Above the knee amputation

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.

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

• heterotopic ossification

• soft-tissue inflammation (stump bursitis) ²

• stump neuromas

• 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.