athlete, coach, or trainer usually accomplishes this maneuver. If the reduction is performed immediately after the injury, it can usually be accomplished without anesthesia. If the reduction is delayed, a digital block with 1% lidocaine (without epinephrine) is helpful.

To perform a digital block, first cleanse the skin with povidone-iodine solution. Insert a 25-gauge needle near the base of the finger and through its dorsolateral aspect just lateral to the periosteum of the base of the proximal digit. Advance the needle posteriorly so that it slides just past the base of the phalanx. As the needle is advanced, inject 1 mL of anesthetic while observing for protrusion of the palmar dermis directly opposite the needle path. Another 1 mL of solution is injected as the needle is withdrawn.

This technique should block both the dorsal and volar digital nerve branches. For complete anesthesia of the finger, it is performed both on the medial side and on the lateral side (see the image below). It is important not to use lidocaine with epinephrine. The digital arteries are end arteries that can spasm and cause ischemia of the fingertip and, potentially, necrosis. To avoid the mechanical pressure generated by injecting solution into a potentially confined space, volumes of 2-4 mL should not be exceeded.

Volar PIP dislocations without a rotational component are usually reducible with gentle traction. Place the wrist in the neutral position, and press dorsally on the base of the middle phalanx and volarly on the proximal phalanx. Although these injuries are usually treatable with closed reduction, they commonly involve an avulsion of the central slip of the extensor tendon.

Volar PIP dislocations with a rotational component are often difficult to reduce by closed means, because the head of the proximal phalanx becomes trapped between the central slip and one of the lateral bands of the extensor mechanism. Sometimes, these injuries can be reduced by placing the MCP and PIP joints in 90° of flexion with the wrist extended, applying traction, and rotating the middle phalanx in the direction opposite to the deformity.

MCP dislocations most commonly occur dorsally (simple type). Closed reduction is the treatment of choice and usually is readily accomplished with gentle traction and flexion of the proximal phalanx. A local digital nerve block may facilitate the process.

If closed reduction is not accomplished after several attempts and displacement or subluxation persists, open reduction is indicated. At the time of operation, the capsule has usually impinged between the 2 bones, preventing reduction. In children, the displacement of the proximal phalanx may be more to the ulnar than the dorsal side, and a shearing type of osteocartilaginous fragment often prevents complete reduction.

In early or acute dislocations of the metacarpals, the carpus closed reduction should be attempted and is usually successful. These dislocations occur dorsally, and reduction can be obtained by placing gentle traction on the finger of the associated metacarpal while pressing dorsally on the carpometacarpal (CMC) joint dislocation through the range from flexion to extension.

The closed reduction can be facilitated with local anesthetic hematoma or intra-articular block at the affected area. After the reduction is accomplished, the wrist and CMC joint should be flexed acutely to determine stability. If closed reduction is successful but the reduction is unstable, continued reduction can be attempted with a dorsiflexion cobra-type cast or percutaneous Kirschner wire (K-wire) fixation.[18]

Although general guidelines have been developed for the treatment of hand injuries, a review of the literature suggests that return-to-play guidelines are dependent on factors such as the severity of the initial injury, age, hand dominance, and the chronicity of injury, which vary with each individual.[19]

Patients with stable DIP dislocations may begin immediate AROM exercises. Unstable dorsal dislocations (which are less common) should be immobilized in 20° of flexion for 2-3 weeks before AROM exercises are begun. Complete collateral ligament injuries should be protected from lateral stress for at least 4 weeks.

Palmar DIP dislocations may involve disruption of the insertion of the terminal extensor tendon as well as collateral ligaments and the palmar plate. Splinting the joint in extension for 8 weeks is required for the extensor tendon to heal.[3, 4, 5, 6, 20, 21, 22, 23, 24]

The duration and position of immobilization of PIP injuries depends on the structures involved and the severity of any disruptions. Dorsal PIP dislocations that are stable after reduction can generally be treated with buddy taping (see the first image below). This limits hyperextension, prevents recurrent dislocation, and allows a combination of AROM and gentle PROM exercises. An alternative is the use of a dorsal aluminum foam splint (see the second image below).

