Diagnostic validity of alternative manual stress radiographic technique detecting subtalar instability with concomitant ankle instability

Ultrasound Imaging of Subtalar Joint Instability for Chronic Ankle Instability

The purpose of this study was to develop the assessment of subtalar joint instability with chronic ankle instability (CAI) using ultrasonography. Forty-six patients with anterior talofibular ligament (ATFL) abnormalities and a history of ankle sprain were divided into CAI (21.2 ± 5.9 y/o, 7 males and 17 females) and asymptomatic groups (21.0 ± 7.4 y/o, 9 males and 12 females) on the basis of subjective ankle instability assessed using the CAIT and the Ankle Instability Instrument Tool (AIIT). Twenty-six age-matched feet participated in a control group (18.9 ± 7.0 y/o, 9 males and 17 females). Ultrasound measurements of the width of the posterior subtalar joint facet were obtained at rest and maximum ankle inversion (subtalar joint excursion; STJE). The differences in STJE among the three groups were assessed by one-way ANOVA. The relationship between STJE and subjective ankle instability was assessed using Spearman's correlation tests. The STJE value was significantly greater in the CAI group (2.3 ± 0.8 mm) than in the asymptomatic (1.0 ±0.4 mm) and control groups (0.8 ±0.2 mm) (p < 0.001, effect size: 0.64). STJE had significant negative correlations with CAIT (r = -0.71, p < 0.01), and significant positive correlations with AIIT (r = 0.74, p < 0.01). The cut-off value to distinguish between the CAI and asymptomatic groups was 1.7 mm using the ROC curve.

Ultrasound or MRI in the Evaluation of Anterior Talofibular Ligament (ATFL) Injuries: Systematic Review and Meta-Analysis

OBJECTIVES

Ankle sprains represent the second most common cause of emergency department access for musculoskeletal injury and lateral ankle ligament complex tears account for 850,000 cases annually in the United States with a relapse rate of 70%. Clinical examination is limited due to its subjectivity and the difficulty of identifying a specific involvement of the ligament; therefore, US and MRI are frequently requested. Therefore, the goal of this study is to analyze the available literature on the use of ultrasound (US) and magnetic resonance imaging (MRI) to diagnose injuries to the anterior talofibular ligament (ATFL) with a meta-analytic approach.

METHODS

According to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines, all studies regarding the diagnostic accuracy of ultrasound and magnetic resonance imaging ATFL injuries were searched and assessed. The data were obtained from two independent reviewers with 12 and 3 years of experience in meta-analysis. A QUADAS-2 (Quality Assessment of Studies of Diagnostic Accuracy Studies) checklist was carried out to assess the risk of biases. From the selected studies, the sensitivity, specificity, and accuracy data were extracted.

RESULTS

Nine studies were included. The results of the meta-analysis demonstrate a greater sensitivity for ultrasound [96.88 (95% CI: 94-99) (fixed effects); 97 (95% CI: 94-99) (random effects)] compared to MRI [88.50 (95% CI: 85-91) (fixed effects); 86.98 (95% CI: 77-94) (random effects)], p < 0.05. The result of this meta-analysis shows that the less expensive diagnostic technique is also the most sensitive for the diagnosis of ATFL tears. Ultrasound articles resulted to have non-heterogeneity [(p = 0.2816; I° = 21.4607%)].

CONCLUSION

This meta-analysis demonstrates that US appears to be a highly sensitive diagnostic technique for diagnosing tears of the ATFL. Compared to MRI, the sensitivity of US result was higher.

