33 WOUND MANAGEMENT

👩‍⚕️ Wound management is a guaranteed MRCS Part A topic. The examiners test it in three flavours: (1) the science — phases of healing, factors that derail them, and how scars go wrong; (2) the classification — clean through dirty, and which intention to close by; (3) the practical decisions — which suture, which dressing, when to graft or flap. Master the four phases, the four classes, and the three intentions and most SBAs become straightforward.

Phases of wound healing

Healing is a continuum, but exams test four overlapping phases. Know the cells, the timing and the dominant event in each.

➡ Haemostasis — immediate (seconds to minutes). Vasoconstriction, platelet plug formation and the coagulation cascade produce a fibrin mesh. Platelets degranulate, releasing PDGF and TGF-β, which set the inflammatory phase in motion.

➡ Inflammation — 0 to 3 days. Vasodilation (histamine, bradykinin, prostaglandins) causes the classic rubor, calor, tumor, dolor. Neutrophils arrive first (peak ~24–48 h) to clear bacteria and debris. Macrophages arrive by day 2–3 and are the orchestrators of healing — they secrete cytokines that recruit fibroblasts and endothelial cells. A wound that does not progress past this stage becomes chronic.

➡ Proliferation — day 3 to week 3. Fibroblasts deposit type III collagen (the "weak" early collagen), endothelial cells form new capillaries (angiogenesis, driven by VEGF), and the wound fills with red, beefy granulation tissue. Myofibroblasts cause wound contraction. Re-epithelialisation occurs from the wound edges and from preserved adnexal structures.

➡ Remodelling — week 3 to 1 year. Collagen is degraded by matrix metalloproteinases and re-synthesised, with type III collagen being progressively replaced by type I. Fibres realign along lines of stress. Tensile strength climbs but never matches uninjured skin: ~20% at 3 weeks, ~50% at 6 weeks, and a maximum of around 80% at one year.

👩‍⚕️ Classic MRCS trap: tensile strength NEVER reaches 100%. If an option says "full strength is restored", it is wrong.

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Healing by primary, secondary and tertiary intention

Intention	What it means	Typical use	Scar
Primary	Clean wound edges apposed immediately (sutures, staples, glue, strips)	Clean surgical incisions, sharp clean lacerations	Fine linear scar
Secondary	Wound left open to granulate, contract and re-epithelialise	Infected, contaminated, necrotic or tissue-loss wounds (abscess cavities, pressure sores)	Broad, often hypertrophic
Tertiary (delayed primary)	Initially left open for 3–5 days, then closed once clean	Contaminated traumatic wounds, bites, perineal wounds, crush injuries	Intermediate

👩‍⚕️ Choose by contamination, not by size. Closing an infected wound primarily creates an abscess; leaving a clean wound open creates an unnecessary scar.

Factors that impair healing

Examiners almost always frame this as "which of the following most impairs healing?". Group the factors mentally into local and systemic.

Local: infection, foreign bodies, poor perfusion (peripheral vascular disease, irradiated tissue), tissue tension, repeated trauma, haematoma, denervation.

Systemic:

- Nutrition — protein deficiency, vitamin C (essential cofactor for prolyl/lysyl hydroxylase in collagen cross-linking; scurvy → wound dehiscence), zinc (cofactor for DNA/RNA polymerases), vitamin A.

- Oxygenation — hypoxia impairs neutrophil killing and collagen hydroxylation; smoking is the classic culprit via nicotine-induced vasoconstriction and carbon monoxide.

- Diabetes — microvascular disease, neuropathy, impaired neutrophil function and glycation of collagen.

- Steroids and immunosuppression — inhibit macrophage function and collagen synthesis. Vitamin A reverses the steroid effect (favourite SBA fact).

- Age, jaundice, uraemia, malignancy, chemotherapy and radiotherapy.

👩‍⚕️ The single most modifiable factor pre-operatively is smoking. Cessation 4 weeks before elective surgery measurably reduces wound complications.

Abnormal scarring: hypertrophic vs keloid

A frequent SBA pairing. The discriminator is whether the scar respects the original wound boundary.

Feature	Hypertrophic scar	Keloid
Boundary	Stays within original wound margins	Extends beyond original wound margins
Onset	Within weeks; often regresses over 1–2 years	Months to years after injury; rarely regresses
Sites	Areas of high tension (across joints, sternum)	Ear lobes, sternum, deltoid, upper back
Skin type	Any	Fitzpatrick IV–VI (darker skin); familial predisposition
Collagen	Type III predominates, aligned parallel to skin	Type I and III, disorganised whorls
Treatment	Pressure dressings, silicone sheets, intralesional steroid	Same plus excision (high recurrence), radiotherapy

👩‍⚕️ "Extends beyond the wound margin in a young Afro-Caribbean patient on the sternum or ear lobe" — keloid every time.

