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Midfoot Arthritis
Updated: Oct 4 2016

Subtalar Arthrodesis

Preoperative Patient Care
Operative Techniques

Preoperative Plan


Radiographic templating

  • CT scan
  • determine length and placement of the implant


Execute surgical walkthrough

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

Room Preparation


Surgical instrumentation

  • guidepins
  • 6.5 mm and 4.0 mm large fragment cannulated lag screws


Room setup and equipment

  • standard OR table
  • bring fluoroscopy from the contralateral side


Patient positioning

  • supine position
  • align sole of the foot with the end of the bed
  • place a soft bump under the ipsilateral sacrum to internally rotate the foot
  • place tourniquet around the upper thigh



Mark and make incision

  • start incision 1 cm below the tip of the lateral malleolus.
  • continue incision distally until the base of the fourth metatarsal is reached


Incise the subcutaneous tissue in line with the skin incision

  • use cautery to cauterize any crossing vessels for hemostasis


Identify the peroneal tendons

  • leave them undisturbed in there sheath

Deep Dissection


Identify anatomical structures

  • identify the sural nerve
  • identify the origin of the extensor digitorum brevis and the sinus tarsi fat pad


Elevate the EDB and Sinus Tarsi fat pad together as one flap

  • leave a small cuff of tissue proximally for reattachment of the flap


Identify and release the talocalcaneal ligament

  • this allows better exposure of the joint surfaces and the middle and anterior facet

Preparation of Arthrodesis Site


Visualize the lateral aspect of the subtalar joint

  • use a rongeur to remove any remaining soft tissues


Remove articular cartilage

  • use a straight curette or chisel to remove cartilage from the lateral half of the inferior talus and superior aspect of the calcaneal facets
  • insert a lamina spreader and remove the remaining medial articular cartilage


Create a vascular channel

  • use curettes and osteotomes to create bleeding subchondral bone
  • use a 2.0 mm drill to create small perforations in bone
  • these channels aid in the fusion


Compress bone together to assess contact of surfaces


Reattach the extensor digitorum brevis to its origin

  • if bone graft is inserted reattach tendon after insertion of graft

Harvesting and Placement of the Tibial Bone Graft (optional)


Create bone window

  • make a 1 cm incision distal to the distal aspect of the tibial tubercle and 1 cm lateral to the anterior tibial crest.
  • incision should be 4 cm long
  • divide the fascia over the anterior compartment musculature in line with the skin incision
  • elevate the muscle and the periosteum over the anterolateral face of the tibia using a periosteal elevator to expose the anterolateral cortex
  • create a 1 by 1 cm square or elliptical window in the center of the anterolateral face


Remove cancellous graft

  • insert a curette into the window and remove the cancellous graft
  • seal the window with the previously removed bone plug


Perform layered closure

  • perform a layered closure of the fascia, subcutaneous tissue and the skin


Place retrieved graft into the subtalar joint

  • make sure to place graft within 30 minutes of harvest

Alignment and Final Fixation


Place guidepins under fluoroscopy

  • create 1 cm incision at the apex of the heel for insertion of the guidepin


Place ankle in 7 degrees of valgus

  • assess alignment with radiographs
  • use kwire for provisional fixation


Place guidepin

  • use the Harris heel and lateral views to drive guidepin through the tuberosity, across the subtalar joint and into the talar neck.
  • make a second 1 cm incision just medial to the anterior tibialis tendon
  • use the Harris heel and lateral views to drive guidepin through the dorsomedial aspect of the talar neck across the subtalar joint into the posterior calcaneal tuberosity


Place cannulated screws with short threads

  • insert a 6.5 or 8 mm large fragment cannulated lag screws after minimal countersinking
  • repeat the procedure for the second guidepin except use a small fragment cannulated screw
  • this screw is usually 3.5 to 4.0 mm
  • depth of this screw is best judged by axial view of the calcaneus


Confirm hardware position

  • obtain final fluoroscopic images to ensure proper screw position

Wound Closure


Irrigation, and hemostasis

  • ensure hemostasis using cautery


Superficial closure

  • use 3-0 nylon horizontal mattress sutures for skin


Deep closure

  • use 2-0 vicryl for the subcutaneous layer


Dressing and immediate immobilization

  • place in well padded non-weightbearing short leg plaster cast
  • split cast in recovery room to allow for post op swelling
Postoperative Patient Care
Private Note

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