Thumb Fractures and Dislocations Treatment & Management

Surgical treatment varies by location.

Thumb Phalangeal Fractures

Fractures of the thumb phalanges have no distinct difference in treatment from fractures of phalanges of digits 2-5.

Distal Phalanx Fractures

Tuft fractures

Tuft fractures rarely require reduction or fixation. Consider association with nail bed injuries as open injuries and undertake nail bed repair with fine absorbable suture. Evacuate painful subungual hematomas prior to nail bed repair. Splint the fracture for up to 4 weeks and then institute early motion.

Shaft fractures

Transverse fractures of the distal phalanx may be unstable secondary to pull of the FPL on the proximal fragment. An apex anterior fracture results secondary to the FPL pull. Unstable fractures may require percutaneous pinning longitudinally across the fracture and into the proximal phalangeal head. Displaced longitudinal fractures of the distal phalanx may be treated with reduction with bone holding forceps and then percutaneously pinned perpendicular to the fracture line.

Proximal Phalanx Fractures

Splint nondisplaced fractures of the proximal phalanx for up to 4 weeks, followed by early motion. Incongruous intra-articular fractures require reduction and fixation.

More than 20-30° of angulation in the lateral plane produces an IP joint extensor lag; thus, undertake reduction in these patients. Less than 20° of angulation in the lateral plane is acceptable. Transverse fractures usually are stable with closed reduction.

Displaced fractures of the proximal phalanx may require operative intervention. Displaced spiral or oblique fractures may be treated either with interfragmentary screws (ORIF) or percutaneous pinning with Kirschner wires. Another option is intramedullary Kirschner wires inserted retrograde through the distal aspect of the thumb across the thumb IP joint.

Mallet Thumb

Treatment for mallet thumb is usually nonoperative. Follow full-time splinting in extension for 6 weeks (splint must be on at all times) by night splinting in extension for an additional 6-8 weeks. Repair open injuries, injuries that do not heal with splinting, and chronic symptomatic injuries operatively.

Operative treatment favors direct repair when possible because the terminal extensor tendon of the thumb is thicker and wider than the terminal extensor tendon of digits 2-5. Dorsal extensor avulsion requires fixation of the avulsed bony fragment.

In a study comparing a case series with a literature review of patients who underwent either surgery or conservative treatment for closed mallet thumb injury, Abe et al suggested that patients who undergo surgery may recover more quickly. The investigators found that clinical results between surgically and conservatively managed patients did not significantly differ, with the exception of immobilization time, which was 4.9 weeks for patients who had surgery versus 9.5 weeks for those treated conservatively. ^[24]

Thumb IP Dislocations

Thumb IP dislocations generally are reduced easily in a closed fashion. Apply an axial traction force on the distal phalanx with the thumb MCP joint and wrist flexed to decrease the tension of the opposing intrinsics and FPL. Following the closed reduction, assess the stability of the IP joint. If the IP joint is stable then immobilize the thumb in 20° of flexion. Review postreduction radiographs to ensure adequate reduction of the IP joint. Irreducible dislocations may be secondary to palmar plate interposition and are best approached with a palmar or mid-axial incision. Expose the IP joint and remove the interposed soft tissue from the joint.

Dorsal MCP Dislocation

Attempt closed reduction in patients with thumb MCP dislocations regardless of the presence of radiographic or clinical signs of irreducible dislocation. Perform closed reduction by hyperextending the MCP joint to approximately 90° (thus exaggerating the deformity). Apply manual pressure to push the proximal phalanx over the metacarpal head. Alternatively, apply longitudinal traction by pulling on the proximal phalanx with the thumb and wrist in flexion to decrease tension of the FPL and intrinsics. ^[25]

If the reduction is successful, test the stability of the collateral ligaments of the thumb MCP joint. If stable, immobilize the joint in 20° of flexion in a thumb spica cast. Initiate movement within 10-14 days.

If reduction is not successful, perform an open reduction with removal of interposed soft tissue from the joint. Avoid a palmar approach if at all possible secondary to tenting of the digital nerves palmarly with dorsal dislocation.

Palmar MCP Dislocation

Palmar MCP joint dislocation is a relatively rare condition. A closed reduction should be performed and an assessment made of collateral ligament stability. An unsuccessful reduction or the presence of unstable collateral ligaments requires an open surgical approach with extrication of the interposed capsule and collateral ligament repair. ^[26]

Thumb Metacarpal Fractures

Metacarpal head

Treat metacarpal head fractures, intra-articular by definition, in an open fashion if evidence of articular surface incongruity or displacement exists. Percutaneous pinning may be attempted. Undertake ORIF to achieve anatomic reduction and allow for early motion. A dorsal approach generally is recommended; attempt open reduction by splitting the dorsal apparatus between the EPL and EPB. Encourage early motion.

