Anterior Drawer vs Talar Tilt in Ankle Sprain
A torn lateral ankle ligament that is missed or undertreated can leave a young athlete with recurrent sprains and an ankle that keeps giving way for years.
Key terminology
- Anterior talofibular ligament (ATFL)
- This ligament runs from the front of the fibula tip to the neck of the talus. It is the weakest lateral ligament and the first to tear.
- Calcaneofibular ligament (CFL)
- This ligament runs from the fibula tip down and back to the side of the calcaneus. It is the second ligament to tear in a lateral sprain.
- Posterior talofibular ligament (PTFL)
- This ligament runs from the back of the fibula tip to the back of the talus. It rarely tears in a sprain unless the ankle dislocates.
- Subtalar joint
- This joint lies between the talus and the calcaneus, just below the ankle joint. It lets the hindfoot invert and evert.
- Anterior drawer test
- This exam holds the tibia still and pulls the heel forward with the ankle slightly plantarflexed. Extra forward glide of the talus points to an ATFL tear.
- Talar tilt test
- This exam inverts the hindfoot with the ankle in neutral and compares the tilt of the talus with the other side. Excess tilt points to a CFL tear.
Takeaways
- The anterior talofibular ligament (ATFL) is the first ligament to tear in a lateral ankle sprain, and usually tears alone. The classic mechanism is inversion of a plantarflexed foot. About 20% of sprains also tear the calcaneofibular ligament (CFL), with an isolated CFL tear being very rare. The ATFL had the lowest load to failure of the ankle ligaments tested in cadavers (Golanó et al, Knee Surg Sports Traumatol Arthrosc 2010;18:557-569, PMID 20309522; Attarian et al, Foot Ankle 1985;6:54-58, PMID 4065775).
- Ankle sprains reach US EDs at 2.15 per 1000 person-years, and teenagers in sport lead the count. Peak incidence was 7.2 per 1000 at 15-19 y/o. Nearly half (49.3%) happened during sport, led by basketball (41.1%), football and soccer. Across 70 sports the ankle was the second most injured site after the knee, and sprain was the most common ankle injury (Waterman et al, J Bone Joint Surg Am 2010;92:2279-2284, PMID 20926721; Fong et al, Sports Med 2007;37:73-94, PMID 17190537).
- Foot position decides which lateral ligament is under strain. The ATFL lies nearly horizontal in neutral and comes under strain only in plantarflexion, especially with inversion. The CFL is strained in dorsiflexion and relaxed in plantarflexion. The CFL is the only lateral ligament that crosses 2 joints, the ankle (talocrural) and the subtalar joint (Golanó et al, Knee Surg Sports Traumatol Arthrosc 2010;18:557-569, PMID 20309522; Sarcon et al, Foot Ankle Orthop 2019;4:2473011419846938, PMID 35097325).
- The anterior drawer test checks the ATFL. The examiner holds the tibia and pulls the heel forward with the ankle in slight plantarflexion, where the ATFL is taut. More forward glide of the talus than on the other side suggests an ATFL tear. Inversion stress done at 10-20° of plantarflexion also loads mainly the ATFL (Sarcon et al, Foot Ankle Orthop 2019;4:2473011419846938, PMID 35097325; Larkins et al, Arch Rehabil Res Clin Transl 2020;2:100072, PMID 33543095).
- The talar tilt test checks the CFL. The hindfoot is inverted with the ankle in neutral or about 10° of dorsiflexion, where the CFL lies perpendicular to the talus and takes the inversion load. Excess tilt compared with the other side suggests a CFL tear. Tearing both ligaments gives more laxity at every ankle angle than tearing one (Sarcon et al, Foot Ankle Orthop 2019;4:2473011419846938, PMID 35097325; Larkins et al, Arch Rehabil Res Clin Transl 2020;2:100072, PMID 33543095).
- A positive drawer rules an ATFL tear in, and a nontender ATFL rules it out. Pooled across 6 studies, the anterior drawer had sensitivity of 54% and specificity of 87%. ATFL palpation had sensitivity of 95-100% with specificity of only 0-32%. The talar tilt test can rule in a CFL tear, and no test is sensitive enough to rule one out. No clinical test reached both sensitivity and specificity above 90% (Netterström-Wedin et al, Sports Health 2022;14:336-347, PMID 34286639).
- The exam is most accurate at 4-5 days after injury, once pain and swelling settle. In 160 inversion injuries, a delayed exam at 5 days had sensitivity of 96% and specificity of 84% for a ligament lesion, equal to arthrography. A 2022 meta-analysis agreed that delay helps and rated this study at unclear risk of bias (van Dijk et al, J Bone Joint Surg Br 1996;78:958-962, PMID 8951015; Vuurberg et al, Br J Sports Med 2018;52:956, PMID 29514819; Netterström-Wedin et al, Sports Health 2022;14:336-347, PMID 34286639).
- Treatment is a brace or tape plus exercise, and up to 34% of patients re-sprain within 3 years. A short period of immobilization may ease pain and swelling, and surgery is reserved for ankles that do not improve with a full exercise program. Pain persisted at 1 year in 5-33% of patients, and subjective instability ranged from 0% to 33% in high-quality studies (Vuurberg et al, Br J Sports Med 2018;52:956, PMID 29514819; van Rijn et al, Am J Med 2008;121:324-331, PMID 18374692).