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

Construction and validation of a nomogram model for predicting different sites of ankle pain in runners with chronic ankle instability

This study aimed to establish a risk prediction nomogram model for anterolateral, mediolateral, and posterolateral ankle pain in runners with chronic ankle instability (CAI) and analyse the potential risk factors for pain at different ankle sites. Thirty recreational runners with CAI who reported ankle pain in the anterolateral, mediolateral, or posterolateral regions were recruited for this study. Kinematic, kinetic, and electromyographic data during running were collected using motion capture system, 3-D force platform, and surface electromyography system. These data were used to generate a dynamic nomogram. The results showed that anterolateral ankle pain in runners with CAI may be caused by insufficient gastrocnemius muscle strength (OR 0.85, 95% CI 0.73-0.97), excessive ground reaction force (GRF, OR 2.64, 95% CI 1.25-6.22), and an increased percentage of ankle energy absorption (OR 9.11, 95% CI 1.50-77.79). Mediolateral ankle pain might be contributed by greater ankle inversion angle (OR 1.08, 95% CI 1.01-1.00) and GRF (OR 2.13, 95% CI 1.17-4.31). Moreover, posterolateral ankle pain was predicted by increased ankle adduction angle (OR 1.06, 95% CI 1.00-1.12), increased GRF (OR 2.16, 95% CI 1.07-4.80), and decreased dynamic stability (OR 0.20, 95% CI 0.05-0.68). To prevent ankle pain, runners with CAI should be encouraged to focus on improving the neuroreceptor sensitivity of the gastrocnemius muscles, and retraining their energy absorption patterns.

Single-legged landing behavior of high school basketball players with chronic ankle instability

OBJECTIVES

Anterior cruciate ligament injury is one of the most serious ligamentous injuries. The purpose is to compare the impact of the ankle joint on the knee during landing between athletes with chronic instability and a control group (coper group) and to verify the effects of the kinetic chain from other joints.

DESIGN

Prospective study.

SETTING

High school basketball.

PARTICIPANTS

Participants were 62 female high school basketball players who had participated in team sports for >6 months.

MAIN OUTCOME MEASURES

Player joint angles, movements, and moments.

RESULTS

The knee valgus moment was significantly higher in the chronic ankle instability group than in the coper group (20%-60% [p < 0.01]; 80%-100% [p < 0.05]) during landing motion. The knee valgus moment was also significantly higher during the change from the maximum knee joint flexion position to the maximum extension (p < 0.05). In addition, the landing motions of the chronic instability group may have utilized suboptimal compensatory motor strategy on the sagittal plane, depending heavily on the knee joint's abduction moment.

CONCLUSIONS

Our findings indicate that the chronic ankle instability group uses a different landing strategy pattern than the coper group by changing the joint moment and joint angle during landing, which may increase the risk of anterior cruciate ligament injury.

Evaluation of Open Versus Arthroscopic Anterior Talofibular Ligament Reconstruction for Chronic Lateral Ankle Instability With Talar and Subtalar Cartilage MRI T2 Mapping: A 3-Year Prospective Study

BACKGROUND

Previous studies have examined patients with chronic lateral ankle instability (CLAI) undergoing open and arthroscopic anterior talofibular ligament (ATFL) reconstruction, reporting equivalent clinical results between the 2 procedures. However, data on the magnetic resonance imaging (MRI) outcomes on cartilage health after the 2 procedures are limited.

PURPOSE

To compare the cartilage MRI T2 values of the talar and subtalar joints between patients with CLAI undergoing open and arthroscopic ATFL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A prospective study was conducted on patients who underwent open or arthroscopic ATFL reconstruction between January 2018 and December 2019, with a mean follow-up duration of 3 years. MRI scans and American Orthopaedic Foot & Ankle Society (AOFAS) and Tegner score estimations were completed by patients ≤1 week before surgery, as a baseline measurement, and at a 3-year follow-up. A total of 21 healthy volunteers were included who underwent MRI at baseline. Cartilage health was evaluated using MRI T2 mapping. The talar and subtalar cartilage regions were segmented into 14 subregions.

RESULTS

At baseline, patients with CLAI had substantially higher T2 values in the medial anterior, medial center, medial posterior, and lateral center regions on the talus compared with the healthy controls (P = .009, .003, .001, and .025, respectively). Remarkable increases in T2 values in the lateral posterior region on the talus were observed from baseline to follow-up in the open group (P = .007). Furthermore, T2 values were considerably higher in the medial center, medial posterior, lateral posterior, and lateral posterior calcaneal facets of the posterior subtalar joint at follow-up in the arthroscopic group compared with the baseline values (P = .025, .002, .006, and .044, respectively). No obvious differences in ΔT2 values were noted between the 2 groups at follow-up. The AOFAS and Tegner scores remarkably improved from baseline to follow-up for the 2 groups (open: 3.25 ± 0.58 vs 5.13 ± 0.81, P < .001; arthroscopic: 3.11 ± 0.90 vs 5.11 ± 1.08, P < .001), with no considerable difference between them.

