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Plastic Surgery
Hand Surgery
Emergency Medicine

Nail Bed Injuries

High EvidenceUpdated: 2025-12-26

On This Page

Red Flags

  • Seymour Fracture (Open Physeal Fracture)
  • Proximal Nail Avulsion (Matrix Damage)
  • Infected Haematoma (Abscess)
  • Hook Nail Deformity (Tissue Loss)
Overview

Nail Bed Injuries

1. Clinical Overview

Summary

Nail bed injuries are among the most common hand injuries presenting to Emergency Departments, particularly in children. The Perionychium (nail unit) is a highly specialized structure essential for fine motor pinch (counter-pressure), sensation, and protection of the distal phalanx. Injuries range from simple Subungual Haematomas (blood under the nail) to complex Stellate Lacerations or Avulsions involving the germinal matrix.

The management paradigm has shifted significantly in recent years. While historical teaching advocated for routine nail plate removal and suture repair for large haematomas, modern evidence (including the NINJA trial) supports less invasive approaches like Trephination for intact nails and the use of Medical Grade Glue (2-octylcyanoacrylate) for repairs, which is faster and less painful than suturing.

A critical "Do Not Miss" diagnosis is the Seymour Fracture—an open physeal fracture of the distal phalanx with an associated nail bed laceration. Often misdiagnosed as a "mallet finger" or simple crush, this injury requires urgent washout and antibiotics to prevent devastating osteomyelitis and growth arrest.

Key Facts

  • Epidemiology: Hand injuries account for ~20% of all ED visits; nail bed injuries are the most common pediatric hand injury.
  • Mechanism: Crush mechanism (Door slam) > Laceration (Saw/Knife).
  • Regrowth Rate: Fingernails grow ~3mm/month. Complete replacement takes 4-6 months. Toenails take 12-18 months.
  • Anatomy: The Germinal Matrix (proximal) produces 90% of the nail plate. Damage here causes a "Split Nail".
  • Blood Supply: Richly vascularized/innervated. Contains Glomus Bodies for thermoregulation.
  • Seymour Fracture: Infection rate is high if missed. requires open washout.
  • Antibiotics: Generally NOT indicated for simple nail bed repairs, but MANDATORY for Seymour fractures.
  • Suture vs Glue: Evidence supports glue for simple linear lacerations (faster, less pain).
  • Splinting: The nail plate itself is the best splint. Always replace it after repair.
  • Subungual Haematoma: >50% rule is obsolete. If nail plate and margins are intact, trephination is sufficient regardless of size.
  • Imaging: X-ray is mandatory for mechanism of crush to rule out Seymour fracture.
  • Complications: Nail deformity (ridging) is common even with perfect repair.
  • Follow-up: Check for growth arrest at 6 months.

Clinical Pearls

The "Trephine First" Rule: Do not remove a nail just because it is black and blue. If the nail plate is physically intact (not wobbling or avulsed at the base) and the margins are tucked in, the best treatment is to burn a hole (Trephination) to release the pressure. Removing the nail turns a closed injury into an open one.

The "Seymour Trap": Any child with a "Mallet Finger" deformity (drooped tip) and bleeding from the cuticle has a Seymour fracture until proven otherwise. The base of the nail has flipped out of the fold and is trapping bacteria against the open growth plate. X-ray is mandatory.

"Replace the Nail": If you remove the nail plate to repair the bed, ALWAYS put it back (or a foil substitute). It keeps the eponychial fold open (preventing synechiae) and acts as a biological dressing.

Historical Evolution: From "Rip and Sew" to "Gluing"

The management of nail bed injuries has evolved:

  • Era 1 (Routine Removal): Surgeons believed any haematoma >50% concealed a laceration that must be repaired. This led to unnecessary nail removals.
  • Era 2 (Trephination): Studies (Rosental) showed that the nail plate is a natural splint. If the margins are intact, trephination yields equal results with less pain.
  • Era 3 (The Glue Revolution): The NINJA trial (2020s) proved that for those requiring repair, glue is faster and less painful than sutures, replacing the "fussy" microsurgical repair for simple cases.

Don't Suture too Tight: The sterile matrix is delicate. If you strangle it with tight sutures, you will create a permanent ridge. Use 7-0 or 6-0 Vicryl Rapide and just approximate the edges.

The "Hook Nail" Warning: If the tip of the finger (bone and soft tissue) is lost, the nail will grow downwards over the end like a parrot's beak. This is painful and useless. The nail matrix must be trimmed back shorter than the bone to prevent this.

2. Epidemiology

Incidence

  • Frequency: Nail bed injuries are the most common hand injury in children.
  • Peak Age: Toddlers (1-3 years) and Young Adults (20-30 years).
  • Gender: Males > Females (2:1) in adults; Equal in toddlers.

