TKA with Computer Navigation & Sensor-Guided Assessment for Soft Tissue Balancing - Dr. William Gallivan

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TECHNIQUE VIDEO
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TECHNIQUE STEPS
 
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Evidence
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Technique Video
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TECHNIQUE STEPS
Preoperative Patient Care
Operative Techniques
D

Simulation

1

Cadaveric demonstration of surgical approach

2

Sawbones demonstration of proper instrumentation techniques

E

Preoperative Plan

1

Radiographic Templating

  • Template implant sizes

2

Execute Surgical Walkthrough

  • Describe steps of the procedure to the attending prior to the case
  • Describe potential complications and steps to avoid them
F

Room Preparation

P

1

Room Setup and Equipment

  • OR table with removable leg padding is used
  • Leg holder (optional)

2

Surgical Instrumentation

  • Confirm all surgical instrumentation is on the back table and sterile
  • Surgical team must have knowledge of the particular implant system and navigational equipment
Pearls
  • OR setup should be consistent and reproducible to maximize efficiency

3

Patient Positioning & Draping

  • Supine position
  • Thigh tourniquet should be placed as proximal as possible to allow adequate room for prepping and draping (ideally placed in hip crease)
  • Secure both arms to well-padded arm boards
  • Secure the patients torso with a seatbelt attached to the table
  • The nonoperative leg is padded and secured with tape
  • Drape in usual sterile fashion
  • Attach leg holder to table, ensuring operative leg can be placed in full extension and hold the knee at 90 degrees or more of flexion during certain parts of the procedure
G

Medial Parapatellar Approach to the Knee

P

1

Identify Anatomy and Draw Incision

  • Identify tibial tubercle, patella, and patellar ligament
  • Cross hatch incision area
  • Draw a straight medial parapatellar incision starting several centimeters (generally two finger breadths) proximal to the proximal pole of the patella and continuing just distal to the tibial tubercle
  • Complete draping with Ioban

2

Insert Navigation Pins and Attach Trackers

  • Insert two 3.2mm navigation pins distal to the tibial tubercle to avoid the patella tendon and interference with tibial implant placement
  • Attach anchoring device with blue navigation tracker
  • Insert two 3.2mm navigation pins into femur, one hand-breadth proximal to the patella. To minimize muscle tension. place the pins with the knee in flexion
  • Attach anchoring device with green navigation tracker

3

Capture External Navigation Landmarks

  • Confirm correct patient information in navigation software
  • Flex the hip. Slowly and smoothly circumduct with changing radii to register the hip's center of rotation with the navigation system
  • Place the navigation pointer's tip onto the most prominent aspect of the medial and lateral malleoli and register with the system
  • Inflate tourniquet after gravity exsanguination

4

Incise to Extensor Mechanism

  • Carry the skin incision straight down to the deep fascia which marks the extensor mechanism (quad tendon, patella, and patellar ligament)
  • Periarticular injection

5

Create Skin Flaps

  • Elevate skin flaps just deep to the fascia
Pearls
  • The perforating arteries which supply the skin run just superficial to the deep fascia
H

Arthrotomy and Deep Exposure

P
P

1

Identify Medial Aspect of Patellar Tendon and Quadriceps Tendon

  • Identify the medial aspect of the patellar ligament, medial aspect of the patella and the quad tendon lateral to the vastus medialis oblique (VMO)

2

Perform Arthrotomy

  • Start from the proximal aspect in a longitudinal manner curving medially around the patella
  • leave 3-5mm of soft tissue on the patella to assist with arthrotomy closure later in the case
  • Split the lower fibers of the VMO for a mini midvastus approach, or use a subvastus approach
  • Complete the arthrotomy with a straight distal cut along the medial border of the patellar ligament
  • avoid any disruption of the tendon insertion on the tibial tubercle
  • Resect fat pad deep to the patellar tendon
Pitfalls
  • A danger of the approach is avulsion of the patellar ligament

3

Perform Proximal Tibial Soft Tissue Release

  • With a #10 blade, sharply dissect enough of the medial capsular sleeve off of the tibia to provide exposure of the joint
  • Place a Cobb elevator and a small Hohmann retractor to complete the proximal tibial soft tissue release using a #10 blade
Pearls
  • The amount of dissection is variable depending on the particular knee, but a good rule of thumb is to dissect the tibia posteriorly to the mid-coronal plane
  • In cases of severe fixed varus deformity dissection may need to be carried even more posteriorly to provide exposure. Medial tibial osteophytes are often present; removal will provide greater release of the medial collateral ligament/capsular sleeve
  • In cases of a severe valgus deformity medial laxity may already be present; a conservative medial dissection is advisable to start

