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STAR Total Ankle Arthroplasty

Planning

B

Preoperative Plan

1

Template components of arthroplasty system

  • template the components of the ankle arthroplasty system

2

Execute surgical walkthrough

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

Room Preparation

1

Surgical instrumentation

  • STAR total ankle arthroplasty system
  • osteotomes

2

Patient positioning

  • patient supine with feet at the end of the bed, small bump under ipsilateral thigh, tourniquet on thigh

3

OR setup and C-arm

  • radiolucent OR table
  • c-arm from contralateral side perpendicular to bed

Technique

D

Anterior Approach to the Ankle

1

Mark and make the incision

  • make an incision using the interval between the tibialis anterior and the extensor hallucis longus tendon
  • make an incision starting about 10 cm proximal to the tibiotalar joint and 1 cm lateral to the tibial crest
  • continue the incision midline over the anterior ankle just distal to the talonavicular joint

2

Do not place any tension on the skin

  • do not put any tension on the skin only use retractors after full thickness flaps have been placed

3

Identify neurovascular structures

  • identify and protect the superficial peroneal nerve
  • retract this nerve laterally

4

Expose the extensor retinaculum

  • identify the course of the EHL tendon

5

Divide the retinaculum

  • sharply but carefully divide the retinaculum over the EHL tendon
  • try to maintain the tibialis anterior tendon in its own sheath
  • by doing this, this prevents bowstringing of the tendon and reduces the stress on the anterior wound

6

Enter the interval

  • enter the interval between the tibialis anterior and the EHL tendon
  • retract the tibialis anterior medially and the EHL tendon laterally
  • identify and carefully retract the deep neurovascular structures
  • this is the anterior tibial-dorsalis pedis artery and the deep peroneal nerve and retract laterally throughout the remainder of the procedure

7

Perform anterior capsulotomy

8

Perform subperiosteal dissection

  • periosteally elevate the tibia and the dorsal talar periosteum 6 to 8 cm proximal to the tibial plafond and talonavicular joints respectively
  • elevate the separated capsule and periosteum medially and laterally to expose the ankle

9

Identify the medial and lateral malleoli

  • access the medial and lateral gutters to visualize the medial and lateral malleoli

10

Remove osteophytes

  • remove anterior tibial and talar osteophytes to facilitate the exposure and to avoid the interference with the instrumentation
E

Tibial Preparation

1

Create reference points

  • place an osteotome in the medial gutter
  • this is to reference the optimal rotation for the tibial preparation
  • place a pin in the proximal tibia via a 1 cm incision over the tibial tubercle
  • when looking at this pin on the AP plane, the pin should be oriented parallel to the reference osteotome in the medial gutter
  • when looking at the pin in the lateral plane the pin should be perpendicular to the tibial shaft axis if the physiologic 3 to 5 degrees of posterior slope to the tibial component is desired

2

Place the alignment guide

  • suspend the external tibial alignment guide from the proximal pin

3

Set the rotation of the cutting block

  • set the rotation of the cutting block for the tibial preparation based on the reference osteotome set in the medial gutter

4

Place a T-guide

  • A T-guide that is temporarily attached to the distal aspect of the guide helps assist in setting the proper rotation
  • lock the rotation of the distal block with a knob connecting the telescoping rods of the guide

5

Set the length

  • after controlling rotation, set the length of the guide with telescoping rods
  • fine tuning of the distal blocks lateral plane position can be done at this point
  • separate this distal block of the guide from the portion of the guide that is used to pin the tibia by at least 10 mm
  • if the initial the initial position of the distal block is set at the apex of the plafond, the desired length of 5 mm should be easily set
  • greater resection is possible in the tighter ankle

6

Place the cutting guides

  • attach the cutting capture guide to the distal block
  • insert the angel wing resecting guide in the capture guide

7

Determine the proper resection level

  • use fluorosocopy in the lateral plane to determine the proper resection level for the tibia cut
  • adjust the cutting guide in the coronal plane to ensure that the malleoli are protected during the resection
  • set the guide based on a loosely placed pin in the medial aspect of the capture guide
  • position the guide so that the medial extent of the tibial preparation is proximal from the transition of the tibial plafond to the medial malleolus

8

Place pins

  • drive the pin that is used as a reference into the tibia through the medial aspect of the capture guide to protect the medial malleolus
  • place a lateral pin the lateral aspect of the capture guide and advance the pin into the lateral malleolus
  • protect the soft tissues paying particular attention to the deep neurovascular structures

