Introduction
Wound assessment and suturing is a high-yield clinical skills OSCE station. Examiners look for patient communication, ANTT compliance, correct wound assessment, and sound suture technique. Before suturing any wound: check tetanus status, wound age, mechanism of injury, and whether deep structures are at risk.
💎 Clinical Pearl
Not all wounds should be sutured primarily. Contaminated wounds, bite wounds, wounds older than 6 hours (12 hours for scalp and face), and infected wounds should not be closed primarily.
Wound Assessment — TIME Framework
🧠 Mnemonic
TIME — Tissue, Infection/Inflammation, Moisture balance, Edge/Epithelial advancement
- Tissue: viable (pink or red) vs non-viable (slough = yellow, eschar = black)
- Infection or Inflammation: erythema, warmth, purulent discharge, cellulitis
- Moisture: dry = needs hydration; macerated = too moist; balanced = optimal for healing
- Edge: advancing (healing) vs non-advancing (chronic wound — investigate underlying cause)
Wound Assessment Checklist
| Assessment point | Clinical significance |
|---|---|
| Depth: superficial, partial, or full thickness | Determines closure method |
| Length and site | Affects cosmetic outcome and technique |
| Contamination: clean, contaminated, or dirty | Primary vs delayed vs secondary closure |
| Structures at risk | Tendons, vessels, nerves distal to wound |
| Wound age | Primary closure safe under 6 hours (face under 24 hours) |
| Tetanus status | Update if incomplete or unknown |
| Allergies | Particularly to lidocaine |
Wound Closure Options
| Method | Indication |
|---|---|
| Primary suture | Clean wound, under 6 hours, no tension |
| Adhesive strips | Superficial, low tension, facial wounds |
| Tissue glue | Scalp, small superficial facial wounds |
| Delayed primary closure | Contaminated wounds — dress and close at 48-72 hours |
| Secondary intention | Infected wounds, large tissue loss |
| Skin staples | Scalp, trunk, limbs (not face) |
Suture Types and Selection
| Suture | Type | Absorbed | Common use |
|---|---|---|---|
| Vicryl (polyglactin) | Braided | 56-70 days | Subcutaneous, deep tissue |
| Monocryl (poliglecaprone) | Monofilament | 90-120 days | Subcuticular skin closure |
| PDS (polydioxanone) | Monofilament | 180-210 days | Fascial closure, high tension |
| Nylon (Ethilon) | Monofilament | Non-absorbable | Standard skin closure |
| Prolene | Monofilament | Non-absorbable | Skin, vascular |
| Vicryl Rapide | Braided | 10-14 days | Mucosal and oral wounds |
Suture Sizes
| Body area | Size |
|---|---|
| Face | 5/0 or 6/0 |
| Scalp | 3/0 or staples |
| Trunk | 3/0 or 4/0 |
| Extremity | 3/0 or 4/0 |
🧠 Mnemonic
Smaller number = thicker suture. Face = fine (5/0 or 6/0). Body = bold (3/0 or 4/0).
Simple Interrupted Suture Technique
- 1Perform hand hygiene; open sterile field with ANTT
- 2Draw up local anaesthetic: lidocaine 1% (max 3 mg/kg plain, 7 mg/kg with adrenaline)
- 3Irrigate the wound thoroughly with normal saline
- 4Debride non-viable tissue if present
- 5Hold needle driver two-thirds along needle
- 6Insert needle perpendicular to skin, 3-5 mm from wound edge
- 7Rotate wrist to follow needle curve through dermis
- 8Emerge equidistant on the opposite side
- 9Leave a 2-3 cm tail
- 10Tie: three throws (first reverse, second forward, third forward) — instrument tie
- 11Approximate wound edges without tension; ensure eversion of skin edges
- 12Space sutures 3-5 mm apart
- 13Dress wound; document suture size, type, number, and removal date
⚠️ Red Flag
Never inject local anaesthetic into infected tissue. Do not use adrenaline-containing solutions in end-arteries: digits, nose, ear, and penis.
Suture Removal Times
| Site | Days |
|---|---|
| Face | 4-5 days |
| Scalp | 7-10 days |
| Upper limb | 7-10 days |
| Trunk | 10 days |
| Lower limb | 10-14 days |
| Over a joint | 10-14 days |
"What is the maximum safe dose of lidocaine?"
Plain lidocaine (without adrenaline): maximum 3 mg/kg. Lidocaine with adrenaline: maximum 7 mg/kg. A 1% solution contains 10 mg/mL. For a 70 kg adult: 21 mL of plain 1% lidocaine or 49 mL with adrenaline. Signs of toxicity include perioral tingling, tinnitus, confusion, arrhythmias, and cardiac arrest.
"When should a wound not be sutured primarily?"
Avoid primary closure for: wounds older than 6 hours (12 hours in highly vascular areas, 24 hours on the face), heavily contaminated or dirty wounds, bite wounds, wounds with significant tissue loss, infected wounds, and puncture wounds. These should be managed with delayed primary closure at 48-72 hours or left to heal by secondary intention.
"What is the purpose of everting skin edges during suturing?"
Everting the wound edges ensures the dermis approximates correctly beneath the surface, preventing a depressed scar. A flat or inverted wound edge heals with a depressed, less cosmetically acceptable scar. Eversion is achieved by inserting the needle perpendicular to the skin and ensuring the bite is wider at the base than at the surface.
"What structures must you check before suturing any wound?"
Before suturing, always check: skin sensation distal to the wound (nerve injury), tendon function with active movement against resistance (tendon injury), and vascular integrity with capillary refill and distal pulses. If any of these are abnormal, do not suture and refer urgently. Also confirm tetanus immunisation status.
Related guides: [Venepuncture and Cannulation OSCE](/blog/venepuncture-cannulation-osce) | [A&E Assessment OSCE](/blog/ae-assessment-osce) | [Prescribing Safety OSCE](/blog/prescribing-safety-osce)