LE Amputation Surgery

Question 1

Indication for amputation

Answer 1

• Insufficient blood supply to support the tissue viability
• Failed medical intervention
• Other surgical intervention has failed ie. Stenting, grafting, bypass, surgical debridement with wound closure

Question 2

Causes of amputation

Answer 2

• Vascular disease (arterial & diabetic most commonly) #1 reason
• Tumors
• Trauma #2 reason
• Chronic infection (fear of systemic infection)
• Deformity, paralysis, limb discrepancy
• Congenital limb deficiency (to increase function)

Question 3

Factors determining amputation level

Answer 3

• Pathological: lowest level of viable tissue
• Anatomical: preserve as many functional joints as possible with a long residual limb length
• Surgical: minimize complication ie. Hemorrhaging, neuroma, necrosis (must take into account previous vascular reconstruction sx)
• Individual: age, contractures, presence of chondrite systemic diseases, neuropathy, impaired balance, loss of vision

Question 4

Percent of amputees that will have an amputation of the same or opposite limb within 5 years

Answer 4

50% (likely d/t progressive disease)

Question 6

General guidelines of surgery

Answer 6

• Major goal is to preserve length
• Vascular surgeons not required to study prosthetics, orthopedic surgeons are required

Question 7

Myoplasty

Answer 7

Attachment of anterior and posterior compartment muscles over end of distal bone

Question 8

Myodesis

Answer 8

Muscle is sutured to bone (more similar to normal functioning)

Question 9

Transtibial amputation

Answer 9

• Flap length; diameter of leg at bone cut plus 1 cm generally 12-15 cm (15 cm of tibia is optimal)
• Fibular is usually 1 cm shorter than tibia for shaping
• Non-viable tissue respected, viable tissue debridement, bone is cut, arteries and veins are lighted separately and as low as possible within the residual limb to maximize collateral circulation, nerves are divided as high as possible, put under tension, cuts and allowed to retract and form the neuroma as far from distal end of residual limb as possible, distal bone is beveled to remove all sharp, harmful edges, drains are inserted and soft tissue/skin flaps are closed

Question 10

Skin flaps

Answer 10

• Need to be as broad as possible, well healed, non tender and non adherent
• Placement of scar not as critical with total contact sockets and use of proper liners as long as the scar is supple and well healed
• Posterior flaps are commonly used with PVD, skin in the posterior leg has better circulation. Posterior musculature is brought forward and attached to the deep fascia of the anterior musculature and periosteum
• Posterior flap is generally 13-15 cm longer than anterior

Question 11

Short transtibial

Answer 11

Less than 20% tibial length

Question 12

Transtibial length (optimal)

Answer 12

Between 20-50% of tibial length

Question 13

Long Transtibial

Answer 13

More than 50% tibial length

Question 14

Transfemoral amputation

Answer 14

• Equal length anterior and posterior flaps
• Thigh muscles into four groups and quadriceps and hamstrings are anchored to each other via myoplasty
• Adductor magnus tendon is brought around distal femur and sutured to lateral femur via myodesis
• Abductors, IR, ER muscles not affected (left intact)

Question 15

Short transfemoral

Answer 15

Less than 35% of femoral length

Question 16

Transfemoral length (optimal)

Answer 16

Between 35-60% length of femur

Question 18

Long transfemoral

Answer 18

Greater than 60% length of femur

Question 19

Knee disarticulation

Answer 19

• Amputation through the knee joint with intact femur
• Uncommon, femoral condyles created bulbous end which can be difficult for prosthetic fitting

Question 20

Transphalangeal amputation

Answer 20

• Entire ray (toe plus metatarsal removed)
• Done due to demarcated gangrene or frostbite

Question 21

Transmetatarsal amputation

Answer 21

• A disarticulation, metatarsal heads left intact
• A functional amputation
• Residual limb is symmetrical and major muscle attachments preserved

Question 22

Advantages of disarticulations

Answer 22

• Intact bone (osteomyelitis)
• Intact epiphyseal plates (children)
• Longer lever arm

Question 23

Disadvantages of disarticulation amputations

Answer 23

• Reduced cosmesis (difficult for prosthetic fitting)
• Fewer components to fit small joint space)

Question 24

Syme disarticulation

Answer 24

• At the ankle occurs at talo-crural joint (most common)
• Weightbearing heel pad is brought under, forward and attached
• Heel pad becomes adhered to bone
• Malleoli may or may not be trimmed

Question 25

Chopart disarticulation

Answer 25

- Occurs at the midtarsal joint through talonavicular and calcaneocuboid joints - Calcaneous is left intact - Tend to develop pes equinas deformity secondary to muscle imbalance - Achilles tendon lengthening prevents equinas formation

Question 26

Hip disarticulations

Answer 26

- Done for untreatable malignancy or severe trauma - Dividing muscles at the pelvic origins of femoral insertion

Question 27

Hemipelvectomy

Answer 27

Removal of all or part of the ilium

Question 28

The ideal residual limb

Answer 28

- Strong well muscled - Correct shape (cylindrical for TT, conical for TF) - Don’t want to see bulbous, dog ears, or adductor rolls - Length is optimal for both good leverage and vascular supply - Skin and subcutaneous tissue is healthy, well vascularized and mobilize - Tissue covers the distal bone without adhesions or excessive tension over the bony end - Incision is well healed and linear, located away from the bony prominences and WB areas - End of long bony shafts have been beveled smoothly without presence of spurs - No significant lesions present - Remaining joints have normal ROM & strength - Blood supply adequate enough to meet demands of working muscles - Venous & lymphatic drainage is not obstructed - Edema free without painful neuromas, incisional pain or irritating phantom pain/sensation - Normal skin sensation with good joint proprioception and kinesthesia - Distal end capable of some pressure load “end bearing”

Question 29

Rehab after amputation

Answer 29

Divided into post surgical or pre-prosthetic phase and the prosthetic phase * The earlier the intervention the better the prognosis for achieving success *