Overview
Hand injuries, including fractures and dislocations, are among the most common musculoskeletal injuries treated in the emergency setting. After distal forearm fractures, phalangeal and metacarpal fractures are the next most common, at 12.5 and 8.4 fractures per 10,000 people per year. The middle phalanx is the least frequently fractured phalanx. Its shaft fractures are treated like proximal phalanx fractures, though closed treatment is often preferred because the soft-tissue cover is less robust. Condylar and base fractures of the middle phalanx can cause significant PIP joint dysfunction if mistreated. (Rockwood)
Evaluation
Mechanism. Indirect bending forces in sport, and direct blunt or sharp trauma. Base fractures arise as avulsion injuries or from combined shear and axial loading of the joint surface. Dorsal base fractures are typically bony avulsions of the central slip when a flexion force is applied to an actively extended PIP joint. Hyperextension injuries causing dorsal PIP dislocation produce either a pure ligamentous tear or a volar lip avulsion fracture (volar plate injury). Greater axial forces involve a larger percentage of the volar lip with joint impaction. High energy with pure axial load shatters the whole joint surface (pilon fracture). (Rockwood)
Associated injuries. Examine for associated soft-tissue and tendon injury, especially after direct trauma, and assess neurovascular function. (Rockwood)
Imaging. PA and lateral radiographs are usually enough. Obtain a true lateral view of the joint (special fluoroscopic views help). A fine-cut CT with sagittal reconstruction can define fragment size, geometry and impaction in complex base fractures. (Rockwood)
Outcome measures. DIP and PIP range of motion (total active motion), grip and pinch strength, VAS pain, and complications such as subluxation, posttraumatic arthritis, infection and neurovascular injury. (Rockwood)
Classification (Rockwood)
Head: unicondylar or bicondylar.
Neck: type I nondisplaced; type II displaced with some bone contact; type III displaced without bone contact.
Shaft.
Base:
Volar base: stable (less than 30% of the joint surface, stable in extension); tenuous (30%–50%, stable at less than 30 degrees of flexion); unstable (over 50%, or requiring more than 30 degrees of flexion for stability).
Dorsal base.
Pilon.
Deforming forces in shaft fractures. The deformity depends on the fracture's position relative to the FDS insertion. Fractures proximal to the FDS insertion have apex dorsal angulation. Fractures distal to the FDS insertion have apex volar angulation. Intra-articular fractures often affect PIP joint stability. (Rockwood)
Condylar, Neck and Shaft Fractures
Nonoperative treatment
Indications: nondisplaced neck and shaft fractures, and reducible and stable neck and shaft fractures. Relative contraindications: significant shortening, angulation or malrotation.
Even with comminution the periosteal sleeve may provide enough stability. Displaced fractures can remain stable after closed reduction. Dynamic fluoroscopic examination confirms stability.
Immobilize the PIP and DIP in extension in a dorsal or volar gutter splint for 4 weeks. Then allow active ROM with buddy taping until 6 weeks after injury.
Confirm no angulation, shortening or malrotation. Check digital scissoring by gentle flexion of the fingers and compare digital overlap with the contralateral hand. The nail plate plane may also help. Malunion is among the most common nonoperative complications and deformity is difficult to correct afterward. (Rockwood)
Operative indications
There is a low threshold for fixation of condylar fractures because of joint involvement. Absolute indications are displaced condylar fractures and coronal step-off.
Most neck fractures show angulation and instability needing reduction and fixation. Occasionally the distal fragment is rotated 180 degrees and needs open reduction.
Unstable shaft fractures are best treated with closed reduction and percutaneous pinning (CRPP). (Rockwood)
Techniques
Condylar fractures. Unicondylar fractures: three pins placed perpendicular to the fracture line and spanning maximally give the best stability, or a 1.0, 1.5 or 2.0 mm lag screw can be used. Avoid injuring the collateral ligament origin. Bicondylar fractures may need transarticular pinning or open reduction. A transarticular pin may be used for neck fractures, and the pins are usually removed at about 5 weeks. Condylar avascular necrosis risk is increased by wide stripping, so use a midaxial approach with care for the collateral ligament.
Shaft fractures. Percutaneous pin fixation is generally preferred to open plating because of the high rate of adhesions with plates. Long oblique and spiral fractures can be fixed with percutaneous mini-fragment lag screws placed perpendicular to the fracture plane with a pointed reduction clamp. This is technically demanding. Place screw holes at least one screw diameter from the fracture line.
Comminuted fractures may need plating. Compared with pins, screws and plates give more stability and permit early ROM, but need careful soft-tissue handling to prevent wound complications. Plating typically uses two 1.5-mm screws on each side of the fracture.
Composite (sidewinder) wiring: after reduction, 0.035-inch K-wires are placed across the fracture, then 24-, 26- or 28-gauge monofilament stainless wire is looped around the K-wire ends over the cortex, tensioned and twisted flat (avoiding contact with tendons). It is useful as a salvage when planned fixation fails.
Transosseous wiring (90-90 wiring): two perpendicular wire loops across the fracture, mostly used for transverse shaft fractures and in replantation. Drill holes with a 0.035-inch K-wire about 4 mm from the fracture in the coronal and sagittal planes, and pass 24 or 26-gauge wire. Do not overtighten, because small-gauge wire breaks easily. The wire loses its metallic shine and looks slightly opaque as it approaches breaking.
