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A below-knee amputation (BKA), or below-the-knee amputation, is a transtibial amputation that involves removing the foot, ankle joint, distal tibia, fibula, and corresponding soft tissue structures. Lower extremity amputation serves as a life-saving procedure. Lower limb ischemia, peripheral arterial disease, and diabetes are considered the major causality of limb amputations in more than 50% of cases. Trauma is the next leading cause of lower-extremity amputations. In general, below-knee amputations are associated with better functional outcomes than above-knee amputations. This activity describes the indications and techniques for performing below-knee amputations and highlights the role of the interprofessional team in the preoperative and postoperative management of the condition. Objectives: Identify the indications for below-knee amputation. Implement guideline-concordant postoperative care for a patient who has undergone a below-knee amputation. Apply best practices to reduce the complications associated with below-knee amputations. Collaborate with the interprofessional team to facilitate safe outcomes for patients requiring below-knee amputations. Access free multiple choice questions on this topic.

Lower-extremity amputation is performed when nonviable lower-extremity tissue is present for many reasons, including ischemia, infection, trauma, or malignancy.[1] Lower-extremity amputation serves as a life-saving procedure. Lower limb ischemia, peripheral arterial disease, and diabetes are considered the primary causality of limb amputations in more than 50% of cases. Trauma is the next leading cause of lower-extremity amputations.[2] The second TransAtlantic Inter-Society Consensus (TASC II) working group reported the incidence of major amputations due to peripheral artery disease for up to 50 per 100,000 individuals annually.[3] A below-knee amputation (BKA) is a transtibial amputation that involves removing the foot, ankle joint, distal tibia, and fibula with related soft tissue structures. Generally, a BKA is preferred over an above-knee amputation (AKA), as the former has better rehabilitation and functional outcomes.[4] Lower extremity amputation rates have declined recently, but 3500 trauma-related amputations are still performed annually in the United States.[5] This surgical operation carries significant morbidity, yet it remains a treatment modality with vital clinical and often life-saving significance given appropriate indications.[6][7] Ernest M. Burgess first described the remarkable functional impact on preserving the transtibial zone.[8]

As with all surgical procedures, there are possible acute complications of uncontrolled bleeding, infection, acute postoperative pain, and broader medical complications, including acute blood loss anemia and stress-induced cardiac ischemia. With a BKA performed for infection or acute soft tissue trauma, a second operation may be necessary if distal skin edges further demarcate or if the area of infection was not adequately resected.[29] Chronic complications of BKAs include the development of painful neuromas from transected nerves, highlighting the importance of proper intraoperative technique as described above. Phantom limb pain, or the perception of pain or troubling sensation in the missing limb, is a common complaint. They address this with a mirror box, local injections, adjustment to the prosthesis, or various other modalities. The psychiatric and psychosomatic effects of a BKA should not be overlooked in postoperative patients, as this cohort has been shown to have higher rates of depression and suicide.[30]

In the peri-surgical environment surrounding a BKA, close communication across all healthcare disciplines forming the interprofessional team is paramount. The initial workup of ischemic and infectious limb-compromising diagnoses often begins in the emergency department or local clinic, where prompt assessment, triage, and workup are critical. The emergency clinician must recognize which patients require emergent versus urgent versus planned surgical care. This is determined via the clinical picture, including vital signs and exam, and through an assessment of infectious labs, CBC, BMP, lactic acid, base deficit, blood cultures, and radiographic imaging. Once surgical services, typically orthopedics, general surgery, or vascular surgery, are consulted, preparation may be made for the operative management of critical lower limb disease. At this point, the healthcare team includes the surgeon, the patient (who must provide informed consent for a BKA, either personally or via proxy), anesthesia providers in the operating room, operating room management and staff, and the bedside nurses either in the emergency department or on the floor. In all urgent cases, close communication between all team members is critical. For instance, a delay in an operating room is available due to inadequate anesthesia coverage can significantly affect a patient's outcome. After BKA, floor nursing plays a significant role in managing pain, recording drain outputs, and informing the covering physicians of any change in vital signs or overall status. Surgical and hospitalist services should closely monitor the postoperative patient for the potential necessity of reoperation, vascular insufficiency at the BKA site, systemic electrolyte disturbances, sepsis, or other medical problems requiring management. Discussion may now be initiated regarding prosthetic devices and a postoperative plan, starting with devices such as a stump shrinker, limb protector, and knee immobilizer.[33] Finally, attention should be given to the postoperative patient's mental status, including the potential need for psychiatric evaluation and care. Every postoperative patient should have an attentive primary healthcare provider to follow up closely after hospital discharge.[30] Interprofessional care coordination before, during, and after these procedures will result in better patient outcomes. [Level 5]