Finger Dislocation

Patients present after acute hand trauma with visible deformity, pain, and inability to move the affected joint. Mechanism stratifies the pattern: hyperextension force (PIP dorsal dislocation), forced extension of a flexed DIP while gripping (jersey finger), or forced flexion of an extended DIP (mallet finger).

Examination:

• •Inspect for deformity, position of the digit, and skin integrity. Open injury (visible bone, large laceration) is an immediate ED referral
• •Active and passive ROM at each joint of the affected digit: differentiates dislocation (joint locked) from sprain (joint mobile but painful)
• •For jersey finger: ask the patient to actively flex the DIP with the PIP held in extension by you. Inability to flex the DIP = FDP avulsion. The middle phalanx-flexor mechanism still works (FDS intact)
• •For mallet: inability to actively extend the DIP with passive extension preserved (covered in the mallet finger topic)
• •Neurovascular check: ulnar and radial digital nerves and pulse at each digit
• •Look for rotational deformity (cascade test: each flexed fingertip should point toward the scaphoid tubercle)

Differentials and overlap: PIP volar plate avulsion (stable PIP after sprain mechanism, not a true dislocation), collateral ligament sprain (radial or ulnar deviation force), and phalangeal fractures (X-ray differential).

Plain radiographs (PA and TRUE LATERAL of the affected finger) are first-line. Isolate the affected finger on the lateral view to avoid overlap with adjacent digits - this is where small avulsion fragments and joint subluxations are detected.

Key radiographic checks:

• •Bony avulsion at the volar middle phalangeal base (PIP volar plate)
• •Bony avulsion at the volar distal phalangeal base (jersey finger, FDP)
• •Bony avulsion at the dorsal distal phalangeal base (mallet finger, terminal extensor)
• •Joint congruity after reduction: subluxation suggests significant volar plate or collateral disruption and may require operative intervention
• •Articular surface step-off: more than 1-2 mm or fragment over 30-40% of the articular surface usually requires fixation
• •Rotational alignment is clinical, not radiographic - the cascade test (flexed fingers point to scaphoid tubercle) is the bedside discriminator

Ultrasound is useful for confirming FDP avulsion when X-ray is normal but clinical jersey finger is suspected. MRI is reserved for complex or chronic injuries where surgical reconstruction is contemplated. CT is rarely indicated; reserved for complex intra-articular fractures or surgical planning.

Management is pattern-specific (BSSH guidance, BSSH BEST guidelines, NICE NG38).

PIP dorsal dislocation:

• •Reduce promptly under digital ring block: longitudinal traction with gentle hyperextension to disengage, then volar pressure on the dorsally displaced middle phalanx
• •Post-reduction X-ray to confirm joint reduction and check for fragment
• •Stable joint without significant fragment: buddy strap to adjacent digit for 2-3 weeks; early active ROM. Most heal well with hand-therapy supervision
• •Articular fragment over 30%, joint subluxation, or instability: surgical referral. Options include extension-block pinning (Eaton-Belsky) or ORIF
• •Volar PIP dislocation: rare but always operative for central slip repair; boutonniere deformity is the long-term risk

Jersey finger (FDP avulsion):

• •Leddy I (FDP retracted to palm, vinculum disrupted): operative emergency - direct primary repair within 7-10 days
• •Leddy II (retracted to PIP, held by vinculum brevis): repair within 4-6 weeks
• •Leddy III-V (large bony fragment with limited retraction): repair within 4-6 weeks; outcomes generally better than soft-tissue avulsions because the bony fragment provides better anatomical reattachment
• •Delayed presentation (over 4-6 weeks): primary repair often not feasible; staged tendon graft reconstruction is the option, with poorer functional outcome

Mallet finger: covered in the mallet-finger topic - in brief, closed tendinous and Doyle IVB managed in continuous extension splinting for 6-8 weeks; Doyle IVC (over 50% fragment or volar subluxation) and open injuries require surgical referral.

Thumb MCP dislocation:

• •Simple: closed reduction under digital block, post-reduction X-ray, buddy strap or splint for 2-3 weeks. Early mobilisation
• •Complex (irreducible due to volar plate interposition): open reduction. Skin dimpling over the volar MCP is the clinical sign. Do not repeat forceful closed reduction attempts

MCP and PIP collateral ligament sprains (radial / ulnar collateral injury without dislocation): buddy strap for 2-3 weeks, early mobilisation. Surgical referral for Grade III complete tears with frank instability.