Wound classification (CDC surgical site classification)

➡ Clean (I) — No entry into respiratory, GI, biliary or GU tract. Elective, primary closure. Infection rate <2%.

➡ Clean-contaminated (II) — Controlled entry into a tract without significant spillage (e.g. elective cholecystectomy, elective bowel resection with bowel prep). Infection rate 3–10%.

➡ Contaminated (III) — Open traumatic wounds <4 hours old, gross spillage from the GI tract, major break in sterile technique, entry into acutely inflamed but non-purulent tissue. Infection rate 10–20%.

➡ Dirty (IV) — Established infection, pus, perforated viscus, old traumatic wounds with devitalised tissue. Infection rate >30%.

👩‍⚕️ Classification is determined by what happens during surgery, not by the outcome or by antibiotic use. Prophylactic antibiotics do not downgrade a wound class.

Other surgical site infection risk factors

Patient factors (diabetes, smoking, obesity, malnutrition, immunosuppression), operative factors (long operative time, emergency surgery, hypothermia, hyperglycaemia, poor haemostasis) and post-operative factors (haematoma, drain tubes left too long).

Closure timing and the reconstructive ladder

Reconstructive ladder, simplest first:

Secondary intention → Primary closure → Delayed primary closure → Split-thickness skin graft (STSG) → Full-thickness skin graft (FTSG) → Local flap → Regional/free flap.

➡ STSG — epidermis + partial dermis. Large defects, donor site re-epithelialises. Needs a vascularised bed (muscle, fascia, granulation). Will not take on bare bone, tendon or hardware.

➡ FTSG — epidermis + full dermis. Better colour, texture and contraction profile. Used for cosmetic units (face, eyelids, fingertips). Donor site must be closed primarily, limiting size.

➡ Flap — brings its own blood supply. Required when grafts will not survive (exposed bone/tendon/hardware) or for bulk/contour reconstruction.

Sutures

A high-yield section. Know the family, the absorption profile and the typical use.

Suture	Type	Absorbable?	Loses tensile strength	Typical use
Vicryl (polyglactin)	Braided synthetic	Yes	~21 days, gone by 60–90 days	Subcutaneous, bowel, ligatures
Vicryl Rapide	Braided synthetic	Yes	~7–10 days	Skin (paediatric, mucosa)
Monocryl (poliglecaprone)	Monofilament synthetic	Yes	~21 days, gone by 90–120 days	Subcuticular skin closure
PDS (polydioxanone)	Monofilament synthetic	Yes	~6 weeks, gone by 6 months	Abdominal fascia, slow-healing tissue
Catgut (rare now)	Braided natural	Yes	7–14 days	Largely obsolete
Nylon (Ethilon)	Monofilament synthetic	No	—	Skin closure
Prolene (polypropylene)	Monofilament synthetic	No	—	Vascular anastomosis, hernia mesh
Silk	Braided natural	No (practically)	Loses strength over months	Drain securing, marking

➡ Monofilament — smooth, low tissue drag, low infection risk, but poorer knot security. Examples: nylon, prolene, PDS, monocryl.

➡ Braided — better handling and knots, but capillarity allows bacterial wicking → higher infection risk. Examples: vicryl, silk.

👩‍⚕️ For an infected or contaminated wound, choose monofilament. For a vascular anastomosis, prolene (non-absorbable monofilament, low thrombogenicity). For abdominal fascia, PDS (long-lasting absorbable monofilament).

Wound dressings

Match the dressing to the wound.

➡ Alginates (e.g. Kaltostat) — derived from seaweed; absorb large volumes of exudate and are haemostatic. Use for heavily exuding or bleeding wounds.

➡ Hydrocolloids (e.g. DuoDERM) — form a gel with exudate, maintain a moist environment. Use for dry-to-low-exudate wounds and pressure sores.

➡ Hydrogels — donate moisture. Use for dry, sloughy or necrotic wounds to promote autolytic debridement.

➡ Foam dressings — absorb moderate exudate while cushioning. Versatile general dressing.

➡ Negative pressure wound therapy (VAC) — sub-atmospheric pressure applied via sealed sponge. Reduces oedema, increases granulation, contracts wound, removes exudate. Used for large open wounds, dehisced laparotomies, post-fasciotomy and to bolster grafts. Contraindicated over exposed vessels, untreated osteomyelitis, malignancy and fistulae into body cavities.

