Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Distraction Subtalar Fusion


Indications

  • Symptomatic osteoarthritis of the subtalar joint

    • After calcaneal fracture

    • In peritalar instability

  • Symptomatic anterior ankle impingement/ankle osteoarthritis due to horizontalized talus

  • Symptomatic valgus instability of the ankle in peritalar instability

  • Painful tarsal coalition

Indications Pitfalls

  • Avascular necrosis of the talar body

  • Fusion of the subtalar joint in a nonanatomic position of the talus

Indications Controversies

  • Crucial for success, for example, obtaining a plantigrade and stable foot, are

    • Appropriate positioning of the talus on top of the calcaneus

    • Restoring talocalcaneal angle in the sagittal and horizontal planes

    • Realigning properly the talus within the ankle mortise

    • Restoring the length of medial pillar of the foot

  • In most instances, this can be achieved only by distraction arthrodesis

Examination/Imaging

Clinical Investigation

  • Careful and thorough assessment of history and complaints, in particular

    • Previous injuries and surgeries

    • Disability in daily activities and sports

    • Impairment by pain

    • Effect of previous conservative measures

  • Careful clinical assessment of

    • Hindfoot alignment when standing

    • Ankle and subtalar range of motion with the patient sitting

    • Ankle stability with the patient sitting and hanging feet

    • Pain using a Visual Analog Scale score of 0–10 points

  • Pain is typically located subfibular and along the subtalar joint, and often also in the anterior ankle

  • Subtalar motion can be

    • Restricted (e.g., in osteoarthritis)

    • Increased (e.g., in peritalar instability)

Assessment by Imaging

  • Bilateral plain weight-bearing radiographs, including anteroposterior views of the foot and ankle, lateral view of the foot, and alignment view, should be used to rule out

    • Articular configuration and integrity of the ankle and subtalar joint

    • Angular deviation of the talus in all three planes as compared with the not-affected contralateral foot

    • Presence of arthritic changes at the ankle and subtalar joint ( Fig. 43.1 )

      FIG. 43.1

  • Computed tomography scans, if possible while weight-bearing, are initiated to

    • Assess articular configuration of the ankle, subtalar, and talonavicular joints

    • Assess osteoarthritic changes (e.g., subchondral sclerosis, cyst formation)

    • Detect other bony abnormalities ( Fig. 43.2 )

      FIG. 43.2

  • Magnetic resonance imaging can be used to

    • Determine the activity of degenerative changes, for example, presence and extent of perifocal edema

    • Assess surrounding soft tissues ( Fig. 43.3 )

      FIG. 43.3

  • Single-photon emission computed tomography with superimposed bone scan may be used to visualize

    • Morphologic pathologies and associated activity process

Treatment Options

  • In situ subtalar fusion

    • By arthroscopy

    • Open approach

  • Interposition subtalar fusion through

    • Classic lateral approach

    • Posterolateral approach

Surgical Anatomy

  • Relevant lateral structures to be protected in the lateral and posterolateral approaches

    • The peroneal tendons are running over the posterior lateral subtalar joint

    • The calcaneofibular ligament attaches posterior to the peroneal tubercle and lies deep to the tendons

    • The sural nerve courses parallel and posterior to the peroneal tendons before passing superficially at the inferior retinaculum ( Fig. 43.4A )

      FIG. 43.4

  • Relevant osseous anatomy

    • The superior surface of the calcaneus includes the anterior, middle, and posterior facets. In 60% of patients, the anterior and middle facets are confluent. The posterior facet is the largest and supports the talar body

    • The inferior surface of the talus includes the corresponding articular surfaces, with a high congruency in the posterior facet, and little congruency in the middle and anterior facets

    • The head of the talus forms a ball-and-socket joint with the navicular ( Fig. 43.4B )

  • The following ligaments can be involved in peritalar instability, thus allowing the talus to experience tilting and translational movement on top of the calcaneus

    • Lateral ankle ligaments

    • Medial ankle ligaments

    • Interosseous ligament

    • Talonavicular ligament

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here

Related Posts