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Below Knee Amputation

Preoperative Patient Care

A

Intermediate Evaluation and Management

1

Obtain focused history and performs focused exam

  • evaluate
  • vascular status
  • if severe vascular dysfunction may require revascularization procedure prior to amputation
  • wound healing potential
  • check with nutrition labs: albumin, prealbumin, transferrin, total lymphocyte count
  • soft tissue injury
  • severe soft tissue injury has the highest impact on decision whether to amputate or reconstruct lower extremity in trauma cases
  • infection
  • CRP, ESR
  • neuropathy
  • trauma
  • vascular exam
  • Doppler (ischemic index)
  • ABI
  • transcutaneous oxygen pressure
  • toe pressures
  • need to assess associated injuries and comorbidities (diabetes)
  • documental baseline neurovascular exam
  • traditional short BKA increases baseline metabolic cost of walking by 40%
  • traumatic BKA 25%

2

Appropriately interprets basic imaging studies

  • AP/Lat views of foot, ankle, and tibia/fibula
  • MRI of the to look for integrity of soft tissue and infection

3

Appropriately orders and interprets advanced imaging studies

  • CT and MRI w/ or w/o contrast)

4

Makes informed decision to proceed with operative treatment

  • documents failure of nonoperative management
  • describes accepted indications and contraindications for surgical intervention

5

Postoperative Rehabilitation

  • phase 2 (weeks 2-10)
  • goals
  • strengthening
  • lumbar and core stabilization
  • balance
  • cardiovascular conditioning
  • range of motion
  • independence with mobility and ambulation with mobility devices
  • independence of limb care
  • phase 3
  • goals
  • progress weightbearing and weight shifting exercises
  • perform rehabilitation exercises independently
  • normalize gait
  • return to high level/high impact exercises
  • start vocation specific training

6

Postop: 2-3 Week Postoperative Visit

  • wound management
  • remove sutures on week three
  • begin shrinker once wounds are closed, healed and dry
  • transition to liner when prosthetist feels appropriate
  • diagnose and management of early complications
  • wound healing
  • infection
  • DVT

7

Postop: ~ 3 month Postoperative Visit

  • diagnosis and management of late complications

8

Postop: 1 year Postoperative Visit

9

Treat postoperative complications

B

Advanced Evaluation and Management

1

Provides complex non-operative treatment

  • multiple co-morbidities
  • non-compliant
C

Preoperative H & P

1

Perform basic medical and orthopaedic history and physical

  • check neurovascular status to determine level of amputation

2

Order basic imaging studies

  • weightbearing images
  • AP/Lat views of foot, ankle, and tibia/fibula

3

Perform operative consent

  • describe complications of surgery including
  • phantom limb pain
  • limb socket interface problems
  • wound breakdown (worse in diabetics, smokers, vascular insufficiency)
  • superficial and deep infections

Operative Techniques

E

Preoperative Plan

1

Radiographic templating

2

Execute surgical workthrough

  • describes the steps of the procedure to the attending prior to the start of the case
  • describe potential complications and steps to avoid them
F

Room Preparation

1

Surgical instrumentation

  • basic major orthopedic set
  • oscillating saw
  • drill
  • amputation knife
  • silk free and stick ties
  • suction drain

2

Room setup and equipment

  • standard OR table
  • fluoroscopy

3

Patient positioning

  • place patient supine
  • place small bump under ipsilateral hip to internally rotate the leg
  • place a thigh tourniquet
G

Mark Out Flap Incision

1

Mark out the tibial tubercle and the medial joint line

  • mark out tibial tubercle

2

Mark out anterior incison

  • mark the anterior incision 10cm distal to tibial tubercle
  • this incision is also15cm from knee joint line
  • anterior incision 2/3 total circumference

3

Mark the posterior incision

  • posterior incision 1/3 total circumference
  • mark out the posterior flap so that it is 1.5 times the length of the anterior flap
  • this is extremely important because it allows for redundant posterior flap upon closure
  • the posterior flap should be distal to the musculotendinous junction of the gastrocnemius
  • round out the distal ends of the posterior skin flap to reduce redundancy of skin upon closure
H

Anterior Soft Tissue Dissection

1

Dissect through underlying fascia

  • incise the entire circumference of the skin incision through the underlying fascia
  • direct the vertical incison over the anterior crest of the tibia to facilitate exposure of the anterior periosteal flap