CONCLUSION

The elevated T2 values of cartilage could not be fully recovered after open or arthroscopic ATFL reconstruction. Both arthroscopic and open ATFL reconstruction displayed similar effects on cartilage health concerning ΔT2, but the arthroscopic group demonstrated more degenerative cartilage subregions than the open group.

The morphology of osseous structure in subtalar joint with chronic ankle instability

BACKGROUND

Osseous structures have been demonstrated as risk factors for chronic ankle instability (CAI). Previously, the researchers only focused on the osseous structures of ankle, but ignored the osseous structures of subtalar joint(STJ). Accordingly, the aim of our study was to investigate the morphological characteristics of STJ osseous structures in CAI.

METHODS

52 patients with CAI and 52 sex- and age- matched control subjects were enrolled from The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University. The lateral radiographs of ankle in weight-bearing were used to compare the diversity of the two groups. Specifically, The Length of calcaneus, Calcaneal facet height and Absolute foot height, Böhler's angle, Gissane's angle, Calcaneal inclination angle, Talocalcaneal angle, Tibiotalar angle, Tibiocalcaneal angle, Talar-horizontal angle, talar declination angle, facet inclination angle were gauged in the two groups.

RESULTS

The Böhler's angle, Calcaneal inclination, Talocalcaneal angle, Tibiotalar angle, Talar-horizontal angle, Talar declination angle, Facet inclination angle and Absolute foot height of CAI group were significantly higher than normal control group (P < 0.05). There were no significant differences in Gissane's angle, Tibiocalcaneal angle, Length of calcaneus and Calcaneal facet height between patients with CAI and normal controls (P > 0.05).

CONCLUSIONS

The osseous structures of STJ in CAI patients are different from normal people in morphology. Therefore, we should pay more attention to the changes of STJ anatomical parameters in the diagnosis and prevention of CAI.

LEVEL OF EVIDENCE

Ⅲ.

Characteristics of the static muscle stiffness of ankle plantar flexors in individuals with chronic ankle instability

PURPOSE

Individuals with chronic ankle instability (CAI) have deficits in closed kinetic chain dorsiflexion that may perpetuate injury. Determining the characteristics of muscle stiffness in the plantar flexors of individuals with CAI may help in developing appropriate treatments. We aimed to highlight the characteristics of static muscle stiffness in ankle plantar flexor muscles during the passive dorsiflexion of the ankle joint in individuals with CAI.

METHODS

A total of 30 patients were included in the study based on the International Ankle Consortium criteria. The patients were categorized evenly into healthy, coper, and CAI groups (i.e., 10 patients in each group). After measuring the dorsiflexion range of motion (non-weight-bearing/weight-bearing) of the ankle joint, the static muscle stiffness measurements of the medial gastrocnemius, lateral gastrocnemius, soleus, and peroneus longus were obtained. The measurements were performed during the knee joint's extension and 50° flexion and passive dorsiflexion between the range of 40° plantar flexion and 20° dorsiflexion.

RESULTS

The dorsiflexion range of motion of the CAI group was significantly smaller than that of the healthy and coper groups in the weight-bearing position. No interaction was observed for muscle stiffness in both the knee flexion and extension positions, and no significant differences were identified among the three groups. The shear modulus of the soleus at 20° ankle dorsiflexion with knee flexion had a significant negative correlation with the weight-bearing range of motion of the ankle.

CONCLUSION

The limitation in the weight-bearing dorsiflexion range of motion in CAI was largely due to factors other than the increased elasticity of the ankle plantar flexor muscles.

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.

Concomitant osteochondral lesions of the talus affect the stair descent biomechanics of patients with chronic ankle instability: A pilot study

BACKGROUND

Previous studies on the kinematics of patients with chronic ankle instability (CAI) that did not incorporate MRI and arthroscopic assessment could not differentiate between patients with CAI without osteochondral lesion of the talus (OLT) and patients with CAI and OLT and have thus presented contradictory results.

RESEARCH QUESTION

This study aimed to investigate the kinematic and electromyographic differences between patients with and without OLT.

METHODS

Sixteen subjects with CAI (eight without OLT and eight with OLT confirmed through MRI and arthroscopic assessment) and eight healthy subjects underwent gait analysis in a stair descent setting. The three groups' patient-reported outcomes; ankle joint range of motion in flexion, inversion and rotation; and muscle activation of the peroneus, tibialis anterior, and gastrocnemius during a gait cycle were analyzed and compared. A curve analysis, namely, one-dimensional statistical parametric mapping, was performed to compare the dynamic ankle kinematics and muscle activation curves over the entire normalized time series.

