Residency · Residency · Orthopedic Surgery
Hand Fractures and Dislocations: Principles of Fixation
Overview
Hand fractures are the most common fractures in the upper extremity. Treatment goals are to restore anatomic alignment, maintain stability, and enable early motion to prevent stiffness. The balance between stable fixation and minimizing soft tissue disruption is critical because stiffness is the primary enemy of hand fracture management.
General Principles
Acceptable Alignment
Rotational malunion is not tolerated in the hand; even 5 degrees of malrotation causes noticeable digital overlap. Rotation is checked by having the patient make a fist, as all fingers should point toward the scaphoid tubercle. Angular deformity tolerance varies by location: the index and long metacarpals tolerate less than 10 degrees (minimal CMC motion), the ring metacarpal tolerates less than 20 degrees, and the small metacarpal tolerates 30-40 degrees (compensated by greater CMC motion). The proximal phalanx tolerates less than 10 degrees, and the middle phalanx tolerates minimal angulation at the PIP level.
Indications for Surgery
Surgical indications include unacceptable alignment after closed reduction, unstable fracture patterns, rotational deformity, intra-articular fractures with displacement greater than 1-2 mm, open fractures, multiple fractures, and associated soft tissue injuries requiring repair.
Metacarpal Fractures
Metacarpal Head Fractures
Metacarpal head fractures are intra-articular, often resulting from axial loading (punching). Nondisplaced fractures are treated with buddy tape and early ROM. Displaced fractures require ORIF with headless compression screws or mini-fragment screws (1.3-1.5 mm). Comminuted fractures may require external fixation or K-wire fixation.
Metacarpal Neck Fractures
Boxer's Fracture (5th Metacarpal Neck)
The boxer's fracture is the most common metacarpal fracture, caused by punching with a closed fist. It produces apex dorsal angulation. Acceptable angulation is up to 40-50 degrees for the 5th metacarpal (high compensatory CMC motion), up to 30 degrees for the 4th, and up to 15 degrees for the 2nd and 3rd. Most are treated nonoperatively with an ulnar gutter splint (MCP flexed 70-90 degrees, IP joints free), transitioning to buddy taping at 3-4 weeks. Surgery is indicated for excessive angulation, rotational deformity, or multiple fractures. Techniques include closed reduction with percutaneous K-wire fixation (cross-pinning or bouquet technique) or intramedullary nailing/pinning.
Metacarpal Shaft Fractures
Transverse metacarpal shaft fractures angulate apex dorsally from interosseous muscle forces. Oblique and spiral fractures tend to shorten and malrotate. Stable, nondisplaced fractures are splinted with early motion. Displaced transverse fractures are treated with closed reduction and K-wire fixation or ORIF with plate and screws. Spiral and oblique fractures with shortening or rotation require lag screw fixation (minimum 2 screws) or plate and screw fixation. Plating uses dorsal or lateral placement with 2.0-2.4 mm low-profile plates to reduce extensor tendon irritation.
Metacarpal Base Fractures
Fractures of the 2nd-5th metacarpal bases are usually stable injuries treated with splinting and early motion. Thumb metacarpal base fractures are distinct entities.
Thumb Metacarpal Base Fractures
Bennett Fracture
The Bennett fracture is an intra-articular fracture-dislocation of the thumb CMC joint. A small volar-ulnar fragment is held by the anterior oblique (beak) ligament while the metacarpal shaft subluxates dorsally and radially from APL pull. Treatment involves closed reduction and percutaneous K-wire fixation (pinning the metacarpal to the trapezium) or ORIF with screws if the fragment is large.
Rolando Fracture
The Rolando fracture is a comminuted intra-articular fracture of the thumb metacarpal base in a Y or T pattern. Treatment involves ORIF if fragments are large enough, or external fixation or K-wire fixation for comminuted patterns.
Extra-articular (Epibasal) Fractures
Extra-articular fractures are usually stable and treated with a thumb spica cast or splint for 4-6 weeks. Operative treatment is indicated for significant apex dorsal angulation.
<image>Bennett and Rolando fracture patterns of the thumb metacarpal base on radiograph</image>
Phalangeal Fractures
Proximal Phalanx Fractures
Proximal phalanx fractures angulate apex volarly because the interossei flex the proximal fragment while the central slip extends the distal fragment. Nondisplaced and stable fractures are treated with buddy taping and early motion (intrinsic-plus splinting initially). Displaced fractures require closed reduction and percutaneous K-wire fixation or ORIF. ORIF options include lag screws for long oblique fractures, dorsal plating (1.3-1.5 mm), or lateral plating. Dorsal plating risks extensor tendon adhesion, demanding meticulous soft tissue handling and early motion.
Middle Phalanx Fractures
Deforming forces on middle phalanx fractures depend on their location relative to the FDS insertion. Fractures proximal to the FDS angulate apex dorsally (central slip extends the proximal fragment, FDS flexes the distal). Fractures distal to the FDS angulate apex volarly (FDS flexes the proximal fragment). Treatment follows similar principles to proximal phalanx fractures, with intra-articular fractures at the PIP base warranting special attention.
Distal Phalanx Fractures
Distal phalanx fractures are the most common phalangeal fracture. Tuft fractures from crush injuries are treated with protective splinting and subungual hematoma drainage if the hematoma involves more than 50% of the nail bed. Shaft fractures are splinted in extension. Dorsal base avulsions represent mallet finger, and volar base avulsions represent FDP avulsion (jersey finger).