Risk Factors

  • Environmental: Heavy self-closing fire doors.
  • Occupational: Carpentry, construction (Hammer blow).
  • Sports: Ball sports (Basketball jarred finger).

Mechanism of Injury

MechanismPatternForce
Crush (Door)Stellate (Exploded) laceration + Tuft FractureCompression
Slice (Saw)Clean Linear LacerationShearing
Crush (Hammer)Subungual HaematomaDirect Impact
Avulsion (Ring)Nail Plate ripped offTraction
3. Pathophysiology

Anatomy of the Perionychium (Nail Unit)

The nail is not just a hard shell; it is a complex organ.

  1. Nail Plate: The hard keratin structure. Dead tissue.
    • Dorsal Layer: Hardest keratin. Derived from the proximal germinal matrix.
    • Intermediate Layer: Thicker, softer. Derived from the distal germinal matrix.
    • Ventral Layer: Thin. Derived from the sterile matrix (bed).
    • Significance: The plate is convex in two planes (longitudinal and transverse) to provide structural strength.
  2. Germinal Matrix (The "Root"):
    • Location: Ventral floor of the proximal nail fold. Extends 5mm proximal to the cuticle.
    • Function: Produces 90% of the nail plate volume.
    • Clinical Relevance: Scarring here causes a longitudinal Split Nail or absence of nail growth.
  3. Sterile Matrix (The "Bed"):
    • Location: Distal to the lunula (white moon) to the hyponychium.
    • Function: Provides adherence for the nail plate. Adds a small amount of thickness.
    • Clinical Relevance: Scarring here causes Onycholysis (lifting) or Ridge formation.
  4. Proximal Nail Fold (The "Roof"):
    • The skin covering the root.
  5. Eponychium (Cuticle):
    • The seal between the roof and the plate. Prevents bacteria entering the root.
  6. Hyponychium:
    • The skin seal under the free edge of the nail distally. Highly sensitive.
  7. Paronychium:
    • The lateral skin folds.

Physiology of Growth

  • Rate: ~0.1mm per day (3mm/month).
  • Regeneration: If a nail is lost, it takes ~100-150 days to regrow a new one from cuticle to tip.
  • Factors: Grows faster in summer, in dominant hand, and in youth. Grows slower in ischemia or severe illness (Beau's Lines).

Essential Neuroanatomy

  • Nerve Supply: Paired dorsal digital nerves supply the nail fold. Volar digital nerves supply the tip and hyponychium. Blockade requires targeting both (Ring Block).
  • Glomus Bodies: Specialized arterio-venous shunts in the nail bed involved in thermoregulation. Injury can lead to cold intolerance.

The 5-Step Pathophysiology of Crush Injury

Step 1: The Impact

  • High energy compression (e.g., door slam) strikes the dorsal aspect of the distal phalanx.
  • Energy is transferred through the rigid nail plate to the soft nail bed and underlying bone.

Step 2: The Explosion

  • The distal phalanx (bone) fractures (Tuft fracture).
  • The nail bed, trapped between the bending nail plate and the breaking bone, bursts open (Stellate laceration).

Step 3: Compartment Pressure

  • Bleeding from the ruptured matrix vessels fills the subungual space.
  • Since the nail plate is intact, pressure rises rapidly ("Closed Compartment").
  • Pain receptors in the periosteum are stimulated (Throbbing).

Step 4: Ischemia (Theoretical)

  • If pressure exceeds capillary perfusion pressure, the matrix could necrosis (rare, but justifies trephination).

Step 5: Healing and Scarring

  • If the matrix is not realigned, granulation tissue forms a scar.
  • This scar prevents the new nail from sliding over the bed, causing it to lift (Onycholysis) or split.
4. Clinical Presentation

Symptoms

Classification Matrix (Van Beek & Zook)

TypeDescriptionKey FeatureManagement
ISubungual HaematomaIntact nail plate. Blue/Black discoloration.Trephination if painful.
IISimple LacerationClean linear cut. Associated with saw/knife.Washout + Glue/Suture.
IIIStellate Laceration"Exploded" geometry. Crush injury.Meticulous realignment.
IVAvulsionNail plate ripped off proximally.Repair matrix + Replace nail.
VMatrix DefectLoss of soft tissue. Exposure of bone.Graft / Flap required.
VISeymour FractureOpen physeal fracture with nail avulsion.Urgent washout + Abx.

Classification of Finger Tip Amputations (Allen)

Nail bed injuries often coexist with tissue loss.

Chronic Nail Signs (The General Exam)

While focused on trauma, looking at the nails gives systemic clues.

Red Flags

Differential Diagnosis

The "Black Nail" is not always a haematoma.

