Chapter 6.3: The Legs

When contemplating wound closures on the lower extremities, clinicians should keep in mind that closures above the knee are fundamentally different from their below-the-knee counterparts. Thigh closures may be conceptualized as similar to closures on the upper arm—the dermis is moderate in thickness, and the area is under often-substantial tension. On the shins, however, closures are often significantly more challenging. The presence of impaired circulation and high tension mean that closures below the knee may be technically challenging to effect and are concomitantly fraught with an increased risk of infection and dehiscence when compared with closures elsewhere on the body.

An important principle when closing wounds below the knee is to anticipate the high risk of closure failure and therefore minimize the size of the defect. Thus, concerns regarding standing cone formation should be set aside when closing most shin defects. The high tension in these areas also means that as the repair heals over time the tension across the central portion of the wound may lead to blunting of the initial valley created by the closure, and therefore the appearance of the dog ears will eventually resolve.

As with other highly mobile areas, it is important to plan appropriately when developing an ideal axis of wound closure. Therefore, the leg should be examined preoperatively both flexed and extended, and individual closure approaches should be tailored to each patient so that a patient who spends most of the day seated at a computer or in a wheelchair may have their wound closed on a slightly different axis than a highly-active patient.

Most wounds on the thighs are closed with a 3-0 absorbable suture material, though in small wounds under minimal tension a 4-0 absorbable suture may be used. Similarly, wounds on the shins are often closed with a 3-0 absorbable suture, though when an adhesive strip bolster technique is used a 3-0 nonabsorbable suture may be used as well.

The standard approach to closure would include the set-back dermal suture or the buried vertical mattress suture for most leg closures. Generally these approaches are used on the thighs, though of course with larger defects under marked tension a pulley variation of the previously mentioned techniques is possible as well. When closing wounds on the shins, however, other specific challenges may emerge. These wounds are often very narrow and the skin is often fairly inelastic, and therefore may not permit easy placement of buried vertically oriented sutures. In such cases, placing a percutaneous set-back dermal suture may be an alternative. Other approaches would also include the percutaneous buried vertical mattress technique (though the shallow portion of the bite may result in tissue tear through in the thin skin of the shins) and the percutaneous horizontal mattress suture (where the horizontal orientation allows for a broader and more robust bite of dermis). The adhesive-strip bolster approach utilized in concert with a horizontal mattress suture is also a mainstay of therapy for closing narrow atrophic wounds on the shins (Figure 6-3).

Superficial closures may be performed utilizing a running subcuticular technique; when absorbable monofilament suture is used with this approach it affords the benefit of long-lasting wound-edge approximation. Other interrupted sutures may be used as well, with simple interrupted, horizontal mattress, and vertical mattress representing some of the most frequently used techniques for wounds on the thighs.

On the shins, care should be taken not to over-sew the area. There is sometimes a temptation to add additional sutures when the wound edges are not precisely approximated. While other anatomic locations, such as the face, are very forgiving when extra sutures are placed, the poor vascular supply to the lower legs means that adding extra suture material, except when necessary, should be avoided.

An additional option when closing the lower legs is to perform a purse-string closure. Since cosmesis on the shins is often subpar, and keeping the wound as small as possible is of paramount importance, the purse-string approach may be a useful adjunct. Since the skin on the shins is often atrophic, the percutaneous purse-string technique may generally be the most appropriate in this location.

On the thighs, the usual approach of utilizing set-back dermal sutures except at the apices where buried vertical mattress techniques are used may be the most appropriate. On the knees, adding additional horizontal mattress sutures layered over top of set-back dermal sutures may aid in tension reduction in these high-mobility areas.

The percutaneous purse-string technique may be used on the shins in concert with simple interrupted or horizontal mattress sutures to obtain wound-edge approximation. Partial closure of large defects on the lower leg with purse-string closures may be augmented by allowing the remainder of the wound to close via secondary intention healing.