Dan Huang, Xiu-Zhen He , Xu-Huan Yang, Si-Min Peng, Ying-Xian Wu

1 Guangzhou Orthopedics Hospital, Guangzhou, Guangdong Province, China

2 Foshan Hospital of Traditional Chinese Medicine, Guangzhou University of Chinese Medicine, Foshan, Guangdong Province, China

INTRODUCTION

Research background

Patients with ankle injury most commonly experience injuries to the lateral collateral ligament (LCL) complex,which greatly affects the joint’s stability and function.1-4Early diagnosis of LCL complex injuries is extremely important.5,6In recent years, much progress has been made in the imaging diagnosis of ankle injury (Table 1).7-9

Although magnetic resonance imaging (MRI) is often used in clinical practice and can easily display the condition of the soft tissues, it is expensive and has limitations (for example, magnetic responance scans at inappropriate angle may provide inaccurate information for final diagnosis).10US has the advantages of low cost,and real-time imaging.11-14Some studies have reported on grading of injuries to the LCL complex using US. However,there is controversy regarding injury grading.

Study objective

This study will investigate the value of US in the grading of injuries of the LCL complex of the ankle.

METHODS/DESIGN

Study design

A prospective, open-label, diagnostic trial.

Study setting

Guangzhou Orthopedics Hospital, China

Recruitment

Recruitment will be performed through posters on a bulletin board that is used to advertise for patients in Guangzhou Orthopedics Hospital, China. After being informed of the trial objective and procedure, patients from the clinics and wards interested in participation or their close relatives will contact the project manager through telephone,e-mail, or Wechat. Patients meeting eligibility criteria will be considered for inclusion.

The researchers will treat and regularly follow-up the patients according to treatment plan. During the trial period, the hospital will subsidize the transportation fee,and there will be no charge for registration and laboratory examination.

Eligibility criteria Test group

- Inclusion criteria

Seventy patients with ankle injury receiving treatment in the clinics and wards of Guangzhou Orthopedics Hospital, China and meet all of the following criteria will be considered for inclusion:

• Patients with ankle injury 1-7 days prior

• Age 16-42 years

- Exclusion criteria

Patients who meet one or more of the following conditions will be excluded from this study:

• Interval between MRI and ultrasound examination ex ceeds 3 days

• Ankle infection

• Ankle fracture

Control group

The ankle on the non-injured side undergoing MRI examination will be included in the control group.

Group allocation

A self-control design that compares the imaging data between patient’s injured and non-injured (healthy) sides will be used. Randomization and blinding will not be used.

US

We will use the available US equipment (Konica Minolta Zaiqi Medical Products Co., Ltd., Shanghai, China; 7–14 MHz probe) will be used for magnetic resonance imaging scanner (GE Signa HDX 3.0T®, GE Healthcare, Milwaukee, WI, USA) will be used for MRI examination. MRI or surgical results will be used as the gold standard for diagnosing LCL injuries.

Table 1: Three representative clinical studies regarding imaging diagnosis of ankle sprain published in 2016-2017

US examination methods Anterior talofibular ligament (ATFL) of the ankle

The ATflwill be first examined. If permitted, the affected limb will be positioned to fully expose the lateral malleolus. The probe will be first placed on the lateral malleolus The probe will be moved anteriorly to display the talus. Anisotropic artifacts will often appear in the ATfldue to the oblique movement and they will present as a homogeneous banded hyperechoic artifacts. If one end of the probe is slightly lifted and the other end is slightly pressed to make the ligament fibers perpendicular to the acoustic beam to eliminate anisotropic artifacts, then the normal long-axis section of the ATflwill be shown as a continuous, dense fibrous band-shaped hyperechoic structure that extends from the fibula to the talus.

Calcaneofibular ligament (CFL)

The probe will be placed in the oblique coronal section of the lateral malleolus, with its upper edge and the tip of the lateral malleolus on the same level. US examination of the attachment site of the Cflat the lateral malleolus is more difficult because of its concave-shaped course.

