JERSEY FINGER
FDP Avulsion Injury
Leddy-Packer Classification
Critical Must-Knows
- Caused by forced extension of a flexed DIPJ (e.g., grabbing a jersey).
- Ring finger is most commonly affected due to tethering by lumbricals/connections.
- Type I injuries loose blood supply (vincula) and must be repaired within 7-10 days.
- Type II/III retain some blood supply via vincula and can be repaired later (up to 3-6 weeks).
- Clinical sign: Loss of active DIP flexion. Finger lies inextension in resting cascade.
- Repair involves re-attaching tendon to bone (Suture anchor or Pull-out button).
Examiner's Pearls
- "Beware the 'sprained finger' diagnosis. Always test active DIP flexion isolation.
- "The FDP avulsion often includes a bony fleck visible on X-ray (Type III).
- "Chronic injuries (greater than 3 months) usually require fusion or 2-stage reconstruction.
The Missed Diagnosis
The Trap
"Just a Sprain" The finger is often swollen and painful. The patient can still flex the PIPJ (FDS intact). If you don't isolate the DIPJ, you will miss the FDP rupture. Missing a Type I injury leads to a permanently functionless FDP due to retraction and necrosis.
The Test
Isolate DIP Flexion Hold the PIPJ and MCPJ in extension. Ask the patient to flex the fingertip. If they can't then think Jersey Finger. Also check resting cascade: The finger will lie straighter than the others.
| Condition | Tendon | Deformity | Urgency |
|---|---|---|---|
| Jersey Finger | FDP Avulsion | Loss of DIP Flexion | High (Type I) |
| Mallet Finger | Extensor Avulsion | Loss of DIP Extension | Medium (Splint) |
| Trigger Finger | Stenosing Tenosynovitis | Locking in Flexion | Low (Elective) |
| Volar Plate | Ligament Avulsion | PIPJ Hyperextension | Medium (Splint) |
PALMLeddy-Packer Classification
Memory Hook:Where did the tendon go?
GRIPSurgical Goals
Memory Hook:Surgery restores GRIP.
IRISPhases of Healing
Memory Hook:The tendon heals like an IRIS opening.
RINGAnatomy of Injury
Memory Hook:The RING finger GRABS.
Overview
Jersey Finger is an avulsion of the Flexor Digitorum Profundus (FDP) tendon from its insertion at the base of the distal phalanx. It typically occurs in contact sports when a player grabs an opponent's jersey, forcing the flexed finger into extension.
The injury is significant because the FDP is the only flexor of the DIP joint. Retraction of the tendon can compromise its vascular supply, dictating the urgency of repair.
Pathophysiology and Mechanisms
Flexor Digitorum Profundus (FDP)
- Origin: Forearm (Ulna).
- Insertion: Base of Distal Phalanx (Volar).
- Action: Flexes DIPJ, PIPJ, MCPJ, Wrist.
- Blood Supply:
- Vincula Longa: From dorsal mesentery at PIPJ level.
- Vincula Brevia: From volar plate at DIPJ level.
- Diffusion: From synovial fluid within the sheath.
The watershed zone is less relevant here than in Zone II.
Classification Systems
Leddy-Packer Classification
This classification guides urgency of repair.
- Type I: Tendon retracted to Palm. Vincula ruptured. URGENT (less than 1 week).
- Type II: Tendon retracted to PIPJ (Zone II). Held by Vincula Longa. FDS allows some blood supply. Semi-Urgent.
- Type III: Tendon at DIPJ (Zone I). Large bony fragment prevents retraction past A4 pulley. Elective.
- Type IV: (Smith) Avulsion of tendon OFF the fracture fragment. Or double level injury. Rare. Urgent.
- Type V: (Al-Qattan) Extra-articular bony avulsion with comminution.
Usually diagnosed on X-ray.
History
History
- Mechanism: "Grabbed a jersey", "Finger got stuck".
- Sensation: "Pop" or "Snap" felt in the finger or palm.
- Pain: Palm pain (Type I) or Finger pain (Type II/III).
Ask about the specific moment of injury (tackle).
Examination
Examination
- Cascade: The finger lies in extension relative to others (Loss of flexor tone).
- Active Motion: Isolate the DIPJ. Hold PIPJ straight. Ask for flexion. Zero active flexion.
- Tenderness: Palpate the flexor sheath proximally to find the retracted stump. (Palm = Type I, PIP = Type II).
- Neuro: Check digital nerves (often neuropraxia).
Compare with the other hand for cascade.
Investigations
Radiology
- Views: AP, Lateral, Oblique.
