A Closer Look At The Three-Knot Layered Krackow Achilles Repair

Neal Blitz DPM FACFAS

When it comes to repairing the ruptured Achilles tendon, there are a variety of methods ranging from wide-open exposures with grafting to percutaneous approaches. All of these options have their advantages and disadvantages. However, the most common is a straightforward open approach in which the surgeon re-approximates the tendon in an end-to-end fashion.

Surgeons are most concerned about the strength of the repair, both on the operating room table and during the healing phase (six to eight weeks). Weakening of the repair may result in a loss of position, which could result in a poor functional outcome.

Several variables determine the “strength” of the repair. The two that are most discussed are: the type of suture (absorbable/non-absorbable) and the method with which the surgeon “weaves” together the tendon. It is clearly understood that a non-absorbable suture will not degenerate and weaken with time. However, some surgeons have concerns about using a lot of non-absorbable suture for its foreign body potential.

With regard to methods of repair, the Krackow stitch allows for intratendinous locking of the stitch (both medially and laterally), which prevents the suture from sliding within the tendon. This is a tremendous advantage for Achilles ruptures that are “mop ended.” The technique bundles together the Achilles tendon, giving it a sense of shape and structure that is necessary for repair. Traditionally, one performs the Krackow stitch on both the proximal and distal sides of the rupture, and ties the ends together at the rupture site (see Figure 1).

Regardless of the method of repair and the type of stitch, the repair appears to be most vulnerable to failure at the knot. The knot is the point at which the surgeon brings together the repair site and thus receives the most force. Also, knots have a tendency to “slip” or stretch with time, or as dorsiflexion occurs postoperatively.

A double repair (or a layered repair) seems to provide additional strength to the repair, and also provides some insurance should one of the sutures fail. The layered approach also allows the surgeon to have four knots instead of two knots, thus reducing the chance of knot failure as the repair is stronger. In a cadaveric study, researchers evaluated a technique called the “gift box” repair.1 With this technique, the surgeon ties the knots of the Krackow technique away from the rupture site. The results demonstrated that the gift box repair technique was twice as strong as the traditional Krackow repair. However, its utility in clinical practice remains to be seen.

In clinical practice, I have moved the knot away from the rupture site for the aforementioned reasons but do this for only one of the Krackow layers. I use a traditional Krackow technique for the deep layer. After determining the optimal position for the Achilles Repair, I tie the two knots (see Figure 2).

This deep layer fixes the position of the repair so the next layer only needs to provide stability and reinforcement. I run a single strand of suture up (medially) and down (laterally) the tendon. This only requires one knot, which is away from the repair site (see Figure 3). The superficial layer has the benefit of being a single strand of suture and a single knot, rather than two knots, which inherently makes it less vulnerable to knot failure.

A strong secure repair allows surgeons to utilize an early range of motion program. The benefits of early mobilization are well known. The post-op protocol for the three-knot layered Achilles repair is illustrated in Figure 4.

Reference

1. Labib SA, Rolf R, Dacus R, Hutton WC. The “Giftbox” repair of the Achilles tendon: a modification of the Krackow technique. Foot Ankle Int 2009; 30(5):410-4.

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