Wound assessment, laceration repair and tetanus prophylaxis

• A laceration is best closed after careful assessment, cleaning and exploration; irrigation under pressure is the single most important step in preventing infection.
• Simple clean wounds may be closed with sutures, skin glue or adhesive strips depending on site and tension; high-tension or heavily contaminated wounds usually need sutures or delayed closure.
• Antibiotics are not routinely needed for simple lacerations; they are reserved for high-risk wounds, open contaminated wounds and specific bite or puncture injuries.
• Tetanus prevention depends on classifying the wound as clean and minor or dirty and major and on the patient's vaccination history; clean and minor wounds never need immunoglobulin.
• Dirty and major wounds in unvaccinated, incompletely vaccinated or severely immunocompromised patients need both a tetanus-containing vaccine dose and 250 international units of tetanus immunoglobulin intramuscularly.

By the end of this page you should be able to:

1. Inspect, classify and clean a traumatic wound and explore it for deep structure injury and retained foreign body.
2. Choose between primary closure, delayed primary closure and healing by secondary intention, and select an appropriate closure method.
3. Irrigate a wound correctly with adequate volume and pressure, and state why tap water is an acceptable irrigant.
4. Decide when antibiotic prophylaxis is and is not justified for a traumatic wound.
5. Classify a wound as clean and minor or dirty and major for tetanus purposes and take a vaccination history.
6. Apply the United States and United Kingdom tetanus prophylaxis algorithms, including the dose of tetanus immunoglobulin.
7. Recognise the wounds and patients at highest risk and manage common complications.

A wound is any break in the skin, mucosa or deeper tissue. A laceration is a wound produced by blunt or sharp force that leaves the skin edges separated and the deeper layers at least partially divided. A traumatic wound is one caused by injury rather than surgery.

A clean and minor wound, for tetanus purposes, is a wound that is less than 6 hours old, non-penetrating, with negligible tissue damage. A dirty or major wound poses an increased risk because it allows Clostridium tetani to proliferate, for example one containing devitalised tissue, a foreign body or gross contamination. ^[2]

Closure can be by primary intention (wound edges brought together immediately), delayed primary intention (left open initially, then closed once clean) or secondary intention (left open to heal from the base up). The choice is governed by contamination, tissue loss and infection risk, not by wound age alone.

Repair is indicated when it is expected to improve one or more of the following:

• Haemostasis of a bleeding wound after pressure has failed.
• Restoration of function, especially when tendons, nerves, vessels, joints or flexor sheaths are divided.
• Restoration of appearance, particularly on the face, hands and exposed sites.
• Protection of deep structures from infection and further injury.
• Reduction of pain and healing time compared with leaving the wound open.
• Prevention of complications such as infection, contracture and joint stiffness.

Almost every wound should have its tetanus status reviewed at the same time, because prevention is far more effective than treatment.

Do not close a wound primarily, or defer closure, when any of the following apply:

• The wound shows active infection (spreading cellulitis, purulence, or systemic sepsis).
• The wound is heavily contaminated and cannot be rendered clean by irrigation and debridement.
• There is devitalised tissue that cannot be debrided safely.
• The wound is an animal or human bite with deep puncture or crush components, especially on the hand, where delayed closure is often safer.
• The wound overlies a closed space (for example the pulp of a finger) where pressure can build; relieve pressure and consider delayed closure.
• Foreign material is suspected but cannot be removed, including glass, thorns or organic matter.
• The patient is severely immunocompromised or has critical limb ischaemia, where healing is unlikely without specialist care.
• The patient's general condition or medications make closure unsafe, for example anticoagulation with uncontrolled bleeding.

In these situations manage the wound openly or by delayed primary closure, treat infection aggressively and involve senior or specialist help early.

Think of a laceration in layers. The epidermis and dermis carry the cosmetic result. The subcutaneous fat and fascia determine tension and haematoma risk. Below these lie the structures that must not be missed:

• Tendons and tendon sheaths, especially on the hands and feet. A divided tendon hidden by a clean skin wound will not recover unless found.
• Nerves, both sensory (digital nerves, cutaneous nerves) and motor (facial nerve branches, extensor mechanism of the fingers).
• Vessels, including the palmar and digital arteries and the scalp vessels, which can bleed briskly.
• Joint capsules and periosteum; an open joint is a surgical emergency.
• Bone, because an open fracture changes both antibiotic and tetanus management. Imaging is required when fracture is possible.

Exploration must be gentle but thorough, under adequate anaesthesia and lighting, and with magnification for hand wounds.

