High Yield Overview

FINGERTIP INJURIES

Nail Bed Repair and Local Flaps

50%Hand Injuries

1cmHeals by Secondary Intention

HookNail Deformity

FlapAtasoy / Moberg

Allen Classification

Type I

PatternPulp only (Distal to Tuft)

Treatment

Type II

PatternPulp + Nail Bed (Exposes Tuft)

Treatment

Type III

PatternThrough Phalanx (Distal 1/3)

Treatment

Type IV

PatternProximal to Lanula (Proximal Phalanx)

Treatment

Critical Must-Knows

Defects less than 1cm with NO exposed bone heal excellently by secondary intention.
Exposed bone requires flap coverage or shortening.
The Germinal Matrix produces the nail plate; the Sterile Matrix allows adherence.
Germinal Matrix scarring causes SPLIT nail.
Sterile Matrix scarring causes NON-ADHERENT nail.
A Hook Nail results from loss of bony support to the nail bed tip.
Subungual hematoma greater than 50% does NOT mandate removal unless nail plate is disrupting the fold.

Examiner's Pearls

"
Moberg flap is for the THUMB only (Dorsal blood supply allows volar advancement).
"
Never advance Volar skin on a standard finger greater than 1cm (Necrosis risk).
"
Trephination is for pain relief, not volume reduction.

Clinical Imaging

Imaging Gallery

Illustration of the operative methodEpineural neurorrhaphy between the pulp branch of the flap and injured finger.Credit: Lee NH et al. via Arch Plast Surg via Open-i (NIH) (Open Access (CC BY))

Illustration of the operative methodThe joined nerves are tucked into the wound and the remainder of the flap margin, and all of the wounds are sutured. — Illustration of the operative methodThe joined nerves are tucked into the wound and the remainder of the flap margin, and all of the wounds are sutureCredit: Lee NH et al. via Arch Plast Surg via Open-i (NIH) (Open Access (CC BY))

Crushing injury of the left index finger by a press machineNeurorrhaphy was performed using 11-0 nylon sutures.Credit: Lee NH et al. via Arch Plast Surg via Open-i (NIH) (Open Access (CC BY))

Intraoperative viewInnervated cross-finger pulp flap was performed using the radial side of the middle finger as the donor site.Credit: Lee NH et al. via Arch Plast Surg via Open-i (NIH) (Open Access (CC BY))

Clinical Imaging

Imaging Gallery

Pre-operative marking showing V-Y rotation advancement flap design for fingertip reconstruction — Pre-operative marking of bilateral V-Y rotation advancement flaps for a dorsal oblique fingertip amputation. The 'V' limbs are drawn in a convex manner to incorporate the neurovascular bundles, ensuring sensate flap coverage.Credit: Sungur N et al. Hand (N Y). 2012. AASH

Illustration showing the steps of V-Y rotation advancement flap for fingertip reconstruction — Surgical technique illustration of bilateral V-Y rotation advancement flaps. Left: V-shaped flap design at the pulp. Centre: Flap elevation with neurovascular bundle preserved. Right: Y-shaped closure providing well-padded, sensate coverage of the fingertip defect.Credit: Sungur N et al. Hand (N Y). 2012. AASH

Post-operative result of V-Y flap fingertip reconstruction showing healed thumb tip with minimal scarring — Post-operative result at one month following V-Y rotation advancement flap for thumb tip amputation. Note the well-contoured pulp, minimal scar visibility, and preserved nail anatomy.Credit: Sungur N et al. Hand (N Y). 2012. AASH

The Hook Nail Deformity

The Cause

Tight Closure over Bone If you pull the nail bed tightly over the tip of a shortened distal phalanx, or if there is insufficient bony support, the nail bed curves volarly. As the nail grows, it curves around the tip like a parrot's beak.

The Prevention

Adequate Bone Support The bone must support the nail bed fully. If the bone is short, trim the nail bed back or advance bone/soft tissue. Do not suture the nail bed under tension over the steep cliff of the amputation.

