LACERATION (OPEN WOUND)

Lacerations to the hand are very common injuries which account for 10-20% of emergency room visits.¹  Lacerations can be superficial or deep.  Superficial lacerations cut the epidermis and dermis if they are full thickness lacerations.  Deep lacerations cut into the subcutaneous tissues.  Whether a broken piece of glass or a knife passed through the subcutaneous tissue to damage underlying structures at risk can be difficult to assess.  This can be particularly difficult with an uncooperative patient or a terrified child with a bleeding hand.

Despite the emergent nature of the injury, a careful examination is necessary in order to evaluate the underlying structures.  One-half of the lacerations that occur in the hand and wrist and enter the subcutaneous tissues cause damage to the underlying structures.^2,3  When a laceration enters the subcutaneous tissue, then the deeper structures at risk can be damaged.  As a knife, for example, passes through the subcutaneous tissues, the Structures At Risk include:

1. Cutaneous nerves like the dorsal radial sensory nerve
2. Extensor and flexor tendons
3. Major nerves like the median nerve, ulnar nerve, common digital nerve and digital nerve
4. Bone – a circular saw can easily lacerate the skin; subcutaneous tissues; extensor tendons and fracture the underlying bone
5. Joint – depending on the exact location of the laceration, the knife may cut the joint capsule, injure joint cartilage or ligaments and contaminate the joint space
6. Arteries and veins – depending on location of injury, the radial artery, the ulnar artery or a major vein like the cephalic vein can be transected during a wrist laceration.^2,3

Untidy wounds that have a crush or skin avulsion component are even more likely to be associated with damage to the deeper structures.

Related Anatomy

• Skin
• Subcutaneous tissue
• Other related anatomic structures will depend on the depth of the wound.  Theoretically, any digit, hand, wrist or forearm structure can be at risk for injury secondary to a deep laceration.

Incidence and Related Conditions

Incidence:  The incidence of hand, wrist and forearm injuries presenting to the emergency room is substantial.  Nascab and his authors’ review found rates of hand injuries between 6.6% and 21% of injuries presenting to the emergency department occurred in the hand.² Glass and knife injuries account for the majority of the hand lacerations.³  Sixty percent of these lacerations had at least one deeper structure cut and 15% of the lacerations had combined injuries involving arteries, nerves and/or tendons.

Related injuries include amputations, partial amputations, crush injuries, avulsion injuries and burns.

Differential Diagnosis

None

A typical patient is a right-handed woman who was preparing a salad and cut her left palm with a knife.  She was trying to remove an avocado pit with a sharp, thin knife when the knife slipped off the pit and into her palm at the base of the index finger.  The wound bled briskly.  The woman quickly applied a temporary pressure dressing.  She noted immediately that she had numbness on one side of the index finger and difficulty flexing the index finger.  Her husband drove her to the emergency room where a laceration with secondary tendon and digital nerve injuries were diagnosed.  The laceration was irrigated and debrided and sutured.  The patient was referred to a hand surgeon for urgent care of her tendon and nerve injuries.  

• Ischemia to digit or hand
• Infection
• Neuroma or neuroma-in-continuity
• Scars, hypertrophic scars and scar contractures
• Missed partial tendon lacerations⁶

All lacerations have a scar;, however, most properly treated superficial lacerations heal and leave minimal residual functional deficit and an acceptable cosmetic result.  

Deep laceration outcomes will depend on the injury to the Structures At Risk.  Flexor tendon lacerations and nerve lacerations rarely have perfect results, particularly in adult patients or very young patients.

• Missed injury to Structures At Risk is a common cause of malpractice actions against emergency medicine physicians because of failure to identify deep injury Structures At Risk.¹
• Ideally, lacerations are closed soon after injury or at least within 24 hours.  Later closures increase the risk of infection.
• In lacerations with continued bleeding despite pressure dressings, look for partially transected artery or vein may be found at surgical exploration.
• Non-medical glues such as superglue should not be used for closing lacerations.⁵
• Have a high index of suspicion for injury to Structures At Risk because 30% of these injuries can be missed by emergency physicians and hand surgeons.¹
• Significant gaps in tendons and nerves usually require delayed complex reconstruction.
• Emergency hand surgery intervention is indicated if the viability of a digit or hand is in question and/or when there are open joint injuries or open fractures.

Cited and New References

1. Coll JP, Harris PA, Percival NJ.  Hand lacerations: An audit of clinical examination.  J Hand Surg 1998;23B;4:482-484.
2. Nassab R, Kok K, Constantinides J, Rajaratnam V. The diagnostic accuracy of clinical examination in hand lacerations.  International J Surg 2007;5:105-108.
3. Tuncali D, Yavaz N, Terzioglu A, Asian G.  The rate of upper extremity deep-structure injuries through small penetrating lacerations. Annals Plast Surg 2005; 55(2):146-148.
4. Strauss EJ, Weil WM, Jordan C, Paksima N.  Octylcyanoacrylate* versus suture repair for nail bed injuries.  J Hand Surg 2008; 33A:250-253 (*Dermabond; Ethicon Inc. Somerville, NJ).
5. Wang AA, Martin CH.  Full-thickness skin necrosis of the fingertip after application of superglue.  J Hand Surg 2003; 28A:696-698.
6. Al-Qattan MM. Conservative management of zone II partial flexor tendon lacerations greater than half the width of the tendon. J Hand Surg 2000; 25A:1118-1121.