Mechanics of the anterior drawer and talar tilt tests. A cadaveric study of lateral ligament injuries of the ankle

Chronic lateral ankle ligament instability - Current evidence and recent management advances

Lateral ankle sprain is a common injury with a substantial negative impact on physical function, quality of life and health economic burden. Chronic lateral ankle instability (CLAI) as a sequela of lateral ankle sprain can lead to the development of posttraumatic ankle osteoarthritis in the long term. In this article, we explore the epidemiology, burden and definition of CLAI for the appropriate clinical assessment and imaging evaluation of patients with lateral ankle sprain and CLAI. Following that, recent advances and evidence on management of CLAI is critically distilled and summarized.

Advances in Diagnosis and Management of Lateral Ankle Instability: A Review of Current Literature

Lateral ankle sprains and instability are an increasingly identified pain point for patients, accounting for 20 to 25% of musculoskeletal injuries. Lateral ankle injuries are especially concerning given the propensity for patients to develop chronic lateral ankle instability and for the high risk of reinjury on an unstable ankle. With the complex articulation of the tibiofibular syndesmosis, subtalar, and talocrural joints, pinpointing ankle dysfunction remains difficult. Multiple reviews have evaluated management and diagnosis of lateral ankle instability, but with newer treatment options available, a more comprehensive assessment of the current literature was conducted. Although multiple surgical options exist, many nonsurgical functional options have also been developed for patients that may help patients prevent the development of chronic lateral ankle instability. In recent times, many new options have come up, including in-office needle arthroscopy and continual advancements in diagnosis and our understanding of this difficult topic. Multiple reviews have evaluated the management and diagnosis of lateral ankle instability, but with newer treatment options available, a more comprehensive assessment of the current literature was conducted. Given this, this review will help to highlight new diagnostic and nonsurgical therapeutic options for the management of lateral ankle instability.

Magnetic Resonance Imaging Characteristics of a Lateral Ligament Injury in Acute Ankle Sprains Among Athletes

Background

It is important to identify the location and pattern of lateral ligament injuries that are related to the development and prognosis of chronic ankle instability in athletes with ankle sprains.

Purpose

To describe the location and pattern of lateral ligament injuries on magnetic resonance imaging (MRI) in elite-level or amateur athletes with acute ankle sprains and to further assess the risk of associated concomitant injuries.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

The anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) of 110 athletes with an ankle lateral ligament injury (mean age, 24.7 years) were evaluated. MRI scans were evaluated for the location and pattern of ATFL and CFL tears such as sleeve avulsions as well as concomitant deltoid ligament injuries, bone contusions, and osteochondral lesions of the talus (OLTs).

Results

On MRI, 52 (47.3%) athletes had an isolated ATFL tear, 56 (50.9%) athletes had both ATFL and CFL tears, and 2 (1.8%) athletes had an isolated CFL tear. ATFL injuries occurred at the fibula, midsubstance, and talus in approximately equal numbers, whereas the majority of CFL injuries occurred at the calcaneal insertion. Concomitant deltoid ligament injuries were identified in 18 (16.4%) athletes. In addition, concomitant bone contusions and OLTs were identified in 38 (34.5%) and 6 (5.5%) athletes, respectively. Using linear-by-linear analysis, CFL injuries correlated with concomitant deltoid ligament and bone injuries (P = .023 and P = .001, respectively) and a sleeve injury pattern (P = .005).

Conclusion

After an acute ankle ligament rupture, almost all athletes involved in this study had injured their ATFL, and approximately 50% had a concomitant injury to the CFL. The rate of sleeve-type CFL injuries at the calcaneal insertion was high, and concomitant deltoid ligament injuries and OLTs were associated with this pattern of injury.

Clinical Relevance and Function of Anterior Talofibular Ligament Superior and Inferior Fascicles: A Robotic Study

BACKGROUND

Ankle lateral ligament sprains are common injuries in sports, and some may result in persistent ankle pain and a feeling of instability without clinical evidence of instability. The anterior talofibular ligament (ATFL) has 2 distinct fascicles, and recent publications have suggested that injury isolated to the superior fascicle might be the cause of these chronic symptoms. This study aimed to identify the biomechanical properties conferred by the fascicles in stabilizing the ankle in order to understand potential clinical problems that may follow when the fascicles are injured.

PURPOSE/HYPOTHESIS

The aim of this study was to determine the contribution of superior and inferior fascicles of the ATFL in restraining anteroposterior tibiotalar resistance, internal external tibial rotation resistance, and inversion eversion talar rotation resistance. It was hypothesized that an isolated injury of the ATFL superior fascicle would have a measurable effect on ankle stability and that the superior and inferior fascicles would restrain different motions of the ankle.

STUDY DESIGN

Descriptive laboratory study.

METHODS

A robotic system with 6 degrees of freedom was used to test ankle instability in 10 cadavers. Serial sectioning following the most common injury pattern (from superior to inferior fascicles) was performed on the ATFL while the robot ensured reproducible movement through a physiological range of dorsiflexion and plantarflexion.

RESULTS

Sectioning of only the ATFL superior fascicle had a significant and measurable effect on ankle stability, resulting in increased internal rotation and anterior translation of the talus, especially in plantarflexion. Sectioning of the entire ATFL resulted in significantly decreased resistance in anterior translation, internal rotation, and inversion of the talus.

CONCLUSION

Rupture of only the superior fascicle of the ATFL may lead to minor instability or microinstability of the ankle joint, without objective clinical findings of gross clinical laxity.

CLINICAL RELEVANCE

Some patients develop chronic symptoms after an ankle sprain without overt signs of instability. This may be explained by an isolated injury to the ATFL superior fascicle, and diagnosis may require careful clinical evaluation and magnetic resonance imaging examination looking at the individual fascicles. It is possible that such patients may benefit from lateral ligament repair despite having no gross clinical instability.

Imaging of Acute Ankle and Foot Sprains

Ankle and foot injuries are very common injuries in the general population, and more so in athletes. MR imaging is the optimal modality to evaluate for ligamentous injuries of the ankle and associated conditions after ankle sprain. In this article, the authors discuss the epidemiology, biomechanics, normal anatomy, and pathology of the ankle as well as injuries of the hindfoot and midfoot that are often associated with ankle injuries.

The Prevalence and Characteristics of Chronic Ankle Instability in Elite Athletes of Different Sports: A Cross-Sectional Study

BACKGROUND

Ankle sprains are one of the most common injuries in athletic populations. Misdiagnosed and untreated ankle sprains will cause chronic ankle instability (CAI), which can significantly affect the performance of athletes. This study aimed to investigate the prevalence and characteristics of CAI in elite athletes of different sports.

METHOD

This cross-sectional study included 198 elite athletes from Guangdong provincial sports teams. All participants answered a questionnaire about ankle sprains and ankle instability. The severity of their ankle instability was evaluated by the Cumberland Ankle Instability Tool (CAIT). Participants further underwent clinical examinations from sports medicine doctors to determine the presence and characteristics of ankle instability. The datasets were analyzed to determine the differences in prevalence between age, gender, sports teams, and sports categories.

RESULTS

In 198 athletes, 39.4% (n = 78) had bilateral CAI while 25.3% (n = 50) had unilateral CAI. Female athletes had a higher prevalence of CAI than male athletes in the study (p = 0.01). Prevalence showed differences between sports categories, and were significantly higher in acrobatic athletes than non-contact athletes (p = 0.03).

CONCLUSIONS

CAI was highly prevalent among elite athletes in this study, with female athletes and athletes in acrobatic sports being associated with a higher risk of developing CAI in their professional careers. Therefore, extra precautions need to be taken into account when applying ankle protections for these athletes.

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.