9

Make the cuts on the tibia

  • make a cut using an oscillating saw through the horizontal portion of the cutting guide
  • to complete the cut, use a reciporicating saw along the medial border of the capture guide extending proximally from the medial gutter

10

Remove the cutting guide and evacuate the resected bone

11

Create autograft for later placement

  • use a small reciprocating saw to morselize the posterior fragments and a combination of curved curette and rongeur to retrieve the fragments that need to be separated from the posterior capsule
  • use the curette directly vertical in the ankle and never lever the curette against the malleolus

12

Resect the posterior capsule

  • perform a posterior capsule resection to optimize dorsiflexion
F

Placement of the 4 in 1 Talar Reference Guide

1

Clear the dorsal talar dome of all debris

  • remove any residual articular cartilage from the dorsal talar dome so that the talar cutting guide can be properly balanced on the dorsal talus
  • this can be done with a thin oscillating saw

2

Place the talar guide

  • position the talar guide within the ankle joint and secure it to the distal block of the external alignment guide
  • hold the ankle in neutral dorsiflexion-plantar flexion

3

Pin the talar guide

  • after perfect contact is achieved on the medial and lateral aspects of the talar dome with the intra-articularly placed paddle of the talar cutting guide along with neutral sagittal alignment is maintained, pin the talar guide

4

Identify and confirm the proper resection level

  • place the angel wing resection guide in the talar cutting guide and use lateral plane fluoroscopy to confirm the proper resection level and the desired orientation for the guide

5

Make the talar cuts

  • make the initial talar cut using an oscillating saw

6

Clear the joint

  • remove the guide
  • evacuate the resected bone from the joint

7

Confirm alignment

  • use a plastic spacer sizing guide impactor and confirm the proper alignment and resection levels using intraoperative fluoroscopy

8

Place the sizing guide

  • position the sizing guide on the dorsal surface of the prepared talus

9

Align the sizing guide

  • rotate it with the second metatarsal
  • the proper sizing guide should leave 3 mm of medial and 3 mm of lateral bone
  • set the AP position of the sizing guide based on the resected surface
  • excessive bone should not be removed from the posterior talus
  • mark the sizing guide on the prepared talar surface

10

Place the 4 in 1 talar reference guide

  • position the 4 in 1 talar reference guide on the prepared surface with proper rotation , proper mediolateral plane position and an estimate of the proper anteroposterior position
  • secure the 4 in 1 cutting guide with pins
  • confirm the position of the 4 in 1 cutting guide using fluoroscopy and take a lateral x ray
  • the center point of the undersurface of the guide should rest directly over the lateral talar process
G

Making Talar Cuts with Chamfer Guides

1

Place the AP talar chamfer cutting guide

  • secure the anteroposterior talar chamfer cutting guide to the 4 in 1 talar reference guide
  • place an additional pin in the guide to stabilize it to the talus

2

Cut the posterior talar chamfer

  • cut the posterior talar chamfer using an oscillating saw in the posterior capture guide

3

Protect the soft tissues

  • mill the anterior chamfer with the soft tissues and protect the deep neurovascular bundles

4

Remove the guide and leave the 4 in 1 guide in place

5

Place the mediolateral chamfer cutting guide

  • secure the mediolateral chamfer cutting guide to the 4 in 1 talar reference guide
  • protect the medial and lateral soft tissues

6

Make the cuts

  • make the medial and lateral chamfer cuts with a reciporical saw
  • the proper depths of the cuts should be as follows
  • the medial cut should be made to depth of 10 mm
  • the lateral cut should be made to a depth of 15 mm

7

Remove the chamfer guide

  • remove the mediaolateral chamfer and 4 in 1 reference guides

8

Remove the loose bone

  • evacuate the resected bone with a thin osteotome, a curved curette and a rongeur
H

Placement of the Window Talar Trial

1

Position the window talar trial on the prepared talus

  • place the talar trial
  • pin the talar trial

2

Create the slots

  • use a router to create the slot in the talus to accommodate the talar implants fin
  • use a stem punch to finish preparing the talar fin slot

3

Orient the talar component

  • orient the correctly sized talar component with the longer side placed laterally to articulate with the fibula

4

Tap the prosthesis

  • gently tap the prosthesis posteriorly with the sets plastic-impactor-spacer-sizer in the optimal position over the fin slot
  • use the talar dome impaction device to impact the talar component
  • protect the anterior tibial cortex during impacting