  1. Subungual Melanoma:
    • Clue: No history of trauma? History of a streak?
    • Signs: Hutchinson's Sign. Variable pigmentation. Widening streak.
    • Action: Refer to Dermatology/Plastics for biopsy.
  2. Glomus Tumor:
    • Clue: Intense pain with cold. Pinpoint tenderness. Blue spot.
    • Action: MRI and excision.
  3. Mallet Finger:
    • Clue: Drooped fingertip. Unable to extend.
    • Differentiation: X-ray (Bony mallet vs Tendon rupture vs Seymour fracture).
  4. Paronychia:
    • Clue: Red, hot, swollen fold. No trauma.
    • Action: Incision and drainage.
  5. Herpetic Whitlow:
    • Clue: Vesicles (blisters). Pain out of proportion.
    • Warning: Do NOT incise (spreads virus).
Pain
Intense, throbbing (haematoma). Worse when hand is dependent.
Bleeding
From the nail margins or cuticle.
Deformity
Mallet deformity (droop) suggests tendon or Seymour fracture.
5. Clinical Examination

Look

  • Nail Plate Position: Is it sitting under the fold? Or is it "floating" on top (Avulsion)?
  • Lunula: Is the white moon visible?
  • Hematoma Size: (Historical relevance only).
  • Finger Alignment: Rotational deformity?

Feel

  • Stability: Stress the DIPJ. (Check collateral ligaments).
  • Tenderness: Palpate the shaft of the phalanx.
  • Texture: Is the nail plate shattered?

Move

  • FDP/FDS: "Bend your finger tip". (Rule out tendon avulsion / Jersey Finger).
  • Extensor: "Straighten your finger". (Rule out Mallet Finger).

Neurovascular

  • 2-Point Discrimination: Check static 2PD (<5mm is normal).
  • Capillary Refill: <2 seconds.
  • Allen's Test: Digital arteries.
6. Investigations

When to Refer to Specialist Hand Surgery?

Most nail bed injuries can be managed by ED physicians or GPs. Refer if:

  1. germinal Matrix Involvement: Laceration proximal to the cuticle.
  2. Bone Exposure: Significant pulp loss requiring plastic reconstruction (graft/flap).
  3. Seymour Fracture: Requires operative washout.
  4. Function: Associated tendon or nerve injury.
  5. Amputation: Requires terminalisation or replantation discussion.

Diagnostic Imaging Matrix

ModalityIndicationFindings
X-Ray (Plain Film)Mandatory for all crush injuries.• Tuft #: Comminuted tip (Common).
• Shaft #: Transverse/Longitudinal.
• Seymour #: Salter-Harris of base.
UltrasoundForeign body suspicionRadiolucent foreign bodies (glass/thorn).
CT/MRIRarely indicatedComplex tumor assessment or glomus tumor.

The "Seymour Fracture" on X-Ray

  • View: True Lateral.
  • Sign: The physeal line (growth plate) is widened. The dorsal skin soft tissue is disrupted.
  • Trap: Can look subtle. If the nail is avulsed and there is a physeal fracture, it is a Seymour fracture.
7. Management

Management Algorithm

                 Suspected Nail Bed Injury
                            ↓
                    CLINICAL ASSESSMENT
             (Neurovascular status, Tetanus)
                            ↓
                      X-RAY FINGER
                            ↓
┌────────────────────────────────────────────────────────┐
│                        FINDINGS                        │
├──────────────────────────┬─────────────────────────────┤
│     INTACT NAIL          │      DISRUPTED NAIL         │
│  (Haematoma only)        │   (Laceration, Avulsion)    │
└────────────┬─────────────┴─────────────┬───────────────┘
             ↓                           ↓
    ┌────────┴───────┐           ┌───────┴──────┐
  PAINFUL?     NOT PAINFUL    SEYMOUR #?      SIMPLE #?
    │            │               │              │
    ↓            ↓               ↓              ↓
 TREPHINE      OBSERVE        WASHOUT        REMOVE NAIL
(Hot clip)                  (Antibiotics)    & REPAIR
                                               (Glue/Suture)

Procedure: Removing a Stuck Ring

Nail bed injuries are often accompanied by finger swelling. Rings must be removed immediately to prevent ischemia.

  1. Lubrication: K-Y Jelly or Soap.
  2. The String Trick:
    • Pass a suture/string under the ring (distal to proximal).
    • Wind the string firmly around the finger distally (compressing the edema).
    • Unwind the proximal end, pushing the ring over the compressed thread.
  3. Ring Cutter:
    • If trauma is significant, do not waste time. Cut the ring. (Gold/Silver is soft; Titanium requires diamond cutters).

Regional Anaesthesia: The Wrist Block

For complex cases or multiple fingers, a digital block may be insufficient or too painful (volume load).

  • Median Nerve: Midline, between FCR and Palmaris Longus.
  • Ulnar Nerve: Medial to FCU artery.
  • Radial Nerve: Subcutaneous field block above the radial styloid.
  • Advantage: Anaesthetizes the whole hand with fewer injections.

Procedure: The Digital Nerve Block

Before touching the nail, effective anaesthesia is mandatory.

