Finger Joint Injuries in Active Patients
Pointers for Acute and Late-Phase Management
Allan W. Bach, MD
THE PHYSICIAN AND SPORTSMEDICINE - VOL 27 - NO. 3 - MARCH 1999
In Brief: Finger joint injuries such as sprains, avulsions, jams, and dislocations can occur with contact and noncontact sports. Recognition and treatment of these injuries is necessary to avoid prolonged or permanent impairment. Many finger joint injuries can be treated conservatively with splinting and occupational therapy. Injuries such as 'mallet finger,' profundus tendon avulsions, large-fragment fracture-dislocations or other injuries with incongruity after reduction, and open extensor-mechanism injuries may require operative treatment. Operative treatment for complete collateral ligament ruptures at the PIP joint, though controversial, is recommended here.
The finger joints are vulnerable to injury in all age-groups and in many athletic activities. Among these activities are contact sports such as football and wrestling, throwing and catching sports such as baseball and basketball, and sports involving high stress to the hand such as gymnastics. Many finger joint injuries are mild and resolve with minimal morbidity, but others require aggressive initial management to ensure an adequate result.
This article discusses the diagnosis and initial management of various acute finger joint injuries that can occur in sports, along with treatment for some residual deformities.
General Management PrinciplesImportant management elements, in sequence, include a history of the mechanism of injury; clear radiographs; and an assessment of deformity, stability, and range of motion. (See also "Serious, Often Subtle Finger Injuries: Avoiding Diagnosis and Treatment Pitfalls," June 192021, page 57.)
History. Whether treating an acute or late-phase finger joint injury, questions should be asked about the nature and magnitude of the trauma. With delayed treatment, the patient should be asked about the initial deformity. Often, an immediate reduction maneuver, usually axial traction, will have been done acutely. With any finger joint injury, it is also important to know whether the digit was injured previously and if the present trauma is a recurrence of this older problem.
Physical exam. On initial physical examination, obvious signs include ecchymosis, swelling, and deformity. Fractures and sprains may be accompanied by a variable amount of swelling, which may not reflect the injury's long-term consequences. An acute deformity such as abnormal angulation of a proximal interphalangeal (PIP) joint secondary to a dislocation is, of course, easily seen.
With joint injuries, the area of maximum tenderness is near the joint rather than at midphalanx. The collateral ligaments as well as the dorsal and palmar (volar) aspects of the joints (figure 1) should be specifically palpated to identify areas of maximum tenderness.
Joint stability and active and passive range of motion should be tested, but because even a minor angular deformity in a digit can represent a significant problem, stability testing should be postponed, if possible, until a radiograph has been obtained. Stability testing is contraindicated if a fracture or dislocation is present.
If x-rays are normal, stability of the collateral ligaments can be assessed by applying gentle medial and lateral stress. Palmar plate stability is assessed by attempting to hyperextend the joint. Comparison with an uninjured finger joint is important since normal PIP and metacarpophalangeal (MCP) joint stability varies greatly between individuals.
The active and passive range-of-motion exam for the MCP joints can be done using a digital nerve block (see "Digital Block Anesthesia," below). The nerve block can also be very helpful for assessing PIP and distal interphalangeal (DIP) joint injuries, particularly in cases of tendon avulsion or rupture.
X-rays. The radiographic exam of the injured digit should include at least a true lateral and an anteroposterior (AP) view of the entire digit, centered over the joint in question. A true lateral view of the joint is very important in assessing congruence of joint surfaces. If a periarticular or intra-articular fracture is suspected, oblique views are helpful because the standard AP and lateral views may not show fracture displacement.
Ruling out a compression fracture of the articular surfaces of the middle phalanx is important with any finger joint injury and can be done with a good-quality x-ray. A dislocation that has been reduced is likely to appear concentric, but with a fracture the joint is deviated, and subtle malalignment of the joint surfaces can be seen. Treatment of these fractures is troublesome, and significant permanent joint stiffness often results. Any malalignment on an x-ray should prompt referral to a hand surgeon.