RESULTS

The patients with and without OLT had no difference in patient-reported outcomes. The maximal ankle plantarflexion of the patients without OLT and the healthy subjects was significantly larger than that of patients with OLT (p = 0.005). The maximal ankle internal rotation of patients without OLT was significantly larger than that of patients with OLT (p = 0.048). The peroneal activation during 0-6% of the gait cycle of patients with OLT was reduced compared with the healthy subjects.

SIGNIFICANCE

Patients with CAI and OLT and patients with CAI without OLT have no difference in patient-reported outcomes, but patients with OLT can be differentiated using the post-initial-contact peroneal activation deficit and the restriction of ankle plantarflexion and internal rotation during stair descent. These variables can be utilized to monitor the function of patients with CAI and their possibility of developing OLT.

Interaction of loading and ligament injuries in subtalar joint instability quantified by 3D weightbearing computed tomography

Despite decades of research since its first description, subtalar joint instability remains a diagnostic enigma within the concept of hindfoot instability. This could be attributed to current imaging techniques, which are impeded by two-dimensional measurements. Therefore, we used weightbearing computed tomography imaging to quantify three-dimensional displacement associated with subtalar joint instability. Three-dimensional models were generated in seven paired cadaver specimens to compute talocalcaneal displacement after different patterns of axial load (85 kg) combined with torque in internal and external rotation (10 Nm). Sequential imaging was repeated in the subtalar joint containing intact ligaments to determine reference displacement. Afterward, the interosseus talocalcaneal ligament (ITCL) or calcaneofibular ligament (CFL) was sectioned, then the ITCL with CFL and after the ITCL, CFL with the deltoid ligament (DL). The highest translation could be detected in the dorsal direction and the highest rotation occurred in the internal direction when external torque was applied to the foot without load. These displacements differed significantly from the condition containing intact ligaments, with a mean difference of 1.6 mm (95% CI, 1.3 to 1.9) for dorsal translation and a mean of 12.4° (95% CI, 10.1 to 14.8) for internal rotation. Clinical relevance: Our study provides a novel and noninvasive analysis to quantify subtalar joint instability based on three-dimensional WBCT imaging. This approach overcomes former studies using trans-osseous fixation to determine three-dimensional subtalar joint displacement and implements an imaging device and software modalities that are readily available. Based on our findings, we recommend applying torque in external rotation to the foot to optimize the detection of subtalar joint instability.

Cartilage Matrix Changes in Hindfoot Joints in Chronic Ankle Instability Patients After Anatomic Repair Using T2-Mapping: Initial Experience With 3-Year Follow-Up

BACKGROUND

Anatomic repair is widely accepted as the primary surgical treatment for chronic lateral ankle instability (CLAI). T2-mapping is a powerful tool for quantitative assessment of biochemical changes in cartilage matrix.

PURPOSE

To longitudinally evaluate cartilage matrix changes in the hindfoot joints of CLAI patients before and after anatomic repair by using T2-mapping with magnetic resonance imaging (MRI).

STUDY TYPE

Prospective.

SUBJECTS

Thirty-two CLAI patients (males/females = 20/12) and 21 healthy controls (males/females = 13/7).

FIELD STRENGTH/SEQUENCE

3 T; sagittal multi-echo spin-echo technique (T2-mapping), coronal, sagittal, and axial spin-echo PD-FS, and sagittal T1WI sequences.

ASSESSMENT

MRI examinations were performed in CLAI patients at baseline (prior to surgery) and 3 years after anatomic repair and in healthy controls. On T2-maps, the hindfoot joints were segmented into 16 cartilage subregions. The T2 value of each subregion was measured. All patients were evaluated with the American Orthopedic Foot and Ankle Society (AOFAS) scale at baseline and after surgery.

STATISTICAL TESTS

Analysis of variance (ANOVA) and Student's t-test were used. The differences corresponding to P < 0.05 were considered statistically significant.

RESULTS

At baseline, the T2 values in most cartilage subregions of talar dome and medial posterior subtalar joint (pSTJ) were higher in CLAI patients than in healthy controls. After surgery, only the T2 value of anteriomedial talar dome decreased from that at baseline (31.11 ± 3.88 msec vs. 34.27 ± 5.30 msec). The T2 values of other subregions with elevated T2 values remained higher than healthy controls. There were no significant differences in T2 values in the midtarsal joints between CLAI patients and healthy controls (P = 0.262, 0.104, 0.169, 0.103). Postoperatively, the patients' AOFAS scores improved significantly from 67.81 to 89.13.

DATA CONCLUSION

CLAI patients exhibited elevated T2 values in most subregions of talar dome and medial pSTJ. After anatomic repair, although the patients exhibited good clinical outcomes, the elevated T2 values could not be fully recovered.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY STAGE: 4.

