import { HighYieldBox, ExamCheatSheet, Tabs, Tab, ComparisonTable, VivaScenario, ContentSection, SpecialTestCard , MedicalImage} from '@/components/content' # Ankle Instability Examination Chronic ankle instability examination focuses on lateral ligament assessment using the anterior drawer and talar tilt tests. Examiners expect you to know the anatomy of the lateral ligament complex (ATFL, CFL, PTFL), understand the difference between mechanical and functional instability, and recognize the importance of peroneal function. ## Quick Reference One-Pager ## Anatomy **Anterior Talofibular Ligament (ATFL):** - Origin: Anterior lateral malleolus - Insertion: Talar neck (anterior) - Function: Resists anterior translation and inversion in plantarflexion - Most commonly injured (85% of ankle sprains) **Calcaneofibular Ligament (CFL):** - Origin: Tip of lateral malleolus - Insertion: Lateral calcaneus - Function: Resists inversion in neutral and dorsiflexion - Injured in more severe sprains (often with ATFL) **Posterior Talofibular Ligament (PTFL):** - Origin: Posterior lateral malleolus - Insertion: Posterior talus - Function: Resists posterior translation - Strongest, rarely injured in isolation **Order of Injury:** In lateral ankle sprains, ligaments tear in sequence: 1. **ATFL** (first and most common) 2. **CFL** (with more force) 3. **PTFL** (only in complete dislocation) **Clinical Implication:** - ATFL tear alone = anterior drawer positive - ATFL + CFL tear = anterior drawer AND talar tilt positive ## Clinical Assessment **Acute Sprain:** - Inversion mechanism - Immediate swelling (lateral) - Difficulty weight bearing - "Popping" sensation **Chronic Instability:** - Recurrent giving way - Multiple previous sprains - Feeling of ankle "looseness" - Pain with uneven ground - May have clicking (osteochondral lesion) **Mechanical vs Functional:** - **Mechanical**: Abnormal joint laxity on testing - **Functional**: Giving way with normal laxity (proprioceptive/neuromuscular deficit) - Often combination of both ## Inspection and Palpation **Standing:** - Hindfoot alignment (varus = predisposing factor) - Coleman block test (if cavovarus) - Muscle bulk (peroneal wasting) **Lying:** - Swelling location (lateral = ATFL/CFL, anteromedial = syndesmosis) - Ecchymosis pattern - Previous surgical scars **Palpation (Lateral):** - ATFL: Anterior to lateral malleolus - CFL: Below and posterior to lateral malleolus - Peroneal tendons - Base of 5th metatarsal (avulsion fracture) - Lateral process of talus **Palpation (Medial):** - Deltoid ligament - Posterior tibial tendon **Palpation (Syndesmosis):** - Along anterior tibiofibular ligament (proximal to joint) ## Lateral Instability Tests **Anterior Drawer Tips:** - Plantarflexion relaxes the CFL and puts ATFL under primary stress - Look for "suction sign" or sulcus anterolaterally - Compare with opposite side (some physiological laxity is normal) - Best performed with patient relaxed (muscle guarding reduces sensitivity) ## Syndesmotic Instability Tests ## Associated Assessment **Balance Tests:** - Single leg stance (eyes open, then closed) - Normal: Can balance for 30 seconds or more each - Compare sides **Romberg Variant:** - Stand on affected leg with eyes closed - Increased sway = proprioceptive deficit ## Grading System ## Differential Diagnosis ## Summary Presentation ## Lateral vs Syndesmotic Instability ## Examiner Tips