- Findings:
- Type I/II: Usually negative (pure tendon), unless small fleck visible in tendon sheath.
- Type III: Large bony fragment at DIPJ base.
X-ray is critical to identify the bony fragment location, which reveals the level of retraction.
Treatment
Acute Repair (less than 3 weeks)
- Type I: Repair within 7-10 days. Reattach to bone.
- Type II/III: Repair within 2-3 weeks. Bony fixation (Screw/Wire) for Type III.
- Technique:
- Pull-out Button: Suture passed through bone and tied over a button on the nail plate.
- Suture Anchor: Mitek anchor into P3 base.
- Retraction: Must retrieve the tendon. Carefully pass through pulleys using a catheter or pediatric feeding tube. DO NOT damage the pulleys.
Preserve the A4 pulley at all costs.
Surgical Considerations
Button vs Anchor
- Pull-out Button:
- Pros: Cheap, strong.
- Cons: External hardware, risk of nail bed injury, infection, catching on clothes.
- Suture Anchor:
- Pros: Internal, easy to use, no button complications.
- Cons: Cost, risk of implant prominence/pullout.
Current trend favors Suture Anchors (minilok/micro).
Complications
- Infection: Especially with button sutures.
- Nail Deformity: If button compresses germinal matrix.
- Flexion Contracture: PIPJ or DIPJ stiffness is very common.
- Rupture: Re-rupture of repair (5-10%).
- Quadriga: If the FDP is shortened too much, it tethers the other fingers (via the common muscle belly), preventing full flexion of the uninjured fingers.
- Bowstringing: If pulleys are sacrificed, the tendon moves away from the bone, increasing the moment arm but causing a flexion contracture and loss of digital tuck.
- Rupture: Highest risk between weeks 3-6 when the patient feels better but the tendon is soft.
- CRPS: Complex Regional Pain Syndrome is a risk with any digit surgery.
- Stiffness: DIPJ stiffness is almost guaranteed. Patients must be warned.
- Pin Site Infection: If K-wires or button used.
- Scar Sensitivity: Volar scars can be painful for gripping.
Rehabilitation
- Splint: Dorsal Blocking Splint (Wrist flexed 30°, MCP flexed 60-70°).
- Protocol: Modified Duran or Belfast (Passive flexion, Active extension within block).
- Therapy: 2-3 times per week with hand therapist.
- Precautions: No active flexion, no resisted motion.
- Splint: Discontinue day splint, night splint continues.
- Motion: Active flexion begins. Blocking exercises for DIP isolation.
- Scar management: Desensitization and scar massage.
- Resistance: Progressive strengthening begins.
- Grip: Therapy putty and grip dynamometer.
- Function: Return to light duties and ADLs.
- Contact sport: Clearance for full contact by 4-6 months.
- Protection: Some athletes wear buddy tape or protection initially.
- Monitoring: Watch for rupture signs during high-load activities.
Prognosis
Outcomes by Leddy-Packer Type
| Type | Prognosis | Key Factor | ROM Recovery |
|---|---|---|---|
| Type I | Guarded | Ischemic if delayed | 60-80% |
| Type II | Good | Vincula intact | 80-90% |
| Type III | Excellent | Bone-to-bone | 90-100% |
| Type IV | Variable | Fracture healing | 70-85% |
Expected Range of Motion
Following successful repair:
- DIP flexion: Typically 50-70 degrees (normal 80-90)
- Extension lag: 10-20 degree extension lag is common and acceptable
- Grip strength: Usually recovers to 85-95% of contralateral side
- Sport return: Most athletes return to full contact by 4-6 months
Factors Predicting Outcome
Positive prognostic factors:
- Early presentation (less than 7 days for Type I)
- Type III injury pattern
- Younger patient age
- Compliant rehabilitation
Negative prognostic factors:
- Delayed presentation
- Type I with retraction to palm
- Smoker
- Manual occupation (higher demands)
- Poor therapy compliance
Salvage Options
For failed primary repair or chronic missed injuries:
- DIPJ Fusion: Most reliable salvage, excellent for grip strength
- Two-stage reconstruction: High failure rate (30-40%) but can restore flexion
- Accept dysfunction: Some patients adapt well without intervention
Even with suboptimal outcomes, most patients achieve functional pinch and grip for activities of daily living.