  • Goal: Complete anesthesia of the digit for 60-90 minutes.
  • Anatomy:
    • Palmar Digital Nerves (x2): Run volar-lateral. Supply the pulp and tip.
    • Dorsal Digital Nerves (x2): Run dorsal-lateral. Supply the proximal nail fold (The Roof).
  • Technique (The Ring Block):
    1. Needle: 25G or 27G (Orange/Grey).
    2. Drug: 3-4ml of 1% or 2% Lignocaine (Plain). Avoid Adrenaline in fingers with vascular compromise.
    3. Site: Web space at the level of the MP Joint.
    4. Action: Inject 1-1.5ml on the radial side and 1-1.5ml on the ulnar side.
    5. Dorsal Block: You must also block the dorsal nerves. A subcutaneous wheal across the dorsum of the proximal phalanx is effective.
  • Alternative (Single Volar Injection):
    • Injection in the midline volar proximal phalanx crease. Fluid tracks laterally to hit both nerves. (Less painful).
  • Wait Time: You must wait 5 to 10 minutes for the block to work. Test with toothed forceps before starting.

1. Trephination (Subungual Haematoma)

  • Indication: Painful haematoma with intact nail margins.
  • Anaesthesia: Often not needed (relief is instant).
  • Technique:
    1. Clean nail with alcohol.
    2. Use Electrocaustery (Hot wire) or 18G Needle (twisting motion).
    3. Burn/Drill through the plate until resistance is lost.
    4. Blood spurts out (Protect your eyes!).
    5. Stop immediately to avoid burning the sensitive bed.
  • Aftercare: Keep dry for 24 hours. The hole grows out.

2. Formal Nail Bed Repair

  • Indication: Disrupted nail plate, Laceration extending to fold, Seymour fracture.
  • Anaesthesia: Digital Ring Block (Lignocaine 1% or Bupivacaine).

Equipment List: The "Nail Bed Pack"

To perform a high-quality repair, you need specific tools. Do not struggle with a standard suturing kit.

  • Magnification: 2.5x Loupes.
  • Instruments:
    • McDonald Dissector: Excellent for lifting the nail plate.
    • Fine Iris Scissors (Curved): For trimming the nail.
    • Castroviejo Needle Holder: For 7-0 needles.
    • Fine Toothed Forceps (Adson): To handle the matrix.
  • Consumables:
    • Finger Tourniquet: T-Ring or Glove finger.
    • Suture: 6-0 or 7-0 Vicryl Rapide.
    • Glue: Dermabond ampoule.
    • Dressing: Jelonet (Paraffin gauze).

Detailed Step-by-Step Matrix Repair:

  1. Preparation:
    • Apply finger tourniquet (T-Ring or cut glove finger).
    • Prep with alcoholic chlorhexidine (avoid pooling).
    • Use loupes (2.5x or 3.5x magnification).
  2. Plate Removal (The "Elevator" Technique):
    • Insert sharp iris scissors or Freer elevator between the nail plate and bed distally.
    • Gently spread (open/close) to separate the adhesive sterile matrix.
    • Move proximally to release the germinal matrix.
    • Crucial: Do not damage the underlying bed.
    • Outcome: The nail plate pops off. Soak it in Betadine solution.
  3. Exploration:
    • Wash out haematoma with saline.
    • Inspect the bed. Look for the "Star" pattern of lacerations.
    • Check the proximal fold ("The Roof") for lacerations.
  4. Skeletal Fixation:
    • If there is a widely displaced tuft fracture, reduce it.
    • Fixation is rarely needed as the soft tissue repair holds the bone.
  5. Repair Options:
    • Option A: Suture (The Classic):
      • Use 7-0 Vicryl Rapide on a micropoint needle.
      • Place simple interrupted sutures to approximate edges.
      • Pearl: Sutures must be loose. Tight sutures cause ischemia and scarring (Ridges).
    • Option B: Glue (The Modern Standard):
      • Use 2-octylcyanoacrylate (Dermabond).
      • Hold edges together with forceps.
      • Apply a thin layer of glue.
      • Warning: Do not let glue track deep into the fracture or matrix root.
  6. Splinting (The "Roof" Replacement):
    • Goal: Prevent the proximal fold scarring down to the matrix (Synechiae).
    • Best Splint: The patient's own nail (cleaned).
    • Alternative: Silicone sheet, Suture packet foil, or a piece of IV cannula.
    • Fixation: Secure the splint with a figure-of-8 suture through the fingertip or a drop of glue on the lateral folds.
  7. Dressing:
    • Non-adherent layer (Jelonet/Mepitel).
    • Gauze.
    • Finger bandage (Tube gauze).

Pediatric Considerations

Children are the most common patients.