Metacarpal shaft

Shortening and collapse frequently occur secondary to the lack of intermetacarpal ligaments and deforming forces of intrinsic muscles. Attempt closed reduction with deformed fractures. Malrotation is usually not a problem. Treatment goals are to restore length and preserve the web space.

Indications for open reduction include shortening of more than 2 mm, angulation of greater than 20°, significant rotation, and open fractures.

Operative treatment includes percutaneous pinning for transverse or short oblique fractures. Long oblique or spiral fractures may require interfragmentary screws with or without a dorsal neutralization plate. Comminuted fractures may require external fixation if comminuted fragments are too small for ORIF.

Metacarpal base

A retrospective study by Abid et al indicated that in intra-articular fractures of the base of the first metacarpal bone, ORIF provides better functional recovery of the thumb than does extrafocal pinning. In the study, which included 38 cases, the investigators found that joint configuration was better restored with direct fixation and that ORIF resulted in better thumb opposition. ^[27]

• Extra-articular fractures

  • Closed reduction of an extra-articular metacarpal base fracture usually is successful and can be maintained in a thumb spica cast that excludes the distal phalanx. The reduction technique incorporates longitudinal traction with downward pressure on the apex of the fracture; distal fragment pronation and thumb extension completes the reduction. Transverse fractures are generally stable, while oblique fractures may displace after reduction with adduction and flexion of the metacarpal shaft occurring.

  • Operative indications include angulation greater than 30°, comminuted fractures with shortening, and open fractures.

  • Oblique fractures may reduce easily but tend to displace, with adduction and flexion of the metacarpal shaft narrowing the first web space. Obtain true lateral radiographs weekly for the first 2 weeks to assess the maintenance of reduction. Displacement of more than 30° may lead to compensatory hyperextension injury at the MCP joint related to muscular imbalance secondary to shortening. Percutaneous pinning of the fracture for 3 weeks tends to prevent displacement. In general, transarticular pinning is recommended for transverse fractures and intermetacarpal pinning is recommended for oblique fractures. ORIF generally is necessary only for comminuted fractures, which may alternatively require external fixation.

• Bennett fracture

  • Closed reduction and thumb spica cast immobilization is effective in the treatment of Bennett fractures if the reduction can be maintained. The closed reduction technique consists of thumb traction with extension, pronation, and abduction of the metacarpal shaft. The "screw-home-torque" that occurs in full opposition may aid reduction. ^[7] The strong pull of the APL frequently leads to displacement, thus open reduction or closed reduction with percutaneous pinning is frequently required. More than 1 mm of articular incongruity after closed reduction indicates operative intervention. Arthroscopy may be useful to assess the degree of displacement. ^[28]

  • If the closed reduction is unsuccessful or the fracture displaces after reduction, then percutaneous pinning may be attempted. The metacarpal may be pinned in place using the described reduction maneuver and then placing one pin through the thumb metacarpal into the index metacarpal and a second pin into the trapezium. Immobilizing the thumb in opposition is preferred to the fully abducted "hitchhiker" position. ^[7]

  • If more than 1 mm of articular incongruity remains after percutaneous pinning, an open reduction internal fixation (ORIF) should be performed. The approach is usually an L-shaped incision over the ulnar border of the thumb metacarpal. The incision continues radially to allow for subperiosteal reflection of the thenar muscles. A bone-holding forceps may be used to reduce the metacarpal to the Bennett fragment and secure fixation with Kirschner wires, ^[4] Kirschner wire and tension band, ^[29] or compression screws. ^[30] A thumb spica cast should be worn for 4-6 weeks if Kirschner wires are used. If more secure fixation is achieved (eg, minifragment screws), active range of motion may be initiated at 10-14 days postoperatively.

  • Van Royen et al described a new procedure for managing a gap of 2 mm or more in a symptomatic Bennett fracture malunion. The surgery involves joint exposure via an anterolateral approach, with Kirschner wires used to mark the malunion under fluoroscopic control. Joint congruency is restored by way of a closing wedge osteotomy, with the malunion site excised. Three interfragmentary screws are used to fix the osteotomy, with immobilization of the joint for 2 weeks, followed by initiation of passive mobilization and, 3-6 months postoperatively, removal of the hardware. ^[31]

• Rolando fracture and comminuted fractures

  • The principles of treatment for both Rolando and comminuted fractures of the metacarpal base are similar because they are both, by definition, comminuted fractures. ^[32] Assess the amount of comminution and size of the fragments with traction radiographs. If the fracture is nondisplaced with less than 1 mm of articular step off, then percutaneous pinning may be attempted. Arthroscopy may be useful to assess the degree of displacement. ^[28]

  • Displacement of the fracture with large (>3 mm) fragments indicates ORIF is necessary. Use an L-shaped incision identical to the incision used for exposure in Bennett fracture. Reduce the pieces and fix them with Kirschner wires, AO minifragment screws, or an upside-down T-plate.