Tetanus prophylaxis

Clostridium tetani spores enter via contaminated puncture wounds; the exotoxin (tetanospasmin) blocks inhibitory neurotransmitter release at spinal interneurones, producing spastic paralysis.

A tetanus-prone wound is any wound that is >6 hours old, deep, contaminated with soil/manure, contains devitalised tissue, has a puncture or crush mechanism, or involves systemic sepsis.

Management depends on the patient's vaccination status:

- Fully immunised, last booster <10 years — nothing required (consider booster only for high-risk wounds).

- Fully immunised, last booster >10 years — give booster vaccine. Add human tetanus immunoglobulin (HTIG) if the wound is high-risk.

- Incomplete or unknown immunisation — give vaccine + HTIG for any tetanus-prone wound.

👩‍⚕️ Garden, farmyard and deep puncture wounds = think tetanus. HTIG is given at a different site from the vaccine.


Test yourself

After an uncomplicated cholecystectomy with minor blood loss and no bile spillage, how is the wound classified?

• ((Clean (I)::Biliary tract is entered — by definition no longer clean.))
• ((Clean-contaminated (II)::☑️ Controlled entry into the biliary tract without spillage — textbook definition.))
• ((Contaminated (III)::Requires gross spillage, open trauma or major sterile breach.))
• ((Dirty (IV)::Requires established infection, pus or perforation.))
• ((Clean with prophylactic antibiotics::Antibiotics do not change wound classification.))

👩‍⚕️ Classification is decided by operative findings, not outcome or antibiotics.

Serosanguinous discharge from an appendicectomy wound on post-op day 6. What is the diagnosis?

• ((Wound dehiscence::☑️ Pink/salmon serosanguinous leak at days 5–7 is the classic warning of impending burst.))
• ((Haematoma::Earlier (24–48 h), dark blood and swelling — not pink fluid at day 6.))
• ((Wound infection::Purulent discharge, erythema, warmth and fever — not serosanguinous.))
• ((Seroma::Clear straw-coloured fluid and rarely heralds dehiscence.))
• ((Normal healing::Serosanguinous leak at day 6 is never normal.))

Day 7 post-laparotomy, the patient is confused with serosanguinous discharge from the wound. What is the most likely explanation?

• ((Anastomotic leak::Causes peritonitis and feculent/bilious drain output, not pink wound fluid.))
• ((Intra-abdominal abscess::Swinging pyrexia and sepsis, not serosanguinous wound leak.))
• ((Wound dehiscence::☑️ Pink leak + day 5–7 + confusion = impending burst abdomen, return to theatre.))
• ((Wound infection::Purulent discharge with localised inflammatory signs.))
• ((Haemolysed haematoma::Dark altered blood, earlier presentation.))

👩‍⚕️ Risk factors: obesity, malnutrition, steroids, chronic cough, emergency surgery, poor closure technique.

A 2-year-old presents with a scald to the dorsal forearm showing erythema and blistering. What is the most appropriate management?

• ((Occlusive moist dressing::☑️ Superficial partial-thickness — heals in 10–14 days with moist dressings.))
• ((Leave wound open::Increases pain, evaporative loss and infection.))
• ((Split-thickness skin graft::Not indicated — these heal spontaneously within 3 weeks.))
• ((Full-thickness skin graft::Reserved for small cosmetic full-thickness defects.))
• ((Local flap::Gross overtreatment.))

A patient's arm was immersed in boiling water. There is superficial partial-thickness injury with blistering. What is the management?

• ((Immediate excision and grafting::Only for deep dermal or full-thickness burns.))
• ((Open dressing technique::Increases pain, evaporative loss and infection risk.))
• ((Occlusive moist dressing::☑️ Superficial partial-thickness — moist occlusive dressings optimise re-epithelialisation.))
• ((Prophylactic systemic antibiotics::Not routine in burns — drives resistance without benefit.))
• ((Escharotomy::Only for circumferential full-thickness burns with compartment syndrome.))

👩‍⚕️ Depth, not mechanism, drives management.

A patient develops a heel pressure sore with necrosis following a colectomy. What is the most appropriate management?

• ((Debridement and healing by secondary intention::☑️ Necrotic contaminated wound — debride and let granulate with pressure relief.))
• ((Primary closure::Closing over necrosis traps infection.))
• ((Flap reconstruction::Reserved for extensive loss with exposed deep structures.))
• ((Split-thickness skin graft::Grafts break down on pressure-bearing surfaces.))
• ((Simple suture::Will dehisce and become infected.))

