Focused examination for chronic ankle instability including lateral ligament assessment, anterior drawer, talar tilt testing, and differentiation from syndesmotic injury.
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.
High-Yield Exam Summary
Anterior Talofibular Ligament (ATFL):
Calcaneofibular Ligament (CFL):
Posterior Talofibular Ligament (PTFL):
Order of Injury: In lateral ankle sprains, ligaments tear in sequence:
Clinical Implication:
Acute Sprain:
Chronic Instability:
Mechanical vs Functional:
Standing:
Lying:
Palpation (Lateral):
Palpation (Medial):
Palpation (Syndesmosis):
ATFL integrity
Increased anterior translation compared to opposite side (greater than 3mm difference) or sulcus sign anterolaterally
ATFL tear/laxity
Ability to detect true positives
Ability to exclude false positives
Anterior Drawer Tips:
CFL and ATFL integrity
Increased talar tilt compared to opposite side (greater than 5° difference)
CFL tear (often with ATFL). Tests calcaneofibular ligament primarily
Ability to detect true positives
Ability to exclude false positives
Differentiate ATFL vs CFL
More tilt in plantarflexion = ATFL involved. More tilt in neutral = CFL involved
Helps identify which ligaments are involved
Ability to detect true positives
Ability to exclude false positives
Syndesmotic (high ankle) sprain
Pain at the syndesmosis (distal tibiofibular joint)
Syndesmotic ligament injury
Ability to detect true positives
Ability to exclude false positives
Syndesmotic instability
Pain at syndesmosis with external rotation
Syndesmotic injury (AITFL, posterior tibiofibular, interosseous membrane)
Ability to detect true positives
Ability to exclude false positives
Syndesmotic widening
Increased lateral translation of fibula
Syndesmotic widening, gross instability
Ability to detect true positives
Ability to exclude false positives
Dynamic stabilizer function
Weakness of eversion
Peroneal weakness contributes to functional instability
Ability to detect true positives
Ability to exclude false positives
Balance Tests:
Romberg Variant:
| grade | ligament | instability | anterior_drawer | talar_tilt |
|---|---|---|---|---|
| Grade I | ATFL stretched | None | Normal | Normal |
| Grade II | ATFL partial/complete tear | Mild to moderate | Positive | May be positive |
| Grade III | ATFL + CFL complete tear | Gross | Grossly positive | Positive |
| condition | location | tests | imaging |
|---|---|---|---|
| Lateral Ligament Instability | Lateral | Anterior drawer +, Talar tilt + | Stress X-rays, MRI |
| Syndesmotic Injury | Anterolateral (higher) | Squeeze +, ER stress + | Widened mortise on X-ray, MRI |
| Peroneal Tendon Pathology | Posterolateral | Eversion weakness, subluxation | Ultrasound, MRI |
| Osteochondral Lesion | Deep ankle pain | May have clicking, effusion | MRI (talar dome) |
| Subtalar Instability | Subtalar region | Subtalar tilt positive | Stress views, CT |
| Anterolateral Impingement | Anterolateral | Tenderness in anterolateral gutter | MRI |
"26-year-old netball player with recurrent ankle 'giving way' over 2 years since initial sprain."
| feature | lateral | syndesmosis |
|---|---|---|
| Mechanism | Inversion, plantarflexion | External rotation, dorsiflexion |
| Location | Below/anterior to lateral malleolus | Above ankle joint, anterolateral |
| Key Tests | Anterior drawer, Talar tilt | Squeeze, External rotation stress |
| Recovery | Usually faster | Prolonged (2-3x longer) |
| Sport Impact | May return quickly | Extended absence |
High-Yield Exam Summary