Lower Extremity Amputation

Amputations - reasons

congenital limb deficiency - when the limb is grossly deformed and useless vascular insufficiency (peripheral vascular disease, or PVD) - ischemic conditions of the limb, such as: -atherosclerosis and/or arteriosclerosis, predominantly diabetic, -Buerger's disease (thromboangiitis obliterans) - acute inflammation and thrombosis (clotting) of arteries and veins in smokers, affecting the hands and feet; decreased blood flow (ischemia) leads to severe pain, skin ulcerations and gangrene of the digits (fingers and toes) malignant tumour of bone or soft tissue, and traumatic (crush) injury to the limb - due to transport and industrial accidents.

Amputation, however, should be attempted only after all forms of treatment have been exhausted.

Rates of Causes for Amputation

70% of amputations are performed for vascular disease including diabetic complications, arteriosclerosis and thromboembolism, 22% due to traumatic injuries and infection4% result from malignancies 4% due to congenital deformities

Lower Extremity AmputationsHemipelvectomy: Removal of leg and half of pelvis.

Hip Disarticulation (H/D): Removal of leg at pelvic joint.

Above-Knee (A/K): Removal of leg between hip and knee.

Knee Disarticulation (K/D): Removal of leg at knee.

Below-Knee (B/K): Between knee and ankle.

Syme Amputation: Removal of foot at ankle (usually performed for injury, not for vascular problems).

Transmetatarsal/Partial Foot: Removal of part of the foot.

Lower Extremity Amputation Levels

Hemipelvectomy and Hip Disarticulation: amputation of the entire leg including lateral portion of pelvis being the ilium, ischium, or pubis of same side. Usually done in cases of malignant tumors, extensive gangrene, infection and trauma Disarticulation: a separation at the joints, hip or knee

Transfemoral Amputation Levels

Short: large weight-bearing surface if done at level of lesser trochanter, retains femoral head, and greater trochanter resulting in an improved prosthetic fit. Declined due to improved surgical techniques and assessment of vascular function.

Transfemoral Amputation Levels

Medium: At least 410 cm above lower end of femur to allow room for prosthetic knee. Knee disarticulation: Retains thigh muscles giving good muscular balance, growth potential is maintained, provides good weight bearing, results in difficulty of swing phase control in walking, cosmetic asymmetry due to a prosthetic knee that extends below the other.

Below knee amputation

The ideal level for amputation in the patient is approximately at the junction of the

proximal/middle thirds of the calf to the mid-calf.

Transtibial Amputation Levels

Very Short: Usually results from trauma, not an elective procedure, very small moment arm, retains knee.Standard: Elective amputation, provides a well padded and effective biomechanical lever arm, at least 8 cm of tibia is required. Long: Not advised due to poor blood supply in distal leg.

Too short for use a prosthesis

Transtibial Amputation Levels

Syme: Named for James Syme, a scottish physician mid 1800s, Ankle disarticulation, residual limb with good function due to long lever arm to control prosthesis, ideally suited for weigh bearing and can last life of patient, can walk without prosthesis, disadvantages of chronic nerve damage to posterior tibial nerve.

Transmetatarsal Amputation

Approximately 10,000 performed in US with a 30% failure rate, attributed to the combination of substantial loss of weight bearing area and reduced length of lever arm to generate a plantarflexor movement. Limited to patients with good anterior tibial pulse and blood flow, usually performed due to trauma, infection, frostbite, diabetes, arteriosclerosis localized to the phalanges.

Post Amputation Complications

Contractures Infections in neglected stumps. Neuromas--scar tissue full of nerves that can

become sensitive to touch, change of temperature. Phantom limb or phantom pain--sensation of

presence of old limb in remaining nerve endings; tends to decrease over time.

Bone spurs. Low back pain with use of prosthetic.

Traumatic amputation

Severe open fracture that leads to loss of extremity

Patient with multiple traumatic injuries poor candidate for reimplantation

Prosthetics Vs. Orthotics

Prosthesis: An artificial device used to replace a missing body part, such as a limb, eye, or heart valve.

Orthosis: An application or apparatus used to support, align, prevent, or correct deformities or to improve existing function of movable parts of the body.