Open finger injuries: ED referral, IV antibiotics, washout, primary repair where feasible. BOAST open fracture principles apply for open fracture-dislocation patterns.

Referral pathway: any open injury, irreducible dislocation, jersey finger, articular fragment over 30%, joint subluxation, or rotational deformity to hand surgery / fracture clinic same day or next day. Stable PIP dislocations and simple thumb MCP dislocations managed in primary care or fracture clinic with structured rehabilitation.

PIP dorsal dislocation (stable, post-reduction):

• •Days 0-3: ice, elevation, gentle active ROM in buddy strap to adjacent digit
• •Weeks 1-3: continued buddy strap with progressive ROM; aim for full ROM by week 3-4
• •Weeks 3-6: strengthening, progressive return to work and sport
• •Return to non-contact sport: 3-4 weeks. Contact sport with protective taping: 4-6 weeks
• •PIP flexion contracture is the commonest complication; early mobilisation is the principal prevention

Jersey finger (post-surgical repair, typical FDP repair):

• •Weeks 0-4: dorsal blocking splint with wrist in flexion 20-30 degrees, MCP in flexion 60-70 degrees, IPs in full extension. Controlled passive ROM under hand therapy supervision (Duran or Kleinert protocols)
• •Weeks 4-6: continued protected ROM; introduction of active place-and-hold
• •Weeks 6-8: active ROM out of splint with continued protection
• •Weeks 8-12: progressive strengthening; full active ROM
• •Return to gripping: 10-12 weeks; sport: 12-16 weeks
• •Adherence and structured hand therapy under specialist supervision are essential

Mallet finger (per the mallet finger topic): continuous DIP extension splinting 6-8 weeks then graded weaning.

Thumb MCP dislocation (post-reduction):

• •Weeks 0-2-3: buddy strap or thumb spica splint; active IP and CMC ROM
• •Weeks 3-6: progressive active MCP ROM and pinch strengthening
• •Weeks 6-10: full return to ADLs and sport

Persistent joint stiffness, swelling, or extensor lag beyond 6-12 weeks warrants hand therapy reassessment for stiffness protocols, dynamic splinting, or surgical reassessment for missed pathology. Counsel patients on the high prevalence of mild residual PIP swelling and stiffness ("sausage finger") even after well-managed PIP dislocations.

• •BSSH BEST Guidelines - UK hand-surgery framework: clinician-facing best-practice statements covering finger dislocations, volar plate injury, and thumb UCL injury.
• •Leddy and Packer classification (1977) - UK and international framework for jersey finger: Type I retraction to palm (operative emergency), Type II retraction to PIP, Type III-V varying bony fragment patterns.
• •Eaton-Belsky extension-block pinning (1980) - Established UK surgical technique for unstable PIP dorsal fracture-dislocations with large volar fragment.
• •NICE NG38 Fractures (non-complex, 2016) - Underpins the general management principles for hand fracture-dislocations and analgesia / follow-up.
• •BOAST Open Fractures - Applies to open fracture-dislocation patterns: early IV antibiotics, limited wound handling, urgent orthopaedic / hand surgery input.

• •The three commonest finger injury patterns are PIP dorsal dislocation (volar plate disruption), jersey finger (FDP avulsion - 75% ring finger), and mallet finger (terminal extensor disruption).
• •Jersey finger Leddy I = retraction to palm with vinculum disruption = operative emergency. Repair within 7-10 days. Delayed repair beyond 4-6 weeks usually requires staged tendon graft reconstruction.
• •Test jersey finger by isolating the PIP in extension and asking the patient to flex the DIP. Loss of active DIP flexion with intact PIP flexion = FDP avulsion.
• •Complex thumb MCP dislocation is irreducible due to volar plate interposition between the metacarpal head and proximal phalanx. Skin dimpling over the volar joint is the clinical sign. Open reduction is required - do not repeat forceful closed attempts.
• •PIP volar plate avulsion with fragment under 30% articular surface and no subluxation = conservative (buddy strap, early ROM). Over 30% fragment or joint subluxation = surgical referral for ORIF or extension-block pinning.
• •Early protected mobilisation is the universal principle in hand injury. Prolonged immobilisation is the commonest cause of irreversible PIP and DIP joint stiffness, particularly after PIP dislocation.