A patient was stabbed in the foot with a garden fork. The wound is discoloured and indurated. What is the most appropriate management?

• ((Delayed primary closure::Not appropriate once active infection is established.))
• ((Primary closure::Closing an infected wound creates an abscess.))
• ((Wound excision and healing by secondary intention::☑️ Established infection — excise devitalised tissue, leave open to drain.))
• ((Wound excision and primary suture::Closing over infection worsens outcome.))
• ((Antibiotics alone::Cannot penetrate devitalised tissue — surgery is essential.))

👩‍⚕️ Garden fork = high tetanus risk. Give HTIG plus booster if immunisation is incomplete or unknown.

A 6cm scalp laceration with dirt and jagged edges presents to ED. What is the most appropriate management?

• ((Flap reconstruction::Overtreatment for a scalp wound that closes after excision.))
• ((Immediate suture without excision::Must excise contaminated jagged edges first.))
• ((Excision and healing by secondary intention::Unnecessary — scalp heals well after primary closure.))
• ((Wound excision and suture::☑️ Excise dirty/ragged edges, then primary close — scalp is highly vascular.))
• ((Delayed primary closure::Scalp's blood supply allows safe immediate primary closure.))

A 1cm facial knife injury is presented. What is the most appropriate management?

• ((Simple suture::☑️ Clean sharp wound on the face — fine sutures give the best cosmesis.))
• ((Debridement and secondary closure::Unnecessary tissue loss on the face.))
• ((Delayed primary closure::Delays closure of a clean wound and worsens cosmesis.))
• ((Split-thickness skin graft::Gross overtreatment and poor cosmetic match.))
• ((Wound excision and suture::Clean knife edges do not need excision.))

👩‍⚕️ Use 5-0 or 6-0 on the face; remove sutures at 5 days to avoid track marks.

A patient has a shrapnel wound beside the anus. What is the most appropriate management?

• ((Primary closure::Perineum is heavily contaminated — high infection risk.))
• ((Delayed primary closure::☑️ Debride, leave open 3–5 days, close when clean — appropriate for contaminated perineal wounds.))
• ((Split-thickness skin graft::Not first-line when delayed primary closure is feasible.))
• ((Full-thickness skin graft::Not indicated.))
• ((Healing by secondary intention::Perineal open wounds are difficult to dress — DPC preferred if possible.))

A large 5x7cm dirty pretibial laceration with rugged edges is presented. What is the most appropriate management?

• ((Immediate STSG::Grafting a contaminated bed fails.))
• ((Delayed STSG::Premature — try delayed primary closure first.))
• ((Delayed primary closure::☑️ Debride, leave open 3–5 days, close when clean and granulating.))
• ((Primary closure::High infection risk with devitalised edges.))
• ((Free flap::Gross overtreatment for a wound treatable with DPC.))

👩‍⚕️ DPC indications: contaminated wounds, bites, crush injuries, perineal wounds.

A 5% abdominal burn that is painless, dry and crusty. What is the most appropriate management?

• ((Simple dressing alone::Full-thickness dermis is destroyed — cannot re-epithelialise.))
• ((Full-thickness skin graft::Reserved for small cosmetic sites — not for trunk burns.))
• ((Split-thickness skin graft::☑️ Painless + dry + crusty = full-thickness — excise and STSG.))
• ((Local flap::Overtreatment when no deep structures are exposed.))
• ((Debridement alone::Leaves a large granulating wound that scars badly.))

👩‍⚕️ Painless burn = full-thickness (nerves destroyed). Painful blistering burn = partial-thickness.

A pretibial flap laceration 6x2cm with intact periosteum but edges cannot be approximated. What is the most appropriate management?

• ((Oppose edges and apply STSG::☑️ Lay flap back, oppose what you can, graft the rest — periosteum is a vascularised bed.))
• ((Oppose edges and allow granulation::Pretibial area heals slowly with poor outcome.))
• ((Excise flap and apply STSG::Wastes viable tissue.))
• ((Excise and primary repair::Edges cannot be approximated.))
• ((FTSG::Higher metabolic demand and less reliable in the pretibial area.))

A 3% forearm burn that is dry, crusted and insensate. After debridement, what is the next step?