In the case of a significant collateral ligament injury, the finger used as a splint should be on the side of the injured collateral ligament whenever possible. Uncomplicated PIP dislocations are usually immobilized in extension for 7-10 days. More serious injuries may be followed by up to 6 weeks of buddy-taped AROM. The patient should follow up within 2 weeks to confirm proper splinting and the absence of skin problems.

After closed reduction of dorsal PIP dislocations, immobilize the joint with a dorsally placed splint in 10-15° of flexion. Once the patient is comfortable, he or she can begin active flexion while in the splint. After 2 weeks, the splint can be discontinued and the finger buddy-taped for 2 more weeks.

Dorsal PIP dislocations that are unstable in extension (including fracture-dislocations) should be initially treated with extension block splinting at the angle required to keep the joint and the fracture (if present) reduced. This splint is often placed dorsally as an outrigger splint that is anchored in a short-arm cast and taped to the cast to maintain the flexion angle. The proximal phalanx must be immobilized (taped to the splint) to prevent the patient from achieving too much PIP extension by flexing the MCP joint while the middle and distal phalanges are left free.

A study by Waris et al evaluated the outcomes of extension block pinning used to treat unstable dorsal fracture dislocations of the proximal interphalangeal (PIP) joint. The study concluded that the extension block pinning technique is a simple and valuable technique for treating unstable dorsal PIP fracture-dislocation injuries producing satisfactory long-term results.[25, 26]

Volar dislocations with an intact extensor mechanism that are stable after reduction can usually be treated with buddy taping. If open reduction is required without extensive surgical repair, the joint can usually be immobilized for a few days and then buddy-taped.

Volar dislocations accompanied by central slip injury require splinting of the PIP joint in extension (with the DIP joint left free), usually for 4-6 weeks, followed by daytime dynamic and nighttime static extension splinting for 2 weeks. The DIP joint should be actively flexed throughout the entire recovery phase.

All of these injuries should be aggressively treated to minimize swelling. Routine elevation consists of propping the forearm and hand up on a pillow at night, wearing a sling, or consciously holding the arm up during the day. Ice is used as needed, especially during the first few days. Wrapping the finger with Coban tape can also be used to treat edema.

For patients seen early after dorsal MCP dislocations that are stable after reduction, rubber band extension block splinting (about 20°) for 2-3 weeks should be tried to prevent recurrence through hyperextension. Collateral ligament injuries should be immobilized in incomplete flexion (50°) for 3 weeks, followed by AROM with the digit buddy-taped to protect against lateral deviation stress. Additional physical therapy should be completed with modalities to prevent hand edema and maintain mobilization of all of the joints of the hand.

In CMC dislocations, the hand and wrist are frequently placed in an extension-type splint or cobra-type (extension) cast. Initial therapy should be directed at elevating the hand, decreasing the swelling, and mobilizing all of the stable joints of the hand.

With almost all of these injuries, early AROM exercises should be encouraged. This is relatively easy with injuries that have been treated with buddy taping or extension block splinting. In general, PROM exercises have a very limited role in the early stages of treatment. The exception involves volar dislocations associated with central slip injuries, which call for aggressive AROM and PROM exercises of the DIP joint with the PIP joint in full extension; this helps to minimize both stiffness at the DIP joint and adhesions between the 2 flexor tendons.

In the early stages of MCP and CMC dislocations, the role of occupational therapy is usually limited. However, aggressive mobilization of the fingers of the hand and the wrist joint should be carried out after the dislocation is stable and as early in the course of treatment as possible.

Surgery is indicated for any open dislocation (irrigation and debridement) and any dislocation that is not reducible by closed means (open reduction).

When reduction by closed methods is unsuccessful, open reduction with removal of the soft tissue in the intra-articular space should be accomplished through a dorsal incision, and the metacarpal base articular surfaces should be fixed in appropriate positions with K-wires after being levered into the normal relationship with the carpus.

