Above-the-knee amputation (AKA) is the surgical removal of the leg from the body by cutting through both the thigh tissue and femoral bone.
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Indications
The procedure may be necessary for a wide variety of reasons 1:
trauma to the lower leg, resulting in a non-viable leg at or near the level of the knee
infection, which has compromised the entire lower leg and is unresectable, possibly due to diabetic wounds, necrotizing fasciitis, or cases of immunocompromised patients
tumors that are unresectable or whose resection would render the distal aspect of the limb non-usable
vascular compromise, whether from injury or disease
additionally, congenital disabilities that render a limb unusable
Contraindications
patients who are not medically stable enough to survive the anesthesia and/or surgery
Procedure
After taking written informed consent, the procedure is done in emergency or elective non-emergency settings.
Technique
The operative technique usually includes the following steps 1:
leg preparation and drape in a sterile fashion
marking the planned skin incisions
flaps may be dictated by what tissue remains viable, especially in trauma
optionally application of a sterile tourniquet to reduce blood loss
incisions as planned with bleeding control using electrocautery
dissection, ligation and transection of the the femoral artery and vein as well as any other large vessel branches
dissection and transection of sciatic and saphenous nerves, typically about 12 cm proximal to the joint line, if the level is not dictated by other factors
Care must be taken to remove the synovium completely from the knee to avoid postoperative effusion and to avoid over-tightening the skin suture to avoid skin necrosis.
Complications
The following complications may occur:
muscle atrophy
surgical site wound infections
dehiscence
wounds from prosthetic wear
aggressive bone spurs
soft-tissue inflammation (stump bursitis) 2
phantom pain
collection
osteomyelitis 3
Radiographic features
Described imaging appearances are those of the normal postoperative status without complication.
This includes the absence of the whole lower limb including the knee and the distal femur up to the level of the amputation 2.