2

Divide the fascia

  • identify the superficial and deep peroneal nerves
  • place gentle traction and resect nerves using sharp dissection
  • sharply dissect through the anterior compartment musculature at the most proximal end of the wound
  • this reduces bulk and makes the myodesis easier
  • identify, isolate and ligate the anterior tibial artery
  • dissect through the deep musculature
I

Bone Bridge(optional)

1

Elevate periosteum

  • elevate the perosteal flap using a single blade wide chisel
  • sharply incise the anterior and posterior margins of the anteriormedial tibia for 8 to 10 cm distally
  • raise the flap with the bevel positioned superiorly
  • protect the flap using a moist gauze sponge
  • isolate the rest of the tibia with a periosteal elevator
  • divide the interosseus membrane and identify the fibula

2

Osteotomize the fibula

  • prepare the fibula for the osteotomy
  • perform cut of the fibula several centimeters distal to the tibia cut
  • the proximal cut of the fibula is at the level of the distal tibia cut
  • elevate the periosteum of the fibula at this level of the cut and continue elevating for 1 cm distally

3

Construct bone bridge

  • cut a notch into the posterolateral tibia to house the fibula
  • secure the bone bridge with non absorbable suture through holes that are made through the lateral aspect of the fibula, through the medullary canal of the transverse fibula to the medial aspect of the tibia
J

Bone Transection

1

Mark the fibula cut

  • without a bone bridge approximately 1 cm proximal to the tibia cut at a lateral angle
  • with a bone bridge
  • measure the interosseous distance
  • distance from the lateral tibia to the media fibula
  • make fibula cut this distance plus 2 cm proximal to the tibia cut

2

Cut the tibia

  • use a power saw with irrigation to make the tibia cut
K

Posterior Soft Tissue Dissection

1

place a sharp amputation knife and

  • transect and taper the posterior musculature

2

Dissect through the deep posterior compartment and soleus

  • this is done to provide a tension free myodesis
  • this should be performed at the level of the tibial bone cut

3

Identify neurovascular structures

  • identify and dissect the tibial nerve from the vasculature
  • inject the nerve with 1% lidocaine then sharpy transect under gentle traction
  • identify and ligate the posterior tibial artery with ligature suture
  • ligate the veins with vasvular clips or ligature suture
  • resect remaining posterior compartment to the level of the distal tibia cut
L

Myodesis

1

Obtain hemostasis

  • release the tourniquet
  • obtain hemostasis of the musculature

2

Bevel Tibia

  • begin the bevel outside of the medullary canal at 45 degree angle
  • rasp and round out the sharp edges

3

Perform myodesis

  • drill holes just anterior to the bone bevel for myodesis
  • use a locking style Krackow suture through the gastroc apneurosis and secure it to the tibia
  • usually # 2 or #5 suture is used
  • place a submuscular drain
  • secure the borders of the gastrocnemius to the proximal anterior fascia

4

Treat intraoperative complications

N

Wound Closure

1

Irrigation & Hemostasis

  • irrigate wounds thoroughly
  • recheck for remaining peripheral bleeders

2

Deep closure

  • 0-vicryl for deep fascia
  • subcutaneous with 2-0 vicryl

3

Superficial closure

  • skin closure with 2-0 nylon (vertical/horizontal mattress)
  • do not want to overly tighten skin as this can necrosis edges

4

Dressing and immediate immobilization

  • soft incision dressing well padded to reduce pressure in incision
  • knee immobilizer or U-shaped splint
  • crutches or walker for ambulation

Postoperative Patient Care

O

Perioperative Inpatient Management

1

Write comprehensive admission orders

  • IV fluids
  • advance diet as tolerated
  • check appropriate labs
  • DVT prophylaxis
  • foley out when ambulating
  • wound care
  • keep dressing on for 1 week
  • remove drain on POD 2
  • continue postoperative antibiotics until the drain is removed
  • order and interprets basic imaging studies
  • inpatient pt
  • phase 1
  • bed to wheelchair mobility
  • range of motion exercises
  • place in knee immobilizer
  • edema control
  • independent gait training with a walker or crutches
  • return balancing and conditioning to normal
  • appropriate medical management and medical consultation

2

Discharges patient appropriately

  • pain meds
  • wound care
  • outpatient PT
  • schedule follow up in 2 weeks
R

Complex Patient Care

1

Develops unique, complex post-operative management plans

 

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