Ankle Stability and Movement Coordination Impairments: Lateral Ankle Ligament Sprains Revision 2021

This revised clinical practice guideline (CPG) addresses the distinct but related lower extremity impairments of those with a first-time lateral ankle sprain (LAS) and those with chronic ankle instability (CAI). Depending on many factors, impairments may continue following injury. While most individuals experience resolution of symptoms, complaints of instability may continue and are defined as CAI. The aims of the revision were to provide a concise summary of the contemporary evidence since publication of the original guideline and to develop new recommendations or revise previously published recommendations to support evidence-based practice. J Orthop Sports Phys Ther 2021;51(4):CPG1-CPG80. doi:10.2519/jospt.2021.0302.

Assignment of local coordinate systems and methods to calculate tibiotalar and subtalar kinematics: A systematic review

The introduction of biplane fluoroscopy has created the ability to evaluate in vivo motion, enabling six degree-of-freedom measurement of the tibiotalar and subtalar joints. Although the International Society of Biomechanics defines a standard method of assigning local coordinate systems for the ankle joint complex, standards for the tibiotalar and subtalar joints are lacking. The objective of this systematic review was to summarize and appraise the existing literature that (1) defined coordinate systems for the tibia, talus, and/or calcaneus or (2) assigned kinematic definitions for the tibiotalar and/or subtalar joints. A systematic literature search was developed with search results limited to English Language from 2006 through 2020. Articles were screened by two independent reviewers based on title and abstract. Methodological quality was evaluated using a modified assessment tool. Following screening, 52 articles were identified as having met inclusion criteria. Methodological assessment of these articles varied in quality from 61 to 97. Included articles adopted primary methods for defining coordinate systems that included: (1) anatomical coordinate system (ACS) based on individual bone landmarks and/or geometric shapes, (2) orthogonal principal axes, and (3) interactive closest point (ICP) registration. Common methods for calculating kinematics included: (1) joint coordinate system (JCS) to calculate rotation and translation, (2) Cardan/Euler sequences, and (3) inclination and deviation angles for helical angles. The methods each have strengths and weaknesses. This summarized knowledge should provide the basis for the foot and ankle biomechanics community to create an accepted standard for calculating and reporting tibiotalar and subtalar kinematics.

Lateral Ankle Sprains and Their Association with Physical Function in Young Soccer Players

Purpose

Lateral ankle sprain (LAS) in childhood can result in lateral malleolus avulsion fractures; additionally, bone nonunion may occur. Physical maturity relates to the development of bone morphology and physical functionality. It is unknown how changes in physical functionality attributable to physical maturity affect young soccer players with abnormal lateral malleolus (ALM) morphology. Hence, the present study aimed to investigate the bone morphology of the lateral malleolus in young soccer players and to examine its relationship with physical functionality at different maturity levels.

Subjects and Methods

Two hundred and ninety young soccer players aged 6–15 years were included. The presence of ALM was assessed using ultrasonography. The subjects were allocated to three groups based on physical maturity (Pre-, Mid-, and Post-peak height velocity age [PHVA]). The prevalence of ALM and the relationship between ALM and physical maturity were examined for body composition, foot pressure distribution, foot alignment, ankle mobility, and single-leg balance.

Results

The prevalence of ALM was 17.6%. For physical maturity, the post-PHVA group showed a decrease in ankle dorsiflexion and eversion and an increase in one-leg hop distance compared to the Pre-PHVA group (P < 0.05). In the ALM group, the center of pressure during heel raising was distributed laterally in the Post-PHVA (P < 0.01), and the weight-bearing dorsiflexion angle was decreased in the Mid- and Post-PHVA (P < 0.05).

Conclusion

In the Post-PHVA young soccer players, decreased ankle dorsiflexion and eversion and increased one-leg hop distance were observed. The ALM group exhibited lateral loading during heel raising in the Post-PHVA group and decreased weight-bearing ankle dorsiflexion angle in the Mid- and Post-PHVA groups. The findings indicate the importance of secondary prevention of LAS and ultrasonography. Prospective studies of LAS in young athletes are required in the future.

Comparison of External Torque to Axial Loading in Detecting 3-Dimensional Displacement of Syndesmotic Ankle Injuries

BACKGROUND

Current imaging techniques try to quantify 3-dimensional displacement of syndesmotic ankle injuries using 2-dimensional measurements, which may obscure an exact diagnosis. Therefore, our aim was to determine 3-dimensional displacement of syndesmotic ankle injuries under load and torque using a weightbearing computed tomography (WBCT) and to assess the relation with previously established 2-dimensional measurements.

METHODS

Seven paired cadaver specimens were mounted into a radiolucent frame. WBCT scans were obtained to generate 3-dimensional models after different patterns of axial load (0 kg, 85 kg) combined with external torque (0, 10 Nm). Sequential imaging was repeated in ankles containing intact syndesmotic ligaments, sectioning of the anterior inferior tibiofibular ligament (AITFL; condition 1A), deltoid ligament (DL; condition 1B), combined AITFL+DL (condition 2), and AITFl+DL+interosseous membrane (condition 3). Reference anatomical landmarks were established relative to the intact position of the fibula to quantify displacement. A subsequent correlation analysis was performed between the obtained 2- and 3-dimensional measurements.