Ultrasound and MRI criteria in the grading of LCL complex injuries

MRI criteria15: grade I injury: LCL complex sprain,displaying complete ligament and swelling of soft tissue surrounding the ligament; grade II injury: partial tear of the ligament, displaying irregular ligament morphology,complete fiber bundle, and liquid signal in the ligament;grade III injury: complete tear of the ligament, i.e., absence of or broken ligament morphology.

LCL complex injury grade by ultrasound16: LCL complex sprain, manifesting as thickened ligament, reduced echo, and good continuity. Partial tear of the ligament: the ligament texture is partially interrupted or thinned, and there is fluid in the surrounding articular cavity. Complete tear of the ligament: completely interrupted ligament,retraction of the stumps, and there is fluid in the sounding articular cavity.

Diagnostic criteria for ligament injury during the surgery

All patients included in this study will undergo surgery for repair of LCL complex injuries. According to the standard anatomical classification issued by the American Medical Association (AMA) (https://www.ama-assn.org/), LCL complex injuries will be graded as follows: grade I: partial or complete rupture of the ATFL, i.e., partial or complete tear of the ligament which are consistent with ultrasound;grade II: partial or complete tear of both ATfland CFL;grade III: partial or complete tear of ATFL.

Outcome measures Primary outcome measure

The sensitivity (sensitivity = true positives/true positives+ false negatives) of US in the diagnosis of complete tear of the LCL complex: True positive rate. It is the percentage of patients in which the LCL complex is completely torn and correctly diagnosed by the diagnostic criteria. Higher sensitivity indicates lower missed diagnosis rate.

Secondary outcome measures

The secondary outcome measures are sensitivity, specificity, positive predicative value, negative predicative value,accuracy, AUC, cut-off value of US and in the diagnosis of sprain and partial tear of the LCL complex as well as US imaging for displaying LCL complex injuries.

-Sensitivity: detection method and criteria are the same as above.

-Specificity (Specificity = true negatives/true negatives +false positives): True negative rate. It is the percentage of patients in which the LCL complex is not injured (healthy side) and is correctly diagnosed as no LCL complex injury.Higher specificity indicates lower missed diagnosis rate.-Positive predicative value: It is the percentage of patients in which the LCL complex is truly injured among patients with positive results (ligament injury) detected by US.The positive predicative value can reflect the possibility of ligament injury in US results.

-Negative predicative value: It is the percentage of patients in which the LCL complex is truly not injured among patients with negative results (no ligament injury) detected by US.

-Accuracy: The percentage of patients with true positive and negative results detected by US in total number of patients. Higher accuracy represents a higher degree of correctness.

-Area under the ROC curve (AUC): The ROC curve will be plotted with Y-axis showing sensitivity and representing true positive rate and X-axis showing 1-specificity and representing false positive rate. AUC will be 0.5-1.0.AUC is > 0.5 and is closer to 1 indicates better diagnostic accuracy. AUC = 0.5 indicates the diagnosis method is of no significance.

Cut-off value: The optimal threshold for US diagnosis will be selected. The closer the ROC curve is to the upper left corner, the higher the diagnostic accuracy. The point closest to the ROC curve in the upper left corner is the best threshold for the least error, with the lowest total number of false positives and false negatives.

US: The LCL complex morphology will be evaluated using US to identify the three LCL injuries (sprain, partial tear and complete tear).

Adverse events

The adverse reactions occurring during the follow-up period will be recorded. All adverse events-related details(first onset time, severity, and management method) will be recorded and reported to the project manager and the study’s ethics committee within 24 hours.

Trial procedure

Seventy patients with ankle sprain who receive surgery for repair of LCL injury in the Guangzhou Orthopedics Hospital, China will be included in this study. These patients will undergo high-frequency ultrasound examination of the ankle. The injured and healthy sides of the ankle will be included as test and control groups, respectively (Figure 1).

Sample size

Figure 1: Flow chart of trial.

