The manual stress test may not be sufficient to differentiate ankle ligament injuries

Objective. To assess the accuracy of stress tests (anterior drawer, talar t ilt) in the diagnosis of lateral ligament injuries. Design. Stress tests were performed in vitro, and rotation and displacement of the calcaneus relative to the tibia were measured. Background. Stress tests are commonly used to diagnose ankle injuries. Howe ver, it is controversial as to whether stress tests can accurately differen tiate between isolated anterior talofibular ligament injuries and combined anterior talofibular and calcaneofibular ligament injuries. Methods. Stress tests were performed in vitro under three conditions with b oth ligaments intact, after sectioning the anterior talofibular ligament, a nd after sectioning the anterior talofibular and calcaneofibular ligament. Motion of the calcaneus relative to the tibia was measured in neutral and i n 20 degrees of plantarflexion at the ankle. Results. There were statistically significant differences among cadavers, e xaminers and positions. There was a difference between isolated anterior ta lofibular ligament sectioning and combined anterior talofibular and calcane ofibular ligament sectioning in lateral tilt but not in anterior displaceme nt, In contrast, a difference was found between intact and anterior talofib ular ligament sectioned specimens in anterior displacement but not in later al tilt. However the differences were not great enough to differentiate bet ween the two conditions. Conclusions. Each of the stress tests provides reasonable hindfoot displace ment but neither is sufficient for accurate diagnosis of specific ligament involvement due to the large amount of individual variation.