Use of portable ultrasonography for the diagnosis of lateral ankle instability

Portable ultrasonography is increasingly used to evaluate ankle stability at the point of care. This study aims to determine the correlation of portable-ultrasonographic and fluoroscopic measurements of ankle laxity in a cadaveric ligament transection model of ankle ligament injury. We hypothesize that there is an association between portable-ultrasonographic and fluoroscopic measurements when performing stress evaluation of lateral ankle instability. Eight fresh-frozen below-knee amputated cadaveric specimens with intact proximal fibula underwent ultrasound and fluoroscopic evaluation of the ankle during anterior drawer and talar tilt testing. The assessment was first performed with all lateral ankle ligaments intact and thereafter with sequential transection of the anterior talofibular ligament, calcaneofibular ligament, and posterior talofibular ligament. The anterior drawer test was performed with both 50N and 80N of force, and talar tilt test was performed with 1.7 Nm of torque. Correlations between (1) portable-ultrasonographic and fluoroscopic measurements and (2) sequential transection of lateral ankle ligaments were evaluated using Spearman's rank correlations. The same statistical test was used to investigate the correlation between the ultrasonographic and the fluoroscopic measurements. The inter- and intra-observer agreement was assessed using the intraclass correlation coefficient through a two-way mixed-effects model with absolute agreement. Portable-ultrasonographic and fluoroscopic measurements increased as additional ligaments of the lateral ankle were transected (Spearman's rank correlation ranged from 0.74 to 0.81, 0.74 to 0.81, p-values < 0.001). Strong positive correlations between ultrasonographic and fluoroscopic measurements were found during the lateral ankle stability evaluation using anterior drawer and talar tilt testing (Spearman's rank correlation ranged from 0.81 to 0.85, 0.81 to 0.85, p-values < 0.001). Inter-rater (0.99, 95% CI: 0.98-0.99) and intra-rater reliability (0.97, 95% CI: 0.95-0.99) for the ultrasonographic measurements were substantial. In conclusion, there was a strong correlation found between ultrasonographic and fluoroscopic values measured during simulated anterior drawer and talar tilt test in a cadaveric ligament transection model. In this model, the portable-ultrasonographic measurement was found to be reliable for repeated measurements of the talar translation and the lateral clear space distance. Based on these data, ultrasonography is likely to become a valuable point of care diagnostic tool due to its ability to readily and dynamically evaluate suspected lateral ankle instability. Clinical Significance: The use of dynamic stress ultrasound to assess the anterior translation of the talus and the lateral clear space distance appears to be a reliable and repeatable technique to evaluate lateral ankle stability with a radiation-free, noninvasive, and low-cost manner.

Effects of lateral instability on ankle coupled motions in vivo using 3D fluoroscopy

Lateral ankle instability (LAI) compromises the normal kinematics of the ankle, affecting activities of daily living. In vitro kinematics of ankles with LAI during single-plane motions are available, but the active control stability of these motions remains unclear. The current study measured the 3D ankle kinematics during unresisted single-plane motion tests using a bi-plane fluoroscope with a CT model-based 2D/3D registration method in 12 patients with LAI and 14 healthy peers. The coupling of the kinematic components at the talocrural and subtalar joints was quantified by the path difference between the forward and return paths of the coupled motion. Significantly increased path differences were found in the subtalar dorsiflexion/plantarflexion and inversion/eversion components during internal/external rotation tests (p < 0.05). During inversion/eversion, significantly reduced tibiocalcaneal ranges of motion and the path differences in the talocrural and subtalar dorsiflexion/plantarflexion components were noted (p < 0.05). The current results suggest that chronic LAI had compromised control stability at the subtalar joint during internal/external rotation tests and a conservative motion control strategy with significantly reduced ranges of motion to maintain good control of out-of-plane motion components in response to direct challenges of the anterior talofibular ligament during inversion/eversion tests. The current results also suggest that, compared to kinematic patterns of individual components, the path difference of the coupled motion may serve as a better measure of the motion control stability of the ankle in differentiating LAI from healthy controls.

Ultrasound-Guided Anterior Talofibular Ligament Repair With Augmentation Can Restore Ankle Kinematics: A Cadaveric Biomechanical Study

Background:

Anterior talofibular ligament (ATFL) repair of the ankle is a common surgical procedure. Ultrasound (US)-guided anchor placement for ATFL repair can be performed anatomically and accurately. However, to our knowledge, no study has investigated ankle kinematics after US-guided ATFL repair.

Hypothesis:

US-guided ATFL repair with and without inferior extensor retinaculum (IER) augmentation will restore ankle kinematics.

Study Design:

Controlled laboratory study; Level of evidence, 4.

Methods:

A 6 degrees of freedom robotic testing system was used to apply multidirectional loads to fresh-frozen cadaveric ankles (N = 9). The following ankle states were evaluated: ATFL intact, ATFL deficient, combined ATFL repair and IER augmentation, and isolated US-guided ATFL repair. Three loading conditions (internal-external rotation torque, anterior-posterior load, and inversion-eversion torque) were applied at 4 ankle positions: 30° of plantarflexion, 15° of plantarflexion, 0° of plantarflexion, and 15° of dorsiflexion. The resulting kinematics were recorded and compared using a 1-way repeated-measures analysis of variance with the Benjamini-Hochberg test.

Results:

Anterior translation in response to an internal rotation torque significantly increased in the ATFL-deficient state compared with the ATFL-intact state at 30° and 15° of plantarflexion (P = .022 and .03, respectively). After the combined US-guided ATFL repair and augmentation, anterior translation was reduced significantly compared with the ATFL-deficient state at 30° and 15° of plantarflexion (P = .0012 and .005, respectively). Anterior translation was not significantly different for the isolated ATFL-repair state compared with the ATFL-deficient or ATFL-intact states at 30° and 15° of plantarflexion.

Conclusion:

Combined US-guided ATFL repair with augmentation of the IER reduced lateral ankle laxity due to ATFL deficiency. Isolated US-guided ATFL repair did not reduce laxity due to ATFL deficiency, nor did it increase instability compared with the intact ankle.

Clinical Relevance:

US-guided ATFL repair with IER augmentation is a minimally-invasive technique to reduce lateral ankle laxity due to ATFL deficiency. Isolated US-guided ATFL repair may be a viable option if accompanied by a period of immobilization.

Lack of Definition of Chronic Ankle Instability With Arthrometer-Assisted Ankle Joint Stress Testing: A Systematic Review of In Vivo Studies

Despite extensive research on ankle instability a consensual and clear objective definition for pathological mechanical lateral ankle instability is yet to be determined. This systematic review aimed to summarize current available arthrometric devices, measuring methods and lateral ankle laxity outcomes in patients with chronic ankle instability that underwent objective arthrometric stress measurement. Sixty-eight studies comprising a total of 3,235 ankles with chronic ankle instability were included. Studies reported a wide range of arthrometric devices, testing position and procedures, and measuring methods. For the anterior drawer test, the average mean differences between injured and uninjured ankles ranged from -0.9 to 4.1 mm, and total translation in the injured ankle from 3.2 to 21.0 mm. Most common pathological threshold was ≥4 mm or ≥10 mm unilaterally and ≥3 mm bilaterally. For the talar tilt test, the average mean differences between injured and uninjured ankles ranged from 0.0° to 8.0°, and total tilt from injured ankle from 3.3 to 60.2°. Most common pathological threshold was ≥ 10° unilaterally and ≥ 6° mm bilaterally. It was found high heterogeneity in the scientific literature regarding the arthrometric devices, use of concomitant imaging and measuring methods of arthrometer-assisted anterior drawer and talar tilt tests which led to variable laxity outcomes in individuals with chronic ankle instability. Future studies should focus on standardizing the testing and measuring methods for an objective definition of mechanical ankle instability.

Evaluation of the Intact Anterior Talofibular and Calcaneofibular Ligaments, Injuries, and Repairs With and Without Augmentation: A Biomechanical Robotic Study

BACKGROUND

Acute ankle sprains are common injuries. The anterior talofibular (ATFL) and calcaneofibular ligaments (CFL) are the most injured lateral structures. However, controversy exists on the optimal surgical treatment when the injury is both acute and severe or becomes chronic and unstable. Studies have evaluated the biomechanics of these ligaments, but no studies have robotically evaluated injury effects and surgical treatment of ATFL or ATFL and CFL injuries.

PURPOSE

To quantitatively evaluate biomechanical effects of ATFL and CFL lesions, ATFL repair, ATFL and CFL repair, and augmentation of ATFL on ankle stability.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten nonpaired cadaveric ankles were tested using a 6 degrees of freedom robot. Each ankle underwent testing in the following states sequentially: (1) intact, (2) ATFL cut, (3) CFL cut, (4) ATFL repair + CFL cut, (5) ATFL repair + CFL repair, and (6) ATFL repair with augmentation with suture tape + CFL repair. Testing included 88 N anterior drawer and 5 N·m varus talar tilt tests at 0° and 30° of plantarflexion, and 88 N Cotton test at 0° of plantarflexion.