RESULTS

Axial load increased lateral translation (mean = -0.9 mm, 95% confidence interval [CI]: 1.3, -0.1) significantly in condition 2 relative to the intact ankle (P < .05) but did not demonstrate other significant displacements. External torque increased displacement significantly in all directions (P < .05), except for dorsal translation of the fibula (P > .05). The highest displacement could be detected when external torque was applied in condition 3 and consisted of posterior translation (mean = -3.1 mm; 95% CI: -4.8, -2.7) and external rotation (mean = -4.7 degrees; 95% CI: -5.6, -2.9). Pearson correlation coefficients between the 2-dimensional and 3-dimensional measurements were moderate and ranged from 0.31 to 0.56 (P < .05).

CONCLUSION

External torque demonstrated superiority over axial load in detecting syndesmotic ankle instability. Axial load increased lateral translation; however, differences were submillimeter in magnitude until torque was applied. A moderate correlation was found with previously established 2-dimensional measurements.

CLINICAL RELEVANCE

In clinical practice these findings substantiate application of external torque in current imaging modalities to improve detection of syndesmotic ankle injuries.

Three-dimensional kinematic change of hindfoot during full weightbearing in standing: an analysis using upright computed tomography and 3D-3D surface registration

Background

Weightbearing of the hindfoot affects positional changes of the ankle joint and subtalar joint (ankle-joint complex [AJC]). However, it is difficult to assess the kinematic changes in the hindfoot in a natural full weightbearing condition using conventional CT or cone beam computed tomography (CT) due to limitations of acquiring foot images under a physiological weightbearing condition using those imaging modalities. Analysis of AJC kinematics using fluoroscopy and 2D-3D registration technique requires data on the number of steps and amount of time to build and match the bones. This study aimed to analyze the effect of full weightbearing on hindfoot motion when standing using upright CT and 3D-3D surface registration.

Methods

Forty-eight AJCs of 24 asymptomatic volunteers (13 women, 11 men) were examined under no weightbearing, 50% weightbearing, and single leg full weightbearing conditions while standing. The CT images were acquired from the distal femur to the whole foot using a 320-row upright CT scanner. The condition of each weightbearing stance was measured using a pressure mat. Bone-to-bone rotations of the talus relative to the tibia and calcaneus relative to the talus were evaluated using the surface registration technique. Image quality of the CT and intra- and interobserver reliabilities of the rotation angle were also evaluated.

Results

All CT images were excellent or good quality and the intra- and interobserver correlation coefficients for the angle were 0.996 and 0.995, respectively. The motion of the ankle joint and subtalar joint under 50% and 100% weightbearing were as follows (in degrees); the talus plantarflexed (5.1 ± 4.5 and 6.8 ± 4.8), inverted (1.3 ± 1.4 and 2.0 ± 1.6), and internally rotated (2.4 ± 4.2 and 4.3 ± 4.6) relative to the tibia, and the calcaneus dorsiflexed (2.8 ± 1.4 and 3.8 ± 1.7), everted (5.3 ± 2.6 and 8.0 ± 3.6), and externally rotated (3.0 ± 2.0 and 4.1 ± 2.4) relative to the talus, respectively.

Conclusions

The effect of weightbearing was clearly identified using an upright CT and the 3D-3D registration technique. Three-dimensional kinematics under static full weightbearing were opposite between the ankle and subtalar joints on their respective axes.

In vivo kinematics of functional ankle instability patients during the stance phase of walking

BACKGROUND

Previous studies showed functional ankle instability (FAI) patients have morphological ligamentous abnormality, despite having no apparent joint laxity.

RESEARCH QUESTION

Whether tibiotalar and subtalar joints hypermobility exists in FAI patients during stance phase of walking, remains controversial.

METHODS

Ten unilateral FAI patients, ten unilateral lateral ankle sprain (LAS) copers and ten healthy controls were included. A dual fluoroscopy imaging system was utilized to capture the fluoroscopic images of tibiotalar and subtalar joint during the stance phase of walking. Kinematic data from six degrees of freedom were calculated utilizing a solid modeling software. The range of motion and joint excursions about six degrees of freedom were compared among the three groups. The correlations between range of motion and Cumberland Ankle Instability Tool (CAIT) scores were assessed utilizing the Spearman's correlation coefficient (r).

RESULTS

During the stance phase, the FAI patients and LAS copers showed larger tibiotalar anterior/posterior translation than the healthy controls (FAI patients, p = .013; LAS copers, p = .002). The FAI patients also showed significantly larger lateral/medial translation (p = .035) and inversion/eversion rotation (p = .003) of subtalar joints than healthy controls. By contrast, the subtalar joints of the LAS copers were not different from those of the healthy controls in the lateral/medial translation (p = .459) and inversion/eversion rotation (p = .091). CAIT scores were negatively correlated with range of motion.