Flap	Indication	Vessel	Movement
Atasoy (V-Y)	Transverse / Dorsal Oblique	Subcutaneous perforators	Advancement
Kutler (Lateral V-Y)	Transverse / Volar Oblique	Lateral digital	Bilateral Advancement
Moberg	Thumb Tip	Neurovascular Bundles	Volar Advancement
Cross Finger	Volar Oblique / Large	Dorsal Digital (Donor)	Transposition

Mnemonic

SPDSGoals of Reconstruction

Sensate

Must have sensation (tactile gnosis).

Painless

No neuroma.

Durable

Thick padding.

Stable

Stable pulp for pinch.

Memory Hook:A fingertip must have SPDS (Speed).

Mnemonic

0.1mmNail Growth

0.1

mm/day

Daily growth rate.

mm/month

Monthly growth rate.

100

days

Time to replace entire nail (3-4 months).

Toe

Slow

Toenails grow at half the speed.

Memory Hook:Nails grow 0.1mm per day.

Mnemonic

GLUENail Bed Repair

Glue

Dermabond is faster/less painful.

Loupes

Magnification is essential.

Undermine

Slightly mobilize to reduce tension.

Eponychium

Splint the fold (Stent).

Memory Hook:Don't forget the glue option.

Overview

Definition

Fingertip injuries are defined as those occurring distal to the insertion of the Flexor Digitorum Profundus (FDP) and Extensor tendons. They involve the specialized organs of the nail complex and the highly sensate digital pulp.

The goal of treatment is to restore a functional, sensate, and non-painful tip. While complex reconstruction (flaps) is elegant, simple management (secondary intention) often yields superior functional and cosmetic results for small defects.

Pathophysiology and Mechanisms

The Perionychium

Nail Plate: Hard keratin structure.
Germinal Matrix: Proximal section (under the fold). Produces 90% of the nail plate. Injury here causes the nail to stop growing or split.
Sterile Matrix: Distal section (under the plate, distal to lunula). Produces a thin layer of keratin that adheres the plate to the bed. Injury here causes non-adherence.
Hyponychium: Thickened skin at the distal edge, a barrier to infection.
Eponychium: Dorsal skin fold (cuticle).
Paronychium: Lateral skin folds.

The germinal matrix extends proximally to the insertion of the extensor tendon.

Classification Systems

Allen Classification

Type I: Pulp only. (No bone exposed).
Type II: Pulp + Nail bed. (Bone exposed).
Type III: Partial loss of distal phalanx.
Type IV: Proximal to lunula (Germinal matrix loss).

Type I and II are the most amenable to conservative management.

History

History Factors

Mechanism: Crush (burst nail bed) vs Laceration (clean cut) vs Avulsion (pulling).
Time: How long since injury? Clean wounds can be closed up to 12-24 hours.
Occupation: Manual labourer (needs durable tip) vs Pianist (needs sensation/shape).
Hand Dominance: Right or left handed? Index/Thumb are critical.
Hobbies: Musical instruments, sports, fine motor activities.
Smoker: Risk for flap necrosis. Counsel for cessation.
Diabetes: Impaired healing, infection risk.
Medications: Anticoagulants, immunosuppressants.

Smoking cessation is critical for flap survival (Moberg/Atasoy).

Investigations

Radiology

Standard: PA and Lateral views.
Look for:
- Tuft Fracture: Comminuted fracture of distal tip (very common with crush). Usually needs no fixation.
- Shaft Fracture: May need K-wire.
- Avulsion: FDP avulsion (Jersey finger) or Extensor (Mallet).
- Foreign Body: Glass/Metal.

Ultrasound is useful for radiolucent foreign bodies (thorn/wood).

Examination

Physical Examination

Bone Exposure: Look carefully. Probe the wound. Small exposed tufts may granulate.
Nail Bed: Check for subungual hematoma, laceration, or avulsion.
Nail Plate: Is it intact, lacerated, or avulsed from the fold?
Tendons: Verify FDP/Extensor function (if injury is proximal to insertion).
Sensation: Test 2PD before local anaesthetic (Normal: 2-4mm).
Perfusion: Cap refill, temperature, Allen's test to digits.
Defect Size: Measure in mm. Critical for treatment planning.

Always document sensation BEFORE injecting lignocaine.

