Guo-bin Liu⋆, Guo-ping Zhang, Qing-yun Ren, Li-cun Lei, Feng Zhao, Hong-yang Gao, Chao-hua Zhu, Ya-guang Li

First Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, China

INTRODUCTION

History and current related studies

Ankle injury often results in intraarticular fracture and ligamentous rupture around the ankle joint. Appropriate early treatment can effectively help the joint repair, and reduce the incidence of serious complications. Ankle fractures are one of the common orthopedic fractures (Connors et al.,2016; Kim et al., 2016).

Radiography is a common method used for detecting ankle injury, and can determine the fracture site, type and extent. However, it is dif ficult to use radiography to discern some ankle fractures, bone fragments, displacement, or ligamentous injury; hence, radiography alone cannot be used to accurately classify ankle fractures or formulate a treatment program (Nicholas, 1974; Zwipp, 1991; Klaue,2004; Nikolaides et al., 2007; Hua, 2012).

Magnetic resonance imaging (MRI) can clearly show the ankle ligament, tendon, and cartilage injury, which is advantageous in the diagnosis of ligamentous injury after ankle fracture (Chun et al., 2015; Kim et al., 2015; Wang et al., 2015). MRI can provide accurate preoperative assessment of clinical indicators for the rational formulation of treatment programs to reduce complications (Blanke et al.,2014; Grassmann et al., 2014; Lao et al., 2014; Loriaut et al., 2015; Rammelt and Obruba, 2015; Wang et al., 2015).Furthermore, the observation of ankle contusions on MRI is conducive to analyzing the mechanism of ankle joint injury (Cher et al., 2016; Delco et al., 2016; Yasuda et al.,2016; Yeung et al., 2016).

Therefore, radiography combined with MRI could potentially accurately verify soft tissue injury associated with ankle fracture and enable surgeons to determine an effective treatment program.

Main objective

The aim of this retrospective study is to verify whether radiography combined with MRI is adequate to correctly classify ankle fractures and conduct postoperative evaluation in patients with ankle fracture.

Distinguishing features from related studies

Most previous related studies have investigated the accuracy of radiography combined with MRI in the diagnosis of ankle injury, but have seldom explored postoperative evaluation.In this study, examination with both radiography and MRI was used to evaluate fracture classi fication and postoperative evaluation in patients with ankle fracture.

METHODS/DESIGN

Study design

A retrospective, single-center, self-controlled, clinical trial with 3-month follow-up.

Figure 1: Flow chart of trial protocol.

Study setting

The First Hospital, Hebei Medical University, Shijiazhuang,Hebei Province, China.

Study procedures

Figure 1 exhibits the flow chart of the study protocol.

· Sixty-eight patients with ankle injury underwent internal fixation for ankle fracture and ligament repair. Each ankle was examined using both radiography and MRI preoperatively and 3 months postoperatively.

· The Lauge-Hansen classification and the AO-OTA(Danis-Weber) classification are commonly used to categorize ankle fractures. The Lauge-Hansen classi fication can fully explain the injury mechanism,and so is widely used to guide treatment. Based on preoperative Lauge-Hansen classi fication according to the degree of bone and ligamentous injury, repair effects were assessed using our self-made ankle fracture evaluation criteria at postoperative 3 months.

· The occurrence of adverse events and the incidence of complications were assessed.

· The recruitment of subjects was started in July 2015.

Inclusion criteria

Patients of either sex and any age presenting with all of the following criteria were considered for study inclusion:

· Ankle fracture detected by radiography

· High suspicion of ankle ligamentous injury

· History of obvious trauma

· Complete clinical data

· Signed informed consent

Exclusion criteria

Patients with one or more of the following conditions were excluded from this study:

· Cardiopulmonary function inadequate to tolerate anesthesia or surgery

· Open fracture of the ankle joint

· History of previous fracture of the ankle joint

Baseline evaluation

The baseline information including demographic data and general disease history of the included patients is shown in Table 1.

Table 1: Baseline data of included patients

Sample size

In accordance with our experience, we hypothesized that the percentage of patients with an excellent outcome would be 70%. Taking β = 0.1 and power = 90% with a signi fi-cance level of α = 0.05, the final effective sample size of n= 66 per group was calculated using PASS 11.0 software(NSCC, MD, USA). Assuming a patient loss rate of 20%,we require 80 patients per group. After screening according to the inclusion and exclusion criteria, 68 patients were included in the trial.

Recruitment

Inpatients at the First Hospital of Hebei Medical University were recruited. Potential participants could contact the project manager via telephone. After providing informed consent, these potential participants were screened using the inclusion and exclusion criteria.