1. Control bleeding with direct pressure. Remove rings, watches and tight clothing before swelling develops.
2. Photograph the wound before cleaning when useful, to record its initial state.
3. Assess tetanus and antibiotic needs now, because the decision is easier before the patient leaves.
4. Give analgesia and anaesthetise the wound. Infiltrate or use a regional block for hand wounds; topical anaesthesia is sometimes enough in children. Use adrenaline-containing solutions with caution in digits and other end-arterial areas.
5. Position the patient and operator comfortably, with the wound at a workable height and the operator's forearms supported.
6. Obtain consent for closure. Discuss pain, infection, bleeding, scarring, paraesthesia, and the possibility that the wound will be left open or closed later. Tell the patient how and when stitches are removed and whom to contact if the wound changes.

Look at the wound as a whole, not just its skin edges. Record the mechanism, time of injury, site, length, depth, visible contamination, foreign body and evidence of deep structure involvement. For tetanus purposes classify it as clean and minor or dirty and major (see the tetanus section below). For surgical infection purposes note whether it is clean, clean-contaminated, contaminated or dirty.

• Remove gross dirt, clothing and foreign material with forceps; do not push debris deeper.
• Irrigate copiously under pressure. A 35 ml syringe with an 18 gauge catheter delivering approximately 8 psi, using roughly 500 ml per wound, is the standard; high-pressure irrigation is the single most effective method of reducing bacterial counts in wounds. A wound becomes infected when it contains more than 10^5 bacteria per gram of tissue, and the infecting dose falls to fewer than 10^2 in the presence of dirt.^[3]
• Tap water is a safe and effective irrigant compared with sterile saline; the largest comparative trial found infection rates of 6.4% with saline and 3.5% with tap water, a non-significant difference with a trend in favour of tap water. Clean the wound under a running tap when facilities allow.^[3]
• Debride obviously devitalised skin, fat and foreign material. Preserve tissue where possible; debridement is crucial for high-risk wounds.
• Never place antiseptic solutions such as povidone-iodine or hydrogen peroxide into the wound; they damage tissue and do not reduce infection. Clean the surrounding skin with antiseptic, but keep it out of the wound.

• Inspect under full extension and flexion, because a tendon injury can hide when the fingers are at rest.
• Test motor function, sensation and capillary refill before and after anaesthesia.
• Look for foreign bodies; radiograph when glass, metal or bone is possible. Ultrasound can help with superficial non-opaque objects.
• Open an apparently simple scalp, hand or foot wound widely if the mechanism or examination suggests deeper injury; missing a divided tendon or nerve is worse than making a generous incision.
• If an open joint, open fracture or tendon sheath infection is found, stop and involve the appropriate specialist.

There is no reliable universal "golden period" after which a wound must not be closed. Older studies often quoted 6 to 12 hours, but primary closure has been successful far later, and the evidence for any fixed cut-off is poor. The strongest predictors of infection are diabetes, wound location (especially the lower limb), wound length greater than 5 cm, contamination and a retained foreign body, not wound age alone.^[4] Assess the wound and the patient individually, and consider delayed primary closure for contaminated or high-risk wounds.

Choose the method by site, tension, depth, age of the wound and cosmetic needs, not by habit.

Practical points:

• Use the smallest effective suture and take bites that evert the edges without strangulating them.
• Aim for a water-tight, tension-free repair; tension causes ischaemia and dehiscence.
• For the face, use fine sutures and close in layers; remove early to optimise the scar.
• For hand and joint wounds, repair tendons and nerves first, then skin with fine interrupted sutures or vertical mattress bites; splint in a functional position.
• Do not suture over a haematoma; if one forms, evacuate it.
• Where a patient cannot tolerate stitches (for example a young child with a small facial wound), consider adhesive strips or glue after cleaning.

• Dress the wound with a non-adherent or interactive dressing; keep the area clean.
• Give clear written instructions on redness spreading, increasing pain, swelling, discharge, fever or wound opening.
• Elevate injured limbs and splint hands and digits to reduce swelling and protect the repair.
• Review the wound early when infection is a concern, and again at suture removal.
• Remove sutures or staples as soon as the wound is strong enough, following local protocols and noting the site and tension; glue and strips fall off or are removed at follow-up. Inadequate or delayed removal can make stitch marks permanent.
• Scar care begins once the wound is healed: sun protection and silicone or pressure where appropriate.
• Document the wound, closure, advice given and follow-up plan.