Treatment

Defect Management Algorithm

No Exposed Bone (Defect less than 1cm):
- Secondary Intention: Dressings. Best sensation. Best padding.
Exposed Bone:
- Shortening: Simple, effective. Good for labourers.
- Local Flap: If length must be preserved.
- Graft: Poor take over bone (needs periosteum).
Thumb: Distinct entity. Length is critical. Use Moberg flap.

Preserving thumb length outweighs cosmetic concerns.

Trephination of a painful subungual hematoma.Credit: OrthoVellum

Surgical Considerations

The V-Y Advancement Flap (Atasoy)

Indication: Transverse or Dorsal Oblique amputations.
Design: V-shaped incision with apex at DIPJ crease.
Dissection: Cut skin only. Tease fibrous septae deep to flap to mobilize it. DO NOT undercut the base (blood supply).
Movement: Advance distally over bone.
Closure: Y-shape closure.
Limit: Advances about 5-10mm max.

Ensure the "V" apex is at the DIPJ crease to avoid scar contracture across the joint.

Complications

Neuroma: Painful nerve ending. Requires resection and burying in muscle/bone.
Hook Nail: Curvature of nail over tip. Difficult to trim. Catching.
Split Nail: scar in germinal matrix.
Non-Adherent Nail: scar in sterile matrix.
Hypersensitivity: Common. Needs desensitization therapy (tapping, texture rubbing).
Cold Intolerance: Persistent problem with replants and flaps.

Rehabilitation

Week 1

Splint: Aluminum tip protector or thermoplastic cap.
Wound: Keep dry. Occlusive dressing for secondary intention.
Nail: Keep stent (nail plate or foil) in place.
Elevation: Reduce swelling.
Pain: Simple analgesia. Avoid NSAIDs initially (may affect healing).

Week 2-3

Sutures: Remove non-absorbable sutures (if used).
Nail Stent: Can remove at 3 weeks.
Desensitization: Start early tapping/rubbing to prevent hypersensitivity.
ROM: Mobilize DIPJ. Active flexion/extension.
Edema Control: Coban wrap if needed.

Week 4-6

Grip Exercises: Putty, stress ball.
Pinch Strength: Key pinch, tripod pinch exercises.
Scar Massage: Soften and desensitize scar tissue.
Light Activities: Typing, writing.

Month 3-6

Nail: New nail plate grows in (3-4 months for full replacement).
Sensation: Returns gradually over 6-12 months.
Cold Intolerance: May persist, improves with time.
Return to Work: Manual workers 4-8 weeks; fine motor 8-12 weeks.

Hand Therapy Principles

Early Motion: Critical to prevent DIPJ stiffness.
Desensitization Program: Texture grading from soft to rough materials.
Protective Splinting: Custom tip guard for return to work.
Work Hardening: Simulate occupational demands.
Psychological Support: Fingertip injuries can be distressing.

Prognosis

Sensation: Secondary intention healing gives BETTER sensation (2PD 3-4mm) than grafts or Cross Finger flaps (2PD 6-8mm).
Aesthetics: Flaps look better initially but secondary intention creates a surprisingly normal fingerprint pattern.
Nail: Deformity is the most common long-term complaint.
Pain: Cold intolerance is rare with secondary intention but common with flaps.

Evidence Base

Conservative Management of Fingertip Injuries

Moneim et al. • Hand Clin (1985)

Key Findings:

Review of defects up to 1cm treated by secondary intention
Excellent sensory recovery (near normal 2PD)
Durable padding
Few complications (cold intolerance less common than flaps)

Clinical Implication: Don't rush to flap small defects.

Antibiotics for Open Tuft Fractures

Rubin et al. • Ann Emerg Med (2010)

Key Findings:

RCT of antibiotics vs placebo for open tuft fractures
No difference in infection rate
Antibiotics NOT indicated for uncomplicated open tuft fractures

Clinical Implication: Stop prescribing Keflex for simple smashed tips.

Subungual Hematoma Drainage

Rosique et al. • J Trauma (2012)

Key Findings:

Comparison of nail removal vs trephination for large hematomas
Nail removal associated with higher rate of nail deformity
Trephination alone is adequate even for large hematomas if nail plate and margin are intact

Clinical Implication: Drill it, don't peel it.

