Jammed Finger

United States statistics

Finger and hand injuries account for 12% of all injuries in American football players.[2]

International statistics

Finger injuries are common (38%) in individuals younger than 5 years. Most of these occur at home (59%), commonly (48%) because of jamming between 2 closeable opposing surfaces and mostly (79%) in doors at home and at school.[3]

A study by Gill et al of Australian football players who presented to the emergency department with a finger, hand, or wrist injury found that ball contact was the most common mechanism of injury (38% of injuries).[4]

The PIP joint is a hinge joint that permits a range of motion (ROM) from 0-120°[5, 6, 7] (see image below). Relatively thick collateral ligaments provide lateral stability. Unlike the metacarpophalangeal (MCP) joint, the tension of these ligaments does not vary during ROM.

The volar plate forms the floor of the joint and separates the joint space from the flexor tendons. The volar plate is ligamentous at its origin on the proximal phalanx and cartilaginous in its insertion onto the middle phalanx.

Dorsally, the central slip of the extensor tendon acts to stabilize the joint and to extend the middle phalanx. The lateral bands, joined by the retinacular ligaments of the intrinsic hand muscles, go around the joint to form the distal extensor tendon and also contribute to joint stability.

The common mechanism of injury at the PIP joint involves the simultaneous application of hyperextension forces with some degree of longitudinal compression.

Volar plate disruption (see image below)

Mild forces may rupture the volar plate at its distal insertion on the middle phalanx; the articular surfaces remain intact. This is a stable injury. Local pain and edema generally produce only short-term disability.

Occasionally, fractures of the middle phalanx at the attachment of the volar plate occur. These fractures usually involve less than 30-40% of the joint surface and are thought to be stable due to maintenance of collateral ligament integrity. (See also the Medscape Reference article Phalangeal Fracture Surgery.)

Dorsal dislocation (see image below)

If the force of injury is great enough, rupture of the volar plate may occur along with longitudinal splitting in the collateral ligament structures, allowing complete dorsal displacement of the middle phalanx. Simple dislocations are readily reduced, often by the player, coach, or trainer on the field. Following reduction, most dorsal dislocations are stable.

Fractures at the base of the middle phalanx also occur in association with dorsal dislocations. If a fracture involves more than 40-50% of the articular surface, collateral ligament support is lost. Combined with the coexistent volar plate disruption, this reduction of collateral ligament support represents a major loss of joint stability. These injuries are often unstable, exhibiting persistent subluxation of the middle phalanx.

Collateral ligament injury

Angular forces may cause partial or complete rupture of a collateral ligament. When combined with volar plate rupture, lateral dislocation can occur. Most lateral dislocations are easily reduced and do not demonstrate gross instability.

Because of scar-tissue formation in the healing ligament, these injuries often result in enlargement of the PIP joint ("fat knuckle"). This may be of cosmetic concern to some patients, but good functional recovery can usually be expected.

Boutonniere deformity (see image below)

The term "boutonniere" comes from the French word for "buttonhole." This injury involves a disruption of the central slip of the extensor tendon at its insertion on the middle phalanx. The mechanism of injury is a blow to the dorsum of the PIP joint, such as when an athlete's hand is stepped on. Occasionally, a small fleck fracture of the middle phalanx is seen at the central slip insertion. Volar dislocation of the PIP joint is thought to be a component in many cases.

Little deformity may be noted immediately after an injury that results in a boutonniere deformity. The lateral bands may still act weakly to aid joint extension. Left untreated, the central slip retracts and the lateral bands displace volarly below the axis of rotation, becoming flexors of the PIP joint. Thus, the classic deformity of PIP joint flexion and distal interphalangeal (DIP) joint hyperextension is produced. Once a deformity becomes chronic or fixed, it presents a difficult surgical challenge, with potentially permanent functional deficits.

Because volar dislocations may be reduced spontaneously or before the office visit and because the symptoms and signs of such injuries may be subtle, practitioners must maintain a high index of suspicion for central slip disruption when evaluating any PIP joint injury. Patients may have more pain dorsally, and there is usually weakness or the inability to fully extend the PIP joint.

The prognosis for a jammed finger is excellent with the proper treatment and protection.

A study by Cheesman et al found that 63% of patients with a PIP joint sprain had complete resolution of swelling within 1 year.[8]

Complications

Possible complications that follow a PIP joint injury include the following[9] :

• Persistent pain and swelling
• Stiffness
• Weakness
• Instability
• Boutonniere deformity

The athlete typically sustains an axial loading blow to the finger that is combined with hyperextension.

Dorsal trauma produces a volar dislocation force with a concurrent central slip injury.

Radial- or ulnar-directed forces could produce a collateral ligament injury/lateral dislocation.

Inquire about potential dislocations that were reduced on the field. Careful attention to the mechanism of injury may help pinpoint the diagnosis.

Consider obtaining radiographs before physical examination of the affected finger to evaluate for potentially unstable fractures/dislocations.

Document the integrity of the neurovascular status of the affected finger as well as that of the entire hand.

Observe and palpate the affected finger, with attention to focal areas of tenderness and edema.

Assess tendon function and ROM of the affected finger, with particular attention to active extension. Loss of active extension indicates a central slip injury.

Assess the joint stability of the affected finger.

If pain of the affected finger precludes a definitive diagnosis, consider using metacarpal block anesthesia to examine the digit's tendon function and stability.[10]

Laboratory studies

Laboratory studies are not indicated for the diagnosis of PIP joint injuries.