Antibiotics are not routinely indicated for simple clean lacerations in immunocompetent patients; previous studies have found no role for routine oral antibiotics after laceration repair. They are unnecessary in low-risk wounds and likely unnecessary in immunocompetent patients with low-risk wounds.^[5]

Reserve prophylaxis for higher-risk situations and base it on the likely organisms and local resistance patterns:

• Tetanus-prone wounds (see below) are treated with antibiotics such as metronidazole, benzylpenicillin or co-amoxiclav as indicated by clinical severity, after discussion with microbiology.^[2]
• Human and animal bite wounds, especially puncture wounds and bites closed by primary suture; antibiotics are warranted in these circumstances rather than for every bite. For all dog bites, antibiotics are likely not beneficial but should be considered case by case, especially for high-risk bite wounds on the extremities.^[5]
• Wounds closed by delayed primary closure or with significant contamination.
• Immunocompromised patients and those with diabetes, peripheral vascular disease or asplenia.
• Open fractures, joint involvement, tendon sheath injuries and plantar puncture wounds.
• Wounds with retained foreign body or gross soil contamination that cannot be fully debrided.

When antibiotics are given, choose the agent, route and duration by local policy, and tell the patient that antibiotics were prescribed. Keep courses short and review daily.

Clean all wounds. Then classify:

• Clean and minor: less than 6 hours old, non-penetrating, with negligible tissue damage. These wounds do not pose a major risk.^[1]
• Dirty or major (tetanus-prone): wounds that foster anaerobic conditions in depth, including puncture injuries, foreign bodies such as splinters, compound fractures, animal bites, and wounds or burns with systemic sepsis.^[2][1]
• High-risk tetanus-prone: any tetanus-prone wound with heavy contamination by material likely to contain spores (such as soil or manure), a wound or burn needing surgical intervention delayed by more than 6 hours, or extensive devitalised tissue.^[2]
• Low-risk tetanus-prone: a tetanus-prone wound without any of the high-risk features.^[2]

Ask and check the record rather than relying on memory.

Vaccination not needed regardless of wound type when both of these hold: the patient completed the primary vaccine series and received the last tetanus-containing vaccine less than 5 years ago.^[1]

Vaccination recommended for all wounds for people with unknown vaccination history, unvaccinated people and people with an incomplete tetanus primary series.^[1]

For clean and minor wounds: people who completed the primary series but received their last tetanus-containing vaccine 10 or more years ago need a dose.^[1]

For dirty or major wounds: people who completed the primary series but received their last tetanus-containing vaccine 5 or more years ago need a dose.^[1]

If indicated, give 250 international units of tetanus immunoglobulin intramuscularly.^[1] Tetanus immunoglobulin is an antitoxin: it binds circulating toxin but cannot neutralise toxin already fixed to nerve endings, so early administration matters.

UK guidance uses three columns (clean wound, tetanus-prone wound, high-risk tetanus-prone wound) and the patient's immunisation status. "Adequate priming" means at least three doses of tetanus-containing vaccine at appropriate intervals, which includes infants who have not finished the primary course; this definition is for wound risk assessment only, since the full UK schedule gives at least five doses.^[2]

• Patients with adequate priming and a last dose within the last 10 years, and children under 5 or 5 to 10 years who have completed the relevant boosters, need no immediate treatment for any wound; they should have the schedule completed to secure future immunity.^[2]
• Patients who received adequate priming but whose last dose was more than 10 years ago, or 5 to 10 year olds without the preschool booster, need no treatment for a clean wound, a reinforcing dose for a tetanus-prone wound, and a reinforcing dose plus one dose of immunoglobulin in a different site for a high-risk wound.^[2]
• Patients who have not received adequate priming, including those with uncertain status and those born before 1961, need a reinforcing dose for a clean wound and a reinforcing dose plus immunoglobulin for every tetanus-prone or high-risk wound.^[2]
• Neonates under 8 weeks are managed by maternal vaccination status: if the mother received a pertussis-containing vaccine at least 2 weeks before delivery, no immunoglobulin is given for a clean wound and no immunoglobulin is needed for a tetanus-prone wound; otherwise an immunoglobulin dose is given for tetanus-prone and high-risk wounds.^[2]

For most cases give intramuscular tetanus immunoglobulin 250 IU; give 500 IU if presentation is delayed, or there is heavy contamination, or following burns. The dose is the same for adults and children; the product is supplied in 1 ml ampoules containing 250 IU.^[2] If access to tetanus immunoglobulin is significantly delayed, human normal immunoglobulin (HNIG) 6 ml is used for most cases and 12 ml for wounds that are old, heavily contaminated or due to burns.^[2]

Patients who are severely immunosuppressed may not be protected despite full immunisation, and may need additional booster doses.^[2] Point-of-care antibody tests are not recommended for assessing tetanus-prone wounds.^[2]