Our preliminary results showed that the sensitivity and specificity of high-frequency ultrasound in the diagnosis of LCL injuries were 84% and 93%, respectively.17In accordance with clinical experience, we hypothesized that the sensitivity and specificity of high-frequency ultrasound in the diagnosis of LCL injuries will be 85% and 95%,respectively. The permitted error was 10% for both the sensitivity and specificity. Assuming 1-α= 95%,α= 0.05(one-sided), a final sample size of n = 58 for evaluating the diagnostic sensitivity of high-frequency ultrasound and a final sample size of n = 29 for evaluating the diagnostic specificity of high-frequency ultrasound were calculated using the PASS 11.0 software (PASS, Kaysville, UT, USA).Following the principle of equal sample size in each group,we will require the largest sample size n = 58. Assuming a participant loss rate of 20%, we will require a total sample size of 70.

Statistical analysis Data description

All data will be statistically processed using the SPSS 20.0 software (IBM, Armonk, NY, USA) following the intentionto-treat principle. Normally distributed measurement data will be expressed as means and standard deviations.Non-normally distributed data will be expressed as lower quartiles (q1), medians, and upper quartiles (q3). Count data and rating data will be expressed as percentages.

Selection of statistical methods

Friedman rank sum test will be used to compare the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of high-frequency ultrasound in the diagnosis of sprain, partial tear and complete tear of the LCL. Paired t test (for normally distributed data) and Wilcoxon Signed-Rank Test (non-normally distributed data) will be used to compare the AUC and cut-off value of high-frequency ultrasound in the diagnosis of LCL injuries of the ankle. SPSS 20.0 software will be used for plotting the ROC curves. An inspection level of α = 0.05(bilateral) will be considered.

Data sets

The subjects included in the final analysis are mainly the population assigned to the per protocol set. Per protocol set refers to the set of subjects who meet inclusion and exclusion criteria, complete the study without major protocol deviations, provide effective baseline efficacy and tight enough compliance, and fulfill the case report form.

Data collection and management Data collection

Case report forms will be filled by the investigators accurately, completely, and on time. Written records will be transferred to an electronic format by professional staff using a double data entry strategy.

Data management

Research data will be statistically analyzed and reported by professional statisticians. A final report will be made by principle investigators and the database will be locked. All data relating to this study will be preserved by Guangzhou Orthopedics Hospital.

MonitoringIndependent Data Monitoring Committee composition

The role and responsibilities of the Independent Data Monitoring Committee relative to the investigators and ethics committee will be identified. The role and responsibilities of the Independent Data Monitoring Committee will be relative to the project steering committee, statisticians, data managers, inspectors, and sponsors.

Investigator qualification

All imaging physicians participating in this study have a wealth of ultrasound and MRI examination experience.The study will be performed mainly by professional subject leaders or chief physicians, and senior deputy chief physicians. Data processing and statistical calculations will be completed by statistical professionals.

Auditing

The monitors will confirm whether the recorded and reported data will be correct, whether case report forms are correctly filled and whether the contents are consistent with original data. Changes in treatment, outbreaks,lost follow-ups, and omissions in each subject should be confirmed and documented.

Compensation to patients

If the clinical trial causes diseases or requires surgeries which are listed on special medical insurance contract and confirmed by the hospital, the patients will receive economic compensations for examination, treatment and nursing.

Table 3: Comparative results of lateral collateral ligament of the ankle between ultrasound and surgery (number of ligaments)

Table 2: Surgery or MRI-confirmed injury sites

Ethics and dissemination

The study protocol was approved by Medical Ethics Committee of Guangzhou Orthopedics, China in May 2018(approval No. 2018-05). The manuscript was prepared in accordance with Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) statements. 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. Anonymized trial data will be published at www.figshare.com.

TRIAL STATUS

Trial design has been completed at the time of submission.Patient recruitment will begin in August 2018. Results of 53 patients with acute ankle sprain included in the preliminary study are reported.