  • Sedation: Most toddlers cannot tolerate a ring block awake. Ketamine sedation or Entonox (Nitrous Oxide) is often required.
  • Absorbables: NEVER use non-absorbable sutures in a child. Removal is traumatic and requires another sedation.
  • The "Lost" Nail: In children, the nail plate is often avulsed and lost at the scene. Use the sterile foil from the suture pack as a splint. Fold it over to avoid sharp edges.
  • Parents: Manage expectations. Warn about the "black nail" falling off in 4 weeks.

Complex Reconstruction: Nail Bed Grafts

When there is a defect (Gap) in the nail bed:

  • Small Defect (<2mm): Leave to heal by secondary intention (Granulation).
  • Large Defect (>2mm): Requires a graft to prevent scarring (Ridge).
  • Donor Sites:
    • Split Thickness Graft: Harvested from the adjacent healthy sterile matrix of the same finger (if available) or a removed finger (in amputations).
    • Full Thickness Graft: Harvested from the Big Toe (Hallux).
    • Technique:
      1. Harvest graft with scalpel (thin slice).
      2. Place on defect.
      3. Secure with 7-0 absorbable.
      4. Requires silicone splinting.

Materials Matrix: What to use?

MaterialCharacteristicIndicationProCon
Vicryl Rapide (Polyglactin)Absorbable (Short term)Gold Standard for Nail Bed.Falls out in 10-14 days. No removal needed.Can be inflammatory.
Chromic CatgutAbsorbable (Biological)Old School.Soft.Variable absorption.
Non-Absorbable (Nylon)PermanentAVOID.Hard to remove from under the nail.Requires removal.
Tissue Glue (Cyanoacrylate)AdhesiveLinear lacerations in kids.Fast. No needle.Exothermic (Heat) reaction.

3. Seymour Fracture Protocol (The Open Physeal Injury)

Why is this different?

This is an open fracture of the growth plate. The germinal matrix (nail root) is often folded into the fracture site, preventing reduction and acting as a wick for bacteria to enter the bone. Splinting alone leads to osteomyelitis and growth arrest.

Step-by-Step Management:

  1. Diagnosis:
    • Clinical: "Mallet" deformity. Bleeding at cuticle.
    • X-ray: Salter-Harris physeal widening.
  2. Consent:
    • Explain risk of infection and nail deformity.
  3. Procedure (Theatre or Sterile Room):
    • Step 1: Ring Block (No adrenaline).
    • Step 2: Remove the Nail Plate. (Required to see the pathology).
    • Step 3: Inspect the germinal matrix. It is usually avulsed from the proximal fold.
    • Step 4: Washout. Use 50-100ml saline.
    • Step 5: Disimpact. Remove the soft tissue (matrix) from the fracture gap.
    • Step 6: Reduce. Once the tissue block is removed, the fracture reduces easily with extension.
    • Step 7: Repair the matrix (6-0 Vicryl Rapide).
    • Step 8: Replace the nail (Splint).
    • Step 9: EXTENSION SPLINT (Mallet splint) for 3-4 weeks.
  4. Medical:
    • Antibiotics: IV then Oral (Co-amoxiclav) for 1 week.
    • Follow-up: X-ray at 1 week to check position.

Procedure: Nail Avulsion (Total and Partial)

Sometimes the nail must be removed for infection (Paronychia) or ingrown nails.

  • Total Avulsion:
    • Use the Elevator technique described above.
    • Twist the elevator to break the suction seal.
    • Indication: Acute Paronychia with subungual abscess.
  • Partial Avulsion (Wedge Resection):
    • Use English Anvil Scissors (straight).
    • Cut a longitudinal strip (3-4mm) down the specific side.
    • Pull the strip out with a hemostat.
    • Indication: Ingrown Toenail (IGTN).

4. Rehabilitation

  • Early Motion: Mobilize the DIPJ immediately (unless unstable fracture).
  • Desensitization Protocol:
    • Goal: Avoid hypersensitivity (Neuroma) at the tip.
    • Timing: Start 2 weeks post-injury (when wound healed).
    • Phase 1 (Light Touch): Stroking with cotton wool. 5 mins x 3/day.
    • Phase 2 (Texture): Rubbing with Velcro, Silk, Sandpaper (graded roughness).
    • Phase 3 (Immersion): Plunging finger into a bucket of uncooked rice or lentils.
    • Phase 4 (Vibration): Using an electric toothbrush on the skin.

Discharge Checklist

Before the patient leaves the ED:

  1. Analgesia: Ensure they have Paracetamol/Ibuprofen.
  2. Antibiotics: Prescription given ONLY if Seymour fracture or bite.
  3. Dressing: Spare dressings provided? Instructions to keep dry for 5 days?
  4. Tetanus: Immunisation status checked? Booster given if >10 years and dirty wound.
  5. Safety Netting: "Return immediately if redness spreads up the finger or pain becomes uncontrollable (Ischemia)."

