Stratification of injuries to the lateral collateral ligament of the ankle using ultrasound: protocol of a prospective, open-label, diagnostic trial and preliminary results

Abstract

Background and objectives: Patients with ankle sprain most commonly experience injuries to the lateral collateral ligament (LCL) complex, which affects the stability and function of the ankle. Early diagnosis of LCL complex injuries is extremely important. In clinical practice, magnetic resonance imaging (MRI) displays the soft tissues of the ankle well, but it is expensive and cannot be used for real-time evaluation. Ultrasound (US) has the advantages of ease of operation, low cost, and real-time capability. Some studies have reported on the stratification of injuries to the LCL complex using US. However, there is controversy regarding the injury grading. The purpose of this study was to investigate the grading of LCL complex injuries (sprain, partial tear, and complete tear) using US. Design: A prospective, open-label, diagnostic trial. Methods: Seventy patients with suspected ankle sprain who have an acute ankle sprain history and present with surgical indicators will be scheduled to receive ankle ligament repair surgery in the Guangzhou Orthopedics Hospital, China. On the day after admission, these patients will undergo US and magnetic resonance imaging (MRI) of the injured ankle prior to ankle ligament repair surgery (test group). The contralateral ankle will be included in the control group and will also undergo MRI and US examination prior to surgery. MRI or surgical results will be used as the gold standard for diagnosing LCL complex injuries. The feasibility of stratification of LCL complex injuries (sprain, partial tear, and complete tear) using US will be evaluated. Outcome measures and preliminary results: The primary outcome measure of this study is the sensitivity of US in the diagnosis of complete LCL complex tear. The secondary outcome measures are the sensitivity of US in the diagnosis of sprain and partial tear of the LCL complex; the specificity, positive predictive value, negative predictive value, accuracy, area under the ROC curve (AUC), and cut-off value of US in the diagnosis of sprain, partial tear, and complete tear of the LCL; and US imaging for the anatomy of the LCL complex. The results of 53 patients with acute ankle sprain included in the preliminary study suggest that there is no significant difference in the type of injuries to the talofibular ligament and calcaneofibular ligament between ultrasound diagnosis results and surgical or MRI findings (P > 0.05). Discussion: The results of this study will reveal whether US has a higher diagnostic value than MRI in the diagnosis of injuries to the LCL complex. Ethics and dissemination: This study was approved by Medical Ethics Committee of Guangzhou Orthopedics Hospital, China in May, 2018 (approval No. 2018-05). This study protocol will be performed in strict accordance with the Declaration of Helsinki. The personal information and data of the testing subjects participating in the clinical trials will be confidential and will be protected in accordance with applicable laws and regulations. The study protocol was designed in February 2018. Patient recruitment will begin in August 2018 and end in August 2019. Data collection will begin in August 2018. Data analysis will be performed in December 2019. The study will end in March 2020. Results will be disseminated through presentations at scientific meetings and/or by publication in a peer-reviewed journal. Trial registration: This trial was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR1800016244). Protocol version: 1.0.