SIGNIFICANCE

During the stance phase of walking, FAI patients showed significantly larger hypermobility of subtalar joints than healthy controls, contrary to the LAS copers. These findings justify the utilization of dual fluoroscopy imaging system to detect joint hypermobility in FAI patients. Treatment for FAI patients may require stabilization of the subtalar joint.

In Vivo Kinematics of Functional Ankle Instability Patients and Lateral Ankle Sprain Copers During Stair Descent

Patients with mechanic ankle instability experience increased tibiotalar and subtalar joint laxity. However, in vivo joint kinematics in functional ankle instability (FAI) patients and lateral ankle sprain (LAS) copers, especially during dynamic activities, are poorly understood. Ten FAI patients, 10 LAS copers, and 10 healthy controls were included in this study. A dual fluoroscopic imaging system was used to analyze the tibiotalar and subtalar joint kinematics during stair descent. Five key poses of stair descent were analyzed. Kinematic data from six degrees of freedom were calculated utilizing a solid modeling software. The range of motion and joint positions in each degree of freedom were compared among the three groups. The tibiotalar joints of FAI patients and LAS copers were significantly more inverted than those of healthy controls during the foot strike (p = 0.016, ηp2  = 0.264). The subtalar joints of FAI patients were significantly more anteriorly translated (pose 2, p = 0.003, ηp2  = 0.352; pose 3, p < 0.001, ηp2  = 0.454; pose 4, p = 0.004, ηp2  = 0.334), inverted (pose 4, p = 0.027, ηp2  = 0.234; pose 5,p = 0.034, ηp2  = 0.221), and externally rotated (pose 4, p = 0.037, ηp2  = 0.217; pose 5; p = 0.004, ηp2  = 0.331) than those of healthy controls during the mid-stance and the heel off. The FAI patients showed excessive tibiotalar inversion and subtalar joint hypermobility during stair descent. Meanwhile, the LAS copers maintained subtalar joint stability, and only showed excessive tibiotalar inversion in foot strike. These data provide insight into the mechanisms behind the development of FAI after initial LAS. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1860-1867, 2019.

Pathological kinematic patterns of the tarsal complex in stage II adult-acquired flatfoot deformity

The in vivo kinematic characteristics of the tarsal joints during gait stance phase were still unclear in adult-acquired foot deformity (AAFD). This study included seven healthy subjects (14 feet) and 12 stage II AAFD patients (14 feet). The 3D models of tarsal bones were reconstructed based on CT scan. Each subject took standard gait on the single fluoroscopy system. Continuous lateral fluoroscopic images were collected. The key postures during the stance phase were selected. The 2D-3D registration technique was applied to explore the spatial motions of the tarsal joints in 6 degrees of freedom (DOF). During the whole stance phase, the AAFD talo-navicular joint (TNJ) exhibited ROM of 13 ± 6° in the sagittal plane while the normal subjects showed ROM of 7 ± 3° (p = 0.004). In AAFD, the subtalar joint (STJ) demonstrated 19 ± 8° and 7 ± 3° of motion in coronal and horizontal plane, respectively, while the normal subjects showed 14 ± 4°(p = 0.031) and 11 ± 3° (p = 0.014) of motion, respectively. Additionally STJ of AAFD patients showed significantly less dorsiflexion during the weight acceptance and showed significantly less external rotation both during the weight acceptance and single limb support of stance phase. In conclusion, for stage II AAFD patients, the talonavicular joint and the subtalar joint showed hypermobility in dorsi/planterflexion and inversion/eversion, respectively, during the gait stance phase while the internal/external rotation of the subtalar joint was reduced. The current study improves our understanding of the pathological kinematics of the tarsal complex in AAFD patients. Notice should be taken about these tarsal joints mobility in AAFD during clinical practice. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:477-482, 2019.

Gait abnormalities in patients with chronic ankle instability can improve following a non-invasive biomechanical therapy: a retrospective analysis

[Purpose] The purpose of this study was to evaluate the changes in gait patterns and clinical outcomes of patients with chronic ankle instability (CAI) following treatment with a home-based non-invasive biomechanical device. [Subjects and Methods] Thirty-three patients with CAI were compared with 43 healthy controls. Patients underwent a spatiotemporal gait assessment before and three months following treatment. Clinical evaluation was recorded with SF-36 Health Survey and the Foot and Ankle Outcome Score (FAOS). [Results] Significant baseline differences were found between groups. Patients with CAI showed a statistically significant improvement in velocity, cadence, symptomatic limb step length and single limb support over time. Significant improvements in SF-36 PCS and FAOS outcome scores were found in patients with CAI. [Conclusion] Patients with CAI have baseline spatiotemporal gait abnormalities as compared with healthy controls. However, clinical and gait metrics improvement can be expected after 12 weeks of perturbation training using a non-invasive biomechanical device.