The Moberg Flap

Moberg E. • J Bone Joint Surg Am (1964)

Key Findings:

Original description of rectangular advancement flap for thumb
Possible due to dorsal blood supply to thumb tip
Contraindicated in fingers (dorsal skin necrosis risk)

Clinical Implication: Know your vascular anatomy.

Nail Bed Repair Materials

Vasudevan et al. • J Hand Surg (2012)

Key Findings:

Comparison of 2-octylcyanoacrylate (Dermabond) vs Suture
Dermabond was faster and less painful
Equivalent cosmetic outcome for nail growth

Clinical Implication: Glue is an option for nail bed repair.

Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

Scenario 1: The Smashed Thumb

EXAMINER

"A carpenter hits his thumb with a hammer. There is a large subungual hematoma (90%) and a transverse laceration through the nail plate. X-ray shows a comminuted tuft fracture. How do you manage this?"

EXCEPTIONAL ANSWER

This is an open tuft fracture with nail bed injury. (Wait, is the nail plate intact? No, lacerated). Since the nail plate is lacerated, the nail bed is likely disrupted. I would remove the nail plate, irrigate the fracture, repair the nail bed with 6-0 Chromic gut visually, and replace the nail plate as a stent. I would NOT start antibiotics based on the evidence (Rubin et al). Tetanus update.

KEY POINTS TO SCORE

Nail plate laceration = Nail bed injury

Need to repair nail bed accurately

No antibiotics typically needed

COMMON TRAPS

✗Just trephining a lacerated nail

✗Using non-absorbable suture on nail bed

LIKELY FOLLOW-UPS

"What if the nail plate was intact but hematoma was 90%?"

"If the nail plate is intact and stable in the fold, I would just trephine it for pain relief. Removing it creates a compound wound unnecessarily."

VIVA SCENARIOStandard

Scenario 2: The Exposed Bone

EXAMINER

"A chef slices off the tip of his index finger. There is a 1cm x 1cm defect with bone exposed. The cut is transverse. He wants to return to work ASAP."

EXCEPTIONAL ANSWER

With exposed bone, secondary intention will take too long and risks osteomyelitis (or unstable scar). I would offer a local flap. A V-Y advancement (Atasoy) flap is ideal for a transverse defect. It advances sensate pulp over the tip. Alternatively, bone shortening and primary closure is the fastest recovery but loses length. Given he is a chef (needs pinch), preserving length is preferred.

KEY POINTS TO SCORE

Exposed bone management

Flap selection (Atasoy)

Patient factors (Chef = Sensation/Length)

COMMON TRAPS

✗Grafting over bone (won't take)

✗Suggesting Cross Finger flap for a chef (stiffness/sensory loss)

LIKELY FOLLOW-UPS

"What if it was the thumb?"

"Moberg volar advancement flap."

VIVA SCENARIOStandard

Scenario 3: The Child

EXAMINER

"A 2-year-old shuts their finger in a door. The tip is amputated through the nail bed, held on by a bridge of skin. It looks dusky. What do you do?"

EXCEPTIONAL ANSWER

In children, the regenerative capacity is massive. 'Composite grafting' (putting the tip back on) works very well in kids less than 4 years old. I would clean it, suture the composite tip back on loosely, and cast it / splint it for protection. Even if the skin sloughs, the underlying tissue often survives. DO NOT discard the tip.

KEY POINTS TO SCORE

Composite grafting in children

Regenerative potential

Conservative approach

COMMON TRAPS

✗Throwing the tip away

✗Complex flaps in a toddler

LIKELY FOLLOW-UPS

"What is the limit for composite grafts?"

"Generally children less than 4 years old and defects distal to the lunula."

VIVA SCENARIOStandard

Scenario 4: The Hook Nail

EXAMINER

"A patient presents 6 months after fingertip amputation with a curved, painful nail that catches on clothing. The tip looks like a parrot's beak. What happened and what are the options?"

EXCEPTIONAL ANSWER

This is a Hook Nail deformity, caused by inadequate bony support for the nail bed. The nail bed was sutured over a shortened distal phalanx without matching the soft tissue. Treatment options include: (1) Conservative: Regular nail trimming, silicone tip protector. (2) Surgical: Shortening and ablation of the germinal matrix (stops nail growth), or revision with bone graft/spacer to support the nail bed (complex).