• ((Split-thickness skin graft::☑️ Insensate + dry + crusted = full-thickness — STSG after debridement.))
• ((Full-thickness skin graft::Reserved for face, eyelids, lips and fingertips.))
• ((Occlusive moist dressing::Only for superficial or superficial partial-thickness burns.))
• ((Healing by secondary intention::Risks contracture and scarring.))
• ((Topical antibiotics alone::Cannot heal a destroyed dermis.))

A patient has 20% superficial partial-thickness and 5% full-thickness burns. What is the management for the full-thickness component?

• ((Split-thickness skin graft::☑️ Standard treatment for large full-thickness burns — durable, widely available donor sites.))
• ((Full-thickness skin graft::Only for small cosmetic areas; donor site limits size.))
• ((Local flap::Reserved for exposed bone/tendon/hardware.))
• ((Microvascular free flap::Overtreatment for routine full-thickness burns.))
• ((Conservative dressings::Full-thickness burns cannot re-epithelialise.))

A leg injury has exposed the tibia. What is the most appropriate management?

• ((STSG::Bare cortical bone has no blood supply — graft will not take.))
• ((Debridement and primary closure::Cannot close soft tissue over exposed bone.))
• ((Local flap::☑️ Exposed bone needs vascularised cover — muscle or fasciocutaneous flap.))
• ((FTSG::Also requires a vascularised bed.))
• ((Healing by secondary intention::Bare bone desiccates and becomes infected.))

👩‍⚕️ Rule: exposed bone, tendon or hardware = flap. Grafts need a vascular bed.

Which suture is most appropriate for closing the abdominal fascia after a laparotomy?

• ((Vicryl::Loses strength by 21 days — too rapid for fascia.))
• ((Monocryl::Loses strength too quickly and is too fine for fascia.))
• ((PDS::☑️ Monofilament absorbable, retains strength ~6 weeks — ideal for slow-healing fascia.))
• ((Prolene::Effective but non-absorbable — risk of sinus formation.))
• ((Silk::Braided non-absorbable — high infection and granuloma risk.))

Which scar feature distinguishes a keloid from a hypertrophic scar?

• ((Onset within weeks::Typical of hypertrophic scars.))
• ((Spontaneous regression::Hypertrophic scars often regress; keloids rarely do.))
• ((Extends beyond the original wound boundary::☑️ Defining feature of a keloid.))
• ((Occurs across joints under tension::Classic for hypertrophic scars.))
• ((Type III collagen predominates::Found in hypertrophic scars, not keloids.))

👩‍⚕️ Keloid: ear lobe, sternum, deltoid; darker skin; extends beyond margin.

Which vitamin deficiency most classically causes wound dehiscence through impaired collagen cross-linking?

• ((Vitamin A::Reverses the steroid effect on healing but not the classic cross-linking vitamin.))
• ((Vitamin C::☑️ Cofactor for prolyl/lysyl hydroxylase — deficiency (scurvy) prevents collagen cross-linking.))
• ((Vitamin K::Affects coagulation, not collagen.))
• ((Vitamin D::Important for bone, not soft-tissue healing.))
• ((Zinc::Important for healing but acts as polymerase cofactor, not in cross-linking.))

Revision summary

➡ Phases: haemostasis (immediate) → inflammation (0–3 d, neutrophils then macrophages) → proliferation (3 d–3 wk, fibroblasts, granulation, type III collagen, angiogenesis) → remodelling (3 wk–1 yr, type III → I, max ~80% tensile strength).

➡ Intentions: primary (clean, apposed), secondary (open, granulate), tertiary/delayed primary (open 3–5 d then close).

➡ Classes: clean (<2%) / clean-contaminated (3–10%) / contaminated (10–20%) / dirty (>30%).

➡ Scars: hypertrophic stays within margin; keloid extends beyond, darker skin, sternum/ear lobes.

➡ Impaired healing: smoking, diabetes, steroids (reversed by vit A), malnutrition (vit C, protein, zinc), infection, ischaemia, irradiation, age.

➡ Sutures: monofilament low infection (prolene, PDS, monocryl, nylon); braided better handling but wicks bacteria (vicryl, silk). Fascia = PDS. Vascular = prolene. Skin = monocryl/nylon.

➡ Reconstructive ladder: secondary → primary → DPC → STSG → FTSG → local flap → free flap. Exposed bone/tendon/hardware = flap.

➡ Tetanus-prone wound: >6 h, deep, contaminated, devitalised, puncture. Give vaccine ± HTIG depending on immunisation status.

➡ Burn rule: painless + dry + insensate = full-thickness → STSG. Painful + blistering = superficial partial-thickness → moist dressings.