Above-Knee and Below-Knee Amputation

Above-Knee and Below-Knee Amputation

Introduction

Amputations above and below the knee are common surgical procedures performed by vascular, orthopedic, and general surgeons. The indications for these procedures include infection, acute ischemia, chronic progressive ischemia, trauma, intractable pain, neuropathy, and nonhealing wounds. In developed countries, the primary indications for lower-extremity amputation are complications of peripheral vascular disease and diabetes mellitus.

Preoperative Evaluation

The level of amputation is predicated on skin healing and the patient’s functional status. In patients who are ambulatory before surgery, the goal is to perform amputation at the most distal level that returns the patient to maximum function. Typically, the below-knee amputation (BKA) requires much less energy postoperatively to walk and allows patients to remain fully ambulatory. Patient can be ambulatory after above-knee amputation (AKA), but walking is more difficult and requires a significant increase in energy expenditure, which may not be available to older patient with significant comorbidities. If a patient is nonambulatory, AKA improves the chance of healing and limits complications from contractures. Preoperative noninvasive testing is helpful in determining lower-extremity blood flow and appropriate level of amputation for successful healing.

Preoperative evaluation and optimization prepare the patient for surgery and minimize perioperative complications. Glucose control and underlying nutritional status should be evaluated and optimized. Occasionally, initial guillotine amputation is indicated to provide drainage and control of deep space infection, with a secondary procedure for definitive closure. Recognition of the importance of amputation as the first step of the patient’s rehabilitation to recovery of functional status should be emphasized to the patient and health care team. Successful rehabilitation depends on aggressive postoperative physical and occupational therapy. Group amputee therapy is helpful in patients with psychological issues surrounding the actual amputation.

Surgical Principles

Surgical technique should emphasize gentle handling of the tissues, strict hemostasis, use of viable tissue for closure, and ligation of nerves under tension to allow retraction out of the area of surgical incision. Retraction and atrophy of tissues associated with normal healing and scarring should be considered when transection of bone is performed, to avoid the complication of wound breakdown from tension on the healed scar.

Use of immediate postoperative prosthesis (IPOP) typically is surgeon and institution specific. IPOP allows for early weight bearing and ambulation and is well suited for younger, motivated patients. The goal of operation is to provide a healed wound with a stump that can fit into a prosthetic limb. For BKA, the long posterior myocutaneous flap is typically used, although circular and fish-mouth incisions may be necessary with wounds in or on the calf. Newer prosthetic techniques allow for mediolateral or anteroposterior flaps with good functional outcome. The importance of identifying the fascial layers for closure and meticulous handling of the tissues should be emphasized (Fig. 39-1).

FIGURE 39–1 Fascial compartments of leg.

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Tags: Netters Surgical Anatomy and Approaches

Aug 12, 2016 | Posted by admin in ANATOMY | Comments Off

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