Role of the intrinsic subtalar ligaments in subtalar instability and consequences for clinical practice

Subtalar instability (STI) is a disabling complication after an acute lateral ankle sprain and remains a challenging problem. The pathophysiology is difficult to understand. Especially the relative contribution of the intrinsic subtalar ligaments in the stability of the subtalar joint is still controversial. Diagnosis is difficult because of the overlapping clinical signs with talocrural instability and the absence of a reliable diagnostic reference test. This often results in misdiagnosis and inappropriate treatment. Recent research offers new insights in the pathophysiology of subtalar instability and the importance of the intrinsic subtalar ligaments. Recent publications clarify the local anatomical and biomechanical characteristics of the subtalar ligaments. The cervical ligament and interosseous talocalcaneal ligament seem to play an important function in the normal kinematics and stability of the subtalar joint. In addition to the calcaneofibular ligament (CFL), these ligaments seem to have an important role in the pathomechanics of subtalar instability (STI). These new insights have an impact on the approach to STI in clinical practice. Diagnosis of STI can be performed be performed by a step-by-step approach to raise the suspicion to STI. This approach consists of clinical signs, abnormalities of the subtalar ligaments on MRI and intraoperative evaluation. Surgical treatment should address all the aspects of the instability and focus on a restoration of the normal anatomical and biomechanical properties. Besides a low threshold to reconstruct the CFL, a reconstruction of the subtalar ligaments should be considered in complex cases of instability. The purpose of this review is to provide a comprehensive update of the current literature focused on the contribution of the different ligaments in the stability of the subtalar joint. This review aims to introduce the more recent findings in the earlier hypotheses on normal kinesiology, pathophysiology and relation with talocrural instability. The consequences of this improved understanding of pathophysiology on patient identification, treatment and future research are described.

Mouse model of subtalar post-traumatic osteoarthritis caused by subtalar joint instability

BACKGROUND

Common ankle sprains are often accompanied by injury to the subtalar joint, which eventually leads to subtalar joint instability. Because the clinical manifestations for subtalar joint instability are similar to ankle joint injuries, these are often overlooked. This study aimed to establish an animal model of subtalar joint instability to study post-traumatic osteoarthritis of the subtalar joint caused by long-term subtalar joint instability and to provide a reference for future clinical research on chronic subtalar joint instability.

METHODS

In all, 24 C57BL/6 male mice were randomly divided into three groups: Sham, cervical ligament (CL) transection and CL + calcaneofibular ligament (CFL) transection groups. One week after surgical operation, all mice were trained to run in the mouse rotation fatigue machine every day. During this period, a balance beam test was used to evaluate the motor level and coordination ability of the mice before the operation and three days, one week, four weeks, eight weeks, and twelve weeks after operation. Further, post-traumatic osteoarthritis of the subtalar joint was quantified via micro-CT and histological staining.

RESULTS

The mice in the partial ligament transection group took significantly longer than those in the Sham group to pass through the balance beam and showed an increased number of hindfoot slips. Micro-CT analysis showed that the subtalar bone volume fraction in the CL + CFL transection group and CL transection group was 5.8% and 2.8% higher than that in the Sham group, respectively. Histological staining showed obvious signs of post-traumatic osteoarthritis (PTOA) in the subtalar joint of the ligament transection group.

CONCLUSIONS

The transection of CL and CL + CFL can cause instability of the subtalar joint in mice, resulting in a decrease in motor coordination, and long-term instability of the subtalar joint in mice can cause PTOA of the subtalar joint, which is manifested as destruction and loss of articular cartilage.

Reconstruction of the cervical ligament in patients with chronic subtalar instability

PURPOSE

Diagnosis and treatment of subtalar instability (STI) remains complicated and challenging. The purpose of this study was to investigate the outcome of an anatomical reconstruction of the cervical ligament in patients with suspected chronic STI.

METHODS

This prospective study assessed the results of a surgical reconstruction of the cervical ligament using a gracilis tendon graft in a group of 14 patients (16 feet). Diagnosis of STI was performed using a predefined algorithm including clinical signs, MRI and peroperative evaluation. All patients had symptoms of chronic hindfoot instability despite prolonged non-surgical treatment. At final follow-up the outcome was assessed using the Karlsson score, the Foot and Ankle Outcome Score and the American Orthopaedic Foot and Ankle Society score.

RESULTS

After an average follow up of 22.6 months (range, 15-36), all patients reported significant improvement compared to their preoperative symptoms. The mean preoperative Karlsson score improved from 36.4 ± 13.5 (median 37, range 10-55) to a mean postoperative Karlsson score was 89.6 ± 8.5 (median 90, range 72-100) (P < 0.0001). The cervical ligament reconstruction was combined with other procedures in 13 cases: calcaneofibular ligament (CFL) reconstruction (3), CFL and anterior talofibular ligament reconstruction (7), bifurcate ligament reconstruction (3).