In vivo kinematic study of the tarsal joints complex based on fluoroscopic 3D-2D registration technique

The tarsal bones articulate with each other and demonstrate complicated kinematic characteristics. The in vivo motions of these tarsal joints during normal gait are still unclear. Seven healthy subjects were recruited and fourteen feet in total were tested in the current study. Three dimensional models of the tarsal bones were first created using CT scanning. Corresponding local 3D coordinate systems of each tarsal bone was subsequently established for 6DOF motion decompositions. The fluoroscopy system captured the lateral fluoroscopic images of the targeted tarsal region whilst the subject was walking. Seven key pose images during the stance phase were selected and 3D to 2D bone model registrations were performed on each image to determine joint positions. The 6DOF motions of each tarsal joint during gait were then obtained by connecting these positions together. The TNJ (talo-navicular joint) exhibited the largest ROMs (range of motion) on all rotational directions with 7.39±2.75°of dorsi/plantarflexion, 21.12±4.68°of inversion/eversion, and 16.11±4.44°of internal/external rotation. From heel strike to midstance, the TNJ, STJ (subtalar joint), and CCJ (calcaneao-cuboid joint) were associated with 5.97°, 5.04°, and 3.93°of dorsiflexion; 15.46°, 8.21°, and 5.82°of eversion; and 9.75°, 7.6°, and 4.99°of external rotation, respectively. Likewise, from midstance to heel off, the TNJ, STJ, and CCJ were associated with 6.39, 6.19°, and 4.47°of plantarflexion; 18.57°, 11.86°, and 6.32°of inversion and 13.95°, 9.66°, and 7.58°of internal rotation, respectively. In conclusion, among the tarsal joints, the TNJ exhibited the greatest rotational mobility. Synchronous and homodromous rotational motions were detected for TNJ, STJ, and CCJ during the stance phase.

The impact of high-heeled shoes on ankle complex during walking in young women-In vivo kinematic study based on 3D to 2D registration technique

OBJECTIVE

To explore the accurate in vivo kinematic changes in the ankle complex when wearing low- and high-heel shoes (LHS and HHS, respectively).

MATERIALS AND METHODS

Twelve young women were tested unilaterally. Three-dimensional models of the tibia, talus, and calcaneus were first created based on CT scan results. The subjects walked at a self-controlled speed in barefoot, LHS (4cm), and HHS (10cm) conditions. A fluoroscopy system captured the lateral fluoroscopic images of the ankle complex. The images of seven key positions in the stance phase were selected, and 3D to 2D bone model registrations were performed to determine the joint positions. The mean of 6 degree of freedom (DOF) range of motions (ROM), joint positions, and angular displacements of the ankle complex during the gait were then obtained.

RESULTS

For the talocrural joint, the rotational ROMs of the subjects either in LHS or HHS condition displayed no significant difference from those in barefoot condition. For the subtalar joint, all the rotational ROMs in the HHS condition and the internal/external rotations in the LHS condition significantly decreased compared with those in the barefoot condition. The talocrural joint was positioned significantly more plantarflexed, inverted, internally rotated, and posteriorly seated in all seven poses in HHS condition, compared with those in barefoot condition.

CONCLUSION

HHS mainly affected the rotational motion of the ankle complex during walking. The talocrural joint position was abnormal, and the subtalar joint ROM decreased during the gait in HHS condition. Only a few kinematic changes occurred in LHS condition relative to the barefoot condition.

Sagittal Fluoroscopy for the Assessment of Hindfoot Kinematics

Current methods of quantifying foot kinematics during gait typically use markers placed externally on bony anatomic locations. These models are unable to analyze talocrural or subtalar motion because the talus lacks palpable landmarks to place external markers. Alternative methods of measuring these clinically relevant joint motions are invasive and have been limited to research purposes only. This study explores the use of fluoroscopy to noninvasively quantify talocrural and subtalar sagittal plane kinematics. A fluoroscopy system (FS) was designed and built to synchronize with an existing motion analysis system (MAS). Simultaneous fluoroscopic, marker motion, and ground reaction force (GRF) data were collected for five subjects to demonstrate system application. A hindfoot sagittal plane model was developed to evaluate talocrural and subtalar joint motion. Maximum talocrural plantar and dorsiflexion angles averaged among all the subjects occur at 12% and 83% of stance, respectively, with a range of motion of 20.1 deg. Maximum talocrural plantar and dorsiflexion angles averaged among all the subjects occur at toe-off and 67% of stance, respectively, with a range of motion of 8.7 deg. Based on the favorable comparison between the current fluoroscopically measured kinematics and previously reported results from alternative methods, it is concluded that fluoroscopic technology is well suited for measuring the sagittal plane hindfoot motion.

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.