5

Fully seat the talar component

I

Final Preparation of the Tibial Plafond, Tibial Component Implantation and Final Polyethylene Implantation

1

Measure the AP dimensions of the tibia

2

Select the corresponding tibia component

  • if the mediolateral dimensions accommodate the component, remove 1 or 2 more millimeters of the medial bone to safely position the tibial trial

3

Remove any soft tissue

  • remove any syndesmotic soft tissue that is impinging in the joint

4

Trial the tibial component

  • the component should be in line with center of the tibial shaft axis, not be tilted in varus or valgus and should not be lateral to the longitudinal center of the tibial shaft

5

Take xrays to confirm the position of of the tibial trial

6

Pin the tibial trial

7

Insert polyethylene trial

  • temporarily insert a polyethylene insert to maintain pressure on the tibial trial

8

Take xrays to confirm proper placement

  • there should not be any tibial tray lift-off from the prepared tibial trial surface
  • the tibial trial should be well aligned with the tibial shaft on the AP view

9

Prepare the barrel holes with the drill and chisel

10

Remove the tibial trial and trial polyethylene

11

Leave the pin placed to secure the tibial trial as a reference point

12

Irrigate the joint

13

Impact the tibial prosthesis

  • impact the tibial component almost fully using the dedicated tibial impaction device
  • use the plastic spacer sizer impactor to advance the tibial component to its final position

14

Determine polyethylene size

  • determine the optimal poly size with the true tibial and talar implants placed
  • size should be based on the trial polyethylenes
J

Wound Closure

1

Irrigate the joint with sterile saline

2

Place autograft

  • fill the anterior barrel holes with bone graft from the resected bone

3

Remove pins

  • remove the pin from the proximal tibia

4

Repair the soft tissue

  • reapproximate the capsule
  • reapproximate the extensor retinaculum

5

Irrigation & Hemostasis

  • deflate tourniquet
  • irrigate and cauterize peripheral bleeding vessels

6

Closure

  • fascia and retinaculum closure with 0-vicryl, watch out for SPN laterally
  • subcutaneous with 2-0 vicryl and skin closure with 3-0 nylon

7

Dressing

  • place sterile dressings on the wound, apply adequate padding and place a short leg cast with the ankle in the neutral position

Patient Care

K

Preoperative H & P

1

Obtain history and perform basic physical exam

  • document neurovascular status
  • check compartments

2

Order basic imaging studies

  • order biplanar radiographs of the tibia and weight bearing triplanar radiographs of the ankle

3

Splint fracture appropriately

  • place in posterior splint with stirrups

4

Perform preoperative consent

  • superficial/deep infection
  • wound dehiscence
  • subsidence
  • osteolysis
  • persistent pain
  • delayed wound healing
  • neurovascular injury
  • malleolar or distal tibial stress fracture
  • implant fracture
L

Perioperative Inpatient Management

1

Write comprehensive admission orders

  • IV fluids
  • DVT prophylaxis
  • pain control
  • advance diet as tolerated
  • foley out when ambulating
  • check appropriate labs
  • wound care
  • drain out post-operative day 1
  • appropriately orders and interprets basic imaging studies
  • xrays of the ankle in postop

2

Appropriate medical management and medical consultation

3

Inpatient physical therapy

  • touch down weightbearing is ok but elevation is encouraged
  • crutches for ambulation

4

Discharge home appropriately

  • pain meds
  • outpatient PT
  • schedule follow up appointment in 2 weeks
M

Intermediate Evaluation and Management

1

Obtain focused history and perform focused exam

  • identify risk factors that correlate with complications and poor outcomes
  • comorbidities
  • diabetes
  • social factors
  • smoking

2

Appropriately interprets basic imaging studies

  • AP/Lat/Mortise views of ankle, AP/Lat views of tibia/fibula

3

Makes informed decision to proceed with operative treatment

  • describes accepted indications and contraindications for surgical intervention

4

Provides post-operative management and rehabilitation

  • 2 weeks post-op
  • wound check
  • sutures removed
  • replace the cast
  • repeat xrays of ankle and tibia/fibula
  • 6 weeks postop
  • weightbearing radiographs of the ankle
  • advance weight bearing status and rehabilitation
N

Advanced Evaluation and Management

1

Provides comprehensive assessment of complex fracture patterns on imaging studies

2

Recognizes indications for and provides non-operative treatment of an unstable fracture

  • diabetes
  • medical comorbidities
O

Complex Patient Care

1

Develops unique, complex post-operative management plans

 

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