Phalangeal Fracture

Phalangeal fracture is a fracture of a proximal, middle or distal phalanx of the finger or thumb. It is the most common hand fracture, with the distal phalanx (often a tuft fracture from a crush injury) accounting for about half.

Patterns are transverse, oblique, spiral, comminuted, intra-articular (condylar), and avulsion fractures (bony mallet, volar plate). The mechanism is crush, twisting or axial load.

Complications are stiffness (the main one), malrotation, malunion, nonunion (uncommon), infection in open fractures, nail bed injury, flexor or extensor tendon adhesions, and flexion contracture.

Pathophysiology.

The proximal phalanx tends to angulate with its apex volar, because the central slip and lateral bands pull the proximal fragment into extension and the interossei flex the distal fragment. The flexor and extensor tendons lie against the bone, so prolonged immobilisation or swelling causes adhesions and stiffness.

Rotation matters most: a few degrees of malrotation produce marked finger overlap on grip.

Swelling, bruising, tenderness and deformity, with loss of movement. Ask the patient to flex the fingers slowly: fingers should converge toward the scaphoid tubercle, and overlap (scissoring) means malrotation. Check capillary refill and digital nerve sensation.

Examine the nail and nail bed for a subungual haematoma or laceration, and the skin for open wounds. Test tendon function: flexor digitorum profundus (distal interphalangeal flexion), flexor digitorum superficialis (proximal interphalangeal flexion) and extensor mechanism.

• Radiographs of the affected finger in three views: posteroanterior, true lateral and oblique. Do not rely on a hand view.
• Measure angulation, shortening, displacement and the articular step. Intra-articular fragments involving over 20 to 30% of the articular surface or a step of over 1 to 2 mm are unstable.
• Rotation is judged clinically.

Differential diagnosis.

• Interphalangeal dislocation and collateral ligament or volar plate injury.
• Mallet finger (tendinous) and jersey finger (flexor digitorum profundus avulsion).
• Nail bed laceration and fight bite.
• Pathological fracture (enchondroma).

Stable undisplaced fractures. Buddy strapping to the adjacent finger with early movement within 1 to 2 weeks. A protective splint for 2 to 3 weeks suits tuft fractures. Avoid long immobilisation.

Distal phalanx.

• Subungual haematoma: trephination with a sterile needle or cautery for pain when the haematoma covers over 50% of the nail, or when the fracture is displaced.
• Nail bed laceration: repair with fine absorbable sutures after removing the nail, and replace the nail as a splint.
• Displaced base fractures with tendon involvement (bony mallet): extension splint of the distal interphalangeal joint for 6 weeks, or fixation by extension block pinning.

Proximal and middle phalanx.

• Displaced, unstable, spiral, or malrotated fractures: closed reduction with percutaneous Kirschner wires (1.0 to 1.4 mm), or open reduction with mini plates and screws (1.5 to 2.0 mm) when rigid fixation is needed for early movement.
• Intra-articular condylar fractures with a step of over 1 to 2 mm: open reduction and fixation with screws or wires.
• Unrestricted malrotation, or angulation of over 10 degrees in the sagittal plane of the proximal phalanx: reduce and fix.
• Immobilise in the safe position (metacarpophalangeal joints at 70 to 90 degrees of flexion, interphalangeal joints straight) for 3 to 4 weeks, then start movement.

Digital block. Lidocaine 1% (10 mg/mL) 2 to 4 mL in total as a ring block at the base of the digit (plain, without adrenaline, 1 to 2 mL on each side of the base) as a single administration (maximum 4.5 mg/kg of plain lidocaine and not exceeding 300 mg); monitor for toxicity (perioral numbness, tinnitus, drowsiness); avoid with infection at the site, vascular compromise or lidocaine allergy; reduce the volume in hepatic impairment.

Open fracture. Irrigate, debride and stabilise. Intravenous co-amoxiclav 1.2 g every 8 hours (or cefazolin 2 g every 8 hours) within 1 hour of injury, then oral co-amoxiclav 500/125 mg every 8 hours to complete 3 to 5 days after clean debridement (maximum 3.6 g intravenously daily; every 12 hours at creatinine clearance 10 to 30 mL/min; avoid with a history of cholestatic jaundice from co-amoxiclav).

With penicillin allergy use doxycycline 100 mg orally twice daily for the same duration. Tetanus booster 0.5 mL intramuscularly if the last dose was over 10 years ago, with tetanus immunoglobulin 250 units intramuscularly (500 units if over 24 hours since injury or heavily contaminated) when immunisation is incomplete or unknown.

Analgesia.

• Paracetamol 1 g orally every 6 hours as needed for up to 5 to 7 days (maximum 4 g daily; 3 g daily when weight is under 50 kg, with chronic alcohol use or hepatic impairment).
• Ibuprofen 400 mg orally every 8 hours with food for up to 5 days (maximum 1200 mg daily); avoid with eGFR under 30 mL/min/1.73 m2, peptic ulcer, heart failure or anticoagulant use.
• Oral morphine 5 to 10 mg every 4 hours as needed for severe pain for up to 3 days (start 2.5 to 5 mg with age over 75 or eGFR under 30 mL/min/1.73 m2; avoid exceeding 60 mg in 24 hours without senior review); monitor sedation and respiration and prescribe a laxative.

Monitoring. Radiographs at 1 week and 2 weeks to detect loss of reduction, and at 4 to 6 weeks for union. Rotation and finger range at each visit. Pin sites weekly. Hand therapy from week 2 to 4 to prevent stiffness.

Referral and escalation. Refer displaced, malrotated, intra-articular, multiple and open fractures to orthopaedics or hand surgery within 24 to 48 hours. Same day referral for fingertip amputation, vascular compromise, flexor tendon injury, or a wound with signs of infection.

Special groups.

• Children: most phalangeal fractures are physeal (Salter-Harris II) and heal well with buddy strapping; Seymour fractures (open distal phalanx physeal injuries with nail bed interposition) need washout and antibiotics.
• Older adults: osteoporotic fractures and stiffness risk favour early movement.
• Kidney impairment: avoid ibuprofen and reduce morphine doses.
• Diabetes and peripheral vascular disease: lower threshold for admission and antibiotics.