4

Prepare the Patella

  • Without everting the patella past 90°, place Army-Navy retractor under the quadriceps tendon
  • Dissect soft tissue from the periphery of the patella
  • Cut the patella with an oscillating saw
  • Drill lug holes with a guide
  • Remove marginal osteophytes
  • Place patella protector
  • Remove proximal femoral fat pad
Pearls
  • The goal is to reproduce the original patellar thickness (remnant cut patella + patellar component)

5

Collect Femoral Navigation Data

  • Use pointer to collect medial and lateral epicondyle navigation data points
  • Flex the knee to 90°
  • Sublux the patella laterally
  • Place a retractor lateral to the lateral meniscus near the mid-coronal plane
  • A medial retractor retracts the medial sleeve
  • Use pointer to collect navigation data (center, then medial, then lateral)
  • knee center - "Whiteside's Line"
  • supratrochlear area, medial distal to lateral distal, then medial posterior to lateral posterior
I

Computer Navigated Tibial Cuts

1

Collect Tibial Navigation Data

  • Use navigation pointer to identify and register center of tibia and low point of worn compartment
  • Place the navigation pointer tip into the sulcus of the medial epicondyle and register
  • Place the navigation pointer tip onto the most prominent point of the lateral epicondyle and register
  • Assess for varus or valgus deformity and flexion contracture or recurvatum
  • Collect stressed ROM curve
  • Use navigation data to plan tibia and femur resection depths

2

Resect Notch Osteophytes and PCL/ACL

  • Resect notch osteophytes with 1" osteotome
  • Resect PCL/ACL with Kocher and knife
  • Resect anterior lateral meniscus and fat pad
  • Place posterior retractor to sublux the tibia
  • Place medial and lateral retractors

3

Perform Tibial Cut

  • Attach black navigation tracker to tibial cutting guide
  • Place 1 headless pin in swivel hole
  • Place additional pins with straight screwdriver in guide
  • Use straight screw driver to adjust device
  • Use computer navigation to determine desired tibial resection depth, slope, and varus/valgus degrees
  • Remove navigation tracker from cutting guide
  • Perform saw cut and remove bone fragment using a 1" osteotome and grasper
  • lever up the fragment with a 1" osteotome and remove it with a grasper
  • use a #10 blade on a long handle to dissect around the fragment anteriorly, spinning externally to dissect
  • Remove tibial cutting guide
  • Use flat plate with attached navigation tracker to check tibia resection for desired depth, posterior slope, and varus/valgus alignment
  • Revise tibia cut if needed
J

Computer Navigated Femoral Cuts and Gap Balancing

P
P

1

Femur Navigation and Prep

  • Attach black navigation tracker to distal femoral cutting guide
  • Use headless pins placed one at a time to fixate the cutting guide/black navigation tracker assembly
  • Use computer navigation to determine desired femoral resection depth, slope, and varus/valgus alignment

2

Initial Distal Femoral Cut

  • Remove navigation tracker from cutting guide
  • Saw cut is made and the resected bone is removed
  • Remove any remaining osteophytes
  • Use flat plate with attached navigation tracker to check distal femoral resection for desired depth, posterior slope, and varus/valgus alignment
  • Revise distal femoral cut if needed
  • Remove distal femoral cutting guide
Pearls
  • Use a large flat osteotome to shield tibia while performing femoral cuts

3

Extension Gap Balancing

  • Double check suggested computer navigated femoral sizing
  • Straighten leg and place “lollypop” (9mm, 11mm) spacer to check for desired extension balance and sizing

4

Flexion Gap Balancing

  • Place the femoral AP sizer with 1 degree external rotation to the correct side (right or left)
  • Adjust for tibial varus
  • Mark desired pin location for the AP sizer with marking pen
  • Draw straight line across the femur
  • use laminar spreaders to tense and assess medial vs. lateral flexion gaps
  • Attach navigation guide
  • Place navigation guide in the desired location using computer navigation to correctly align
  • drill two holes
  • Remove navigation guide once alignment is confirmed
Pearls
  • Draw a second line parallel to the tibia if gap not symmetrical
  • Use flat plate to verify medial vs. lateral flexion gaps are symmetrical

5

AP and Chamfer Femoral Cuts

  • Place and secure appropriately sized femoral AP cutting jig
  • Skim cut femur if navigation shows potential anterior notching
  • Complete the remaining four bone cuts
  • Remove cutting jig
  • Remove resected bone and osteophytes
Pearls
  • The next larger sized AP cutting jig can be used to perform the femoral skim cut if navigation shows potential anterior notching
  • Shield the quad tendon and skin during proximal femoral cuts
  • Use retractors to shield the collateral ligaments
Pitfalls
  • Potential complications during bone cuts are cutting the MCL or, very rarely, the popliteal artery