Treatment. All uninjured joints should be allowed to move actively as soon as possible, and limited movement of the involved joint should start soon after injury. With hyperextension injuries of the PIP joints, for example, range-of-motion exercises can often begin a few days after injury as long as the terminal 10° to 20° of extension is avoided. Extension-block splinting can be used to limit extension. Digital edema-control techniques such as massage and gentle compressive wraps will decrease the time required to regain full range of motion.
An occupational therapist can often facilitate rehabilitation. In general, therapy should not cause swelling, which may indicate that the therapy is too aggressive or another problem exists, such as a missed fracture. Mild swelling may persist for months, but stiffness more than 6 weeks after injury may signal a problem.
Distal Interphalangeal Joint InjuriesMost DIP joint injuries are acute. An exception is the chronic DIP joint discomfort frequently seen in rock climbers (1). (See "Hand Injuries in Rock Climbing: Reaching the Right Treatment," May 1997, page 54.) In rock climbing, heavy loads on the DIP joints can cause chronic synovitis or capsule inflammation. The usual sports-related mechanism is a direct axial blow, frequently by a ball striking the end of the finger.
Dislocations. Dislocations of the DIP joints are uncommon (2) and usually occur with a crushing injury in contact sports such as football or rugby. Axial, angular, and rotational deformities, if present, are obvious both clinically and radiographically. Direct traction on the joint with a digital anesthetic should allow reduction.
After reduction, flexor digitorum profundus and extensor tendon function can be assessed by active flexion and extension. Full active range of motion is not expected because of swelling and pain, but if active flexion is absent after reduction, a profundus or extensor tendon rupture is a strong possibility. Collateral ligament function is checked by applying medial-lateral stress.
Treatment. Because these joints are small and can be quite unstable, splinting is important for about 3 weeks postinjury. A metal and foam splint will work in most cases. After 3 weeks, range-of-motion exercises can begin and a soft splint of athletic tape or adhesive wrap can be used.
Extensor mechanism avulsion. A much more common DIP joint injury than dislocation is extensor mechanism avulsion. This is commonly known as "mallet finger" but is also called "baseball finger" or "drop finger" and occurs when a player strikes the finger on a ball, helmet, or other piece of equipment (3). The last few millimeters of the extensor tendon that inserts into the distal phalanx is very thin and has a tenuous blood supply. This site is vulnerable to injury with forced flexion of the DIP joints. This injury also can occur at the DIP joint of the thumb.
DIP extensor mechanism injuries can occur in four patterns. Type 1 is an extensor avulsion with no bony injury, type 2 is an extensor avulsion with a small fragment of bone, type 3 is an extensor avulsion incorporating a large part of the articular surface of the distal phalanx, and type 4 is a bony avulsion without concentric reduction of the DIP joint. With type 4 injuries, which are uncommon, the palmar portion of the articular surface usually migrates toward the palmar surface of the finger (figure 2).
Treatment. Operative repair is required for type 4 extensor tendon injuries. For the other types, acute operative repair has no advantage over splinting except for an open injury with laceration of the extensor mechanism (4-6).
Splinting of the DIP joint should generally be done with the joint in slight hyperextension (no more than 10°), but the neutral position is acceptable if slight hyperextension is painful or causes skin blanching. Splinting in a flexed position will not lead to an acceptable outcome. The adjacent PIP joint should not be immobilized because increased swelling and stiffness of the finger is observed when this is done. Many types of commercial splints such as Stack splints are made to control the position of the DIP joint.
The skin of the dorsal aspect of the finger needs to be cared for since it is vulnerable to direct pressure and hypovascularity from the splint. The patient should check the skin daily by removing the splint, but while this is done the joint must be maintained in extension. Dorsal splinting of the DIP joint with a metal and foam splint may put too much pressure on the skin just proximal to the DIP joint, so it must be done carefully. The splint should not cause pain.