CONCLUSION

Anatomical reconstruction of the cervical ligament is a valid technique to treat patients with STI. It is a safe procedure and produces good clinical results with minimal complications. This technique can be considered in more complex cases and can be combined with other procedures according to the specific location of the instability.

LEVEL OF EVIDENCE

Level III.

Fluoroscopic Evaluation of the Role of Syndesmotic Injury in Lateral Ankle Instability in a Cadaver Model

BACKGROUND

There is a high prevalence of concomitant lateral ankle ligament injuries and syndesmotic ligamentous injuries. However, it is unclear whether syndesmotic ligaments directly contribute toward the stability of the lateral ankle. Therefore, the aim of this study was to fluoroscopically evaluate the role of the syndesmotic ligaments in stabilizing the lateral ankle.

METHODS

Twenty-four cadaveric specimens were divided into 3 groups and fluoroscopically evaluated for lateral ankle stability with all syndesmotic and ankle ligaments intact and then following serial differential ligamentous transection. Group 1: (1) anterior talofibular ligament (ATFL), (2) calcaneofibular ligament (CFL), and (3) posterior talofibular ligament (PTFL). Group 2: (1) anterior inferior tibiofibular ligament (AITFL), (2) interosseous ligament (IOL), (3) posterior inferior tibiofibular ligament (PITFL), (4) ATFL, (5) CFL, and (6) PTFL. Group 3: (1) AITFL, (2) ATFL, (3) CFL, (4) IOL, (5) PTFL, and (6) PITFL. At each transection state, 3 loading conditions were used: (1) anterior drawer test performed using 50 and 80 N of direct force, (2) talar tilt <1.7 Nm torque, and (2) lateral clear space (LCS) <1.7 Nm torque. These measurements were in turn compared with those of the stressed intact ligamentous state. Wilcoxon rank-sum test was used to compare the findings of each ligamentous transection state to the intact state. A P value <.05 was considered statistically significant.

RESULTS

The lateral ankle remained stable after transection of all syndesmotic ligaments (AITFL, IOL, PITFL). However, after additional transection of the ATFL, the lateral ankle became unstable in varus and anterior drawer testing conditions (P values ranging from .036 to .012). Lateral ankle instability was also observed after transection of the ATFL and AITFL in varus and anterior drawer testing conditions (P values ranging from .036 to .012). Subsequent transection of the CFL and PTFL worsened the lateral ankle instability.

CONCLUSION

Our findings suggest that isolated syndesmosis disruption does not result in lateral ankle instability. However, the lateral ankle became unstable when the syndesmosis was injured along with ATFL disruption.

CLINICAL RELEVANCE

When combined with ATFL release, disruption of the syndesmosis appeared to destabilize the lateral ankle.

A mouse model of ankle-subtalar joint complex instability induced post-traumatic osteoarthritis

BACKGROUND

Ankle-subtalar joint complex instability is not uncommonly presented in the clinic, but symptoms and signs similar to other conditions can easily lead to its misdiagnosis. Due to the lack of appropriate animal models, research on ankle-subtalar joint complex instability is limited. The aims of the present study were to establish an animal model of ankle-subtalar joint complex instability in mice and to explore its relationship with post-traumatic osteoarthritis (PTOA).

METHODS

Twenty-one male C57BL/6J mice were randomly divided into three groups: SHAM group (sham surgery group), transected cervical ligament + anterior talofibular ligament (CL+ATFL) group, and transected cervical ligament + deltoid ligament (CL+DL) group. Two weeks after surgery, all mice underwent cage running training. Balance beam and gait tests were used to evaluate the changes in self-movement in the mice after ankle-subtalar ligament injury. Micro-CT and histological staining were used to evaluate the progress of PTOA.