RESULTS

After all surgical treatments ankles still had increased laxity compared with intact state testing, except after augmented ATFL repair + CFL repair in anterior drawer testing at 30° of plantarflexion (P = .393). Sectioning the CFL caused a significant increase in talar tilt compared with the ATFL cut state at 0° (P < .001) and 30° of plantarflexion (P < .001), but no increase in anterior drawer or Cotton tests.

CONCLUSION

Complete native stability may not be attainable at time zero repair with the tested treatments. The option that best returned stability in anterior translation was augmented ATFL repair with nonaugmented CFL repair. The importance of the CFL as a primary ligamentous stabilizer for talar tilt was confirmed.

CLINICAL RELEVANCE

Evaluating lateral ankle stability and treatment with a 6 degrees of freedom robot should help delineate optimal treatment options. Findings in this study show that none of the repair methods at time zero restored kinematics to the intact state. Of the tested states, the augmented ATFL repair with CFL repair was the best option for controlling anterior translation at time zero. The importance of addressing the CFL to correct talar tilt instability was suggested as was the importance of a period of immobilization before beginning protected rehabilitation. The benefit of ATFL repair augmentation with suture tape is in limiting the postoperative motion in an anterior drawer motion to just 0.5 to 1 mm, but there was no significant improvement to talar tilt even with CFL repair, suggesting that further consideration should be given to CFL augmentation in future studies.

Physical Examination of the Ankle: A Review of the Original Orthopedic Special Test Description and Scientific Validity of Common Tests for Ankle Examination

Objectives

To review the literature, identify and describe commonly used special tests for diagnosing injury to the ligaments of the ankle complex, present the distinguishing characteristics and limitations of each test, and discuss the current evidence for the clinical use of each test.

Data Sources

Multiple PubMed (1920-2018) and CINAHL (1920-2018) searches were conducted and various musculoskeletal examination textbooks were reviewed to examine common orthopedic tests used to assess the ankle. The articles were reviewed for additional references and the search continued until the original description was found when possible.

Study Selection

All articles discussing the performance of the test or its validity (ie, sensitivity and specificity) were reviewed and summarized.

Data Extraction

Articles were reviewed for additional references and the search continued until the original description was found when possible.

Data Synthesis

The literature was reviewed, commonly used special tests for diagnosing ankle injuries were identified and described, distinguishing characteristics and limitations of each test were presented, and the current evidence for the clinical use of each test was discussed.

Conclusions

A complete physical examination is critical in the diagnosis of ankle injuries. The combination of available information such as mechanism of injury, all signs and symptoms, and changes in gait, is key to a conclusive and correct diagnosis. Clinicians should be aware of the severely limited evidence supporting the use of many commonly used special tests. Applying evidence from the literature will improve diagnostic accuracy. Further research is needed to understand the performance ability of special tests, both individually and when grouped as part of a test battery.

Diagnosis and Treatment of Chronic Lateral Ankle Instability: Review of Our Biomechanical Evidence

Definitive diagnosis and optimal surgical treatment of chronic lateral ankle instability remains controversial. This review distills available biomechanical evidence as it pertains to the clinical assessment, imaging work up, and surgical treatment of lateral ankle instability. Current data suggest that accurate assessment of ligament integrity during physical examination requires the ankle to ideally be held in 16° of plantar flexion when performing the anterior drawer test and 18° of dorsiflexion when performing the talar tilt test, respectively. Stress radiographs are limited by their low sensitivity, and MRI is limited by its static nature. Surgically, both arthroscopic and open repair techniques appear biomechanically equivalent in their ability to restore ankle stability, although sufficient evidence is still lacking for any particular procedure to be considered a superior construct. When performing reconstruction, grafts should be tensioned at 10 N and use of nonabsorbable augmentations lacking viscoelastic creep must factor in the potential for overtensioning. Anatomic lateral ligament surgery provides sufficient biomechanical strength to safely enable immediate postoperative weight bearing if lateral ankle stress is neutralized with a boot. Further research and comparative clinical trials will be necessary to define which of these ever-increasing procedural options actually optimizes patient outcome for chronic lateral ankle instability.

Chronic Lateral Ankle Instability: Topical Review

Chronic ankle instability can result from untreated or badly managed acute lateral ankle ligament injuries. Conservative management is the modality of choice for acute lateral ankle ligament injuries, and operative treatment is reserved for special cases. Failure after strict rehabilitation may be an indication for surgery. Several operative options are available, including anatomic repair, anatomic reconstruction, and tenodesis procedures. Anatomic repair can be performed when the quality of the damaged ligaments permits. Anatomic reconstruction with an autograft or allograft should be considered when the torn ligaments are not adequate. Ankle arthroscopy is a useful adjunct to ligamentous procedures, performed at the time of repair to identify and treat intra-articular conditions that may be associated with chronic ankle instability. Tenodesis techniques are not recommended because of their suboptimal long-term results related to the modification of ankle and hindfoot biomechanics.Level of Evidence: Level V, expert opinion.

Biomechanics of Ankle Ligament Reconstruction: A Cadaveric Study to Compare Stability of Reconstruction Techniques Using 1 or 2 Fibular Tunnels

Background

Anatomic lateral ankle ligament reconstruction has been proposed for patients with chronic ankle instability. A reliable approach is a reconstruction technique using an allograft and 2 fibular tunnels. A recently introduced approach that entails 1-fibular tunnel reconstruction might reduce the risk of intraoperative complications and ultimately improve patient outcome.

Hypothesis

We hypothesized that both reconstruction techniques show similar ankle stability (joint laxity and stiffness) and are similar to the intact joint condition.

Study Design

Controlled laboratory study.

Methods

A total of 10 Thiel-conserved cadaveric ankles were divided into 2 groups and tested in 3 stages-intact, transected, and reconstructed lateral ankle ligaments-using either the 1- or the 2-fibular tunnel technique. To quantify stability in each stage, anterior drawer and talar tilt tests were performed in 0°, 10°, and 20° of plantarflexion (anterior drawer test) or dorsiflexion (talar tilt test). Bone displacements were measured using motion capture, from which laxity and stiffness were calculated together with applied forces. Finally, reconstructed ligaments were tested to failure in neutral position with a maximal applicable torque in inversion. A mixed linear model was used to describe and compare the outcomes.

Results

When ankle stability of intact and reconstructed ligaments was compared, no significant difference was found between reconstruction techniques for any flexion angle. Also, no significant difference was found when the maximal applicable torque of the 1-tunnel technique (9.1 ± 4.4 N·m) was compared with the 2-tunnel technique (8.9 ± 4.8 N·m).

Conclusion

Lateral ankle ligament reconstruction with an allograft using 1 fibular tunnel demonstrated similar biomechanical stability to the 2-tunnel approach.

Clinical Relevance

Demonstrating similar stability in a cadaveric study and given the potential to reduce intraoperative complications, the 1-fibular tunnel approach should be considered a viable option for the surgical therapy of chronic ankle instability. Clinical randomized prospective trials are needed to determine the clinical outcome of the 1-tunnel approach.

Varus talar tilt combined with an internal rotation pivot stress assesses the supination instability vector in lateral ankle ligaments' injury - cadaver study

BACKGROUND

The lack of consensus on the relevance of the varus talar tilt test (VTTT) might be due to the divergence between the insufficiency vector of lateral ankle instability and the direction of this clinical test. Our hypothesis is that the VTTT is more accurate to diagnose lateral ankle ligaments rupture when it's applied with a pre-positioning of the foot in internal rotation (IR).

METHODS

We compared, in 12 cadaver ankles, the varus opening during a classic VTTT with the same test starting in an IR pivot, using a new arthrometer.

RESULTS

The classic VTTT caused a 13° tilt after ATFL section and 23,8° after ATFL and CFL section. The application of a VTTT with an IR prepositioning caused a 21,2° tilt after ATFL section (p = 0,002) and 29,5° after ATFL and CFL section (p = 0,006).

CONCLUSION

The VTTT is better to identify lateral ankle ligaments' insufficiency when it's applied with a pre-positioning of the foot in internal rotation. The resulting vector is similar to the supination trauma.