Splinting is often required for 6 to 8 weeks to allow solid healing of the extensor mechanism (7). After 4 weeks of splinting, the DIP joint should be able to stay extended without support, but discontinuing splinting at this time is a mistake because the extensor lag will often redevelop. After splint removal, circular taping about the joint can prevent reinjury.
Flexor digitorum profundus avulsion. Flexor digitorum profundus avulsion at the DIP joint, which has been discussed by Leddy and Packer (8), involves forced extension of the DIP joint while the patient is grasping. This is often referred to as "jersey finger" in football, because it can occur when a player catches a finger on another player's jersey. The physical finding with this injury is the patient's inability to fully flex the DIP joint.
With the most common type of profundus avulsion, the profundus attachment to the distal phalanx retracts to the PIP joint. A lateral x-ray of the finger may reveal a very small fragment of bone with tendon from the distal phalanx visible just palmar to the middle phalanx. The patient's ability to slightly flex the DIP joint does not rule out avulsion of the tendon, because the vinculum and synovial layers around the tendon usually remain attached to the palmar plate of the DIP joint, and thus some flexion force can be transferred to the distal phalanx without the tendon itself having a bony attachment.
A less common DIP joint avulsion occurs when the profundus tendon is avulsed into the palm and no longer has a vincular attachment. In this situation, the blood supply to the tendon is compromised.
Treatment. Because direct repair of these injuries after 10 to 14 days may be impossible (8), it is recommended that all DIP joint profundus tendon avulsions be treated within 2 weeks by operative repair.
Proximal Interphalangeal Joint InjuriesInjuries to the PIP joint in athletics are often lumped together as "coach's finger," so named because the injury is often evaluated at the sideline by a coach who assures the player that the injury is not serious (3). However, some PIP joint injuries can require operative treatment. These injuries involve numerous mechanisms, and an exact diagnosis is important in order to direct treatment.
PIP joint injuries include dorsal dislocations of the joint with or without fractures, collateral ligament ruptures or sprains, and extensor mechanism injuries including boutonniere deformity. Another PIP joint injury is "jammed finger," a diagnosis of exclusion.
Simple dorsal dislocations. Dislocation of the PIP joint usually occurs with a forced hyperextension of the finger; the middle phalanx usually is displaced dorsally in relation to the proximal phalanx. Dorsal PIP joint dislocation is the most common dislocation in the hand and is very common in football and basketball (9). PIP joint dislocation also may involve a radial or ulnar deviation of the finger.
PIP joint dislocations often can be reduced on the field with simple traction on the digit. If this is done before the onset of swelling, reduction is easy. When reduction is delayed, a digital block is usually necessary to achieve it without causing undue pain. (See also the Clinical Techniques article: "On-Site Treatment of PIP Joint Dislocations," August 192021, page 85.)
After reduction, no lateral deviation of the finger should be present at the PIP joint, and the lateral x-ray should show concentric reduction of the middle phalanx on the proximal phalanx. In a true PIP joint dislocation, the palmar plate is avulsed, and a small avulsion fragment will often be seen on a lateral x-ray (figure 3a). This contrasts with the appearance of a fracture-dislocation described by Wilson and Rowland (10), which involves a larger fragment and incongruity after reduction and requires operative treatment (figure 3b).
Following reduction of the joint and radiographic assessment, its functional stability should be tested by stressing the collateral ligaments in full extension and in 30° of flexion. Active range of motion reflects tendon function and joint congruity but does not necessarily demonstrate joint stability.
Treatment. For treatment of stable dorsal dislocations, most authors recommend splinting the joint for 2 to 3 weeks in 20° to 30° of flexion (1). Use of an extension block splint will allow some joint mobility without risking hyperextension. Range-of-motion activities with "buddy taping" of the injured finger should then be started (1). If the patient cannot achieve full, active extension of the PIP joint following reduction, a boutonniere deformity (discussed later) is suspected, and splinting of the PIP joint in extension for at least 6 weeks may be necessary. This is seen frequently with palmar PIP joint dislocations.