RESULTS

Compared with the SHAM group, balance and gait were affected in the ligament transection group. Twelve weeks after surgery, the time required to cross the balance beam in the CL+ATFL group was 35.1% longer and the mice slipped 3.6-fold more often than before surgery, and the mean step length on the right side was 7.2% smaller than that in the SHAM group. The time required to cross the balance beam in the CL+DL group was 32.1% longer and the mice slipped 3-fold more often than prior to surgery, and the average step length on the right side was 5.6% smaller than that in the SHAM group. CT images indicated that 28.6% of the mice in the CL+DL group displayed dislocation of the talus. Tissue staining suggested that articular cartilage degeneration occurred in mice with ligament transection 12 weeks after surgery.

CONCLUSIONS

Transected mice in the CL+ATFL and CL+DL groups displayed mechanical instability of the ankle-subtalar joint complex, and some mice in the CL+DL group also suffered from talus dislocation due to ligament injury leading to loss of stability of the bone structure. In addition, as time progressed, the articular cartilage displayed degenerative changes, which affected the ability of animals to move normally.

Current Concepts on Subtalar Instability

Subtalar instability remains a topic of debate, and its precise cause is still unknown. The mechanism of injury and clinical symptoms of ankle and subtalar instabilities largely overlap, resulting in many cases of isolated or combined subtalar instability that are often misdiagnosed. Neglecting the subtalar instability may lead to failure of conservative or surgical treatment and result in chronic ankle instability. Understanding the accurate anatomy and biomechanics of the subtalar joint, their interplay, and the contributions of the different subtalar soft tissue structures is fundamental to correctly diagnose and manage subtalar instability. An accurate diagnosis is crucial to correctly identify those patients with instability who may require conservative or surgical treatment. Many different nonsurgical and surgical approaches have been proposed to manage combined or isolated subtalar instability, and the clinician should be aware of available treatment options to make an informed decision. In this current concepts narrative review, we provide a comprehensive overview of the current knowledge on the anatomy, biomechanics, clinical and imaging diagnosis, nonsurgical and surgical treatment options, and outcomes after subtalar instability treatment.

Quantitative Evaluation of Ankle Instability Using a Capacitance-Type Strain Sensor

BACKGROUND

Manual evaluation is an important method for assessing ankle instability, but it is not quantitative. Capacitance-type sensors can be used to measure the distance on the basis of the capacitance value. We applied the sensor to the noninvasive device for measuring ankle instability and showed its utility.

METHODS

First, 5 ankles embalmed by Thiel's method were used in an experiment using a cadaver. The capacitance-type sensor was fixed alongside the anterior talofibular ligament (ATFL) of a specially made brace, and the anterior drawer test was performed. The test had been performed for the intact ankle, with the ATFL transected and with both the ATFL and calcaneofibular ligament (CFL) transected. The anterior drawer distance was calculated by the sensor. Intra- and interinvestigator reliability were also analyzed.Next, as a clinical study, a brace with a sensor was fitted to 22 ankles of 20 patients with a history of ankle sprain. An anterior drawer test at a load of 150 N was conducted using a Telos stress device. The anterior drawer distances measured by the sensor and based on radiographic images were then compared.

RESULTS

The mean anterior drawer distances were 3.7 ± 1.0 mm for the intact cadavers, 6.1 ± 1.6 mm with the ATFL transected (P < .001), and 7.9 ± 1.8 mm with the ATFL and CFL transected (P < .001). The intrainvestigator intraclass correlation coefficients (ICCs) were 0.862 to 0.939, and the interinvestigator ICC was 0.815. In the experiments on patients, the mean anterior drawer distance measured by the sensor was 2.9 ± 0.9 mm, and it was 2.7 ± 0.9 mm for the radiographic images. The correlation coefficient between the sensor and the radiographic images was 0.843.

CONCLUSION

We quantitatively evaluated anterior drawer laxity using a capacitance-type sensor and found it had high reproducibility and strongly correlated with stress radiography measurements in patients with ankle instability. Capacitance-type sensors can be used for the safe, simple, and accurate evaluation of ankle instability.