6

Box Cut

  • Place and secure appropriately sized box cutting jig
  • Perform box cut using precision saw
  • Chiseling is performed through the guide to complete box cut
  • Remove box cutting jig
Pearls
  • A middle relief cut is used to prevent potential fracture during chiseling and to provide two equal halves of bone which are used for retraction later in the case

7

Posterior Osteophyte and Meniscus Removal

  • Place jack under femur and extend to provide better visualization of the joint
  • Keep jack extended
  • Use 1/2" curved osteotome to remove osteophytes
  • A large curved curette can be used to remove posterior osteophytes
  • Remove menisci using curved Kocher and knife
Pearls
  • Osteophyte removal is important in patients with a pre-operative flexion contracture, especially over 10 degrees
K

Trial Reduction and Sensor-Guided Soft Tissue Balancing

P

1

Final Tibia Preparation

  • Place a retractor posteriorly to subluxate the tibia. Place medial and lateral retractors
  • Place the appropriately sized trial tibial base plate in the proper rotational position (medial 1/3 of patellar ligament) and secure with pins
  • Use freer to ensure there is no overhang of the tibial base plate
  • Use burr to outline keel punch if bone is sclerotic
  • Attach keel punch guide to trial baseplate
  • Perform keel punch bone cut
  • Remove keel punch guide and baseplate

2

Place Femoral Trial

  • Remove any remaining medial/lateral osteophytes

3

Assemble Tibial Baseplate Trial and Sensor Trial

  • Insert tibial baseplate trial with appropriately sized sensor trial in place

4

Balance Knee using Navigation

  • Assess for any flexion contracture, recurvatum, or varus/valgus malalignment
  • Check medial and lateral compartment readings at 10 and 90 degrees of flexion
  • Readings between the medial and lateral compartments should be within 15 pounds per square inch of each other
  • Pounds per square inch measurements over 70 indicate joint overload
  • Remove additional tibial bone as necessary to achieve balanced knee for tight ligaments
  • Perform soft tissue releases as necessary to achieve balanced knee
  • Remove trials
Pearls
  • Medial slightly tighter than lateral is preferred
  • 20 - 25 psi range is preferred
L

Component Implantation and Confirm Balanced Knee

1

Confirm Implant Sizes / Prepare Cement

2

Prepare Tibia for Implant

  • Place previous box cut bone in notch to shield femur from posterior retractor
  • Pulse lavage bone to prepare for cementing and dry as well as possible
  • Apply cement to tibia with wet fingers
  • Apply cement to tibial implant

3

Place Tibial Implant

  • Place tibia implant and remove excess cement using freer and small, curved curette

4

Prepare Femur for Implant

  • Pulse lavage bone to prepare for cementing and dry as well as possible
  • Apply cement to femur and femoral implant

5

Place Femoral Implant

  • Place femoral implant and remove excess cement using plastic cement knife so as not to scratch femoral component
  • Secondary impaction if implant is not fully seated
  • Carefully remove cement from posterior condyles and notch using finger device or curette

6

Place Trial Poly

7

Prepare Patella for Implant

  • Pulse lavage bone to prepare for cementing and dry as well as possible
  • Apply cement to patella, using marking pen to identify lug holes
  • Place patella implant and apply clamp
  • Remove excess cement from patella using freer

8

Cure Cement

  • Place warm saline in joint to speed cement curing time
M

Confirm Stability

P

1

Confirm final flexion/extension and varus/valgus stability

  • Remove trial poly
  • Remove any cement
  • Place sensor trial
  • Check medial and lateral compartment sensor readings at 10 and 90 degrees of flexion
  • Confirm final flexion/extension and varus/valgus stability
  • Balance ligaments if needed

2

Insert Final Poly

  • Remove sensor trial
  • Capsular injections
  • Insert final poly insert and secure to baseplate
  • Record final navigational readings
  • Deflate tourniquet
Pitfalls
  • Perform posterior capsular injection medial to midline to avoid popliteal artery
N

Wound Closure

1

Irrigate and Obtain Hemostasis

2

Close Capsule/Arthrotomy

  • Place drain (optional)
  • Close joint capsule in 90° flexion with a #1 absorbable vicryl figure-8 suture, followed by #1 barbed monofilament running suture

3

Perform Superficial Closure

  • Subcutaneous closure with 2-0 vicryl interrupted sutures
  • Subcuticular closure with 2-0 barbed monofilament running suture
  • Pin site closure with 3-0 nylon sutures
  • Surgical skin glue applied to incision
  • Steri-strips applied perpendicular to the incision

4

Apply Dressing

Postoperative Patient Care
 

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