Avulsion Injuries: Definition, Types & Severity

An avulsion is the traumatic tearing away of a body structure—skin, tendon, ligament, bone fragment, or entire digit/limb—from its attachment. It results from high-energy shear, traction, or crushing forces.

Classification by Severity

Type	Description	Management
Complete avulsion	Total separation of part (digit, limb, scalp, ear, tooth)	Emergent replantation if viable (ischemia time <6–12 hr for digits, <6 hr for major limbs); otherwise revision amputation
Partial avulsion	Partially attached by skin, fascia, or neurovascular bundle	Assess viability; revascularize if possible; débride nonviable tissue; skin graft/flap if needed
Avulsion fracture	Bone fragment pulled off by tendon/ligament (e.g., tibial tubercle, medial epicondyle, 5th metatarsal base)	Non-displaced: immobilization; Displaced: ORIF; consider growth plate in adolescents
Degloving (Morbid-Lanquet)	Skin/subcutaneous tissue stripped from fascia; open or closed (closed = Morel-Lavallée)	Open: débridement, coverage (graft/flap); Closed: aspiration, compression, possible debridement
Nail avulsion	Nail plate torn from nail bed	Remove remnant, protect bed, allow regrowth; suture if lacerated

Common Mechanisms

• Industrial/agricultural machinery (rings, rollers, PTO shafts)
• Motor vehicle crashes (ejection, entrapment)
• Sports (cleat entrapment, falls)
• Animal/human bites
• Jewelry entrapment (ring avulsion – "Jimmy Fallon injury")

Immediate First Aid

1. Control hemorrhage: direct pressure, tourniquet if life-threatening limb bleed.
2. Recover amputated part: wrap in saline-moistened gauze → plastic bag → on ice (do not freeze directly).
3. Immobilize, elevate, keep warm.
4. Tetanus prophylaxis, IV antibiotics (broad-spectrum), analgesia.
5. Urgent surgical referral (replantation center for major parts).

Prognostic Factors for Replantation

• Ischemia time (warm vs. cold)
• Level of injury (distal better than proximal)
• Mechanism (sharp/guillotine > crush > avulsion)
• Patient age, smoking, comorbidities
• Venous outflow reconstruction feasibility

Avulsion injuries demand rapid, coordinated trauma and microsurgical response. Functional recovery depends on nerve regeneration, which proceeds ~1 mm/day.