Does subtalar instability really exist? A systematic review

BACKGROUND

Subtalar joint instability (STI) is considered as a potential source of chronic lateral hindfoot instability. However, clinical diagnosis of STI is still challenging. This systematic review was conducted to assess the consistency of the clinical entity "subtalar instability", to investigate the reliability of available diagnostic tools and to provide a critical overview of related studies.

METHODS

A systematic review of the Medline, Web of Sciences and EMBASE databases was performed for studies reporting on tests to investigate subtalar instability or lesions of the subtalar ligaments. To investigate the relation with chronic STI, studies focusing on sinus tarsi syndrome (STS) or acute lesions of the subtalar ligaments were also included in the search strategy and were assessed separately.

RESULTS

This review identified 25 studies focusing on different topics: chronic STI (16), acute lesions of the subtalar ligaments (5) and STS (4). Twelve studies, assessing STI, demonstrated the existence of a subgroup with instability complaints related to abnormal increased subtalar motion (7) or abnormalities of the subtalar ligaments (6). We found insufficient evidence for measuring subtalar tilting using stress radiographs. MRI was able to assess abnormalities of the ligaments and stress-MRI detected abnormally increased motion.

CONCLUSION

Complaints of instability can be related to subtalar ligaments injuries and an abnormally increased motion of the subtalar joint. Stress radiographs should be interpreted with caution and should not have the status of a reference test. Clinical diagnosis should rely on several parameters including MRI.

Can Weightbearing Computed Tomography Scans Be Used to Diagnose Subtalar Joint Instability? A Cadaver Study

Chronic hindfoot instability is a frequent problem that includes the ankle and/or the subtalar joint. While ankle joint instability can be diagnosed clinically, accurate assessment of the subtalar joint remains elusive. This study's purpose was to assess the ability of weightbearing computed tomography (CT) scans to detect subtalar joint instability. Seven pairs of fresh frozen male cadavers (tibial plateau to toe-tip) were tested. A radiolucent frame held specimens in a plantigrade position while non-weightbearing and weightbearing CT scans (with and without torque application) were taken. First, intact ankles (Native) were scanned. Second, one specimen from each pair underwent interosseous talo-calcaneal ligament (ITCL) transection, while the contralateral underwent calcaneo-fibular ligament (CFL) transection. Third, the remaining intact ITCL or CFL was transected. Finally, the deltoid ligament was transected in all ankles. Eight radiographic measurements were performed to assess the congruency of the subtalar joint on digitally reconstructed radiographs and single CT images. Axial loading did not impact most measurements, whereas torque did impact most measurements. Radiographic measurements performed at the subtalar joint level were more reliable and better predictors for subtalar joint instability compared with measurements performed at the ankle joint level. While torque application is crucial to identify subtalar joint instability, axial load application should be avoided. Measurements to assess the subtalar joint stability should primarily be performed at the subtalar joint level rather than at the ankle joint level when using weightbearing CT scans. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2457-2465, 2019.

Currently used imaging options cannot accurately predict subtalar joint instability

PURPOSE

To give a systematic overview of current diagnostic imaging options and surgical treatment for chronic subtalar joint instability.

METHODS

A systematic literature search across the following sources was performed: PubMed, ScienceDirect, and SpringerLink. Twenty-three imaging studies and 19 outcome studies were included. The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS 2) tool was used to assess the methodologic quality of the imaging articles, while the modified Coleman Score was used to assess the methodologic quality of the outcome studies.

RESULTS

Conventional radiographs were most frequently used to assess chronic subtalar joint instability. Talar tilt, anterior talar translation, and subtalar tilt were the three most commonly used measurement methods. Surgery often included calcaneofibular ligament reconstruction.

CONCLUSION

Current imaging options do not reliably predict subtalar joint instability. Distinction between chronic lateral ankle instability and subtalar joint instability remains challenging. Recognition of subtalar joint instability as an identifiable and treatable cause of ankle pain requires vigilant clinical investigation.

LEVEL OF EVIDENCE

Systematic Review of Level III and Level IV Studies, Level IV.

