I'm going to start the presentation. The title is a new evaluation method for ankle instability using ultrasound. Ultrasound for orthopedic clinics has become a standard tool in the aspect of simplicity, accuracy, cost, and radiation exposure. To visualize ankle ligaments is a common method for assessing ligament injury with ultrasound, whereas stress X-ray is still a standard method for assessing ankle instability. Dr. Noche showed the evaluation method for syndesmotic instability using ultrasound. In this study, she measures the fibular AP movement under manual stress. However, there is no consensus on how to measure ankle instability using ultrasound. So this study aim is to report an evaluation method of ankle instability using ultrasound. Focused anterior drawer test and varus stress test. The subject is a man in his 30s with a history of lateral ankle ligament injury. Measurement items is anterior drawer distance and the distance between lateral malleolus to lateral process of talus that is called lateral clear space. For measuring anterior drawer distance, subjects sit and place the heel on the footrest in the knee extension position, then provide anterior stress to the ankle joint by pushing the lower leg backward. A probe is set on the posterior medial ankle joint. Measure the amount of movement of the talus based on the posterior edge of the tibia. Next for measuring lateral clear space, firstly apply varus stress to the ankle, then set the probe at the distal tip of the fibula, finally measure the distance between lateral malleolus to lateral process of the talus. We perform the same measurement using fluoroscopy under the same stress, then compare the result of ultrasound with fluoroscopy. This is a result chart. The measurement results for ultrasound and fluoroscopy were almost the same under anterior drawer stress and varus stress. Discussion limitation number one, since there are individual difference in bone morphology, there are some variations in the image that are depicted. However, the amount of talus movement is measured in this study, not ligament length itself. So individual differences will not cause a large error if the measurement point is determined properly. Limitation number two, the amount of stress is not constant among examiners, because during measuring lateral clear space, we need to apply stress with one hand and operate the probe with another hand. But we think stress-force discrepancies are the same as in traditional manual stress test. Probe position of anterior drawer test. Probe is set on the posterior medial side of the ankle because of Achilles tendon. So image measurement is done from little oblique side. Therefore, there is a risk of underestimating the actual movement. However, almost the same reproducibility was obtained as under fluoroscopy. Conclusion, this new method with ultrasound is useful for evaluation of ankle instability under anterior drawer and varus stress test. Proper measurement point setting, one-handed stress application, and probe placement are critical for accurate measurement.

evaluation method

ankle instability

ultrasound

ligament injuries

syndesmotic instability