Accuracy and feasibility of high-speed dual fluoroscopy and model-based tracking to measure in vivo ankle arthrokinematics

The relationship between altered tibiotalar and subtalar kinematics and development of ankle osteoarthritis is unknown, as skin marker motion analysis cannot measure articulations of each joint independently. Here, we quantified the accuracy and demonstrated the feasibility of high-speed dual fluoroscopy (DF) to measure and visualize the three-dimensional articulation (i.e., arthrokinematics) of the tibiotalar and subtalar joints. Metal beads were implanted in the tibia, talus and calcaneus of two cadavers. Three-dimensional surface models of the cadaver and volunteer bones were reconstructed from computed tomography images. A custom DF system was positioned adjacent to an instrumented treadmill. DF images of the cadavers were acquired during maximal rotation about three axes (dorsal-plantar flexion, inversion-eversion, internal-external rotation) and simulated gait (treadmill at 0.5 and 1.0 m/s). Positions of implanted beads were tracked using dynamic radiostereometric analysis (DRSA). Bead locations were also calculated using model-based markerless tracking (MBT) and compared, along with joint angles and translations, to DRSA results. The mean positional difference between DRSA and MBT for all frames defined bias; standard deviation of the difference defined precision. The volunteer was imaged with DF during treadmill gait. From these movements, joint kinematics and tibiotalar and subtalar bone-to-bone distance were calculated. The mean positional and rotational bias (±standard deviation) of MBT was 0.03±0.35 mm and 0.25±0.81°, respectively. Mean translational and rotational precision was 0.30±0.12 mm and 0.63±0.28°, respectively. With excellent measurement accuracy, DF and MBT may elucidate the kinematic pathways responsible for osteoarthritis of the tibiotalar and subtalar joints in living subjects.

The effects of a semi-rigid brace or taping on talocrural and subtalar kinematics in chronic ankle instability

BACKGROUND

A semi-rigid brace or taping is often used to prevent giving-ways in the joint with chronic ankle instability (CAI). However, it remains unknown whether the application of a semi-rigid brace or taping modifies abnormal kinematics in CAI joints. The objective of this study was to determine if the application of a semi-rigid brace or taping of the ankle normalizes abnormal weight-bearing kinematics in CAI joints during ankle internal rotation in plantar flexion.

METHODS

A total of 14 male patients with unilateral CAI (mean age 21.1 ± 2.5 years) were enrolled. Three-dimensional bone models created from the computed tomography images were matched to the fluoroscopic images to compute the 6 degrees-of-freedom talocrural, subtalar, and ankle joint complex (AJC) kinematics for the healthy and contralateral CAI joints, as well as for CAI joints with a brace or taping. Selected outcome measures were talocrural anterior translation, talocrural internal rotation, and subtalar internal rotation.

RESULTS

There was no significant difference in talocrural anterior translation and internal rotation induced by applying either a semi-rigid brace or taping (P > .05). For subtalar internal rotation, there was a tendency toward restoration of normal kinematics in CAI joints after applying a semi-rigid brace or taping. However, the difference was not significant (P > .05).

DISCUSSION

Application of a semi-rigid brace or taping had limited effects on the CAI joint during weight-bearing ankle internal rotation in plantar flexion. Further studies using a variety of testing conditions should be conducted in the future.

LEVELS OF EVIDENCE

Therapeutic, Level IV: Cross-Sectional Case Series.

Fibular malalignment in individuals with chronic ankle instability

STUDY DESIGN

Case series.

OBJECTIVES

To determine whether abnormal fibular alignment is present in individuals with chronic ankle instability (CAI) using 3-D analysis of computed tomography (CT)-based bone models.

BACKGROUND

A positional difference of the distal fibula in individuals with unilateral CAI, when compared to the contralateral side, has been suggested. However, previous studies report no consistent pattern of fibular malalignment in the anteroposterior direction and, to our knowledge, no study has investigated mediolateral malalignment.

METHODS

Seventeen males with unilateral CAI (mean ± SD age, 21.0 ± 2.4 years) and no history of injury in the contralateral side were enrolled. Geometric bone models of the tibia and fibula were created from non-weight-bearing CT images, and anatomical coordinate systems were embedded in the tibia model. Bilateral tibiae were superimposed using a best-fit algorithm that moved the tibia to the position of best congruity, and the amount of side-to-side difference in position of the fibulae was measured. The anteroposterior and mediolateral positional difference of the fibula of the ankle with CAI relative to the contralateral ankle, for the distal 10 cm of the fibula length, was determined using a color-coded map.

RESULTS

The fibula of the ankle with CAI was significantly more lateral (0.57-0.68 mm) than that of the contralateral healthy ankle at all reference points from distal 10 cm to the lateral malleolus. There was no significant difference in anteroposterior position between the healthy ankles and those with CAI.

CONCLUSION

This study detected malalignment of the distal fibula in ankles with CAI in a non-weight-bearing position. The fibula of the ankles with CAI had a significantly more lateral position than that of the healthy ankles, which may contribute to recurrent lateral ankle sprain or giving-way episodes.

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.