Evidence Base
Leddy and Packer Original
- Original description of the classification system
- Highlighted the importance of vinra and level of retraction
- Established the 7-10 day window for Type I
Button vs Anchor
- Comparison of pull-out button vs suture anchor
- Anchors showed superior biomechanical strength (in some studies)
- Buttons had higher complication rate (nail deformity, infection)
- Clinical outcomes similar regarding ROM
Chronic Reconstruction
- Results of 2-stage tendon grafting for zone I
- Fair results only reported
- High complication rate (adhesions, rupture)
- Recommended fusion for manual workers
Zone I Repair Techniques
- Biomechanics of suture anchors vs pull out buttons
- Anchors allow earlier mobilization
- Pull out buttons have high complication rate
- Recommended using 2 anchors for rotation control
Type IV Injury
- Description of Type IV: Avulsion of tendon from the fracture fragment
- Rare injury
- Require open reduction and separate tendon repair
- High risk of non-union if not rigid
Viva Scenarios
Practice these scenarios to excel in your viva examination
Scenario 1: The Missed Injury
"A rugby player presents 4 weeks after 'spraining' his ring finger. He has no active DIP flexion. X-ray is normal. What is the diagnosis and management?"
Scenario 2: The Bony Avulsion
"X-ray shows a large bony fragment at the volar aspect of the DIPJ. 10 days post injury."
Scenario 3: The 'Lump in the Palm'
"A patient complains of a tender lump in the palm 3 months after a finger injury. No DIP flexion."
MCQ Practice Points
Anatomy
Q: Why is the Ring finger most commonly affected (75%)? A: The FDP is tethered by the common muscle belly and lumbricals, limiting independent extension during grip.
Classification
Q: Which Vincula are ruptured in a Type I injury? A: Both Vincula Longa and Brevia.
Complications
Q: What is the Quadriga effect? A: Incomplete flexion of adjacent fingers due to overtightening of the repaired FDP (shared muscle belly).
Treatment
Q: What is the maximal delay for primary repair of a Type I injury? A: 7-10 days (before necrosis/contracture).
Clinical Sign
Q: What is the clinical sign of a jersey finger? A: Loss of isolated DIPJ flexion. The finger lies in extension in the resting cascade.
Type III Prognosis
Q: Which Leddy-Packer type has the best prognosis? A: Type III - bony fragment prevents retraction, vincula intact, bone-to-bone healing.
Australian Context
Epidemiology in Australian Sport
Jersey finger is one of the most common hand injuries in Australian contact sports. The highest incidence is seen in:
- Rugby Union/League: The tackle mechanism creates ideal conditions for FDP avulsion
- Australian Rules Football (AFL): Grabbing guernseys during marking contests
- Touch Football: Even non-tackle codes see jersey finger during inadvertent jersey grabs
- Martial Arts: Particularly Judo and Brazilian Jiu-Jitsu where gi grips are common
Presentation Patterns
Rural and regional players often present later than urban counterparts due to:
- Distance to specialist care: Limited access to hand surgeons outside metropolitan areas
- Initial misdiagnosis: GP may diagnose as "sprain" if DIP isolation not tested
- Stoic culture: Players often "play through" injuries, especially in amateur leagues
- Weekend injuries: Most injuries occur Saturday/Sunday with delayed Monday presentation
Healthcare System Considerations
Management in the Australian public system requires understanding of:
- Type I urgency: These patients need access to urgent hand surgery lists (within 7-10 days)
- Referral pathways: Clear referral from ED to hand surgery is essential
- Hand therapy access: Duran/Belfast protocols require skilled hand therapists
- Private insurance: Many elite athletes have private cover enabling rapid surgery
WorkCover Implications
Jersey finger also occurs in occupational settings:
- Manual laborers: Similar mechanism when grabbing materials
- Slaughterhouse workers: High-risk environment
- Return to work: Usually 3-6 months depending on occupation
Rehabilitation Resources
Successful outcomes require:
- Hand therapy: Ideally 2-3 times per week for first 6 weeks
- Splinting: Access to custom thermoplastic splint fabrication
- Patient compliance: Education about the fragile repair window
- Sport-specific rehab: Return to contact sport protocols
High-Yield Exam Summary
Classification (Leddy-Packer)
- •Type I: Palm (Urgent)
- •Type II: PIP (Semi-Urgent)
- •Type III: DIP (Bone)
- •Type IV: Fx + Avulsion
Management
- •Acute: Repair (Anchor/Button)
- •Chronic: Fusion / Graft
- •Rehab: Dorsal Block 6w
- •Preserve A2/A4 pulleys
Key Concepts
- •Ring Finger (75%)
- •Vincula Blood Supply
- •Quadriga Effect
- •Isolate DIP Flexion