Collateral ligament injuries. Collateral ligament sprains and avulsions at the PIP joint may occur with dislocations or may be isolated findings. Complete collateral ligament injuries are those in which stressing the collateral ligaments medially or laterally produces more than 20° of deviation.
Treatment. Incomplete collateral ligament injuries are generally treated by splinting of the PIP joint in full extension. If the palmar plate is injured, as with PIP joint dislocation, the joint should be splinted in 30° of flexion. The splint should be worn constantly for 10 to 14 days, after which buddy taping can be used and range-of-motion exercises can be started.
Whether complete collateral ligament injuries at the PIP joint should be treated operatively or nonoperatively is debatable (11). Many authors recommend surgical repair, and it is my opinion that these injuries should be treated operatively. If the collateral ligament has been completely avulsed from the bone, nonoperative treatment may leave the patient with some joint instability and chronic swelling where scar tissue has interposed between the ligament and bone. Operative repair can improve this, but 3 or more months may pass before full range of motion is restored after surgical repair.
The most important PIP joint finding, and one that should prompt aggressive treatment, is complete collateral ligament instability on the radial side of the index finger (figure 4). This ligament is subject to high loads with pinching, and instability at this site can be painful.
Residual angular radial or ulnar deformity following a collateral ligament injury or dislocation is cause for concern. Lack of concentric reduction on an AP x-ray may be secondary to entrapment of a portion of the capsule between the articular surfaces of the proximal and middle phalanges. Inability to obtain concentric reduction in an acute injury usually indicates operative treatment.
Extensor mechanism injuries. Injury to the extensor mechanism, often resulting in a boutonniere deformity (in which the PIP joint cannot be completely extended and the DIP joint remains hyperextended, figure 5), can occur with jamming or sudden forced flexion of the PIP joint.
Rarely, this injury can also include palmar dislocation of the PIP joint, in which the extensor mechanism attachment to the middle phalanx is ruptured.
Initial management of an extensor mechanism injury includes determination of the degree of injury. A digital block is often helpful. With the patient's finger anesthetized, full active extension of the PIP joint should be attempted. Limited active extension indicates that the fibers of the extensor tendon mechanism that attach to the proximal dorsal aspect of the middle phalanx (the central slip) have been partially or completely detached. Another clue that the central slip is injured is acute local tenderness over the dorsum of the PIP joint. In some complete avulsions, the defect in the tendon can be palpated.
Treatment. Open injuries to the extensor mechanism should be treated operatively. Closed injuries can often be treated by nonoperative means if the extensor injury is an isolated finding (12). If other injuries accompany the extensor injury (fractures, ligament avulsions), treatment is often operative.
Splinting for up to 12 weeks may be necessary, and rehabilitation is complicated; experience in how best to progress to minimize swelling is very important for a good result. The PIP joint is splinted in full extension, while the DIP joint is allowed to flex actively. A 6-week period of intermittent splinting is usually started after 6 weeks of continuous splinting. Operative treatment for these injuries does not decrease the time necessary for splinting.
Jammed finger. "Jammed finger" is PIP joint swelling of more than 6 to 8 weeks' duration. Diagnostic criteria include lack of radiographic changes, complete functional stability of the joint, and no joint stiffness or evidence of extensor tendon avulsion. The pathology is uncertain; symptoms may be secondary to cartilage bruising and chondromalacia or chronic synovitis of the joint.
Treatment. The usual treatment for jammed finger involves therapeutic heat, passive and active range-of-motion exercises, and edema-control techniques. Occasionally, corticosteroid injection to the joint is necessary to calm down the synovitis.