A syringe external fixator can be used when conventional implants cannot give reliable axial stability. (Rockwood)
Approaches
Midaxial approach: a lateral incision along the line joining the dorsal apices of the PIP and DIP flexion creases. Identify the neurovascular bundle volarly and retract the lateral band dorsally. For proximal fractures, the transverse retinacular ligament may be divided. Incise periosteum at the fracture and close it afterward over the implant to isolate it from overlying soft tissue.
Dorsal approach: a longitudinal incision along the finger, full-thickness flaps, preserving longitudinal dorsal veins if possible. Identify and protect the central slip proximally and divide the triangular ligament when needed distally. Close the periosteum separately over the implant when possible, then repair the triangular ligament and skin. (Rockwood)
Base Fractures and Pilon Fractures
Stability depends on fragment size. Fractures involving under 30% of the joint surface are generally stable. Over 50% are mostly unstable (the fragment includes the lateral collateral ligament and volar plate, leaving the middle phalanx dorsally unstable). Fractures with 30%–50% need careful clinical and radiographic evaluation. After reduction of a dislocation, test stability. Take the joint through full ROM clinically. On a true lateral radiograph, the dorsal half of a stable PIP joint has parallel surfaces. Dorsal subluxation shows a dorsal "V sign." Live fluoroscopy shows gliding in a stable joint, but hinging on the bony defect in an unstable one. (Rockwood)
Dorsal base fractures: nondisplaced and stable with no volar subluxation: splint in PIP extension for 4 to 6 weeks, allowing active DIP flexion. Displaced fractures need dorsal-approach fixation with a screw, a dorsal buttress plate, or tension band wire, with enough stability for early mobilization.
Volar base fractures: those needing under 30 degrees of flexion for stability are treated with a dorsal extension-block splint (including a dorsal-supported cast, or hand-based or finger-based block splints for reliable patients). Take weekly radiographs. PIP extension is initially blocked at 30 degrees and increased by 10 degrees weekly, ending splinting at 4 weeks. Surgery is indicated for fractures involving over 50% of the joint, requiring more than 30 degrees of flexion to remain reduced, or showing hinging instead of gliding.
Pilon fractures: result from axial loading and are intra-articular with joint depression and comminution. Nonoperative treatment usually gives poor results, with residual angular and rotational deformity. Radiographs can underestimate the injury, so coronal and sagittal CT is useful. Surgical treatment is recommended. (Rockwood)
Operative techniques for volar base fractures and PIP fracture–dislocations
Dorsal block pinning (extension-block pinning): a K-wire placed in the head of the proximal phalanx blocks dorsal subluxation. With the middle phalanx base reduced, the pin is placed dorsally into the proximal phalanx head, leaving the middle phalanx at 45 degrees of flexion at rest. Alternatively a transarticular pin from the middle phalanx base to the proximal phalanx head with the PIP flexed 20 to 40 degrees. Pins come out at 3–4 weeks. Percutaneous intramedullary reduction of impacted articular fragments has been added in some series.
Dynamic distraction: because long immobilization causes stiffness, dynamic traction while allowing PIP motion was developed. Options include bulky dynamic traction splints, lighter traction devices (a transverse 0.035-inch K-wire through the middle phalanx shaft attached to a circular splint with a dorsal block on the MP joint, traction held 4 to 6 weeks), hinged distraction external fixators, and Slade's dynamic distraction external fixation (introduced 1990), used for fracture–dislocation and pilon fractures.
Force couple (Agee, 1978): three K-wires joined by rubber bands lift the middle phalanx base volarly while pushing the proximal phalanx head dorsally. Place a transverse 0.045-inch K-wire in the middle phalanx just distal to the PIP joint, dorsal to the fracture and volar to the lateral bands, a second parallel 0.045-inch wire at the proximal phalangeal neck–metaphyseal flare, and a 0.062-inch threaded K-wire dorsal to volar in the proximal third of the middle phalanx. Bend the wires and connect with small elastic bands. It needs an intact dorsal rim, so it is contraindicated in pilon fractures. Leave in place about 6 to 8 weeks. (Rockwood)
Pitfalls
Missing malrotation, angulation or shortening in nonoperative treatment. (Rockwood)
Missing dorsal subluxation (V sign) in base fractures treated as "stable" because of fragment size. (Rockwood)
Prolonged immobilization of the PIP leading to stiffness. (Rockwood)
Postoperative Care and Complications
Pins are typically removed at 3 to 6 weeks, followed by active motion. Dynamic traction devices stay for 4–8 weeks. (Rockwood)
Complications include fracture subluxation, posttraumatic arthritis, infection (pin-site), neurovascular injury, stiffness, malunion and loss of reduction. (Rockwood)
References
Chapter 45, fractures and dislocations of the hand (middle phalanx). In: Tornetta P III, Ricci WM, Ostrum RF, McKee MD, Ollivere BJ, de Ridder VA, eds. Rockwood and Green's Fractures in Adults. 10th ed. Wolters Kluwer; 2024 (Turkish edition: Erişkin Kırıkları).