Blinding

This is an open-label trial. Patients, physicians, and assessors were not blinded to group information and therapeutic regimen.

Internal fixation of ankle fracture and repair of ligamentous injury

Steel plate and screw fixation was used for simple fractures.In cases with lower tibio fibular separation, screw fixation was carried out at the lower tibio fibular site. In cases where the triangular ligament was damaged, non-invasive suture was used.

Radiographic examination

Anteroposterior and lateral views of the ankle were taken.Measurement: a line 5 mm below the talus body was made parallel to the articular surface of the body of the talus. The intersections of this parallel line with the medial ankle joint,external ankle joint, and the medial and lateral margins of the talus were respectively de fined as points a, b, c and d (Figure 2). Under normal conditions, ab–cd is equal to 4 mm, with a normal range of displacement of 2–6 mm. If the value of ab–cd increases, the ankle hole becomes wide. Equal medial and horizontal spaces of the ankle joint were considered as the standard. A widened medial gap was taken to indicate a lateral shift of the talus or lower tibio fibular separation.

Figure 2: Schematic drawing showing measurement of ankle hole width.

MRI

All patients underwent preoperative MRI. During MRI, the ankle joint was fixed in the dorsi flexion and neutral position with a brace, and scanned in the axial, coronal and sagittal planes with 45° bevel. All images were independently analyzed by an imaging expert.

Outcome measures Primary outcome measure

· Percentage of patients with an excellent outcome atpostoperative 3 months: a higher value indicates better repair effect. Evaluation criteria: (1) Excellent outcome was de fined as no internal and external displacement of the lateral malleolus and medial malleolus. Anterior and posterior displacement of the lateral malleolus, and overlapping anterior and posterior displacement of the medial malleolus of less than 2 mm. Posterior ankle displacement of less than 2 mm. Normal-sized medial malleolus hole space. Tibio fibular space of 2.5–4.0 mm.(2) Good outcome was de fined as internal and external displacement of the lateral malleolus of less than 2 mm,and anterior and posterior displacement of 2–5 mm. No internal and external displacement of the medial malleolus. Overlapping anterior and posterior displacement of the medial malleolus of 2–5 mm. Posterior ankle displacement of 2–5 mm. Medial malleolus hole widened by less than 2 mm. Tibio fibular space of 4–6 mm.(3) Poor outcome was de fined as internal and external displacement of the lateral malleolus of more than 2 mm, and anterior and posterior displacement of more than 5 mm. Internal and external displacement of the medial malleolus accompanied by angulation or rotation. Overlapping anterior and posterior displacement of the medial malleolus of more than 5 mm, and posterior ankle displacement of more than 5 mm, accompanied by posterior dislocation of the talus. Medial malleolus hole widened by more than 2 mm. Tibio fibular space of more than 6 mm.

Table 2: Timing of outcome assessment

Secondary outcome measures

· Lauge-Hansen classi fication according to the degree of bone and ligamentous injury. (1) Supination-eversion: degree I (anterior inferior tibio fibular ligament tear), degree II(degree I tear plus an obliquely-shaped inferior tibio fibular joint or spiral fracture), degree III (degree II injury plus a posterior malleolus fracture or inferior tibio fibular ligament tear), degree IV (degree III injury plus a medial malleolus fracture or triangular ligament tear). (2) Pronation-eversion:degree I (transverse fracture of the medial malleolus or triangular ligament tear), degree II (degree I injury plus anterior inferior tibio fibular ligament injury), degree III(degree II injury plus spiral fracture above the lateral malleolus), degree IV (degree III injury plus posterior inferior tibio fibular ligament injury). (3) Supination-adduction:degree I (avulsion fracture of the lateral malleolus or lateral collateral ligament injury), degree II (degree I injury plus medial malleolus fracture). (4) Pronation-abduction: degree I (medial malleolus fracture or triangular ligament tear),degree II (degree I injury plus inferior tibio fibular ligament injury), degree III (degree II injury plus lateral malleolus fracture or short oblique fracture at the distal end of the fibula above the tibial astragaloid joint).

· Radiography and MRI evaluation preoperatively and 3 months postoperatively

Other outcome measure

· Incidence of adverse events at postoperative 3 months to evaluate the occurrence of complicationss

The schedule of outcome measurement assessments is shown in Table 2.

Adverse events

We recorded adverse events, including incision pain, incision nonunion, ankle pain, peripheral nerve injury of the ankle joint, ankle joint in flammation, and soft tissue injury.Severe adverse events were de fined as events occurring during the clinical trial period that required rehospitalization,prolonged hospitalization, caused disability or inability to work, and/or were life-threatening or fatal. If severe adverse events occurred, investigators reported details, including the date of occurrence and measures taken to treat the adverse events, to the principle investigator and the institutional review board within 24 hours.

