Wound Healing and Sutures
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Direct answer
Wound healing proceeds through overlapping phases — haemostasis, inflammation, proliferation and remodelling — with collagen laid down as type III and later remodelled to stronger type I, though a healed wound never regains full native strength. Closure is by primary intention for clean wounds, delayed primary closure for contaminated ones after three to five days, or secondary intention for infected and granulating wounds. Suture choice balances absorbable against non-absorbable and monofilament against braided, and removal timing depends on the site.
What you must remember
- Phases with timing: haemostasis at once; inflammation over the first three to four days; proliferation from day three to week three with fibroblasts, granulation and epithelialisation; remodelling over months, with strength rising to a fraction of native strength.
- Intentions of healing: primary closure for clean wounds; delayed primary closure after three to five days for contaminated wounds; secondary intention by granulation and contraction for infected wounds; skin grafts close what cannot close itself.
- Factors that impair healing: diabetes, smoking, malnutrition, vitamin C and zinc deficiency, corticosteroids, anaemia, hypoxia, local infection, foreign bodies and irradiated tissue.
- Suture materials: absorbable threads include braided polyglactin for rapid approximation and long-lasting monofilament polydioxanone for fascia; non-absorbable threads include braided silk and monofilament nylon and polypropylene for skin and vessels.
- Monofilament versus braided: monofilaments drag tissue less and harbour fewer organisms, preferred in contaminated fields; braided materials knot better but increase infection risk in dirty wounds.
- Suture removal in common teaching: face around five days, scalp and trunk seven to ten, limbs ten to fourteen — a rough guide, with deeper-layer support reducing scar spread.
- Keloid scars extend beyond the wound margins, do not regress and recur after excision, with a propensity in darker skin; hypertrophic scars stay within the wound and often settle — silicone sheets and intralesional steroids are the options.
Common confusion
Keloid versus hypertrophic scarring is the classic pair, decided by whether the scar crosses the original wound border. Candidates also confuse delayed primary with secondary closure — the former approximates a contaminated wound after a few days, the latter leaves it open to granulate. In suture questions, the recurring trap is braided silk in a contaminated field, where monofilament is safer.
Exam-focused takeaway
FMGE wound questions are list-and-match questions. Phase questions reward timing anchors — inflammation to day four, proliferation to week three, remodelling to a year — and the collagen switch from type III to type I. Closure questions match wound to intention: clean and primary, contaminated and delayed primary, infected and secondary. Suture questions match material to tissue: polyglactin for mucosa and fat, polydioxanone for fascia, monofilament for skin, vessels and contaminated fields. Finish with removal timing and the keloid that overgrows its boundaries.
Frequently asked questions
What are the phases of wound healing?
Haemostasis, inflammation (days 0 to 4), proliferation (day 3 to week 3) and remodelling (weeks to a year), with collagen maturing from type III to type I.
What is delayed primary closure?
Approximation of a contaminated wound after three to five days of observation, once infection risk has fallen, rather than immediate closure.
Which suture is preferred in a contaminated wound?
A monofilament material such as polypropylene or nylon, because braided sutures harbour bacteria within their strands.
When are skin sutures removed?
Roughly five days on the face, seven to ten on the trunk and scalp, and ten to fourteen on the limbs, individualised to healing.
How do keloid and hypertrophic scars differ?
Keloids extend beyond the wound margins and do not regress, recurring after excision; hypertrophic scars stay within the wound and often settle with time.
Does a healed wound regain full strength?
No — final strength plateaus below that of unwounded skin, so healed wounds can reopen under renewed stress.