Metacarpophalangeal Joint InjuriesDislocations. Dorsal dislocations of the MCP joint, in which the proximal phalanx moves dorsally relative to the metacarpal, can be simple or complex, and the mechanism is hyperextension of the MCP joint. In a complex dislocation the metacarpal head is buttonholed between the palmar fascia and lumbrical and flexor tendons, making closed reduction impossible (13).
Treatment. If the dislocation is treated immediately, the reduction technique involves hyperextension of the MCP joint to re-create the deformity and then gradual reduction by flexing the MCP joint while pressing the joint surfaces together. Traction on the MCP joint during attempted reduction will only serve to entrap the ruptured palmar plate between the joint surfaces and make closed reduction impossible. If a closed reduction fails, immediate open reduction is recommended.
After a successful closed reduction, splinting with the joint in 60° of flexion for 3 weeks is recommended. The patient then should gradually begin range-of-motion activity while avoiding hyperextension of the MCP joint.
Collateral ligament injuries. The collateral ligaments of the MCP joint are taut across the cam-shaped metacarpal head when the MCP joint is in flexion. They are, for the most part, lax across the concave sides of the head when the joint is extended. The palmar plate of the MCP joint is loosely attached to the neck of the metacarpal bone, has a strong, thick attachment to the base of the proximal phalanx, and is largely fibrocartilaginous in this area. When the MCP joints are in full extension, active adduction and abduction at these joints is possible, but when the joints are flexed, the collateral ligament tension prevents this.
Sprains or avulsions of the collateral ligaments can therefore occur when the fingers are forced into adduction or abduction while the MCP joints are flexed. This can occur in contact sports such as basketball when an opponent grabs an unprotected finger. Avulsions can be either from the distal metacarpal bone or from the palmar side of the proximal phalanx.
Hyperextension of the MCP joint without adduction or abduction, which can cause a palmar plate injury and dorsal dislocation of the joint, usually does not involve a collateral ligament rupture (14).
The diagnosis of collateral ligament injury to the MCP joint is made by assessing stability. This is done by passive radial and ulnar deviation with the MCP joint in flexion. Pain or instability of the collateral ligament as compared with the opposite, intact side indicates injury. Injuries to the intrinsic tendons in this area can sometimes occur simultaneously. The intrinsic stretch test (figure 6) can identify injury to the intrinsic tendons. Most commonly, ligament injury occurs without any radiographic changes.
Treatment. Collateral ligament injuries can be treated by splinting of the MCP joint in slight flexion for 3 weeks followed by gradual institution of range-of-motion activities. Prolonged instability is not common, but buddy taping may be necessary for 2 to 3 months to avoid reinjury. When a collateral ligament injury involves avulsion with displacement of more than 2 mm either from the proximal phalanx or the metacarpal head, operative repair should be considered. The presence of an intrinsic muscle injury may prolong rehab and require a post-injury stretching program.
Pinpoint Injuries EarlyInjuries to finger joints are common in athletics and can, for the most part, be treated by nonoperative means. Careful assessment of joint stability and adequate radiographic views help immensely in avoiding long-term morbidity.
Digital Block Anesthesia
A successful digital block is very helpful in evaluating finger injuries because it permits assessment of active and passive range of motion without causing pain. The block should be done at the metacarpophalangeal joint level.
A combination of 1% lidocaine hydrochloride and 0.5% bupivacaine hydrochloride without epinephrine will have a rapid onset and long duration. Use a 25- or 27-gauge needle and penetrate the dorsal web space on each side of the metacarpal head (figure A). About 5 mL of fluid is used on each side in an adult to infiltrate around the digital nerve and complete a dorsal ring block.
This article was solicited by Warren B. Howe, MD, Emergencies Series editor.
Dr Bach is a hand surgeon at the Colorado Springs Orthopedic Group in Colorado Springs. Address correspondence to Allan W. Bach, MD, 629 N Nevada Ave, Colorado Springs, CO 80906.