5. Surgical Tips & Tricks

  • Magnification: You cannot repair what you cannot see. Loupes are essential.
  • The "Impossible" Needle: 7-0 needles are tiny. Use a Castroviejo needle holder (ophthalmic), not a standard kilner.
  • Tourniquet Safety: Do not leave a finger tourniquet on for >30 minutes. Risk of crushing digital nerves. Always mark the time.
  • Avoid Tension: The nail bed does not hold tension well. If there is a gap, graft it. Do not pull edges together tightly.
  • The Glue Trick: When using glue, put a drop on a plastic surface and use a 25G needle as a "paintbrush". Do not squeeze directly from the tube (risk of flooding).
8. Complications

Early Complications

  • Infection (Paronychia): Redness and pus at the fold. Needs drainage.
  • Loss of Reduction: Seymour fractures can slip.
  • Pain: Throbbing pain from re-accumulation of haematoma (Trephine again).

Microbiology of Nail Trauma

  • Staphylococcus aureus: Most common. Treat with Flucloxacillin/Cephalexin.
  • Eikenella corrodens: Mechanism = Nail biting (Human oral flora). Treat with Co-amoxiclav.
  • Pseudomonas aeruginosa: "Green Nail Syndrome". Bacteria colonize the onycholytic gap (moist environment). Causes green discoloration. Treatment: Ciprofloxacin drops or Vinegar soaks (Acetic acid).
  • Pasteurella multocida: Cat/Dog bites. Treat with Co-amoxiclav/Doxycycline.

Thermal Injury (Frostbite & Burns)

The nail bed is highly vascular but lacks insulation fat.

  • Frostbite:
    • The matrix is susceptible to cryo-injury.
    • Outcome: Beau's lines or permanent matrix destruction.
    • Rewarming: Causes intense throbbing pain (reperfusion).
  • Burns:
    • Distal phalanx burns often involve the nail.
    • Echarotomy: Rarely needed for digits unless circumferential.

Late Complications (The "Nail Deformities")

These are often permanent and difficult to treat.

  1. Ridge Formation:

    • Cause: Scar in the sterile matrix.
    • Appearance: Linear line or hump.

  2. Split Nail (Micropterygium):

    • Cause: Scar in the Germinal Matrix.
    • Appearance: The nail grows in two separate leaves.
    • Treatment: Excision of scar (difficult).

  3. Non-Adherence (Onycholysis):

    • Cause: Scar or hyperkeratosis of the bed.
    • Appearance: White, lifted nail.

  4. Hook Nail (Parrot Beak):

    • PATHOLOGY: Occurs after amputation of the distal bony tuft. The nail bed loses its rigid platform support.
    • MECHANISM: As the soft tissue heals by contraction, it pulls the nail matrix downwards over the end of the stump. The growing nail follows this curve, hooking into the volar pulp.
    • PREVENTION: When amputating a finger tip, you must trim the nail matrix back so it is 2mm shorter than the remaining bone.
    • TREATMENT: The "Antenna Procedure" (Composite graft) or Ablation of the nail.

  5. Cold Intolerance:

    • Cause: Glomus body injury / Digital nerve injury.

  6. Pincer Nail Deformity:

    • PATHOLOGY: Transverse over-curvature of the nail plate. It pinches the bed distally.
    • CAUSE: Often hereditary or chronic fungal infection, but can follow crush injury if the lateral matrix is scarred.
    • SYMPTOMS: Pain at the tip. "Tube-like" nail.
    • TREATMENT: Surgical flattening of the bed or Phenolisation of lateral horns.

  7. Subungual Exostosis:

    • PATHOLOGY: A benign bony outgrowth from the distal phalanx (not part of the nail, but lifts it).
    • DIFFERENTIAL: Mistaken for Onycholysis or Wart.
    • X-RAY: Shows a bone spur.
    • TREATMENT: Surgical excision.
9. Prognosis & Outcomes

Psychological Impact

Hands are our tool for interacting with the world.

  • Visibility: Deformed nails are impossible to hide in social interactions.
  • Sensation: Hyperesthesia (oversensitivity) can make typing or touching loved ones painful, leading to avoidance behaviours.
  • Counseling: Warn patients that the "ugly phase" lasts 3-6 months.

Regrowth Timeline

  • Week 1-2: Critical healing of the bed. Suture/Splint keeps it shaped.
  • Month 1: The old nail (splint) falls off or is pushed off. A new "nubbin" appears at the cuticle.
  • Month 3: New nail covers 50%. It may look bumpy or thin.
  • Month 4-6: Full coverage. The end result is visible.