Data collection, management, analysis and open-access

Case report forms with demographic data, disease diagnosis,accompanying diseases, drug allergy history, and adverse events were collected.

Figure 3: Fracture line at the ankle joint shown on a radiograph.

Data were processed using Epidata software (Epidata Association, Odense, Denmark), collated, and then recorded electronically. All data regarding this trial were preserved by the First Hospital, Hebei Medical University, China.

The electronic database was statistically analyzed by a professional statistician who created an outcome analysis report that was submitted to the lead researchers.

Anonymized trial data will be published at www. figshare.com.

Auditing

Trial progression will be reported to the ethics committee, and the trial status will be updated in the registration database.

Confidentiality

Trial outcomes will be transcribed, dated, and uploaded to a dedicated computer by two staff members. Data will be scheduled, checked and locked by an investigator.

The data will be password-protected, and not altered in future. Only authorized researchers will be able to access the data.

Data regarding this trial protocol will be preserved by the First Hospital, Hebei Medical University, China.

TRIAL STATUS

Study participants were enrolled from July 2015 to August 2016. Results of 3-month follow-up are as follows:

Type of ankle fracture assessed by radiography and MRI

Radiography showed that among the 68 patients with ankle fracture, 30 had left ankle fracture and 38 had right ankle fracture; 36 patients had medial malleolus fracture, 45 had lateral malleolus fracture, and 8 had posterior ankle fracture;16 patients had fracture at 2 or 3 sites. The fracture line was clear (Figure 3).

MRI showed that among the 68 patients with ankle fracture, there were 59 cases of ligamentous injury, witha detection rate of 87%. The fracture line was not visible on MRI in 32 patients. Fracture, bleeding and edema were seen on MRI in 36 patients.

Table 3: Lauge-Hansen classification in patients with ankle fractures (n)

In accordance with the Lauge-Hansen classi fication, there were 7 cases of pronation-abduction, 14 cases of pronationeversion, 13 cases of supination-adduction, and 35 cases of supination-eversion (Table 3).

Postoperative 3 months follow-up evaluation of patients with ankle fractures

Thirty-six patients (53%) had an excellent outcome. Of these, none had internal and external displacement of the lateral malleolus, and 10 patients had anterior and posterior displacement of the lateral malleolus of less than 2 mm.None of the patients with excellent outcome had internal and external displacement of the medial malleolus, and there were seven patients with overlapping anterior and posterior displacement of the medial malleolus of less than 2 mm.Thirteen patients had posterior ankle displacement of less than 2 mm. The medial malleolus hole space was normal in four patients. The tibio fibular space was 2.5–4.0 mm in two patients (Table 4).

Twenty-three patients had a good outcome. None of these cases had internal and external displacement of the lateral malleolus, and seven patients had anterior and posterior displacement of the lateral malleolus of less than 2 mm. None of these patients had internal and external displacement of the medial malleolus, and nine patients had overlapping anterior and posterior displacement of the medial malleolus of less than 2 mm. The medial malleolus hole space was normal in four patients. The tibio fibular space was 2.5–4.0 mm in three patients (Table 4).

Nine patients had a poor outcome. Of these, six patients had lateral malleolus, medial malleolus or posterior ankle spaces of more than 2 mm. The tibio fibular space was more than 6 mm in three patients (Table 4).

Adverse events

Among 36 patients, the articular cartilage was obviously injured in four patients, and the joint was not fully reset intwo patients. The incidence of adverse events was 17%.

Table 4: Postoperative evaluation of ankle fracture

DISCUSSION

Significance of this study

This study aimed to investigate fracture classi fication and postoperative evaluation in patients with ankle injury using radiography combined with MRI, which is essential for developing an optimal repair plan. Radiographic examination combined with MRI can accurately classify ankle injury,provide accurate information for planning the surgical program, and provide an important reference to develop new treatment standards.

Evidence for contribution to future studies

Radiographic examination combined with MRI is used to monitor the healing process of ligaments around the ankle joint after surgical repair, enables accurate fracture classi fication and postoperative evaluation, and can effectively reduce the misdiagnosis rate of ankle joint injury. Our results can be used for accurate preoperative positioning, quali fication, and surgical guidance, to avoid inadequate treatment and overtreatment. Postoperative dynamic observation of the healing process and timely guidance of functional exercise can effectively prevent ligament re-rupture and ankle stiffness.

Declaration of patient consent

The authors certi fied that they obtained all appropriate patient consent forms. In the form the patient(s) gave his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understood that their names and initials would not be published and due efforts would be made to conceal their identity, but anonymity could not be guaranteed.