In situations where management is delayed and the metacarpal bases cannot be reduced, repositioning of the metacarpal bases is best accomplished by bony resection of the bases that overlap the carpus and pushing the bases into the normal relationship with the carpus.

Any joint that is grossly unstable or that cannot maintain reduction with buddy taping or extension block splinting may require repair of supporting structures (eg, the volar plate or collateral ligaments) to maintain the reduction. Volar dislocations accompanied by complete loss of extension at the PIP joint may require open reattachment of the central slip.

DIP injuries are considered chronic after 3 weeks. Chronically subluxated joints may have to be opened so that scar tissue can be resected to allow tension-free reduction.

Complex fracture-dislocations may require surgery for some combination of open reduction, internal fixation, and repair of supporting structures. External fixation (compass hinge) has been used on some complex PIP fracture-dislocations to provide distraction across the joint, maintain reduction, and allow controlled range of motion (ROM).

A number of procedures are possible to treat instability, stiffness, and fracture nonunions in and around the interphalangeal joints. Severe DIP problems may be treated with arthrodesis, depending on the demands placed on the hand. However, this is not a good option for the PIP joint. Any procedure on the PIP joint is likely to result in some loss of ROM. Therefore, compliance with occupational therapy is critical.

In the recovery phase, stable hand injuries should continue to be treated with gentle AROM exercises and should not require extensive formal occupational therapy unless complications develop. Boutonniere injuries should be treated by early occupational therapy to ensure that ROM exercises are done properly and often, as well as for splint fabrication and more aggressive ROM when full-time immobilization is discontinued.

Occupational therapy is also important in most postoperative patients, in patients with fracture-dislocations, and in any patient whose injury begins to develop significant stiffness at any point in the course of recovery.

Several complications can arise during the recovery phase. At the first follow-up, the examiner should specifically look for recurrent instability or subluxation in the joint. Early boutonniere deformity (ie, hyperextension at the DIP joint with fixed flexion at the PIP joint) is indicative of a central slip injury and often progresses to a disabling deformity without appropriate treatment.

Stiffness can occur in any of these injuries; this can be minimized in most cases by avoidance of excess immobilization and appropriate involvement of occupational therapy and hand surgery at an early stage in high-risk injuries.

In MCP and CMC dislocations, the same problems that are observed in the acute phase can be observed in the recovery phase. However, stiffness becomes a more predominant complication, and it can occur in any of the joints of the fingers, the MCP joints, and the CMC joints. Treatment involves aggressive occupational therapy to prevent joint ankylosis.

The majority of patients with uncomplicated hand dislocations should recover good function and do not require ongoing treatment in the maintenance phase. Most long-term complications of finger dislocations are related to either stiffness or instability. Stiffness, especially in the PIP joint, is initially best treated with intensive occupational therapy, but a hand surgeon should assess all significant contractures. Even if surgery is planned, the patient benefits the most if ROM is maximized by means of dynamic splinting and exercise preoperatively.

Lateral instability is usually due to collateral ligament injury, instability in extension to volar plate injury, or a missed fracture.[27] Most volar plate injuries heal with immobilization that prevents hyperextension (usually buddy taping); consequently, this complication is often preventable. Depending on the demands of the activity that caused the dislocation, the finger and specific structures involved, and the degree of instability, some of these problems may benefit from surgery.

To a limited extent, hand dislocations may be preventable. They are essentially inevitable in contact sports, but taping the fingers in especially high-risk sports (eg, football) may help minimize them. Failure to adequately treat a jammed finger with an isolated partial collateral ligament tear may predispose the athlete to repeat injury and possible dorsolateral dislocation. Finger injuries should be adequately assessed by the team physician or trainer and buddy-taped or splinted as necessary to allow healing and prevent recurrence.

In general, athletes with simple dorsal dislocations of the PIP joint may return to play with buddy taping or splinting as soon as the same game if a stable reduction is achieved; exceptions are players whose position places unusual demands on the finger (eg, quarterbacks or pitchers with an injury to the dominant hand).