In vivo arthrometer measurements of mechanical ankle instability-A systematic review

Chronic ankle instability is caused by functional and/or mechanical deficits. To differentiate the two entities, mechanical ankle instability can be assessed using arthrometers. The measurement of mechanical instability is essential, since it can only be addressed surgically. The aim of this systematic literature review was to find out whether chronic mechanical ankle instability could be adequately and objectively assessed using in vivo arthrometer measurements. Articles were included if the main focus was to evaluate the contribution of mechanical deficits to chronic ankle instability and if they provided sufficient description of the device used. This systematic review was performed according to the PRISMA-recommendations. Initially 47 articles were screened for eligibility, of which 33 studies reporting 10 different devices were included. While the reliability of the measurements was mostly good to excellent, only two studies aimed to assess the sensitivity and specificity of their results in regard to chronic ankle instability. Several devices reported conflicting results about mechanical deficits. In summary, this systematic review reveals a substantial deficit in diagnostic accuracy when assessing mechanical ankle instability in a clinical setting. Biases in recruiting and classification of participants raise the question whether the two entities of functional and mechanical ankle instability are properly defined. Clinical Significance: In recent years, this may have led to a misinterpretation of mechanical deficits and the subsequent need for surgical intervention. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Rotational Instability after Anterior Talofibular and Calcaneofibular Ligament Section: The Experimental Basis for the Ankle Pivot Test

The clinical diagnosis of the anterior talofibular ligament (ATFL) rupture is based on the findings from the medical history and the anterior drawer test, a maneuver that allegedly pushes the talus and rearfoot anteriorly, although with great variability in its sensitivity. We consider that an ATFL rupture is best evaluated by a rotational vector (i.e., a pivot test) owing to the uncompromised medial ligaments that will block any pure anterior translation of the talus underneath the tibia. We idealized a constrained ankle cadaver model that only allows talar movements in the axial plane. Our hypothesis was that progressive sectioning of the lateral ankle ligaments in this model would cause a progressive and significant angular laxity in internal rotation. Our results showed 3.67 degrees ± 1.2 degrees of talus rotational laxity in the intact ankle, 9.6 degrees ± 3.2 degrees after ATFL sectioning, and 13.43 degrees ± 3.2 degrees after ATFL and calcaneofibular ligament sectioning, indicating almost threefold increase in internal talocrural rotation after single ATFL sectioning and an almost fourfold increase after double (ATFL and calcaneofibular ligament) sectioning. We consider this evidence of rotational ankle laxity to be a major step in defining the correct movement to diagnose an ATFL rupture and propose a new term to avoid further inconsistencies and variability, "the pivot test."

Effect of simulated joint instability and bracing on ankle and subtalar joint flexibility

It is clinically challenging to distinguish between ankle and subtalar joints instability in vivo. Understanding the changes in load-displacement at the ankle and subtalar joints after ligament injuries may detect specific changes in joint characteristics that cannot be detected by investigating changes in range of motion alone. The effect of restricting joints end range of motion with ankle braces was already established, but little is known about the effect of an ankle brace on the flexibility of the injured ankle and subtalar joints. Therefore, the purposes of this study were to (1) understand how flexibility is affected at the ankle and subtalar joints after sectioning lateral and intrinsic ligaments during combined sagittal foot position and inversion and during internal rotation and (2) investigate the effect of a semi-rigid ankle brace on the ankle and subtalar joint flexibility. Kinematics and kinetics were collected from nine cadaver feet during inversion through the range of ankle flexion and during internal rotation. Motion was applied with and without a brace on an intact foot and after sequentially sectioning the calcaneofibular ligament (CFL) and the intrinsic ligaments. Segmental flexibility was defined as the slope of the angle-moment curve for each 1 Nm interval. Early flexibility significantly increased at the ankle and subtalar joint after CFL sectioning during inversion. The semi-rigid ankle brace significantly decreased early flexibility at the subtalar joint during inversion and internal rotation for all ligament conditions and at the ankle joint after all ligaments were cut.

Morphological evaluation of the calcaneofibular ligament in different ankle positions using a three-dimensional MRI sequence

PURPOSE

Evaluating images of the lateral ligament of the ankle is not easy, and evaluation of the calcaneofibular ligament (CFL) in particular is difficult. We prospectively conducted morphological measurements of the CFL in different ankle positions and obtain basic data for use in functional assessment of the CFL, diagnosis of CFL injury, and determination of treatment effects.

METHODS

The subjects were ten healthy volunteers (ten ankles) with a mean age of 27.8 years and no history of ankle disease. Imaging was done using a 3-T magnetic resonance imaging (MRI) machine and fast imaging employing steady-state acquisition cycled phases (FIESTA-C), a three-dimensional (3D) sequence, with the ankle in a neutral position, maximum dorsiflexion, and maximum plantar flexion. 3D images of the CFL, peroneal muscle tendons, fibula, and calcaneus were prepared at a workstation, and morphological measurements of the CFL were made.

RESULTS

In all positions, the CFL showed a gently curving course with the peroneal muscle tendons as a fulcrum. The tortuosity angle was significantly smaller in plantar flexion (30.0° ± 7.4°) than in the neutral position (41.7° ± 8.3°).

CONCLUSIONS

3D MRI sequences showed that, in all positions, the CFL curved due to the influence of the peroneal muscle tendons. With maximum plantar flexion, the CFL tortuosity angle was small, which was thought to have been due to the tension in the CFL.

Evaluation of the Anterior Talofibular Ligament via Stress Sonography in Asymptomatic and Symptomatic Populations

OBJECTIVES

Sonography during externally applied stress has the potential to identify ligamentous instability, but diagnostic parameters for the most commonly sprained ankle ligament, the anterior talofibular ligament (ATFL), have not yet been established. The purpose of this study was to determine normative values of the change in the length of the ATFL in an asymptomatic population during manual stress sonography and to compare these values to those in patients with clinical findings of anterolateral ankle instability.

METHODS

Sonography of the ATFL at rest and with maximally applied manual stress was performed bilaterally in 20 asymptomatic volunteers from each of three 10-year age groups from 20 to 50 years. Data were compared to those for 34 patients retrospectively identified who underwent stress sonography of the ATFL for clinical signs and symptoms of chronic anterolateral ankle instability.

RESULTS

In the asymptomatic population (10 men and 10 women), for men, the mean change in ATFL length between stress and neutral positions was 0.44 mm (95% confidence interval [CI], 0.32-0.57 mm). For women, it was 0.43 mm (95% CI, 0.31-0.55 mm). The difference in laxity between sexes was not significant (P = .85). In the symptomatic population, the mean ATFL length difference between stress and neutral positions was 1.26 mm (95% CI, 0.97-1.55 mm). A t test comparing the mean change in ATFL length showed a statistically significant increase in laxity in the symptomatic group (P < .0001).

CONCLUSIONS

The normal ATFL shows minimal laxity in both men and women on stress sonography, with significantly greater laxity among patients with ankle instability. Given these findings, stress sonography may have an important role in the imaging diagnosis of anterolateral ankle instability.

A new classification of anterior talofibular ligament injuries based on ultrasonography findings

BACKGROUND

Ultrasonography (US) has become a useful tool in the evaluation of thickness and continuity of damaged ligaments owing to the rapid advances in its performance and availability. Furthermore, US examination is economical and can be undertaken in a more timely manner than MRI, as it can be performed during the first patient visit. It is also likely to be more accurate than the traditional method of palpating ligaments to diagnose possible injury. The anterior talofibular ligament (ATFL) is most frequently injured of the lateral ankle ligaments and easy to depict on US. This study aimed to assess the treatment outcomes of lateral ankle ligament injuries using a new classification for ATFL injuries based on US findings.

METHODS

A total of 140 acute lateral ankle ligament injuries in 132 patients (46 men, 86 women) treated non-operatively were evaluated retrospectively. The average age of the patients was 17.8 years (range, 7-57 years). Patients with a complaint of lateral ankle injury were examined using US, and the anterior talofibular ligament damage was classified into 5 types depending on the type of the injury. The treatment method was selected based on the ultrasonographic classification, and the clinical results were assessed by original evaluation and compared between treatment methods and classification types.