PIP Joint Fracture-Dislocations
Dorsal Fracture-Dislocation
Dorsal fracture-dislocation is the most common PIP injury pattern, involving a volar lip fracture of the middle phalanx base with dorsal subluxation or dislocation. Stability depends on the percentage of articular surface involved. Less than 30% is usually stable after closed reduction and managed with extension block splinting (Slade technique). Fractures involving 30-50% have tenuous stability and may require extension block pinning or ORIF. Greater than 50% involvement is unstable and requires operative management (ORIF, hemihamate autograft, volar plate arthroplasty, or dynamic external fixator).
Extension Block Splinting (Slade)
After achieving concentric reduction, the angle at which the joint redislocates is determined. The PIP is splinted in flexion 10-15 degrees beyond the unstable angle, with weekly reduction of the flexion angle (10-15 degrees per week) while ensuring concentric reduction on weekly lateral radiographs.
Volar Plate Arthroplasty
For comminuted volar base fractures involving 40-60% of the articular surface, the volar plate is advanced into the fracture defect as a spacer, providing a stable concentric reduction.
Hemihamate Autograft
For large volar base fractures with articular comminution, an osteochondral graft is harvested from the dorsal distal hamate, which provides an anatomic match to the PIP base anatomy. It is fixed with countersunk mini-screws.
Pilon Fractures of the PIP
Pilon fractures of the PIP result from axial load injuries causing central depression of the middle phalanx base. These challenging injuries often require dynamic external fixation (ligamentotaxis) with or without ORIF.
<image>Extension block splinting technique for dorsal PIP fracture-dislocation with weekly progression</image>
Thumb UCL Injuries (Gamekeeper's / Skier's Thumb)
Anatomy
The UCL of the thumb MCP joint is the primary restraint to valgus stress, consisting of the proper collateral ligament (taut in flexion) and accessory collateral ligament (taut in extension).
Mechanism
The mechanism is forced abduction and hyperextension at the thumb MCP joint. Acute injuries are termed skier's thumb (ski pole injury), while chronic injuries are termed gamekeeper's thumb (repetitive stress).
Stener Lesion
In a Stener lesion, the torn UCL retracts and folds superficial to the adductor aponeurosis, which interposes between the ligament and its insertion, preventing healing. Present in approximately 80% of complete tears, a Stener lesion cannot heal nonoperatively and represents a surgical indication.
Diagnosis
Clinical findings include tenderness over the ulnar aspect of the thumb MCP joint. Stress testing applies valgus stress at 0 degrees (testing the proper plus accessory collateral) and 30 degrees of flexion (testing the proper collateral). Greater than 30-35 degrees of opening or more than 15 degrees compared to the contralateral side indicates a complete tear. MRI or ultrasound confirms the tear and evaluates for a Stener lesion. Radiographs evaluate for avulsion fracture at the proximal phalanx base.
Treatment
Partial tears that are stable on stress testing are treated with a thumb spica cast or splint for 4-6 weeks. Complete tears with a Stener lesion require surgical repair using suture anchors to the proximal phalanx; if there is a large avulsion fracture, screw or tension band fixation is used. Chronic injuries require UCL reconstruction with tendon graft (palmaris longus).
<image>Stener lesion of the thumb UCL with adductor aponeurosis interposition preventing ligament healing</image>
Fixation Options Summary
K-Wires
K-wires are versatile, simple, and inexpensive. Disadvantages include pin tract infection, loosening, lack of compression, and the need for supplemental splinting. They are removed at 3-6 weeks.
Lag Screws
Lag screws provide compression across the fracture site and are ideal for long oblique and spiral fractures (fracture length greater than 2 times the bone diameter). Sizes are 1.0-1.5 mm for phalanges and 2.0-2.4 mm for metacarpals. Headless compression screws (such as Acutrak) can be fully buried.
Plates and Screws
Plates and screws provide the most rigid fixation and allow early motion. The lowest profile plate possible minimizes tendon irritation. Dorsal plating provides good access but risks extensor adhesion, while lateral plating avoids the extensor mechanism but is technically harder. Indications include comminuted, segmental, and periarticular fractures.
External Fixation
Dynamic external fixators are used for PIP pilon fractures and comminuted injuries. They use distraction and ligamentotaxis for articular restoration while allowing early motion and maintaining alignment.
Clinical Pearls
Rotational deformity must always be checked by having the patient flex all fingers; digital scissoring is a surgical indication even if angular alignment appears acceptable. The "safe position" for hand splinting (intrinsic-plus) maintains MCP flexion of 70-90 degrees with IP extension to prevent collateral ligament contracture. Fight bite wounds require irrigation and debridement, antibiotics, and open wound management; these wounds should never be primarily closed or ignored. Stiffness is the most common complication of hand fractures, and early protected motion should be pursued whenever fixation stability allows. In Bennett fractures, perfect articular reduction is desirable but imperfect reduction is surprisingly well tolerated functionally. When PIP stability is uncertain after reduction, a true lateral radiograph with the finger in slight flexion should be obtained; the "V-sign" (widening of the dorsal joint space) indicates persistent subluxation.
References
- Kozin SH, et al. Metacarpal fractures. In: Green's Operative Hand Surgery. 7th ed.
- Strauch RJ, et al. Boxer's fracture: a systematic review. J Hand Surg Am. 2017;42(10):e425-e431.
- Slade JF, et al. Extension block pinning for proximal interphalangeal joint fracture dislocations. J Hand Surg Am. 2004;29(6):1113-1118.
- Stener B. Displacement of the ruptured ulnar collateral ligament of the metacarpo-phalangeal joint of the thumb. J Bone Joint Surg Br. 1962;44(4):869-879.
- Williams RM, et al. Hemihamate arthroplasty for PIP fracture-dislocation. J Hand Surg Am. 2003;28(1):14-20.