  • Displacement of the fracture with small (< 3 mm) fragments indicates a need for distraction techniques. External fixation or oblique skeletal traction with a transmetacarpal pin may be used. Place a Kirschner wire obliquely through the shaft of the metacarpal, bend the distal end of the wire into a loop, and bend the proximal end into a hook to perform the oblique traction technique. The hook engages the shaft while traction is applied through the loop via an outrigger for 6 weeks. Initiate motion immediately postoperatively.

Thumb CMC Dislocations

Thumb CMC joint dislocations frequently reduce spontaneously. The "screw-home-torque" that occurs in full opposition may aid in closed reduction. ^[7] The joint stability should be assessed prior to thumb spica cast application. For irreducible dislocations or unstable injuries, a surgical approach is indicated. Treatment options include percutaneous pinning, screw anchor stabilization, ^[33] or flexor carpi radialis (FCR) tendon for ligament reconstruction. ^[17]

Thumb MCP Ulnar Collateral Ligament Injuries (Skier and/or Gamekeeper Thumb)

Acute incomplete ruptures

Place these injuries in a short arm thumb spica cast for 4 weeks. After removing the cast, reassess the clinical symptoms of the thumb MCP joint. Begin range-of-motion exercises immediately following cast removal. ^[5]

Acute complete ruptures

Surgical repair is generally recommended. ^[19] Make a longitudinal skin incision along the ulnar aspect of the thumb MCP joint and then carefully carry the dissection down to the adductor aponeurosis. Identify the displaced collateral ligament. Incise the adductor aponeurosis and identify, if possible, both ends of the collateral ligament. A variety of techniques may be used to repair the ligament. Suture anchors, ^[34] transosseous sutures, the technique of tying over a button, or direct repair may be used. Repair both the proper and accessory collateral ligaments as close to their original anatomic positions as possible. If a question remains of the repaired ligaments' ability to maintain reduction of the joint, percutaneously pin the joint to protect the ligament.

Chronic ruptures

These are usually secondary to a misdiagnosis or delay in diagnosis. As it is difficult to repair these injuries with primary tissue, they usually require reconstruction. Weave a free tendon graft, such as the palmaris longus, through holes made in the base of the proximal phalanx and the metacarpal neck. (Arthritic changes may indicate arthrodesis.) ^[5]

However, a retrospective study by Delma et al did find a high success rate for primary repair of chronic MCP ulnar collateral ligament injury of the thumb with local tissue and suture anchors. All acute and chronic patients in the study for whom outcome measures were completed (total = 36) reported that they were satisfied with the surgical results. Moreover, 87% and 86% of the acute and chronic patients, respectively, reported themselves to be very satisfied. The rates at which individuals returned to their previous occupation or to preinjury level of sports participation were reportedly 100% for acute patients and 93% for chronic patients. The acute and chronic patients were followed up for an average of 3.5 years and 38.1 months, respectively. ^[35]

Intra-articular fractures predispose the patient to stiffness and/or degenerative posttraumatic arthritis and a loss of motion within the affected joints. Restoration of articular congruity within these joints is essential in preventing the complication of degenerative arthritis. In some patients, degenerative arthritis develops regardless of anatomic restoration secondary to the articular surface injury sustained as a result of the initial trauma.

Loss of motion also occurs secondary to prolonged immobilization. It is essential to instruct patients to begin active range-of-motion exercises as soon after injury as possible. Strong fixation enables patients to initiate movement sooner postoperatively. Loss of motion occasionally occurs secondary to the development of tendinous adhesions as a result of surgical trauma. Maintain a high index of suspicion in postoperative follow-up care. Tenolysis frequently establishes near-normal motion in these patients.

A study by Tsujii et al suggested that in arthroscopic surgery on the CMC joint of the thumb, the use of a thenar portal may reduce the risk of radial sensory nerve damage, since this entry point is further from the radial nerve than is the more standardly used CMC radial portal. The study included six patients with Bennett fractures and 15 with osteoarthritis. ^[36]

Medical/legal pitfalls

The hand is an essential aspect of employment for a large percentage of the labor force. Injuries to the hand, particularly to the thumb, lead to a great deal of disability. ^[9] Preoperative and postoperative documentation of sensory and motor function are imperative medicolegally and in assessing postoperative hand ability. This information is invaluable in worker's compensation and disability claims.

Outcome and prognosis of thumb fractures and dislocations is related to the amount of energy associated with the original injury. High-energy injuries produce comminution, articular surface damage, and extensive soft tissue injury. These factors predispose the patient to degenerative changes and stiffness, leading to a poor outcome. Anatomically restore any intra-articular fracture to diminish the likelihood of developing these injuries. Low-energy injuries with simple fracture patterns and limited soft tissue involvement are associated with an excellent prognosis.