Ankle & Foot – Osteochondral Talus Lesions

Ankle & Foot – Osteochondral Talus Lesions

Talus Osteochondral Lesions

Lower limb/ankle anatomy

 

The talocrural (ankle) joint is the junction of three bones: distal ends of tibia and fibular and the talus trochlear

The tibia and fibular are bound by the ligamentous structures that include the syndesmosis, anterior/posterior/transverse tibiofibular ligaments.

Collateral ligaments include the anterior and posterior fibulotalar ligaments, fibulocalcanear on the lateral side while the medial side is supported by the deltoid ligament and calcaneonavicular ligaments.

The ankle joint is not a pure hinge joint as there is some rotation around the helical axis of the joint due to the asymmetrical shape of the talus

Precise ankle joint congruence is important for load distribution of the compressive forces across the joint

Ankle sprain/fractures and osteochondral lesions

The ankle joint consists of the distal end of the fibular and tibia. The fibular and posterior/medial malleoli of the tibia articulates with the talus bone thereby completing the ankle joint with supporting ligaments. Injury and fractures of the ankle joint implies breakage of these related structures.

Ankle ligament/s and/or fractures commonly occur.

Occasional osteochondral talus fractures are associated with ankle sprains/fractures.

Causes:

  • Twisting/rotational movements with ankle inversion mechanism during activity, especially during sport activities

Presentation:

  • Pain
  • Swelling
  • Mechanical problems like clicking/locking
  • Chronic cases may present with intermittent ankle swelling ± associated ankle mechanical catching symptoms

Clinically:

  • Assess ankle ligament stability
  • Bone tenderness over the lesions with posteromedial tenderness behind the medial malleolus with ankle in dorsiflexion while anterolateral lesions having anterolateral bone tenderness when ankle in maximum plantarflexion

Talus osteochondral lesion (OC)

OC lesions may be on medial or lateral side

 

Ankle injury mechanism

Injury Mechanism:

  • Ankle inversion or eversion movement ±rotational component. Either the ligament is torn or the ankle is fractured
  • Ankle inversion injury associated with Talus osteochondral lesions

 

Ferkel CT classification of talus OC lesions

 

Ⅰ: Cystic lesion with roof intact
ⅡA: Cystic lesion communicating with talar dome
ⅡB: Open articular surface lesion overlying the undisplaced fragment
Ⅲ: Undisplaced lesion with lucency
Ⅳ: Displaced fragment

Berndt & Harty classification of talus OC lesions

 

Stage Ⅰ: Subchondral bone compression with marrow oedema
Stage Ⅱ

  • Stage Ⅱa: Subchondral cyst
  • Stage Ⅱb: Incomplete fragment separation

Stage Ⅲ: complete fragment separation but no displacement
Stage IV : Displaced fragment

Investigations

X-Rays may show the talus osteochondral lesion

CT scan: useful for assessment of the bony component of the OC lesion and for cystic change evaluation. Useful for preoperative planning

MRI scan useful to identify osteochondral lesion and assess lesion stability together with assessing any associated bone bruising and/or ligamentous injury

Treatment principles

Non-operative:

  • immobilization with brace/cast with non-weight bearing for associated ankle fractures and stable OC lesions (acute, nondisplaced) that require conservative treatment

Surgery:

  • Displaced osteochondral lesions
  • Large lesions

Surgery options:

Ankle arthroscopic removal of loose body ± microfracture for lesions < 1cm

OC grafting

  • Mosaicplasty
  • Allograft implantation
  • Autologous chondrocyte implantation

Surgery Technique

 

Ankle arthroscopy

 

Ankle arthroscopy procedure
Removal of OC lesions
± microfracture
± mosaicplasty
± autologous chondrocyte implantation

Surgery: Talus microfracture or mosaicplasty

 

Match readiness

Return to sport & match readiness:

  • After appropriate rehabilitation
  • Assess return to sport after completing battery of testing

Foot Strengthening Exercise

Resistance Strength Exercise

Ankle Strapping

Download ASSIC performance fingerprint app or ASSIC strength/conditioning app for ankle rehab guidelines and strapping technique under professional supervision

References

  1. Fractures of the ankle joint. Hans Goost, Matthias D Wimmer, Alexej Barg, Kouroush Kabir, Victor Valderrabano, Christof Burger. Dtsch Arztebl Int. 2014 May;111(21): 377-388.
  2. Osteochondral lesions of the talus. RD Santrock, MM Buchanan, TH Lee, GC Berlet. Foot Ankle Clin N Am;8(2003): 73-90.
  3. Osteochondral lesions of the talus: Current concept. O Laffenêtre. Orthop Traumatol Surg res. 2010 Sep;96(5): 554-66.
  4. Osteochondral lesions of the talus: a new magnetic resonance grading system with arthroscopic correlation. DN Mintz, GS Tashjian, DA Connell, JT Deland, M O’Malley, HG Potter. Arthroscopy. 2003 Apr;19(4): 353-9.

Contributors

Dr M Y Hassan
Dr C Marais