RESULTS

A Good or Excellent treatment result was obtained in 133 out of 140 injuries (95.0%). Significant differences were observed in the distribution of treatment methods by injury type (P < 0.001), and the distribution of outcomes was significantly different from the uniform distribution (P < 0.001). Our findings demonstrate that the ultrasonographic classification proposed in this study can be used to determine the appropriate treatment resulting in good outcomes for all types of anterior talofibular ligament damage.

CONCLUSION

Visualization of injured ligaments using US may introduce a novel approach of rating and treating ligament injuries.

Endoscopic reconstruction of CFL and the ATFL with a gracilis graft: a cadaveric study

PURPOSE

The purpose of this study was to evaluate a step-by-step approach to endoscopic reconstruction of the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL).

METHODS

Fourteen lower extremity cadaveric specimens were used. Four standard portals were defined and used. A step-by-step approach using several anatomical landmarks was used to reconstruct the ATFL and CFL. The feasibility of visualising the anatomical landmarks and both ligaments and their footprints was assessed. Both ligaments were reconstructed using a gracilis graft fixed in bone tunnels. The lateral side of the ankle was completely exposed and dissected. The specimen was assessed for clinical stability of the reconstruction and damage to the surrounding anatomical structures. The distance between the centre of the tunnel and the anatomical insertions of the ligaments was measured. The distance between the portals and the nerves was measured.

RESULTS

The step-by-step approach allowed a good visualisation of the entire course of the ATFL and CFL. An endoscopic reconstruction of both ligaments was performed, and good stability was obtained. The measurements revealed a good positioning of the reconstructed ligament insertions with a maximal error of 2 mm in most specimens. Anatomical dissection revealed no damage to the surrounding anatomical structures that were at risk. The average distance to the superficial peroneal nerve was 11.9 ± 5.3 mm (standard deviation), and the average distance to the sural nerve was 17.4 ± 3.2 mm (standard deviation). A safe zone was defined with regard to the surrounding nerves.

CONCLUSION

The described technique, which involves an anatomical endoscopic reconstruction of the ATFL and CFL, using a gracilis graft, is a viable option to treat lateral ankle instability. This technique is reproducible and safe with regard to the surrounding anatomical structures.

Anterolateral Drawer Versus Anterior Drawer Test for Ankle Instability: A Biomechanical Model

BACKGROUND

The addition of unconstrained internal rotation to the physical examination could allow for detection of more subtle degrees of ankle instability. We hypothesized that a simulated anterolateral drawer test allowing unconstrained internal rotation of the ankle would provoke greater displacement of the lateral talus in the mortise versus the anterior drawer test.

METHODS

Ten cadaveric lower extremities were tested in a custom apparatus designed to reproduce the anterior drawer test and the anterolateral drawer test, in which the ankle was allowed to internally rotate about the intact deep deltoid ligament while being subluxed anteriorly. Specimens were tested intact and with anterior tibiofibular ligament sectioned. A differential variable reluctance transducer was used to measure lateral talar displacement with anterior forces of 25 and 50 N.

RESULTS

No significant differences in talar displacement or ankle rotation were noted in intact specimens between the groups. Among sectioned specimens, significantly more talar displacement (25 N [6.5 ± 1.7 mm vs 3.8 ± 2.4 mm] and 50 N [8.7 ± 0.9 mm vs 4.5 ± 2.5 mm], P < .001) and ankle rotation (25 N [13.9 ± 8.0 degrees vs 0.0 ± 0.0 degrees] and 50 N [23.7 ± 5.8 degrees vs 0.0 ± 0.0 degrees], P < .001) were found in the anterolateral drawer versus anterior drawer group.

CONCLUSION

In an ankle instability model, the anterolateral drawer test provoked almost twice the lateral talus displacement found with the anterior drawer test.

CLINICAL RELEVANCE

Allowing internal rotation of the ankle while testing for ankle instability may allow the examiner to detect more subtle degrees of ankle instability.

Preventive lateral ligament tester (PLLT): a novel method to evaluate mechanical properties of lateral ankle joint ligaments in the intact ankle

PURPOSE

To construct and evaluate an ankle arthrometer that registers inversion joint deflection at standardized inversion loads and that, moreover, allows conclusions about the mechanical strain of intact ankle joint ligaments at these loads.

METHODS

Twelve healthy ankles and 12 lower limb cadaver specimens were tested in a self-developed measuring device monitoring passive ankle inversion movement (Inv-ROM) at standardized application of inversion loads of 5, 10 and 15 N. To adjust in vivo and in vitro conditions, the muscular inactivity of the evertor muscles was assured by EMG in vivo. Preliminary, test-retest and trial-to-trial reliabilities were tested in vivo. To detect lateral ligament strain, the cadaveric calcaneofibular ligament was instrumented with a buckle transducer. After post-test harvesting of the ligament with its bony attachments, previously obtained resistance strain gauge results were then transferred to tensile loads, mounting the specimens with their buckle transducers into a hydraulic material testing machine.

RESULTS

ICC reliability considering the Inv-ROM and torsional stiffness varied between 0.80 and 0.90. Inv-ROM ranged from 15.3° (±7.3°) at 5 N to 28.3° (±7.6) at 15 N. The different tests revealed a CFL tensile load of 31.9 (±14.0) N at 5 N, 51.0 (±15.8) at 10 N and 75.4 (±21.3) N at 15 N inversion load.

CONCLUSIONS

A highly reliable arthrometer was constructed allowing not only the accurate detection of passive joint deflections at standardized inversion loads but also reveals some objective conclusions of the intact CFL properties in correlation with the individual inversion deflections. The detection of individual joint deflections at predefined loads in correlation with the knowledge of tensile ligament loads in the future could enable more individual preventive measures, e.g., in high-level athletes.

Individuals with both perceived ankle instability and mechanical laxity demonstrate dynamic postural stability deficits

BACKGROUND

Chronic ankle instability is a frequent and serious consequence of lateral ankle sprains. The contribution of perceived instability and potential for mechanical laxity to contribute to the overall deficit in dynamic postural stability is unclear. The purpose was to determine if those with mechanical laxity demonstrated significant differences in dynamic postural stability compared to controls, copers and those with perceived instability.

METHODS

Of 93 participants, 83 recreationally active individuals were divided into 4 groups: controls, copers, those with perceived instability, and those with both perceived instability and mechanical laxity. Injury history and the Cumberland Ankle Instability Tool were collected, and an instrumented arthrometer was applied. Participants completed a single limb jump landing, balancing upon completion. Ground reaction force data were collected, scaled to body mass, and the Dynamic Postural Stability Indices were calculated for anterior-posterior, medial-lateral, vertical and composite. One-way ANOVAs with Tukey post-hoc tests (α<0.05) were conducted on each of the stability indices among the four groups.

FINDINGS

The mechanically lax group had significantly greater mean (standard deviation) medial-lateral stability index scores 0.57 (0.62) than the coper group 0.24 (0.20; P=0.02) and significantly greater composite index scores 0.73 (0.57) than the perceived instability 0.49 (0.09) and coper groups 0.47 (0.12 P=0.05). No other indices were significantly different among groups.

INTERPRETATION

Individuals with perceived instability and mechanical laxity exhibited dynamic postural deficits compared to copers and those with perceived instability alone. Mechanical laxity may contribute to the deficits in dynamic postural stability.

In Vivo Talocrural Joint Contact Mechanics With Functional Ankle Instability

BACKGROUND

Functional ankle instability (FAI) may involve abnormal kinematics and contact mechanics during ankle internal rotation. Understanding of these abnormalities is important to prevent secondary problems in patients with FAI. However, there are no in vivo studies that have investigated talocrural joint contact mechanics during weightbearing ankle internal rotation. The objective of this study to determine talocrural contact mechanics during weightbearing ankle internal rotation in patients with FAI.

METHODS

Twelve male subjects with unilateral FAI (age range, 18-26 years) were enrolled. Computed tomography and fluoroscopic imaging of both lower extremities were obtained during weightbearing passive ankle joint complex rotation. Three-dimensional bone models created from the computed tomographic images were matched to the fluoroscopic images to compute 6 degrees of freedom for talocrural joint kinematics. The closest contact area in the talocrural joint in ankle neutral rotation and maximum internal rotation during either dorsiflexion or plantar flexion was determined using geometric bone models and talocrural joint kinematics data.