KEY POINTS TO SCORE

Hook nail = Inadequate bone support

Prevention is easier than cure

Germinal matrix ablation is definitive

COMMON TRAPS

✗Trying to trim the nail repeatedly without addressing cause

✗Attempting complex reconstruction for a minor deformity

LIKELY FOLLOW-UPS

"How do you ablate the germinal matrix?"

"Curettage, excision, or chemical ablation (phenol) under the proximal nail fold."

MCQ Practice Points

Anatomy

Q: Which part of the nail matrix is responsible for nail plate adherence? A: The Sterile Matrix.

Pathology

Q: What deformity results from scarring of the germinal matrix? A: Split Nail (as the nail plate is not formed uniformly).

Surgical Technique

Q: The Moberg flap is contraindicated in which digit? A: The Index Finger (and all except Thumb).

Management

Q: What is the maximum size defect that heals well by secondary intention (if no bone exposed)? A: 1 cm (can heal up to 1.5 cm but slower).

Hook Nail Prevention

Q: How do you prevent a Hook Nail deformity? A: Ensure adequate bony support for the nail bed. Do not suture nail bed under tension over shortened bone.

Flap Selection

Q: For a volar oblique fingertip amputation with exposed bone, which flap is most appropriate? A: Cross Finger Flap (Atasoy V-Y advances less volar tissue; Cross Finger provides volar coverage).

Australian Context

Epidemiology

Incidence: Fingertip injuries account for 45% of all hand injuries presenting to Australian EDs.
Demographics: Peak incidence in working-age males (20-40 years).
Mechanism: Machinery and power tools are the leading causes in occupational settings.

WorkCover Considerations

Documentation: Detailed documentation of mechanism is medico-legally essential.
Photography: Always photograph the injury before and after treatment.
Functional Assessment: Document pinch strength, grip strength, 2PD.
Disability Rating: May be required for permanent impairment assessment.

Healthcare Access

Emergency Departments: Initial assessment and stabilization.
Plastics/Hand Surgery: Complex injuries requiring flaps or replantation.
Hand Therapy: Essential for rehabilitation and return to work.
Rural Areas: Telemedicine consultation for remote injuries.

Practical Points

Tetanus: Ensure ADT status is current. ADT if greater than 5 years since booster.
Antibiotics: Generally NOT indicated for clean fingertip injuries (evidence-based).
Follow-up: GP or hand clinic review at 1 week.
Smoking Cessation: Critical counseling for flap patients. NRT available OTC.

High-Yield Exam Summary

Classification

•Allen I: Pulp only
•Allen II: Pulp + Nail
•Allen III: Distal Phalanx
•Allen IV: Proximal to Lunula

Management

•No Bone: Secondary Intention
•Bone Exposed: Atasoy (Transverse), Kutler (Lateral)
•Thumb: Moberg
•Large/Volar: Cross Finger

Nail Bed

•Repair: 6-0 Chromic
•Hematoma: Trephine if painful
•Hook Nail: Prevent by bone support
•Stent: Replace nail plate or foil

Flap

Indication

Vessel

Movement

Atasoy (V-Y)

Transverse / Dorsal Oblique

Subcutaneous perforators

Advancement

Kutler (Lateral V-Y)

Transverse / Volar Oblique

Lateral digital

Bilateral Advancement

Moberg

Thumb Tip

Neurovascular Bundles

Volar Advancement

Cross Finger

Volar Oblique / Large

Dorsal Digital (Donor)

Transposition

The V-Y Advancement Flap (Atasoy)

Indication: Transverse or Dorsal Oblique amputations.
Design: V-shaped incision with apex at DIPJ crease.
Dissection: Cut skin only. Tease fibrous septae deep to flap to mobilize it. DO NOT undercut the base (blood supply).
Movement: Advance distally over bone.
Closure: Y-shape closure.
Limit: Advances about 5-10mm max.

Ensure the "V" apex is at the DIPJ crease to avoid scar contracture across the joint.