Treatment of Thumb Laceration with Nail Involvement
For thumb lacerations involving the nail, immediate wound irrigation, pain control with topical anesthetics, and meticulous nail bed repair are essential, with nail plate removal required when the nail bed is lacerated to allow proper visualization and suturing. 1, 2
Initial Assessment and Wound Preparation
Pain Management
- Apply topical anesthetic (LET solution: lidocaine, epinephrine, tetracaine) directly to the open wound for 10-20 minutes until wound edges appear blanched 1
- For children >17 kg, use 3 mL of LET; for those <17 kg, use 0.175 mL/kg 1
- If immediate repair is needed, inject buffered lidocaine with bicarbonate slowly using a small-gauge needle to minimize pain 1
- Local anesthetic with epinephrine in concentrations up to 1:100,000 is safe for use on digits 3
Wound Irrigation and Examination
- Irrigate thoroughly with potable tap water or sterile saline to remove debris and microscopic infectious agents 3, 4
- Assess for foreign bodies, noting that not all are visible on plain radiographs 4
- Determine mechanism of injury to gauge contamination level and tissue loss 2
- Look for signs of infection including pus, increased warmth, erythema, or purulent drainage 5
Nail Plate Management
When the nail bed is lacerated, the nail plate must be removed to allow proper repair of the underlying nail bed. 2
- Remove the nail plate completely to visualize the nail bed injury 2
- Any free segments of nail bed should be sutured back in place as a free graft 2
- After nail bed repair, the removed nail plate can be replaced as a protective splint 6, 2
Wound Closure Technique
Timing Considerations
- Time from injury to closure is less critical than previously thought; wounds may be safely closed even 18+ hours after injury depending on contamination level 3, 7
- Diabetes, wound contamination, length >5 cm, and lower extremity location increase infection risk more than delayed closure 7
Repair Method
- Use absorbable sutures for nail bed repair to avoid the pain of suture removal 1
- For superficial wounds without exposed bone or tendon, consider allowing healing by secondary intention, especially in children 2
- Direct closure may be appropriate for small amputations of 2-3 mm 2
Infection Prevention and Management
Prophylaxis
- Tetanus prophylaxis should be provided if indicated 3, 4
- Consider prophylactic antibiotics for contaminated wounds, diabetes, or wounds >5 cm 7
Post-Repair Care
- Implement daily antiseptic soaks with dilute vinegar (50:50 dilution) or 2% povidone-iodine for 10-15 minutes twice daily 8, 9
- Apply mid to high-potency topical steroid ointment to nail folds twice daily to reduce inflammation 8, 9
- If infection develops, initiate oral antibiotics targeting Staphylococcus aureus and gram-positive organisms 5
- If initial treatment with cephalexin fails, switch to sulfamethoxazole-trimethoprim for broader coverage including MRSA 8
Wound Dressing
- Use occlusive or semiocclusive dressings to promote faster healing in a moist environment 3
- Keep the area clean with gentle washing and avoid manipulation of the nail or cuticle 5
- Protect from further trauma with appropriate hand protection 9
Follow-Up and Monitoring
- Reassess after 2 weeks to evaluate wound healing 9
- Monitor for signs of infection including increased pain, redness, swelling, or purulent drainage 9
- If pus develops, obtain cultures and drain any abscess formation 9, 5
- For persistent pain or drainage beyond 2-4 weeks, consider referral to hand surgery or dermatology 9
Special Considerations
- In children, treatment should be conservative with emphasis on preservation of digital length 2
- Even amputated fingertips in children may heal by secondary intention with the tip sutured back as a biologic dressing 2
- Be aware that secondary bacterial or fungal superinfections occur in up to 25% of nail injury cases 8