38 Metacarpal Fracture Open Reduction and Internal Fixation (ORIF)
Metacarpal fractures are among the most common hand injuries, often caused by a direct blow to the hand or by axial load. They are classified into fractures of the head, neck, and shaft and may be associated with soft tissue injury such as tendon lacerations and neurovascular injury. While some fractures can be treated conservatively with immobilization, many require operative treatment, varying from closed reduction and percutaneous pinning with immobilization to open reduction and internal fixation (ORIF). There are various indications for ORIF of meta-carpal fractures as well as multiple approaches and techniques.
A number ofdifferent open reduction and internal fixation (ORIF) options for metacarpal fractures are available, including utilization of Kirschner wires (K-wires), lag screw, neutralization plate, dynamic compression plating (DCP), and headless screw use.
38.2 Key Principles
There are various fixation options that exist for metacarpal fractures. Selection of the optimal treatment depends on several factors, including fracture location, severity of deformity, whether the fracture is open or closed, involvement of the articular surface, extent of osseous injury, degree of associated soft tissue injury, and intrinsic fracture stability. Anatomic reduction of these fractures is vital and a clinical evaluation for scissoring should be performed. Additional factors to consider include the patient’s age, occupation, presence of systemic illnesses, and patient compliance.
Tendons are less intimately associated with metacarpal bones compared to phalangeal fractures; therefore, outcomes in metacarpal fractures are typically better. Closed reduction may be attempted for displaced transverse metacarpal shaft fractures, but most displaced metacarpal fractures require fixation. Options include use of K-wires, interosseous wires, lag screws, and plates as per surgeon preference. In addition, isolated injuries tend to have significantly better outcomes than combined injuries.
38.3.1 Metacarpal Head Fractures
Noncomminuted, displaced fractures that constitute more than 25% ofthe articular surface or exhibit more than 1 mm of articular step-off are treated operatively with K-wires and immobilization. Comminuted fractures require fixation with multiple K-wires or cerclage wires. Unstable reductions may require immobilization for 2 to 3 weeks before range-of-motion exercises are initiated. Skeletal traction or external fixation (► Fig. 38.1, ► Fig. 38.2, ► Fig. 38.3) may be needed if there are associated comminuted fractures of the adjacent base of the proximal phalanx. For open comminuted head fractures, especially fractures with bone loss, prosthetic arthroplasty is a reasonable alternative.
38.3.2 Metacarpal Neck Fractures
Most closed metacarpal neck fractures can be treated nonoperatively. In the absence of pseudoclawing or rotational malalignment, they produce minimal to no functional problems. If pseudoclawing is not present, functional brace or dorsalulnar gutter splint can be used for 2 weeks. Reduction is indicated for pseudoclawing or rotational deformity using the Jahss maneuver and then subsequently immobilization for 2 weeks. The patient may return to sports and unrestricted activity at 4 to 6 weeks.
If an acceptable reduction cannot be maintained because of volar comminution and intrinsic muscle pull, percutaneous K-wires can be inserted crossed or transversely; intramedullary fixation under fluoroscopic guidance can be utilized. Care should be taken not to induce lateral translation of the fractured metacarpal head. If open reduction is necessary, crossed K-wires, dorsal tension band wire with a supplemental K-wire, or a laterally applied minicondylar plate can be utilized. Immobilization in an ulnar gutter splint is usually maintained for 2 to 3 weeks after percutaneous pin fixation.
38.3.3 Metacarpal Shaft Fractures
Most metacarpal shaft fractures are inherently stable and can be treated conservatively with acceptable functional outcomes. Open reduction and internal fixation (ORIF) can be accomplished using numerous techniques, including K-wire fixation, composite and cerclage wiring, intramedullary fixation, screw fixation, and plate fixation. Generally, the least invasive method that can reliably restore and maintain anatomic alignment of metacarpal shaft fractures is preferable for successful outcomes.
38.4.1 General Indications
Malrotation (scissoring, spiral, and oblique)
Segmental bone loss
Associated soft tissue injury
38.4.2 Metacarpal Neck fractures
Open, articular displacement
Angulation (index/middle 10-15 degrees; ring 40 degrees; small 60 degrees)
Pseudoclaw formation, and the presence of a palpable head in the palm that can make grip painful