PRELIMINARY RESULTS

Information of 53 patients included in the preliminary study

These 53 patients with acute ankle sprain, consisting of 31 males and 22 females, aged 16-42 years who received treatment between May 2016 and May 2017 in Guangzhou Orthopedics Hospital, China will be included in this study.All of these patients had a history of trauma caused by falling down stairs (n = 11), traffic accidents (n = 4) and sports (n = 38).

Confirmation of LCL injuries by surgery or MRI

Partial and complete tear of LCL complex were confirmed by surgery, and sprain of LCL complex by MRI.Among 53 patients, 30 had ATflinjuries (complete tear in 30 patients, partial tear in 13 patients, and sprain in 7 patients). Ultrasound examination revealed complete tears of the ATflin 31 patients, and partial tears in 15 patients. Complete tear was misdiagnosed in one patient by ultrasound as partial tear of the anterior talofibular ligament because the surrounding synovium and soft tissue filled the space left by the complete tear. ATflwas misdiagnosed in one patient by US as partial tear because of anisotropy. Twenty-two patients had ATflinjuries complicated by Cflligament injuries. These were not identified by US in one patient. No patients had isolated Cflinjuries. Twenty-seven patients had anterior tibial ligament injuries. One was not identified by US. Another 18 patients had fibular avulsion fractures, which were not identified by MRI in three patients (Tables 2, 3).

Comparative analysis of US results and surgical results

As shown in Table 2, there were no significant differences in the diagnostic results regarding ATfland Cflbetween ultrasound and MRI (P > 0.05). Therefore, our preliminary results showed that there were no significant differences in diagnostic results of LCL complex injuries between ultrasound and MRI or surgery.

US imaging results of typical cases are shown in Figure 2.

DISCUSSION

Previous contributions and existing problems in this field

The commonly used auxiliary examination methods for the diagnosis of LCL injuries have many shortcomings. It can accurately display LCL complex injuries within a short time by using the healthy limb as the reference, without radiation exposure.11-14Therefore, it is very suitable for being a standard for diagnosing acute ankle injury.

Features of this study

Caution should be made to conclude the diagnosis of complete tear of the LCL complex because ATflinjury is often accompanied by Cflinjuries. There is the possibility that ATflinjury often occurs together with lateral malleolar avulsion fracture. This is a tiny fracture and it is not easily visualized on X-ray, but it can be easily detected by ultrasound. Therefore, in this study, we will evaluate the diagnosis of different injuries to ATFL, CFL, and anterior tibial ligament using US.

Limitations of this study

The healthy side imaging data of the same patient will be used as a control. Non-injured control groups will not be used. This may lead to certain error in the evaluation of diagnostic specificity, which will be explored in future trials.

Significance of this study

Findings from this study offer hope for providing clinical evidence that US has a relatively high accuracy in the diagnosis of different injuries to the anterior talofibular ligament, calcaneofibular ligament, and anterior tibiofibular ligament.

Figure 2: Ultrasound images of lateral collateral ligament injuries.

Additional file

Additional file 1: SPIRIT checklist.

Author contributions

DH designed this study and wrote the manuscript. XHY will be responsible for patient recruitment. XZH, SMP, and YXW will be responsible for data collection and analysis. All authors approved the final version of this manuscript.

Conflicts of interest

There are no conflicts of interest.

Financial support

None.

Institutional review board statement

This study will be performed in strict accordance with the Declaration of Helsinki and relevant applicable ethical requirements.

The study protocol was approved by the Ethics Committee of Guangzhou Orthopedics Hospital (approval No. 2018-05).

Reporting statement

This study follows the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) guidance for protocol reporting.

Biostatistics statement

The statistical methods of this study were reviewed by the biostatistician of Guangzhou Orthopedics Hospital in China.

Copyright license agreement

The Copyright License Agreement has been signed by all authors before publication.

Data sharing statement

Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures, and appendices) will be available. Study protocol, informed consent,and clinical study report will be available in September 2020.

Anonymized trial data will be available indefinitely at http://www.jsxyfy.com.