RESULTS

The closest contact area in the talus shifted anteromedially during ankle dorsiflexion-internal rotation, whereas it shifted posteromedially during ankle plantar flexion-internal rotation. The closest contact area in FAI joints was significantly more medial than that in healthy joints during maximum ankle internal rotation and was associated with excessive talocrural internal rotation or inversion.

DISCUSSION

This study demonstrated abnormal talocrural kinematics and contact mechanics in FAI subjects. Such abnormal kinematics may contribute to abnormal contact mechanics and may increase cartilage stress in FAI joints.

LEVEL OF EVIDENCE

Therapeutic, Level IV: cross-sectional case-control study.

A Three-Dimensional Ankle Kinetostatic Model to Simulate Loaded and Unloaded Joint Motion

A kinetostatic model able to replicate both the natural unloaded motion of the tibiotalar (or ankle) joint and the joint behavior under external loads is presented. The model is developed as the second step of a sequential procedure, which allows the definition of a kinetostatic model as a generalization of a kinematic model of the joint defined at the first step. Specifically, this kinematic model taken as the starting point of the definition procedure is a parallel spatial mechanism which replicates the ankle unloaded motion. It features two rigid bodies (representing the tibia–fibula and the talus–calcaneus complexes) interconnected by five rigid binary links, that mimic three articular contacts and two nearly isometric fibers (IFs) of the tibiocalcaneal ligament (TiCaL) and calcaneofibular ligament (CaFiL). In the kinetostatic model, the five links are considered as compliant; moreover, further elastic structures are added to represent all the main ankle passive structures of the joint. Thanks to this definition procedure, the kinetostatic model still replicates the ankle unloaded motion with the same accuracy as the kinematic model. In addition, the model can replicate the behavior of the joint when external loads are applied. Finally, the structures that guide these motions are consistent with the anatomical evidence. The parameters of the model are identified for two specimens from both subject-specific and published data. Loads are then applied to the model in order to simulate two common clinical tests. The model-predicted ankle motion shows good agreement with results from the literature.

Lateral Ankle Sprain and Chronic Ankle Instability: A Critical Review

Many studies investigated the contributing factors of chronic ankle instability, but a consensus has not yet been obtained. The objective of this critical review is to provide recent scientific evidence on chronic ankle instability, including the epidemiology and pathology of lateral ankle sprain as well as the causative factors of chronic ankle instability. We searched MEDLINE from 1964 to December 2013 using the terms ankle, sprain, ligament, injury, chronic, functional, mechanical, and instability. Lateral ankle sprain shows a very high recurrence rate and causes considerable economic loss due to medical care, prevention, and secondary disability. During the acute phase, patients with ankle sprain demonstrate symptoms such as pain, range of motion deficit, postural control deficit, and muscle weakness, and these symptoms may persist, leading to chronic ankle instability. Although some agreement regarding the effects of chronic ankle instability with deficits in postural control and/or concentric eversion strength exists, the cause of chronic ankle instability remains controversial.

LEVELS OF EVIDENCE

Therapeutic Level IV: Review of Level IV studies.

Joint stability characteristics of the ankle complex after lateral ligamentous injury, part I: a laboratory comparison using arthrometric measurement

CONTEXT

The mechanical property of stiffness may be important to investigating how lateral ankle ligament injury affects the behavior of the viscoelastic properties of the ankle complex. A better understanding of injury effects on tissue elastic characteristics in relation to joint laxity could be obtained from cadaveric study.

OBJECTIVE

To biomechanically determine the laxity and stiffness characteristics of the cadaver ankle complex before and after simulated injury to the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) during anterior drawer and inversion loading.

DESIGN

Cross-sectional study.

SETTING

University research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Seven fresh-frozen cadaver ankle specimens.

INTERVENTION(S)

All ankles underwent loading before and after simulated lateral ankle injury using an ankle arthrometer.

MAIN OUTCOME MEASURE(S)

The dependent variables were anterior displacement, anterior end-range stiffness, inversion rotation, and inversion end-range stiffness.

RESULTS

Isolated ATFL and combined ATFL and CFL sectioning resulted in increased anterior displacement but not end-range stiffness when compared with the intact ankle. With inversion loading, combined ATFL and CFL sectioning resulted in increased range of motion and decreased end-range stiffness when compared with the intact and ATFL-sectioned ankles.

CONCLUSIONS

The absence of change in anterior end-range stiffness between the intact and ligament-deficient ankles indicated bony and other soft tissues functioned to maintain stiffness after pathologic joint displacement, whereas inversion loading of the CFL-deficient ankle after pathologic joint displacement indicated the ankle complex was less stiff when supported only by the secondary joint structures.

Narrowing the normal range for lateral ankle ligament stability with stress radiography

Stress radiographs are commonly performed to evaluate lateral ankle ligament stability; however, little agreement exists on the physiologic limits obtained from the anterior drawer and talar tilt stress tests. Published studies have reported the normal range for the anterior drawer test to be 3 to 10 mm and the normal range for the talar tilt test to be 0° to 23° for the uninjured ankle, leading to inconsistent interpretation. The primary objective of the present study was to narrow the threshold for the diagnosis of ankle ligament injury using stress radiographs by refining the values seen in the normal ankle. An improved understanding of normal ankle motion could allow for a more accurate determination of ligament injury using stress imaging. Conducted in a simplified, yet reproducible, manner, we hoped the present study would draw a parallel with generalized use in an office setting and would allow physicians the ability to more effectively diagnose ankle ligament injury. Bilateral radiographic images of anterior drawer and talar tilt stress tests were taken of 50 participants (100 ankles) with no history of ankle fracture or surgical intervention for ankle instability. Participants with a previous ankle sprain were later excluded from the result computations. Factors such as patient age and gender were evaluated. In the final analysis, 46 participants (76 ankles) were included, with a mean anterior drawer test result of 2.00 mm ± 1.71 mm and talar tilt test result of 3.39° ± 2.70° in the normal ankle. The results of the present study suggest that stress radiographs for lateral ankle stability can be performed in a simple and reliable manner. These results also support a much lower threshold for the diagnosis of lateral ankle injury than previously reported.

Biomechanics of the natural, arthritic, and replaced human ankle joint

The human ankle joint complex plays a fundamental role in gait and other activities of daily living. At the same time, it is a very complicated anatomical system but the large literature of experimental and modelling studies has not fully described the coupled joint motion, position and orientation of the joint axis of rotation, stress and strain in the ligaments and their role in guiding and stabilizing joint motion, conformity and congruence of the articular surfaces, patterns of contact at the articular surfaces, patterns of rolling and sliding at the joint surfaces, and muscle lever arm lengths.

The present review article addresses these issues as described in the literature, reporting the most recent relevant findings.

Arthroscopic treatment of ankle anterior bony impingement: the long-term clinical outcome

BACKGROUND

Arthroscopic treatment of anterior ankle bony impingement provides good results, with a tendency to decrease over time. The purpose of this study was to analyze the factors affecting long-term results.

METHODS

Eighty consecutive patients with a mean age of 37.3 years were treated between 2000 and 2004. Impingement lesions were identified according to Scranton-McDermott classification. Preoperative ankle osteoarthritis was documented by van Dijk scale upon the x-rays. Bone spurs were analyzed and classified according to location and size. The associated chondral lesions were classified following the International Cartilage Repair Society (ICRS) criteria. Patient data, foot morphology, and previous traumas were recorded. Patients were evaluated after a mean of 104.6 months follow-up with the American Orthopaedic Foot and Ankle Society (AOFAS) scale. The influence of different factors on outcomes was statistically analyzed.

RESULTS

The mean preoperative AOFAS score was 50.9, while at follow-up it was 70.7 (P < .05). The different grades of Scranton-McDermott impingement classification did not affect the results, but the different grades of van Dijk scale significantly affected the result but not the preoperative stage. Tibial localized spurs had better outcome at follow-up. The grade of the chondral lesions significantly affected the outcome. Other factors negatively affecting the results were age, cavus foot morphology, and history of previous ankle fracture.

CONCLUSION

Arthroscopic treatment provides overall good results, but the long-term presence of associated conditions such as chondral lesions, advanced age, and previous trauma are relevant as prognostic factors. Based on these results, a new classification for bony impingement syndrome system is proposed.

LEVEL OF EVIDENCE

Level IV, case series.

