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.

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

Clinical assessment:

• 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

OC lesions may be on medial or lateral side

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

• Stage Ⅰ: Cystic lesion with roof intact
• Stage Ⅱ-A: Subchondral Cyst
• Stage Ⅱ-B: Incomplete fragment separation
• Stage Ⅲ: Complete fragment separation but no displacement
• Stage Ⅳ: Displaced fragment

• Stage Ⅰ: Articular cartilage injury
• Stage Ⅱ-A: Articular cartilage injury with bone fracture with bone oedema (Acute flap lesion)
• Stage Ⅱ-B: Articular cartilage injury with bone fracture without bone oedema (chronic lesion)
• Stage Ⅲ: Detached bony fragment (fluid rim beneath fragment)
• Stage Ⅳ: Displaced fragment, uncovered subchondral bone
• Stage V: Subchondral cyst

• 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
• X-ray additional anatomical areas where clinically indicated
• MRI scan useful to identify osteochondral lesion and assess lesion stability together with assessing any associated bone bruising and/or ligamentous injury

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

Ankle arthroscopy procedure

Removal of OC lesions

± microfracture

± mosaicplasty

± autologous chondrocyte implantation

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

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.