Imaging studies

Obtain anteroposterior, lateral, and oblique radiographs of the injured digit. Radiographic interpretation includes assessing the PIP joint for dislocation, subluxation, and fractures.

Rehabilitation Program

Physical Therapy

• Volar plate sprain: Treatment of a mild finger hyperextension injury usually requires only 1-2 weeks of protective buddy taping to an adjacent finger in addition to the institution of early ROM exercises.[11] Taping should continue during athletic or at-risk activities until full pain-free ROM is obtained. Volar plate disruptions that involve fractures of the middle phalanx should be treated as dislocations.

• Dorsal dislocation: Simple dorsal PIP dislocations, including those with small middle phalanx fractures, are generally stable following reduction. The usual treatment is dorsal splinting with the joint in 10-30° of flexion for 2 weeks. Such an extension block splinting limits further injury to the volar plate (see image below). The stabilizing tape on the middle phalanx can be removed to allow the finger to flex but not for it to fully extend. Place 2 stabilizing tapes on the proximal phalanx to hold the splint in place. Aluminum foam splints are commonly used, and some commercial devices are available; Coban wrapping (3M Health Care, St Paul, Minn) can be used to control swelling. Following the initial treatment period, begin ROM exercises. Continue protective splinting or buddy taping for 4-6 weeks during athletic or at-risk activities.

  Extension block splint with the proximal interphalangeal joint at 30°.

• Collateral ligament injury: Partial collateral ligament tears may be treated with buddy taping and early ROM exercises. Lateral dislocations are also typically treated with dorsal splinting in slight flexion for 2 weeks. Additionally, buddy taping to the digit that is ipsilateral to the injured ligament is recommended to help control joint stability. Initiate ROM exercises after 2 weeks. Continue protective buddy taping of the digit for sports activities until pain-free function returns.

• Boutonniere deformity: Treatment of an acute central slip injury consists of splinting the PIP joint in full extension for 6 weeks (see image below); DIP joint ROM exercises are encouraged. Typically, an aluminum foam splint is placed over the dorsum of the joint. Some commercial splints are available, including dynamic spring devices (see image below). After 6 weeks, ROM exercises are initiated. The use of a static splint at night or a dynamic ROM splint device for an additional 2 weeks is often recommended. The use of protective splinting in extension is advised during sports or at-risk activities for 4-6 weeks or until full pain-free function is restored.

  Proximal interphalangeal joint that has been splinted in extension for the treatment of a central slip injury.

  Dynamic spring extension splint for the treatment of a boutonniere finger deformity.

Surgical Intervention

Any dislocation that cannot be easily reduced by the usual means may indicate the interposition of soft-tissue structures. This should prompt consultation with an orthopedic surgeon for open reduction.[12, 13, 14, 15]

Fracture-dislocations that are unstable, exhibit persistent subluxation of the middle phalanx, or involve large portions of the articular surface should be referred for surgical fixation.[14, 16, 17]

Grossly unstable collateral ligament injuries may be considered for surgical repair.

Surgical reconstruction is the treatment of choice for chronic boutonniere deformity.[7, 18, 19]

The time frame for an athlete's return to play is dependent on the severity of the finger injury. An athlete with a mild PIP joint sprain without ligamentous disruption may be permitted to return to play after being evaluated on the sideline, provided the finger is properly buddy-taped. Those individuals with more severe sprains or dislocations/fractures may be recommended to remain out of competition for a longer period (2-6 wk). Protective splinting or buddy taping is advised during athletic or at-risk activities until full pain-free function is restored.

Prevention

Most cases of jammed finger injuries are not preventable in sports activities.

Nonsteroidal anti-inflammatory drugs (NSAIDs) and analgesics are generally used to treat the pain that is associated with a PIP joint injury.

Class Summary

NSAIDs have analgesic, anti-inflammatory, and antipyretic activities. The mechanism of action of these agents is not known, but NSAIDs may inhibit cyclooxygenase activity and prostaglandin synthesis. Other mechanisms may exist as well, such as inhibition of leukotriene synthesis, lysosomal enzyme release, lipoxygenase activity, neutrophil aggregation, and various cell membrane functions.

Ibuprofen (Motrin, Ibuprin)

DOC for patients with mild to moderate pain. Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis

Ketoprofen (Oruvail, Orudis, Actron)

For the relief of mild to moderate pain and inflammation.

Small dosages are initially indicated in small and elderly patients and in those with renal or liver disease. Doses over 75 mg do not increase therapeutic effects.

Administer high doses with caution and closely observe the patient for response.

Naproxen (Naprelan, Anaprox, Naprosyn, Aleve)

For the relief of mild to moderate pain; inhibits inflammatory reactions and pain by decreasing the activity of cyclooxygenase, which results in a decrease of prostaglandin synthesis

Class Summary

Pain control is essential to quality patient care. Analgesics ensure patient comfort, promote pulmonary toilet, and have sedating properties, which are beneficial for patients who have sustained trauma or who have sustained injuries.

Acetaminophen and codeine (Tylenol #3)

For the relief of mild to moderate pain; inhibits inflammatory reactions and pain by decreasing the activity of cyclooxygenase, which results in a decrease of prostaglandin synthesis

Hydrocodone bitartrate and acetaminophen (Vicodin ES, Lortab, Lorcet-HD)

Drug combination that is indicated for moderate to severe pain

Propoxyphene and acetaminophen (Darvocet-N 100, Wygesic)

Drug combination that is indicated for mild to moderate pain