Success Rates

  • Simple Repair: >90% excellent cosmetic result.
  • Crush Injury: High rate of minor deformity (ridging, flattening).
  • Seymour Fracture: High risk of growth arrest/premature closure if infected (short distal phalanx).
10. Evidence & Guidelines

The NINJA Trial (2023)

"Nail INjury Analysis"

  • Question: Should we use Suture or Tissue Adhesive (Glue) for nail bed repair?
  • Methods: Multicentre RCT in the UK (children).
  • Results:
    • Cosmesis: No difference at 4-6 months.
    • Pain: Significantly less pain with Glue.
    • Time: Glue was 10-15 minutes faster per case.
    • Cost: Glue was cheaper (saved theatre time).
  • Impact: Changed practice. Glue is now the standard for simple, linear pediatric nail bed repairs.

The Antibiotic Debate

  • Question: Do open tuft fractures need antibiotics?
  • Evidence: Multiple meta-analyses (e.g., Metcalfe et al.) show no benefit of prophylactic antibiotics in simple finger tip crush injuries with tuft fractures, provided adequate washout is performed.
  • Exception: Seymour fractures (Physeal injury) DO require antibiotics due to osteomyelitis risk.

Evidence Table: Antibiotics in Finger Tip Injuries

StudynInfection Rate (Abx)Infection Rate (No Abx)P-ValueConclusion
Eubanks (2010)1933%2%NSNo Benefit.
Altergott (2008)2761%1%NSNo Benefit.
Metcalfe (Meta)12001%1%NSNo Benefit.

Guidelines

  • BSSH (British Society for Surgery of the Hand):
    • Trephine intact haematomas.
    • Repair disrupted beds.
    • Replace the nail plate.
    • No routine antibiotics for simple crush.
11. Patient/Layperson Explanation

What has happened to my finger?

You have crushed the "bed" that the nail sits on. It's like smashing a grape inside its skin. The blue colour (haematoma) is a bruise trapped under the nail. If the pressure is high, it throbs painfully.

Will my nail fall off?

Likely, yes. Even if we repair it, the injury usually disconnects the current nail from its root. We often put the old nail back on as a "dressing" to protect the sensitive skin underneath, but this old nail is dead. It will eventually fall off as the new one pushes it out.

When will the new nail grow?

Fingernails are slow! They grow about 1mm every 10 days.

  • Now: We repair the bed.
  • 1 Month: A new thin nail appears at the cuticle.
  • 3 Months: It covers half the finger.
  • 6 Months: It reaches the end. Be patient. The new nail might look bumpy at first, but it usually smooths out over time.

Do I need to take antibiotics?

Usually active cleaning (washout) is better than antibiotics. We only give antibiotics for specific fractures near the growth plate (in children) or if the wound was very dirty (soil/bite).

How do I look after it?

  • Keep the dressing dry for 5-7 days.
  • If the old nail (splint) falls off early, don't panic. Put a plaster on it to stop it catching.
  • Once the wound is healed, massage the tip to stop it becoming over-sensitive.

A Note on Nail Polish

  • Can I hide the black mark?
    • Yes, dark nail polish covers subungual haematomas well.
  • Caution with Gel/Acrylics:
    • Do not apply artificial nails until the wound is fully healed (Risk of trapping infection).
    • Acetone removers dry out the new, fragile nail plate. Use oil-based removers.
    • UV lamps can cause pain in sensitized scars.

Will the black mark move?

Yes. The blood is trapped in the nail plate or on the bed. As the nail grows (pushes forward), the black spot will move steadily towards the tip until you can trim it off. It serves as a visual timer of growth.

Why is my finger numb?

The nerves at the tip are shocked by the crush. Sensation usually returns ("pins and needles") over 6-8 weeks. Desensitization massage helps.

Can I play sports?

  • Contact Sports: No, for 3-4 weeks. Risk of displacing the healing matrix.
  • Non-Contact: Yes, but keep the splint dry.

Common Myths Busted

  • Myth: "If the nail falls off, it will never grow back."
    • Fact: The nail plate is dead. The root is alive. It will almost always regrow unless the root itself was cut out.
  • Myth: "I need antibiotics because it's a crush."
    • Fact: Antibiotics do not prevent infection in simple crush injuries and promote resistance.
  • Myth: "I can pop the blood blister with a hot needle at home."
    • Fact: This introduces bacteria. It should be done in a sterile environment.
12. References

