Wound Closure Techniques

Wound closure is how the surgeon brings tissue layers back together at the end of an operation (or after an injury) so the wound can heal by primary intention - clean edges held in apposition until they knit. It sounds simple, but the choices made here directly affect the scar, the risk of wound breakdown, and the risk of infection - and they are favourite basic-science and operative viva material.

There are really three decisions: how to organise the closure (almost always in layers), what to close it with (the suture material, staples, glue or strips), and which technique to use (the specific stitch or device). Underneath all of them sits one principle that the examiner keeps coming back to: the wound should be closed with well-apposed, slightly everted, tension-free edges, because that is what gives a fine, strong scar and protects the healing wound.

For the exam, three threads run through this topic: suture materials (the absorbable-versus-non-absorbable and monofilament-versus-braided grid), suture techniques and the alternatives (interrupted, continuous, mattress, subcuticular, plus staples and glue), and how to choose and apply them well (layers, tension, eversion, and timing of removal). This topic builds directly on wound healing - you are closing the wound so those healing phases can proceed undisturbed.

The first decision is structural: close the wound in layers. Each anatomical layer (fascia, then subcutaneous/deep dermal, then skin) is brought together separately. There are two reasons this matters so much:

• It removes tension from the skin. The strong deep layers are closed first and carry the load, so the skin can be apposed under little or no tension. Skin closed under tension heals as a wide, stretched scar and is much more likely to break down.
• It obliterates dead space. Closing the layers leaves no pocket under the skin for blood or fluid to collect. A haematoma or seroma in dead space is a culture medium for infection and pushes the wound edges apart.

The second set of principles is about how the edges meet:

• Equal bites either side. Take the same depth and width of tissue on each side so the edges come up level, not stepped.
• Eversion. Aim to evert the edges very slightly (turn them outward) - they then settle flat as they heal. Inverted or overlapping edges heal as a depressed, weak scar with epithelium trapped below.
• Approximate, do not strangulate. Tie just tight enough to bring the edges together. Too tight and the suture cuts off the blood supply at the edge, causing necrosis, cross-hatch marks, and wound problems.
• Atraumatic, aseptic handling. Handle tissue gently, use the fine instruments, and keep the field sterile - crushed or contaminated edges heal badly.

Every suture can be placed on two axes, and examiners expect you to classify a named suture instantly.

A few extra points are worth knowing. Suture size runs the "0" scale: more zeros means a finer suture (5-0 is finer than 2-0), and you use the finest suture that will safely hold the load. Knot security depends on the material - a slippery monofilament needs more throws than a braided suture to hold. And absorbable sutures lose strength before they fully disappear, so the layer must be healed enough to be self-supporting by the time the suture weakens.

A point examiners probe is that an absorbable suture loses its tensile strength well before it is physically absorbed - the two timelines are different. Strength retention is what holds the wound; absorption is when the foreign material finally clears. The rule is to choose a suture whose strength outlasts the time the tissue needs to become self-supporting.

This is why PDS is chosen for fascia, tendon and other slow-healing layers that need weeks of strength, Vicryl is the deep-layer workhorse for tissues that heal faster, and Monocryl suits a subcuticular skin closure where the deep layer carries the load and only brief skin-edge support is needed.

The needle is half the instrument and a favourite basic-science question. A modern surgical needle has three parts: the swage (the crimped end where the suture is attached so the thread trails the needle through a single track - an "atraumatic" eyeless needle), the body (held by the needle holder), and the point. Two features decide its use: the point geometry and the curvature.

Curvature is described as a fraction of a circle: a 3/8 circle needle suits superficial work on a flat surface (most skin closure), while a 1/2 circle turns within a confined space (deep cavities). A tapercut needle combines a taper body with a cutting tip for dense or calcified tissue. The orthopaedic rule of thumb is a reverse-cutting needle for skin and a taper (or tapercut) needle for fascia and the deeper layers.

The same material can be placed in several ways, each with a job it does best.

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Sutures are not the only way to close skin, and each alternative has a clear niche.

Staples are popular for long orthopaedic incisions because they are quick and consistent, and they hold the edges without an inflammatory knot in the wound. They still need a remover and the cosmetic result is debated. Tissue adhesive (skin glue) polymerises across apposed edges to form a flexible water-resistant film; it is fast and needs no removal, but it is only for clean, dry, low-tension, well-apposed superficial wounds - never inside the wound or on a gaping/high-tension edge. Adhesive strips are best as a supplement (for example over a subcuticular closure) or for the most superficial low-tension wounds.

Putting it together, the choice flows from the wound and the patient:

Timing of suture removal balances scar quality against wound strength. Take them out earlier where the blood supply is good and cosmesis matters, and later where tension and movement are high:

Wound closure is the last step of almost every orthopaedic operation, and it is one of the few parts of the case entirely under the surgeon's control. A poorly closed wound - under tension, with dead space, with inverted edges - can undo an otherwise excellent operation by breaking down or becoming infected, which around a joint replacement or fracture fixation can be catastrophic. In trauma, the choice to close primarily, leave open for delayed closure, or close with interrupted sutures over a contaminated wound is a daily judgement. In elective surgery, the choice between staples, a subcuticular suture, or glue affects speed, cost, and the scar the patient lives with. In the basic-science and operative viva, classifying suture materials, naming the techniques, and explaining the principles of a good closure are classic, examinable, high-yield material - and they all reduce to the same idea: bring the layers together, take the tension off the skin, and appose the edges cleanly.

• Surgical site infection (SSI) guidance worldwide (for example WHO global SSI guidelines and NICE in the UK) frames closure as part of infection prevention: aseptic technique, gentle tissue handling, obliteration of dead space, and avoidance of tension all protect the healing wound. No major guideline mandates one skin-closure device over another for routine clean wounds.
• Sutures versus staples in orthopaedics is broadly a wash for infection in the best evidence; practice varies by surgeon, unit, and incision type, with staples favoured for speed on long approaches (hip, knee, spine) and subcuticular sutures or glue favoured where cosmesis or no-return-for-removal matters.
• Tissue adhesives and adhesive strips are widely endorsed for clean, low-tension, well-apposed superficial wounds, and as a supplement to a deeper closure - never as the sole closure of a high-tension or contaminated wound.
• Across all settings the principle is constant: closure quality depends far more on sound technique - layered, tension-free, everted, aseptic - than on the particular suture, staple, or glue chosen.