Distal Tibiofibular Syndesmosis

Original Editor - Tarina van der Stockt

Top Contributors - Tarina van der Stockt and George Prudden

Description

A syndesmosis is a fibrous joint between two bones and linked by ligaments and a strong membrane.  [1]

The distal tibiofibular syndesmosis is a syndesmotic joint.  It is formed between the distal tibia and fibula and it is attached by the interosseous ligament (IOL), the  anterior-inferior tibiofibular ligament (AITFL), the  posterior-inferior tibiofibular ligament (PITFL) and the transverse tibiofibular ligament (TTFL).  [1][2]  

Lateral view of ankle.PNG

Interosseous membrane.JPG


Anatomy

Syndesmosis ligaments.jpg
Articulating Surfaces

  • Distal fibula (rough medial convex surface)
  • Distal tibia (the triangular notch of the lateral surface)

This forms a mortise for the trochlea of the Talus

Ligaments & Interosseus membrane

INTEROSSEUS MEMBRANE:

Function:

  • The inferior segment assists in stabilising the tibiofibular syndesmosis.
SYNDESMOSIS LIGAMENTS
LIGAMENTS DESCRIPTION PROXIMAL ATTACHMENT DISTAL ATTACHMENT ROLE / FUNCTION

Anterior-inferior tibiofibular ligament

(AITFL)

Trapezoid shape (the tibial insertion is wider)

The ligament runs obliquely

Weaker than the PITFL

20% intra-articular

Anterior tubercle of the distal tibia Anterior surface of the distal fibula at the lateral malleolus

One of the primary stabilisers


Limits excessive:

  • external rotation of the foot on the leg
  • distal fibular motion on the tibia

Posterior or posterior-inferior tibiofibular ligament

(PITFL)

Strong compact ligament

Known as the Superficial component of the PITFL   

Posterior edge of the lateral malleolus

Posterior tibial tubercle   

One of the primary stabilisers

Limits excessive:

  • external rotation of the foot on the leg
  • distal fibular motion on the tibia

Transverse ligament or the Transverse tibiofibular ligament

(TTFL)


Cone shaped

Also known as the Deep component of the PTIFL


Proximal area of the malleolar fossa Posterior edge of the tibia -- directly posterior to the cartilaginous covering of the inferior tibial articular surface and may extent up to the medial malleolus  

Forms a true labrum 

Provides talocrural joint stability. 

Prevents Posterior translation

Interosseus ligament or the interosseous tibiofibular ligament

(IOL)

Thickened portion of the distal interosseous membrane   

Dense mass of short fibers with adipose tissue and small branching vessels from the peroneal artery   

Span between the tibia and fibula    


The most proximal fibres attach to the apex of the incisura tibialis on the tibia

Most distal fibres attach to the anterior tubercle of the tibia and descends straight to the talocrural joint of the fibula

The length of the fibres increase from proximal to distal     

One of the primary stabilisers

Buffer to neutralise forces during weight bearing as it transfers some of the axial compressive load to the fibula

'Spring' action - allowing for minor separation between the distal tibia and fibula during dorsiflexion. Allowing slight wedging of the talus in the mortise   

[3][4][2][1][3]

There exists controversy in the literature if the TTFL and the PITFL are two components of one anatomical structure or two different structures.  [1]

Function

The function of syndesmosis ligament complex:

  • Provide strong stabilization and dynamic support to the ankle mortise
  • Maintain the integrity between the distal tibia and fibula
  • Resist forces (axial, rotational and translational) that attempt to seperate the two bones [2][4][3]

Motions Available

  • 2° fibula external rotation relative to the tibia
  • As the ankle joint moves from end range plantar flexion to end range dorsiflexion the ankle mortise widens only about 1mm.  [2]

Pathology/Injury

Injury to the syndesmotic joint is described in the literature as an injury to the syndesmotic ligaments.  [1]

Clinical conditions:

  • High ankle sprain or syndesmotic ankle sprain (syndesmosis injury)
    • AITFL injury is normally combined with a tear of the IOL.[2]
  • Tibiofibular Diastasis
  • Ankle fracture
  • Syndesmotic Impingement (anterolateral soft tissue impingement) 
    • A fatty synovial fringe (small bundle of adipose tissue) moves during ankle movement.  It rises during dorsiflexion and thus retracts between the tibia and the fibula and descends during plantar flexion thus lowering towards the ankle joint.  
    • May cause chronic pain after an ankle sprain.  [3]


[5]

Examination

Examination of syndesmotic injuries or sprains.

Treatment

Treatment of syndesmotic injuries or sprains.

Resources

References

 
  1. 1.0 1.1 1.2 1.3 1.4 Hermans JJ, Beumer A, De Jong TA, Kleinrensink GJ. Anatomy of the distal tibiofibular syndesmosis in adults: a pictorial essay with a multimodality approach. Journal of anatomy. 2010 Dec 1;217(6):633-45.
  2. 2.0 2.1 2.2 2.3 2.4 Lin CF, Gross MT, Weinhold P. Ankle syndesmosis injuries: anatomy, biomechanics, mechanism of injury, and clinical guidelines for diagnosis and intervention. Journal of Orthopaedic&Sports Physical Therapy. 2006 Jun;36(6):372-84.
  3. 3.0 3.1 3.2 3.3 Golanó P, Vega J, De Leeuw PA, Malagelada F, Manzanares MC, Götzens V, Van Dijk CN. Anatomy of the ankle ligaments: a pictorial essay. Knee Surgery, Sports Traumatology, Arthroscopy. 2010 May 1;18(5):557-69.
  4. 4.0 4.1 Ebraheim NA, Taser F, Shafiq Q, Yeasting RA. Anatomical evaluation and clinical importance of the tibiofibular syndesmosis ligaments. Surgical and Radiologic Anatomy. 2006 May 1;28(2):142-9.
  5. Christopher F. Beaulieu. Imaging of the Tibiofibular Syndesmosis and High Ankle Sprain. Available From: https://www.youtube.com/watch?v=_DyO1_YZKM4
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