Subtalar and Triple Arthodesis

 

STJ DoubleTriple

 

Definitions

 

Subtalar arthrodesis: Talocalcalcaneal joint

Double arthrodesis: Subtalar joint (STJ) + talonavicular joint (TNJ)

Triple arthrodesis: Subtalar + talonavicular + calcaneocuboid joint (CCJ)

 

Anatomy

 

Movement Posterior facet Middle facet Anterior facet

Inversion / eversion

Pronation / supination

Largest

Saddle shaped

Medial / sustentacular facet of talus

Middle facet of the sustenaculum tali of the calcaneus

Smallest

Head of talus with anterior facet of the calcaneus

Walking on uneven terrain      

 

 

Subtalar anatomy

 

Indications

 

Concept

 

Cannot correct hindfoot deformity without correcting / reducing TNJ +/- CCJ

 

Subtalar arthrodesis Double / triple arthrodesis

Isolated subtalar osteoarthritis

Preserved TNJ and CCJ

Arthritis of TNJ and CCJ as well as STJ
Post fracture with minimal deformity

Deformity correction

- fixed acquired planovalgus

- calcaneal fracture with collapse and deformity

- subluxed talus

- rheumatoid arthritis

- Charcot / Polio / Cerebral palsy

 

Results

 

Outcomes

 

Variable due to high number of different indications for triple arthrodesis

 

Ebalard et al Orthop Traumatol Surg Res 2014

- 72 hind and midfoot fusions with minimum 10 year follow up

- 26% poor or bad outcomes

- 84% of patients had pain

- better outcomes with normal alignment

 

Double versus triple arthrodesis

 

DeVries et al J Foot Ankle Surg 2015

- 40 arthrodesis for valgus hindfoot deformity

- 20 double arthrodesis (STJ + TNJ), 20 triple arthrodesis (STJ + TNJ + CCJ)

- no difference in deformity correction between two groups

- suggest may not need CCJ fusion

 

CT

 

doubleDouble CT

Subluxation of TNJ with advanced STJ OA

 

 

STJSTJSTJSTJ

TNJ OA with posterior / medial / anterior facet OA of the subtalar joint

 

Injections

 

Subtalar OAInjection

Injection to subtalar joint to see level of improvement

 

Subtalar Arthrodesis

 

Indication

 

Isolated STJ arthritis with minimal deformity

 

STJ

 

Options

 

Open

Arthroscopic

 

Silvampatti et al J ISAKOS 2023

- systematic review of open versus arthroscopic

- 22 studies with 1000 patients

- open: union rate 91% at average 16 weeks, complication rate 20%

- arthroscopic: union rate 96% at average 12 weeks, complication rate 13%

 

Open subtalar arthrodesis

 

STJ STJ

 

Technique

 

Arthrex open subtalar arthrodesis video

 

JOMI open subtalar arthrodesis video

 

Patient supine with roll under hip to expose lateral aspect foot

 

Direct lateral approach

- tip of fibula toward base of 4th metatarsal

- internervous plane between SPN and sural nerve

 

Superficial dissection

- peroneal tendons lifted dorsally

- elevate EBD and fatty tissue over sinus tarsi

- expose STJ / CCJ / sinus tarsi

 

Deep dissection

- remove talocalcaneal interosseous ligament

- clear out sinus tarsi

- diathermy artery of tarsal sinus

- insert lamina spreader to expose posterior facet

- need to expose medial facet

 

Debridement of cartilage and bone

- recreate 2 flat surfaces that come together in 5o valgus

- drill holes to stimulate bleeding +/- bone graft

- if previous calcaneal fracture, decompress lateral wall (5 - 10mm removed)

 

Fixation

- 6.5 mm/ 8.0 mm cannulated screw

- inferior calcaneum into body and neck of talus / talus to calcaneum

 

Arthroscopic subtalar arthrodesis

 

Options

 

Lateral / supine position with lateral portals

Prone position with posterior +/- accessory lateral portals

 

Technique

 

Vumedi posterior arthroscopic subtalar arthrodesis video

 

Arthroscopic techniques lateral arthroscopic subtalar arthrodesis video

 

JBJS Essential Techniques Posterior Arthroscopic Subtalar PDF

 

Results

 

Banerjee et al J Foot Ankle Surg 2021

- systematic review of 10 studies and 240 feet

- union rate with arthroscopic subtalar fusion 95%

- time to union 10wks

- higher fusion rate with lateral approach

- lower complication rate with posterior approach

 

Shamrock et al Orthop JSM 2020

- systematic review of portals for arthroscopic subtalar fusion

- lateral portals nonunion rate: 1%

- 2 posterior portals nonunion rate: 8%

- posterior portals with accessory lateral portal nonunion rate: 6%

- no difference in complication rate

 

Triple arthrodesis

 

TripleTriple

 

Valgus deformity

 

Goal

- correct position of the calcaneum under the  talus - 5 degrees of valgus

 

Deformity

- talus internally rotated on calcaneum

- navicular abducted on talus

 

Issues

- TNJ / CCJ subluxed - need to open and reduce prior to reducing STJ

- may require tendoachilles lengthening

- may require allograft bone block

- may have deficient skin laterally

 

Technique

 

Acumed triple arthrodesis video

 

Acumed triple arthrodesis video 2

 

Lateral approach

- expose subtalar joint and CCJ

 

Medial approach to TNJ

- between Tibialis anterior and Tibialis posterior

- protect saphenous nerve and vein

- expose TNJ and debride joint

- reduce joint by adduction /plantar flexion / pronation

 

CCJ

- open and reduce joint

 

STJ

- reducing calcaneum back under talus difficult

- lamina spreader between lateral process talus and anterior aspect of calcaneum

- calcaneum internally rotates / talus externally rotates in screw like motion

- need to have all joints opened and exposed for this to occur

 

Tendoachilles lengthening

- formal Z lenthening

- Hoke lengthening - 2 half incisions laterally, 1 half incision medially between them

 

Fixation

- TJN screws

- CCJ screws +/- plate

- STJ screws

 

Complications

 

Infection / wound complications

 

Ebalard et al Orthop Traumatol Surg Res 2014

- 72 hind and midfoot fusions with minimum 10 year follow up

- 2 deep infections, 2 superficial infections

- 7 delayed wound healing

- 10 CRPS

 

Malunion / Deformity

Varus malunion

- relatively uncommon

- patients with cavovarus foot initially

- varus position of subtalar joint

- walk on lateral border of foot

- lateral column overload

 

Valgus malunion

- patient with planovalgus foot initially

- subfibular impingement / fibular stress fracture

- can lead to deltoid ligament failure and ankle OA

 

Nonunion

 

Cates et al J Foot Ankle Surg 2022

- systematic review of double versus triple arthrodesis

- union rate double: 92%

- union rate triple: 93%

- time to union 16 - 17 weeks

 

Allport et al Foot Ankle Int 2021

- 381 hind or midfoot arthrodesis

- 6X higher risk of nonunion in smokers

 

CT triple

Union

 

NU NUNU

Nonunion

 

Ankle joint arthritis

 

Ebalard et al Orthop Traumatol Surg Res 2014

- 72 hind and midfoot fusions with minimum 10 year follow up

- 73% tibiotalar arthritis