Athletes with dorsal fracture-dislocations of the PIP joint and dislocations that are unstable in extension require a minimum of 3-4 weeks (the time during which extension block splinting is required) before return to play. Open reduction or volar plate repair necessitates 6 weeks away from sports.

Patients with volar PIP dislocations are more likely to be kept from rapid return by associated injuries and problems with reduction. Injury to the central slip of the extensor tendon is common with volar dislocations and necessitates splinting the DIP joint in extension for approximately 6 weeks. If this does not interfere with function, the athlete may return to play, although ball handlers may have some difficulty with the splint.

Patients with volar dislocations requiring open reduction may return to play after a few days of immobilization if the central slip is intact. As with dorsal dislocations, if internal fixation or repair of structures around the joint is required, the athlete may be out for 6 weeks. Most DIP dislocations should not require time away from play, except for a few days postoperatively if open reduction or irrigation and debridement is necessary.

Athletes with MCP joint or CMC joint dislocations generally remain out of sports for 6-8 weeks. This time includes a period for extension block splinting or extension cobra casting, as well a period for regaining full functional mobilization of the fingers, hand, and wrist with appropriate return of grip and wrist flexion and extension strength.

A hand surgeon should see any patient with hand dislocations which require or may require surgery. In addition to the surgical indications previously mentioned (including open dislocation and failure of closed reduction), referral to a hand surgeon is usually indicated for fracture-dislocations, most volar dislocations, and any dislocation with associated tendon injury.

A hand surgeon should be involved early in the treatment of any complicated PIP or DIP injury. The need for such consultation would be indicated if the patient presents late after the injury, was inadequately assessed at initial presentation, or develops an unforeseen complication (eg, recurrent subluxation in a joint that appeared to be stable after reduction).

Most patients with chronic instability or stiffness in a finger (especially if it involves the PIP joint) should be referred for assessment by a hand surgeon.

Appropriate expectations regarding the outcome of any hand injury should be discussed with the patient.

All patients with hand dislocations should follow up within 1 week to be checked for some of the more common complications.[28] Dorsal PIP dislocations that initially appear stable may become subluxated with extension, requiring more aggressive treatment. Volar PIP dislocations may also lose reduction, or they may be associated with an occult central slip injury at initial presentation (usually reflected by tenderness over the insertion) that progresses to a complete rupture over the next few days.

Stiffness is a common complication at all stages of treatment, especially with PIP dislocations. The patient should perform gentle AROM exercises of any joint that does not require rigid immobilization. Resolution of stiffness and soreness may take as long as 12-18 months, and permanent residual enlargement of the joint is a possibility.

Collateral ligament injuries (usually radial) commonly accompany finger dislocations and usually respond well to closed treatment, with no significant long-term disability. However, the patient should be made aware that the pain from these injuries may take months (or even as long as a year) to resolve completely and that permanent enlargement of the joint is a common sequela.

Complications associated with MCP and CMC dislocations usually fit into the following 3 categories:

• Skin problems

• Recurrent subluxations or dislocations

• Stiffness or lack of motion of the joints

The patient should be monitored in the week following the dislocation to evaluate whether any posttraumatic skin ulceration, sloughing, or breakdown is present that may have to be treated with wound care or antibiotics. Early on, patients should undergo intermittent repeat radiography to verify that the reduction is maintained.

After appropriate immobilization, patients may show evidence of dislocation or subluxation of the extensor tendon to the radial or ulnar side of the MCP joints occupying a place between the 2 metacarpal heads. This is best treated by surgical intervention and proper repair of the torn extensor expansion with a row of interrupted sutures.

In long-term hand dislocation or recurrences, surgery is suggested to expose the joint dorsally and to perform a capsulectomy on either side of the MCP joint to achieve stable reduction. In some cases of acute MCP joint dislocation, the collateral ligament may rupture where it attaches to the tubercle of the metacarpal.