Update on Subtalar Joint Instability

Subtalar joint stability is ensured by the osseous geometry of the talocalcaneal joint and the complex array of the ligaments at the medial and lateral aspect of the ankle joint, the sinus and canalis tarsi, and the talocalcaneonavicular joint, respectively. There is still a substantial lack of knowledge about the interaction of the ankle and subtalar joint complex. Subtalar joint instability appears to be more frequent than is generally assumed. The diagnosis of chronic subtalar joint instability makes the application of a comprehensive algorithm necessary. There is ongoing debate about the preferable techniques for restoration of subtalar joint stability.

ACR Appropriateness Criteria® Chronic Ankle Pain

Chronic ankle pain is a common clinical problem whose cause is often elucidated by imaging. The ACR Appropriateness Criteria for chronic ankle pain define best practices of image ordering. Clinical scenarios are followed by the imaging choices and their appropriateness. The information is in ordered tables with an accompanying narrative explanation to guide physicians to order the right test. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Surgical Procedures for Chronic Lateral Ankle Instability

Surgical procedures for managing chronic lateral ankle instability include anatomic direct repair, anatomic reconstruction with an autograft or allograft, and arthroscopic repair. Open direct repair is commonly used for patients with sufficient ligament quality. Reconstruction incorporating either an autograft or an allograft is another promising option in the short term, although the longevity of this procedure remains unclear. Use of an allograft avoids donor site morbidity, but it comes with inherent risks. Arthroscopic repair of chronic lateral ankle instability can provide good to excellent short- and long-term clinical outcomes, but the evidence supporting this technique is limited. Deterioration of the ankle joint after surgery is also a concern. Studies are needed on not only treating ligament insufficiency but also on reducing the risk of ankle joint deterioration.

Subtalar instability: imaging features of subtalar ligaments on 3D isotropic ankle MRI

BACKGROUND

MRI analysis of subtalar ligaments in the tarsal sinus has not been well performed. We retrospectively investigated the appearance of subtalar ligaments using 3D isotropic MRI and compared imaging findings of subtalar ligaments between patients with subtalar instability (STI) and controls.

METHODS

Preoperative MRIs of 23 STI patients treated with arthroscopic subtalar reconstruction were compared to MRIs of 23 age- and sex-matched control subjects without STI. Thickness and width of anterior capsular ligament (ACL) and interosseous talocalcaneal ligament (ITCL) as well as thickness of calcaneofibular ligament (CFL) and anterior talofibular ligament (ATFL) were measured. Abnormalities in ACL, ITCL, CFL, ATFL, cervical ligament, and inferior extensor retinaculum were analyzed.

RESULTS

STI patients had significantly smaller ACL thickness and ACL width than controls (ACL thickness: 1.73 mm vs. 2.22 mm, p = 0.007; ACL width: 7.21 mm vs. 8.80 mm, p = 0.004). ACL thickness of ≤2.1 mm had a sensitivity of 66.7% and a specificity of 66.7% for diagnosis of STI. ACL width of ≤7.9 mm had a sensitivity of 80.0% and a specificity of 76.2% for the diagnosis of STI. However, thickness and width of ITCL, thickness of CFL, or thickness of ATFL was not significantly different between the two groups. Absence or complete tear of ACL was significantly more frequent in STI patients than that in controls (34.8% vs. 8.7%, p = 0.035). Complete tear of CFL and ATFL was more common in STI patients than that in controls, although the difference between the two groups was not statistically significant. Abnormalities of ITCL, cervical ligament, or inferior extensor retinaculum were not significantly different between the two groups.

CONCLUSIONS

MRI features of thin or narrow ACLs may suggest STI. Absence or complete tear of ACL was significantly more common in STI patients than that in controls.

Simultaneous Radiographic Technique to Evaluate Ankle Instability

The use of ankle stress radiographs is common to evaluate ankle instability. However, the majority of the studies report the use of a manual method to apply the stress, increasing radiation exposure to the physician. Furthermore, as reported in other studies, the force applied during the stress may vary between examiners according the strength and experience. In this Technical Note, we describe our preferred method to evaluate ankle instability, either using an inversion or eversion stress, avoiding the necessity of a physician in the radiographic room.