In vivo kinematics of the talocrural and subtalar joints during weightbearing ankle rotation in chronic ankle instability

BACKGROUND

Chronic ankle instability (CAI) results in abnormal ankle kinematics, but there exists limited quantitative data characterizing these alterations. This study was undertaken to investigate kinematic alterations of the talocrural and subtalar joints in CAI.

METHODS

A total of 14 male patients with unilateral CAI (mean age = 21.1 ± 2.5 years) were enrolled. Computed tomography and fluoroscopic imaging of both lower extremities during weightbearing passive ankle joint complex (AJC) rotation were obtained. Three-dimensional bone models created from the computed tomography images were matched with the fluoroscopic images to compute the 6 degrees-of-freedom talocrural, subtalar, and AJC kinematics.

RESULTS

In 20° plantarflexion, ankles with CAI demonstrated significantly increased anterior translation of the talocrural joint during AJC internal rotation from 5° to 7° and significantly decreased talocrural internal rotation within an AJC arc of motion from -1° to 5°. CAI joints demonstrated significantly increased internal rotation of the subtalar joint within an AJC arc of motion from -1° to 3°.

DISCUSSION

In CAI, altered subtalar internal rotation occurs with increased talocrural anterior translation and reduced talocrural internal rotation during weightbearing ankle internal rotation in plantarflexion. These results suggest that altered subtalar mechanics may contribute to CAI symptoms.

Increased frequency of ankle sprain does not lead to an increase in ligament laxity

OBJECTIVE

Ankle sprains are the most common injury in the active population. With high reinjury rates and complaints of the ankle "giving way," it has been suggested that laxity of ankle ligaments increases with repeated sprains. The objective of this study was to determine if a relationship exists between ligament laxity and the number of ankle sprains.

DESIGN

Cross-sectional study.

SETTING

Biomechanics laboratory.

PARTICIPANTS

A total of 203 Division I collegiate athletes (84 women; 119 men; age, 18.5 ± 1.1 years; height, 178.5 ± 10.8 cm; mass, 79.8 ± 18.7 kg) participated in the study.

INTERVENTION

Each participant reported the number of previous sprains on each ankle. Ligament laxity was measured using an instrumented ankle arthrometer.

MAIN OUTCOME MEASURES

Measurements for anterior displacement (AD), inversion (IV), and eversion (EV) rotation of the ankle were obtained using an instrumented ankle arthrometer.

RESULTS

There was no relationship between ligament laxity and the number of ankle sprains in either direction (AD, P = 0.86; IV, P = 0.64; EV, P = 0.81). In addition, comparing ligament laxity between previously sprained ankles and ankles that have never been sprained resulted in no differences in the direction of movement (AD, P = 0.98; IV, P = 0.96; EV, P = 0.67).

CONCLUSIONS

Despite anecdotal evidence suggesting repeated ankle sprains increase ligament laxity, this report involving a large data set and a reliable measurement analysis found no relationship between the two. The results of this study make it necessary to rethink the causes of ligament laxity. Therefore, further research is necessary to understand the causes of "giving way" of the ankle and their role in repeated ankle sprains.

Quantitative evaluation of the viscoelastic properties of the ankle joint complex in patients suffering from ankle sprain by the anterior drawer test

PURPOSE

Biological tissues such as ligaments exhibit viscoelastic behaviours. Injury to the ligament may induce changes of these viscoelastic properties, and these changes could serve as biomarkers to detect the injury. In the present study, a novel instrument was developed to non-invasive quantify the viscoelastic properties of the ankle in vivo by the anterior drawer test. The purpose of the study was to investigate the reliability of the instrument and to compare the viscoelastic properties of the ankle between patients suffering from ankle sprain and controls.

METHODS

Eight patients and eight controls participated in the present study. The reliability test was performed on three randomly chosen subjects. In patient and control test, both ankles of each subject were tested to evaluate the viscoelastic properties of the ankle. The viscosity index was defined for quantitatively evaluating the viscosity of the ankle. Greater viscosity index was associated with lower viscosity. Injured and uninjured ankles of patient and both ankles of controls were compared.

RESULTS

The instrument exhibited excellent test-retest reliability (r > 0.9). Injured ankles exhibited significantly less viscosity than uninjured ankles, since injured ankles of patients had significantly higher viscosity index (8,148 ± 5,266) compared with uninjured ankles of patients (948 ± 617; p = 0.008) and controls (1,326 ± 613; p < 0.001).

CONCLUSIONS

The study revealed that the viscoelastic properties of the ankle can serve as sensitive and useful clinical biomarkers to differentiate between injured and uninjured ankles. The method may provide a clinical examination for objectively evaluating lateral ankle ligament injuries.

In vivo kinematics of the talocrural and subtalar joints with functional ankle instability during weight-bearing ankle internal rotation: a pilot study

Functional ankle instability (FAI) may involve abnormal kinematics. However, reliable quantitative data for kinematics of FAI have not been reported. The objective of this study was to determine if the abnormal kinematics exist in the talocrural and subtalar joints in patients with FAI. Five male subjects with unilateral FAI (a mean age of 33.4 ± 13.2 years) were enrolled. All subjects were examined with stress radiography and found to have no mechanical ankle instability (MAI). Lateral radiography at weight-bearing ankle internal rotation of 0° and 20° was taken with the ankle at 30° dorsiflexion and 30° plantar flexion. Patients underwent computed tomography scan at 1.0 mm slice pitch spanning distal one third of the lower leg and the distal end of the calcaneus. Three-dimensional (3D) kinematics of the talocrural and subtalar joints as well as the ankle joint complex (AJC) were determined using a 3D-to-2D registration technique using a 3D-to-2D registration technique with 3D bone models and plain radiography. FAI joints in ankle dorsiflexion demonstrated significantly greater subtalar internal rotation from 0° to 20° internal rotation. No statistical differences in plantar flexion were detected in talocrural, subtalar or ankle joint complex kinematics between the FAI and contralateral healthy joints. During ankle internal rotation in dorsiflexion, FAI joints demonstrated greater subtalar internal rotation. The FAI joints without mechanical instability presented abnormal kinematics. This suggests that abnormal kinematics of the FAI joints may contribute to chronic instability. FAI joints may involve unrecognized abnormal subtalar kinematics during internal rotation in ankle dorsiflexion which may contribute to chronic instability and frequent feelings of instability.

Examining the diagnostic accuracy of dynamic postural stability measures in differentiating among ankle instability status

BACKGROUND

Dynamic postural stability is defined as the ability to transition from a dynamic movement to a stable condition over one's base of support. Measures of dynamic stability have been used extensively to classify ankle instability status and assist clinicians with ankle injury interventions. Therefore, the purpose of this study was to determine if current methods of quantifying dynamic stability are accurate in differentiating among healthy, coper, and unstable ankles.

METHODS

One hundred ninety four Division-I collegiate athletes (football, volleyball, field hockey, men's/women's soccer, men's/women's lacrosse, men's/women's basketball) volunteered for this study. Participants were categorized into healthy, coper, and stable groups by a self-reported questionnaire and previous history of ankle injuries. Dynamic postural stability was assessed using the Multi-Directional Dynamic Stability Protocol by jumping and landing single-legged onto a force platform from four different directions. Receiver operator curves were used to analyze the accuracy of current techniques of calculating dynamic stability among groups.

FINDINGS

None of the existing methods were found to be accurate in differentiating ankle instability status in any of the jump landings.

INTERPRETATION

Researchers have commonly used these existing methods to quantify dynamic postural stability. None of the current calculation techniques worked with our jump landing protocol. Researchers need to pay attention to the protocol and calculation technique pairings in that using inaccurate measures of dynamic postural stability makes any findings of that research ineffective. Therefore, this challenges researchers to develop a more accurate calculation to quantify dynamic postural stability, or develop a jump landing protocol that exposes sensorimotor deficits in the more able-bodied population.

Biomechanical evaluation of tenodesis reconstruction in ankle with deltoid ligament deficiency: a finite element analysis

PURPOSE

Isolated deltoid ligament injuries are relatively uncommon but can be a significant source of pain and disability. Several approaches to deltoid reconstruction have been reported. However, there is no previous comparative study of Wiltberger, Deland, Kitaoka and Hintermann procedures with respect to biomechanical characteristics such as kinematics, ligaments and grafts stresses using finite element analysis. The purpose of this study was to evaluate the biomechanical results of those deltoid ligament reconstructions using finite element analysis.

