Amputations II – 2

AMPUTATIONS 2

BELOW-KNEE AMPUTATION

The most proximal level at which near-normal function is available.

INDICATIONS (Haimovici, 1996)
� Gangrene of several toes, extending to or beyond the adjacent metatarsal lesion and showing no tendency to demarcate.
� Spreading gangrene of the foot, with or without associated gangrene of the heel or ankle.
� Spreading gangrene of the toes, associated with uncontrollable infection of the foot.
� Failure of a transmetatarsal or Syme amputation.
� Trauma
� Neoplasia

CONTRAINDICATIONS
� Inadequate circulation for healing!
� Extensive gangrene and infection of the leg with absence of femoral pulses
� Gangrene of the foot associated with irreducible flexion contracture of the knee joint.
� Recent acute occlusion of the femoral or iliac artery with inadequate collateral supply at the below-knee level. (Need a 2-3 month interval for the development of collateral circulation.)
� The nonambulatory patient with a dysvascular limb and flexion contracture of the knee – will be better off with a knee dysarticulation. (McCollough et al., 1981)

TECHNICAL OPTIONS

Long Posterior Myocutaneous Flap
� Most common. Takes advantage of the vascularity of the posterior musculature.
� Moore et al. (1972, Am. J. Surg): superior healing rate (89% vs 72%) after changing from equal AP flaps.

Equal Anterior and Posterior Myocutaneous Flaps
� Still popular in some centres, though falling out of favor.

Equal Medial and Lateral (Sagittal) Myocutaneous Flaps
� Reduces the amount of poorly vascularized anterior skin, utilizes wide-based, short flaps, may provide better bony coverage and wound drainage, and is useful if necrotic skin is present posteriorly.
� Persson, (1974, J. Bone Joint Surg): superior healing rate (74% vs 41%) in 58 pt compared to 40 with equal AP flaps.
� Termansen, (1977, Acta Orthop. Scand): equal healing rate (58% vs 59%) in 41 pt compared to 47 with long posterior flap.

Suffice to say, that in certain situations (trauma in particular), the flap configuration may be dictated by the pattern of tissue loss, so it is important to be aware that there are more than one way to perform the operation.

TECHNICAL OPTIONS (cont�)

Osteomyoplasty
� Requires raising two one-inch osteoperiosteal flaps from the anteromedial and lateral tibia. The tibia and fibula are divided at the level of the osteoperiosteal flap hinge (the fibula 5mm shorter). The flaps are then swung over and attached to the fibula. An osseous bridge then develops between the tibia and fibula, which is believed to stabilize the fibula and improve the end-bearing characteristics of the stump.
� Questionable role in vascular disease – requires the sacrifice of 7.5 cm of stump length, and significantly increased operative time.
� May be indicated in young patients to provide a stronger stump, or in revisions of traumatic supramalleolar amputation. (McCollogough, 1981)

POSTOPERATIVE STUMP MANAGEMENT

Drain vs No Drain?

� A hematoma is a major complication, predisposing to infection which may delay wound healing or sabotage it completely. Revision surgery or more proximal amputation have been known to be caused hematoma formation.
� Kacy et al. (1982, Surg. Gynecol. Obstet.) 113 BKA’s in 100 patients. Wound complications in 55% of drained patients, 16% in those not drained (Penrose drains)
� Tripses and Pollak (1981, Am. J. Surg.) 64 BKA patients. 46% infection rate in drained patients, 20% in undrained.

Conclusion: Meticulous hemostasis is critical. Open drainage is hazardous. Closed drainage may be useful if the patient is oozing a great deal at the conclusion of the case.

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