Plagiarism check

Checked twice by iThenticate.

Peer review

Externally peer reviewed.Open access statement

This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms.

RefeRenceS

1. Zhou L, Sun K, Chen Y, et al. Efficacy of Shangbai ointment in alleviating pain in patients with acute ankle joint lateral collateral ligament injury: a randomized controlled trial. Nan Fang Yi Ke Da Xue Xue Bao. 2017;37:398-401.

2. Tang WJ, Jiang CG, Chen LR, Pang Y, Li J, Huang Y. Effects of acupuncture-moxibustion intervention on proprioception in athletes with lateral collateral ligament injury of ankle joint.Zhen Ci Yan Jiu. 2013;38:314-318.

3. Zhou YF, Lu XL, Lai HY, Zuo HQ, Ye C, Hong JJ. Biomechanical comparison of Evans procedure and Chrisman-Snook technique for the treatment of II degree lateral collateral ligament of ankle joint. Zhongguo Gu Shang. 2012;25:654-657.

4. Kulenović E. Nonoperative approach to injuries of the lateral collateral ligament of the ankle joint. Med Arh. 1993;47:77-78.

5. Vuurberg G, Hoorntje A, Wink LM, et al. Diagnosis, treatment and prevention of ankle sprains: update of an evidence-based clinical guideline. Br J Sports Med. 2018. doi: 10.1136/bjsports-2017-098106.

6. Sun Y, Wang H, Tang Y, et al. Diagnosis and treatment of chronic lateral ankle instability with ligamentum bifurcatum injury:an observational study. Medicine (Baltimore). 2018;97:e0028.

7. Cho JH, Lee DH, Song HK, Bang JY, Lee KT, Park YU. Value of stress ultrasound for the diagnosis of chronic ankle instability compared to manual anterior drawer test, stress radiography, magnetic resonance imaging, and arthroscopy. Knee Surg Sports Traumatol Arthrosc. 2016;24:1022-1028.

8. Jung HG, Kim NR, Kim TH, Eom JS, Lee DO. Magnetic resonance imaging and stress radiography in chronic lateral ankle instability. Foot Ankle Int. 2017;38:621-626.

9. Jolman S, Robbins J, Lewis L, Wilkes M, Ryan P. Comparison of magnetic resonance imaging and stress radiographs in the evaluation of chronic lateral ankle instability. Foot Ankle Int.2017;38:397-404.

10. Zheng ZZ, Hu YL, Li X, et al.Traumatic injuries of ankle: MRI evaluation. Zhongguo Yixue Yingxiang Jishu. 2007;23:905-908.

11. Valderrabano V, Leumann A, Pagenstert G, Frigg A, Ebneter L,Hintermann B. Chronic ankle instability in sports-a review for sports physicians. Sportverletz Sportschaden. 2006;20:177-183.

12. Bonvin F, Montet X, Copercini M, Martinoli C, Bianchi S.Imag ing of fractures of the lateral process of the talus, a frequently missed diagnosis. Eur J Radiol. 2003;47:64-70.

13. Collard XR, Danse EM, Rombouts JJ. The syndrome of external ligament sprain in the horse. Acta Orthop Belg.2000;66:229-241.

14. Milz P, Milz S, Steinborn M, Mittlmeier T, Reiser M. 13-MHc high frequency ultrasound of the lateral ligaments of the ankle joint and the anterior tibia-fibular ligament. Comparison and results of MRI in 64 patients. Radiologe. 1999;39:34-40.

15. Chhabra A, Subhawong TK, Carrino JA. MR imaging of deltoid ligament pathologic findings and associated impingement syndromes. Radiographics. 2010;30:751-761.

16. Wang YX. Musculoskeletal ultrasound. Beijing: Science Press,China; 2017.

17. Dong XY, Zeng XL, He XZ, Fang TS, He Q. Comparison of MRI with high-frequency ultrasound in diagnosis of lateral collateral ligament injury of the ankle. Xiandai Yixue Yingxiangxue. 2015; 24:140-144.