METHODS

A three-dimensional finite element model of the ankle including six bony structures, cartilage and nine principal ligaments surrounding the ankle joint complex was developed and validated. In addition to the intact model, superficial deltoid-deficient, deltoid-deficient, Wiltberger reconstruction, Deland reconstruction, Kitaoka reconstruction and Hintermann reconstruction models were simulated. Then, the forces in the ligaments and grafts and the kinematics of talus and calcaneus were predicted for an eversional or external torque through the range of ankle flexion.

RESULTS

No reconstructions could completely restore the values for ankle flexibility and the stresses of the lateral ligaments to normality. The Kitaoka procedure was the most effective technique in eliminating external rotation displacement. The Deland procedure restored better the talar tilt than the other three reconstructions.

CONCLUSION

This study showed that Kitaoka and Deland procedures have advantages with regard to rotational stabilities as well as ligaments stress in comparison with other methods.

The role of ankle ligaments and articular geometry in stabilizing the ankle

BACKGROUND

Ankle joint stability is a function of multiple factors, but it is unclear to what extent extrinsic factors such as ligaments and intrinsic elements such as geometry of the articular surfaces play a role. The purposes of this study were to determine the contribution of the ligaments and the articular geometry to ankle stability and to determine the effects of ankle position and simulated physiological loading upon ankle stability.

METHODS

Sixteen cadaveric lower extremities were studied in unloaded and with axial load equivalent to body weight. Anterior-posterior, medial-lateral translation and internal-external rotation tests were performed in neutral, dorsiflexion and plantarflexion ankle positions. Intact ankle stability was measured; ankle ligaments were serially sectioned and retested.

FINDINGS

For unloaded condition, the lateral ligament accounted for 70% to 80% of anterior stability and the deltoid ligaments for 50% to 80% of posterior stability. Both ligaments contributed 50% to 80% to rotational stability; however, the ligaments did not provide the primary restraints to medial-lateral stability. For loaded ankle condition, articular geometry contributed 100% to translational and 60% to rotational stability. The ankle was less stable in plantarflexion and more stable in dorsiflexion.

INTERPRETATION

The contribution of extrinsic and intrinsic elements to ankle stability is dependent upon the load and direction of force applied. This study underscores the importance of restoring soft tissues about the ankle to the anatomic condition during reconstruction operations for instability, trauma and arthritis.

Influence of kinematic analysis methods on detecting ankle and subtalar joint instability

Patients with subtalar joint instability may be misdiagnosed with ankle instability, which may lead to chronic instability at the subtalar joint. Therefore, it is important to understand the difference in kinematics after ligament sectioning and differentiate the changes in kinematics between ankle and subtalar instability. Three methods may be used to determine the joint kinematics; the Euler angles, the Joint Coordinate System (JCS) and the helical axis (HA). The purpose of this study was to investigate the influence of using either method to detect subtalar and ankle joints instability. 3D kinematics at the ankle and subtalar joint were analyzed on 8 cadaveric specimens while the foot was intact and after sequentially sectioning the anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), the cervical ligament and the interosseous talocalcaneal ligament (ITCL). Comparison in kinematics calculated from sensor and anatomical landmarks was conducted as well as the influence of Euler angles and JCS rotation sequence (between ISB recommendation and previous research) on the subtalar joint. All data showed a significant increase in inversion when the ITCL was sectioned. There were differences in the data calculated using sensors coordinate systems vs. anatomic coordinate systems. Anatomic coordinate systems were recommended for these calculations. The Euler angle and JCS gave similar results. Differences in Euler angles and JCS sequence lead to the same conclusion in detecting instability at the ankle and subtalar joint. As expected, the HA detected instability in plantarflexion at the ankle joint and in inversion at the subtalar joint.

Analysis of ankle-hindfoot stability in patients with ankle instability and normals

PURPOSE

We devised a testing apparatus for in vivo analysis of ankle stability. The purpose of the study was to test the reliability of this apparatus and to determine the stability pattern of the ankle-hindfoot complex in healthy, asymptomatic volunteers and in patients with ankle instability.

METHODS

Ten healthy individuals were studied, and testing was repeated on the same day and different days. Three patients with symptomatic, unstable ankles were also tested on both involved and uninvolved sides. Constant inversion torque was applied, then internal rotation torque, while moving the ankle throughout the range of sagittal motion. Three-dimensional kinematics of the ankle-hindfoot complex were measured by an electromagnetic tracking system.

RESULTS

Measurements were repeatable, with intraclass correlation coefficients 0.9 or better. Variability was observed among controls, but motion curve patterns were consistent. Motion curve slopes were sensitive in differentiating between unstable and stable ankles.

CONCLUSIONS

Most previous reports are in vitro studies conducted with the ankle in one position, manual stress applied, or joint positions estimated with planar radiographs. Our study indicated that more accurate diagnosis of severity of ankle ligament injuries may be possible.

Mechanical stability of the subtalar joint after lateral ligament sectioning and ankle brace application: a biomechanical experimental study

BACKGROUND

The roles of each ligament supporting the subtalar joint have not been clarified despite several biomechanical studies. The effects of ankle braces on subtalar instability have not been shown.

HYPOTHESIS

The ankle brace has a partial effect on restricting excessive motion of the subtalar joint.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten normal fresh-frozen cadaveric specimens were used. The angular motions of the talus were measured via a magnetic tracking system. The specimens were tested while inversion and eversion forces, as well as internal and external rotation torques, were applied. The calcaneofibular ligament, cervical ligament, and interosseous talocalcaneal ligament were sectioned sequentially, and the roles of each ligament, as well as the stabilizing effects of the ankle brace, were examined.

RESULTS

Complete sectioning of the ligaments increased the angle between the talus and calcaneus in the frontal plane to 51.7 degrees + or - 11.8 degrees compared with 35.7 degrees + or - 6.0 degrees in the intact state when inversion force was applied. There was a statistically significant difference in the angles between complete sectioning of the ligaments and after application of the brace (34.1 degrees + or - 7.3 degrees ) when inversion force was applied. On the other hand, significant differences in subtalar rotation were not found between complete sectioning of the ligaments and application of the brace when internal and external rotational torques were applied.

CONCLUSION

The ankle brace limited inversion of the subtalar joint, but it did not restrict motion after application of internal or external rotational torques.

CLINICAL RELEVANCE

In cases of severe ankle sprains involving the calcaneofibular ligament, cervical ligament, and interosseous talocalcaneal ligament injuries, application of an ankle brace might be less effective in limiting internal-external rotational instabilities than in cases of inversion instabilities in the subtalar joint. An improvement in the design of the brace is needed to restore better rotational stability in the subtalar joint.

Analysis of joint laxity after total ankle arthroplasty: cadaver study

BACKGROUND

Clinical results of total ankle arthroplasty with early designs were disappointing. Recently-developed ankle prostheses have good mid-term results; however, limited information is available regarding effects of total ankle arthroplasty on ankle laxity.

METHODS

Eight cadaveric lower extremities were tested with a custom device which enabled measurement of multi-axial forces, moments, and displacement during applied axial, shear, and rotational loading. Tests consisted of anterior-posterior and medial-lateral translation and internal-external rotation of the talus relative to the tibia during axial loads on the tibia simulating body weight (700 N) and an unloaded condition (5 N). Tests were performed in neutral, dorsiflexion, and plantarflexion. Laxity was determined for the intact ankle, and following insertion of an unconstrained total ankle implant, comparing load-displacement curve.

FINDINGS

Laxity after total ankle arthroplasty did not approximate the normal ankle in most conditions tested. Displacement was significantly greater for total ankle arthroplasty in both posterior and lateral translation, and internal rotation, with 5 N axial loading, and anterior-posterior, medial-lateral translation, and internal-external rotation for 700 N axial loading. For the 700 N axial load condition, in the neutral ankle position, total anterior-posterior translation averaged 0.4 mm (SD 0.2 mm), but 6.0 mm (SD 1.5 mm) after total ankle arthroplasty (P<0.01). This study demonstrated more laxity in the replaced ankle than normal ankle for both unloaded and 700 N axially loaded conditions.

INTERPRETATION

These data indicate the increased responsibility of the ligaments for ankle laxity after total ankle arthroplasty and suggest the importance of meticulous ligament reconstruction with total ankle arthroplasty operations.