This collateral ligament rupture may lead to recurrent instability, but it can usually be treated nonoperatively, except when the rupture occurs on the radial side of the MCP joint of the little finger. In this case, the short abductor muscle of the little finger may pull it into ulnar deviation, necessitating operative repair.

Drugs used for injuries involving the hand include various analgesics. Near-immediate pain relief can be provided when the patient receives an injection of a local anesthetic along the path of the digital nerve (digital, web-space, or palmar block). Of course, the digital block must be preceded by a very thorough neurosensory examination and (when indicated) discussion with the hand specialist.

Oral medications should be prescribed for the patient who is being discharged from the emergency department (ED).

Class Summary

Pain control is essential to quality patient care: It ensures patient comfort, promotes pulmonary toilet, and aids physical therapy regimens. Analgesic agents are used for pain relief. Acetaminophen is used in patients with mild pain, especially those with a contraindication to NSAID use; narcotics are used in those with moderate to severe pain. Many analgesics have sedating properties that benefit patients who have sustained injuries.

Acetaminophen (Tylenol, Feverall, Aspirin Free Anacin)

Acetaminophen is the drug of choice for mild pain in patients with documented hypersensitivity to aspirin or NSAIDs, those with upper gastrointestinal (GI) disease, or those who are taking oral anticoagulants.

Codeine and acetaminophen (Tylenol With Codeine)

This drug combination is indicated for the treatment of mild to moderate pain.

Hydrocodone bitartrate and acetaminophen (Vicodin ES, Lorcet Plus, Lortab)

This drug combination is indicated for the relief of moderate to severe pain.

Oxycodone and acetaminophen (Percocet, Endocet, Tylox)

This drug combination is indicated for the relief of moderately severe to severe pain. It is the agent of choice for aspirin-hypersensitive patients. Different strengths are available.

Oxycodone and aspirin (Percodan, Endodan)

This drug combination is indicated for the relief of moderately severe to severe pain.

Class Summary

Patients with painful injuries usually experience significant anxiety. Administration of anxiolytics allows the clinician to achieve the same degree of pain relief with a smaller analgesic dose.

Lorazepam (Ativan)

Lorazepam is a sedative-hypnotic of the benzodiazepine class that has a rapid onset of effect and a relatively long half-life. By increasing the action of gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter, it may depress all levels of the central nervous system (CNS), including the limbic system and reticular formations. Lorazepam is excellent for patients who need to be sedated for longer than 24 hours.

Diazepam (Valium, Diastat)

Diazepam depresses all levels of CNS (eg, limbic and reticular formation), possibly by increasing activity of GABA. It is considered second-line therapy for seizures.

Class Summary

Local anesthetic agents are used for digital block to facilitate reduction or examination of fingers.

Lidocaine (Anestafoam, Xylocaine, Lidoderm, Topicaine)

Lidocaine is an amide local anesthetic used in 1-2% concentration. The 1% preparation contains 10 mg of lidocaine for each 1 mL of solution; the 2% preparation contains 20 mg of lidocaine for each 1 mL of solution. Lidocaine inhibits depolarization of type C sensory neurons by blocking sodium channels. For a digital block, lidocaine must not be used with epinephrine; 1% lidocaine without epinephrine is the drug of choice.

To improve local anesthetic injection, cool the skin with ethyl chloride before injection. Use smaller-gauge needles (eg, 27 gauge or 30 gauge). Make sure the solution is at body temperature. Infiltrate very slowly to minimize the pain. The time from administration to onset of action is 2-5 minutes, and the effect lasts for 1.5-2 hours.

Buffering the solution helps reduce the pain of local lidocaine injection. Sodium bicarbonate can be added to injectable lidocaine vials (1 part bicarbonate to 9 parts lidocaine) to produce buffered lidocaine. The shelf-life of buffered lidocaine is approximately 1 week at room temperature. All vials should be marked "buffered," labeled with the time and date, and signed by the person who created the buffered mixture.