United Kingdom practice includes thorough cleaning of all wounds, surgical debridement of devitalised tissue in high-risk wounds, antibiotics as indicated, a reinforcing vaccine dose, and immunoglobulin for those at risk. Recovery from tetanus may not result in immunity, so vaccination after tetanus is indicated.^[2]

A full course of tetanus and diphtheria vaccination consists of at least five doses at appropriate intervals. In the UK this is three infant doses, a dose at 18 months, a preschool dose and an adolescent dose; adults who have not been primed receive three doses of tetanus-containing vaccine one month apart, a fourth dose some years later and a fifth after another interval. Five doses are considered to provide lifelong immunity, although the schedule now includes a sixth dose for adolescents leaving school.^[2]

For completeness: in clinical tetanus, after early wound debridement, benzylpenicillin or metronidazole is used (choice and dose discussed with microbiology), with human intravenous immunoglobulin or intravenous immunoglobulin products in weight-based doses and modern intensive care support; IVIG is used in the UK because intravenous tetanus immunoglobulin is no longer available. This emergency treatment is outside the scope of prophylaxis but is the reason the wound decision matters.^[2]

• Human bites: treat as high risk for infection; do not close deep puncture wounds primarily; use antibiotic prophylaxis and review.
• Animal bites: dog bites often need irrigation only; give antibiotics case by case, especially punctures and hand wounds. Cat bites have a high infection rate due to Pasteurella and usually need antibiotics.
• Puncture wounds, including through a shoe, need thorough cleaning and tetanus assessment; antibiotics by local policy for bone or joint proximity.
• Hand and finger injuries: protect flexor sheaths; splint; refer early for deep structure injury.
• Facial lacerations: meticulous layered repair; glue is useful for low-tension wounds; tetanus decisions as above.
• Scalp wounds: check for galea laceration; staples give fast closure in emergencies.
• Contaminated or delayed wounds: consider delayed primary closure and reassess early.

• Infection of the wound or deeper tissues, presenting as cellulitis, abscess, stitch abscess or systemic sepsis.
• Dehiscence and, in abdominal wounds, evisceration.
• Retained foreign body, leading to infection or chronic inflammation.
• Injury to tendons, nerves or vessels overlooked at exploration.
• Hypertrophic or keloid scarring, infection and tension being common triggers.
• Contracture and joint stiffness, especially after hand injury.
• Allergic or irritant reaction to adhesive or dressing materials.
• Tetanus if assessment or prophylaxis was missed, which carries substantial mortality.

• Use tap water for irrigation when sterile saline is unavailable; it is safe and effective.^[3]
• Create pressure safely using a 20 or 35 ml syringe and an 18 gauge needle or catheter; improvise only when no proper equipment exists, and protect the operator with eye protection.
• Debride aggressively and keep dirty wounds open when closure cannot be followed up.
• Use the tetanus status and vaccination history as rigorously as possible; where immunoglobulin is unavailable, prompt vaccination and early referral become even more important.^[2]
• Document the wound and plan; arrange review with community or district services.

• Assess the whole wound before touching it, and explore for tendon, nerve, vessel and foreign body injury under good anaesthesia.
• Irrigation at approximately 8 psi using roughly 500 ml per wound is the most effective single step for reducing infection; tap water is an acceptable irrigant.
• There is no fixed "golden period" for closure; weigh diabetes, contamination, site, size and retained foreign body when deciding.
• Match the closure method to tension, depth, site and cosmetic need; glue is limited to clean, low-tension wounds.
• Antibiotics are not routine for simple lacerations; they are used for tetanus-prone wounds, bites, delayed closure, open fractures and immunocompromised patients.
• Classify every wound as clean and minor or dirty and major for tetanus before the patient leaves.
• Clean and minor wounds never need tetanus immunoglobulin; dirty or major wounds in unprotected patients need a vaccine dose plus 250 international units of immunoglobulin intramuscularly.
• In the US algorithm, use 10 years for clean, minor wounds and 5 years for dirty, major wounds when deciding whether to vaccinate a primed patient.
• In the UK algorithm, high-risk wounds that are old or heavily contaminated need 500 IU rather than 250 IU of immunoglobulin.
• Five doses of tetanus-containing vaccine are considered to provide lifelong immunity, so recovered tetanus still requires vaccination.
• Always document the tetanus decision and the patient's follow-up plan.

Plain text (no links): tetanus in Infectious Disease; bites, stings and envenomation; secondary survey and penetrating trauma; wound healing and surgical site infection; plastic and reconstructive surgery; childhood vaccinations; emergency medicine overview; anaphylaxis and angioedema; sepsis; shock.