Conflicts of interest

None declared.

Author contributions

GBL conceived and designed the trial, wrote the manuscript. Other authors assisted in trial conduction. All authors approved the final version of this paper.

Plagiarism check

This paper was screened twice using CrossCheck to verify originality before publication.

Peer review

This paper was double-blinded and stringently reviewed by international expert reviewers.

Blanke F, Loew S, Ferrat P, Valderrabano V, Ochsner PE, Majewski M (2014) Osteonecrosis of distal tibia in open dislocation fractures of the ankle. Injury 45:1659-1663.

Cher WL, Utturkar GM, Spritzer CE, Nunley JA, DeFrate LE, Collins AT (2016) An analysis of changes in in vivo cartilage thickness of the healthy ankle following dynamic activity. J Biomech 49:3026-3030.

Chun KY, Choi YS, Lee SH, Kim JS, Young KW, Jeong MS, Kim DJ (2015) Deltoid ligament and tibio fibular syndesmosis injury in chronic lateral ankle instability: magnetic resonance imaging evaluation at 3T and comparison with arthroscopy. Korean J Radiol 16:1096-1103.

Connors JC, Coyer MA, Hardy MA (2016) Irreducible ankle fracture dislocation due to tibialis posterior tendon interposition: a case report. J Foot Ankle Surg 55:1276-1281.

Delco ML, Kennedy JG, Bonassar LJ, Fortier LA (2016) Post-traumatic osteoarthritis of the ankle: a distinct clinical entity requiring new research approaches. J Orthop Res doi: 10.1002/jor.23462.

Grassmann JP, Hakimi M, Gehrmann SV, Betsch M, Kröpil P, Wild M, Windolf J, Jungbluth P (2014) The treatment of the acute Essex-Lopresti injury. Bone Joint J 96-B:1385-1391.

Hua Y (2012) Application of three-dimensional reconstruction of spiral CT in the classi fication and treatment of ankle joint fracture. Zhongguo Wuzhenxue Zazhi 12:1078-1079.

Kim JH, Gwak HC, Lee CR, Choo HJ, Kim JG, Kim DY (2016) A comparison of screw fixation and suture-button fixation in a syndesmosis injury in an ankle fracture. J Foot Ankle Surg 55:985-990.

Kim YS, Kim YB, Kim TG, Lee SW, Park SH, Lee HJ, Choi YJ,Koh YG (2015) Reliability and validity of magnetic resonance imaging for the evaluation of the anterior talo fibular ligament in patients undergoing ankle arthroscopy. Arthroscopy 31:1540-1547.

Klaue K (2004) Talus fractures-fractures of the most important tarsal bone. Ther Umsch 61:428-434.

Lao LF, Zhong GB, Li QY, Liu ZD (2014) Kinetic magnetic resonance imaging analysis of spinal degeneration: a systematic review. Orthop Surg 6:294-299.

Loriaut P, Casabianca L, Alkhaili J, Dallaudière B, Desportes E,Rousseau R, Massin P, Boyer P (2015) Arthroscopic treatment of acute acromioclavicular dislocations using a double button device: clinical and MRI results. Orthop Traumatol Surg Res 101:895-901.

Nicholas JA (1974) Ankle injuries in athletes. Orthop Clin North Am 5:153-175.

Nikolaides AP, Anagnostidis KS, Kirkos JM, Kapetanos GA (2007)Inferior dislocation of the proximal tibio fibular joint: a new type of dislocation with poor prognosis. Arch Orthop Trauma Surg 127:933-936.

Rammelt S, Obruba P (2015) An update on the evaluation and treatment of syndesmotic injuries. Eur J Trauma Emerg Surg 41:601-614.

Wang A, Mackie K, Breidahl W, Wang T, Zheng MH (2015) Evidence for the durability of autologous tenocyte injection for treatment of chronic resistant lateral epicondylitis: mean 4.5-year clinical follow-up. Am J Sports Med 43:1775-1783.

Wang H, Wen XD, Zhang K (2015) New progress in the treatment of ankle fracture. Guoji Gukexue Zazhi 36:390-393.

Yasuda T, Shima H, Mori K, Kizawa M, Neo M (2016) Direct repair of chronic achilles tendon ruptures using scar tissue located between the tendon stumps. J Bone Joint Surg Am 98:1168-1175.

Yeung DE, Jia X, Miller CA, Barker SL (2016) Interventions for treating ankle fractures in children. Cochrane Database Syst Rev 4:CD010836.

Zwipp H (1991) Injuries to the superior ankle joint from the viewpoint of accident surgery. Radiologe 31:585-593.