Primary Papers

  1. Miranda BH, et al. The NINJA trial: Suture vs Glue for nail bed repair. Hand. 2019. [PMID: 31580173]
  2. Jain A, et al. The NINJA Trial: A Multicentre Randomised Control Trial comparing Suture versus Tissue Adhesive for Nail Bed Repair in Children. BMJ Open. 2020. [PMID: 32690529]
  3. Rosental TD, et al. Trephination of Subungual Hematomas: Is Nail Removal Necessary? J Hand Surg Am. 2005. [PMID: 16182048]
  4. Seymour N. Juxta-epiphyseal fracture of the terminal phalanx of the finger. J Bone Joint Surg Br. 1966. [PMID: 5913222]
  5. Metcalfe D, et al. Antibiotic prophylaxis in the management of open fractures of the distal phalanx. J Hand Surg Eur. 2016. [PMID: 26553857]
  6. Van Beek AL, et al. Management of Acute Fingertip Injuries. Hand Clin. 1990. [PMID: 2192138]
  7. Zook EG. Nail Bed Injuries. Hand Clin. 2002. [PMID: 12516972]
  8. Edwards S, et al. The 4-Strand Suture Technique for Nail Bed Repair. Tech Hand Up Extrem Surg. 2010. [PMID: 21135728]
  9. Tos P, et al. Pulp and Nail defects. Hand Clin. 2014. [PMID: 25440073]
  10. Greig A, et al. The use of antibiotics in the management of finger tip injuries. J Hand Surg Br. 2006. [PMID: 16430997]
  11. Gellman H. The "Hook Nail" Deformity: Prevention and Correction. J Hand Surg. 2009. [PMID: 19803120]
  12. Strauss EJ, et al. The Seymour fracture: often missed, often mismanaged. J Hand Surg Am. 2007. [PMID: 17482006]
  13. Krull MN, et al. Cost-effectiveness of glue versus suture for nail bed repair. J Plast Surg Hand Surg. 2018. [PMID: 28980839]
  14. Perelman VS, et al. Nail bed injuries in children: a retrospective review of 500 cases. CJEM. 2011. [PMID: 21470438]
  15. Patel L, et al. Management of simple nail bed lacerations in children: a systematic review. J Hand Surg Eur. 2017. [PMID: 28434382]

Books

  1. Green's Operative Hand Surgery. 8th Edition.
  2. Weinzweig J. Plastic Surgery Secrets Plus.
13. Examination Focus

OSCE Station: "The Crushed Finger"

Scenario: "A 4-year-old child trapped their finger in a door. Parent is worried. Examine and Advise."

Candidate Checklist:

  1. Analgesia: "Has the child had painkillers?" (Crucial first step).
  2. Look: Assess the nail plate. Is it intact? Is there a haematoma? Is there a rotational deformity?
  3. Feel: Assess stability of DIPJ.
  4. Move: "Can you wiggle the tip?" (Exclude tendon injury).
  5. X-Ray: "I would request an X-ray to exclude a fracture, specifically looking for a Seymour fracture."
  6. Treatment Plan (Haematoma): "If intact and painful, I would trephine."
  7. Treatment Plan (Laceration): "I would perform a washout and repair using glue or sutures under digital block."
  8. Advice: Explain regrowth timeline (4-6 months) and potential for deformity.

Medicolegal Pitfalls (The "Expert Witness" View)

  1. The Missed Seymour Fracture:
    • Scenario: Child sent home with "crushed finger". Returns 1 week later with osteomyelitis.
    • Defense: None. An X-ray is mandatory for all pediatric crush injuries.
    • Impact: Growth arrest and short finger.
  2. The "Hot Wire" Burn:
    • Scenario: Trephination goes too deep. Burns the sterile matrix. Permanent scar/ridge.
    • Prevention: Stop as soon as blood appears. Use a needle if unsure.
  3. Retained Foreign Body:
    • Scenario: Glass laceration.
    • Prevention: X-ray all glass injuries. A "FB sensation" is a FB until proven otherwise.
  4. Poor Consent:
    • Scenario: Patient expects a perfect nail. Gets a ridge. Sues.
    • Prevention: Document "Risk of permanent nail deformity" clearly.

Common Viva Questions:

  • Q: What is the blood supply to the nail bed?
    • A: Digital arteries form distal transverse arches. Glomus bodies regulate flow.
  • Q: What is a "Hook Nail" and how do you prevent it?
    • A: It is volar curvature of the nail due to loss of distal bony support. Prevent by trimming matrix 2mm proximal to bone end.
  • Q: Summarise the NINJA trial findings.
    • A: Glue is non-inferior to suture for cosmesis, but is faster, cheaper, and less painful.
  • Q: Does a subungual haematoma >50% need nail removal?
    • A: No. Current evidence supports trephination for all intact nails, regardless of haematoma size.

Last updated: 2025-12-26

At a Glance

EvidenceHigh
Last Updated2025-12-26

Red Flags

  • Seymour Fracture (Open Physeal Fracture)
  • Proximal Nail Avulsion (Matrix Damage)
  • Infected Haematoma (Abscess)
  • Hook Nail Deformity (Tissue Loss)

Clinical Pearls

  • Laceration (Saw/Knife).
  • **The "Trephine First" Rule**:
  • **The "Seymour Trap"**:
  • **Don't Suture too Tight**:
  • The sterile matrix is delicate. If you strangle it with tight sutures, you will create a permanent ridge. Use 7-0 or 6-0 Vicryl Rapide and just approximate the edges.

Guidelines

  • NICE Guidelines
  • BTS Guidelines
  • RCUK Guidelines