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

The evaluation of rotational lateral ankle laxity in gravity stress position by ultrasonography: normative value in uninjured ankles

BACKGROUND

The evaluation of lateral ankle laxity remains challenging when diagnosing chronic lateral ankle instability (CLAI). Several studies have reported that internal rotation of the talus as an indicator of rotational lateral ankle laxity (RLAL) increases in patients with CLAI. However, there is no established method for detecting and evaluating the RLAL. This study aimed to report a novel method for evaluating the RLAL in the gravity stress position by measuring the talofibular distance (TFD) using ultrasonography (US) and show the normative value of the TFD.

METHODS

The TFDs in the subjects with healthy ankles were prospectively measured 10 mm distal to the ankle joint in the neutral ankle position and gravity stress position using US. The differences in the TFD between the two ankle positions were evaluated. The differences in the TFD by gender and ankle laterality were also evaluated.

RESULTS

A total of 52 healthy ankles of 28 subjects (mean age, 24.0 ± 1.6; male/female, 12/16) were finally included. There was a significant difference in the TFD between the neutral ankle position (6.9 ± 0.9 mm) and gravity stress position (9.0 ± 0.9 mm) (p < 0.001). The mean difference in the TFD between the two ankle positions was 2.1 ± 0.6 mm. There were no significant differences in the TFD by gender and ankle laterality.

CONCLUSIONS

The present study reported a novel US method for evaluating RLAL by applying gravity stress and the normative value of the TFD.

Screening of Undiagnosed Increased Lateral Ankle Laxity Using Stress Ultrasonography

Background

Some patients with lateral ankle sprain (LAS) will experience chronic lateral ankle instability (CLAI). However, not all of those with residual increased lateral ankle laxity (ILAL) become symptomatic. There is a lack of evidence regarding the prevalence of undiagnosed ILAL in the general population.

Purpose

To evaluate the prevalence of undiagnosed ILAL with the use of stress ultrasonography (US) and to investigate the percentage of ankle sprain copers (ASCs) with ILAL.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

The anterior talofibular ligament (ATFL) lengths in college students without diagnosis of CLAI were measured consecutively in stress and nonstress positions. The ATFL ratio was calculated as an indicator of lateral ankle laxity according to a previously reported method. The manual anterior drawer test was also performed. The Cumberland Ankle Instability Tool (CAIT) and Ankle Instability Instrument (AII) were used to assess subjective impairments related to CLAI. The correlation between the ATFL ratio and CAIT score was evaluated.

Results

A total of 207 ankles from 106 participants (mean age, 23.9 ± 2.2 years; male/female, 64/42) were included. Overall, 38 participants (35.8%; 50 ankles [24.2%]) were classified as having undiagnosed ILAL. Of the ankles with no history of LAS, 8% showed ILAL. Overall, 53 participants (50%) had a history of LAS and were all classified as ASCs. Of the 82 ankles from these ASCs, 40 (48.8%) were regarded as having undiagnosed ILAL. There was no correlation between the ATFL ratio and CAIT scores (r = -0.09, P = .414).

Conclusion

The prevalence of undiagnosed ILAL by stress US screening was approximately one-third in young adults. In this study, 48.8% of the ankles from ASCs showed ILAL.

Comparison of Direct Repair Versus Anatomic Graft Reconstruction of the Anterior Talofibular Ligament: A Biomechanical Cadaveric Study

The goal of our study is to compare the stability of the anatomic reconstruction of the anterior talofibular ligament (ATFL) with direct repair of the ATFL, in a cadaver model. We performed the following techniques in 18 cadaveric ankles: the intact ATFL was cut, after which a direct repair using 2 anchors was performed. The repair was sectioned, and anatomic reconstruction was then performed with a tendon autograft. We measured angular displacement in 3 anatomic planes (axial, coronal, sagittal) for each situation in response to the anterior drawer test (ADT), talar tilt test (TTT) and pivot test (PT), using a specifically constructed arthrometer. The sectioned ATFL was inferior to the intact ATFL in the axial plane with the ADT (p = .012), in the axial plane with the PT (p = .001) and in the axial and coronal planes with the TTT (p = .013 and p = .016, respectively). Direct anatomic repair was inferior to the intact ATFL in the axial plane upon the PT (p = .009). No differences could be found between anatomic graft reconstructions and the intact ATFL with any manoeuver, nor when comparing anatomic graft reconstruction and direct repair with 2 anchors. We were able to conclude that anatomic graft reconstruction of the ATFL reproduces angular stability of the native ligament in a cadaver model. While we could not detect if anatomic graft reconstruction was superior to direct repair, the latter proved to be less stable in the axial plane upon internal rotation (pivot test) versus the intact ATFL.

Anatomy of the Ankle and Subtalar Joint Ligaments: What We Do Not Know About It?

Understanding of the ankle and subtalar joint ligaments is essential to recognize and manage foot and ankle disorders. The stability of both joints relies on the integrity of its ligaments. The ankle joint is stabilized by the lateral and medial ligamentous complexes while the subtalar joint is stabilized by its extrinsic and intrinsic ligaments. Most injuries to these ligaments are linked with ankle sprains. Inversion or eversion mechanics affect the ligamentous complexes. A profound knowledge of the ligament's anatomy allows orthopedic surgeons to further understand anatomic or nonanatomic reconstructions.

The anterior talofibular ligament ratio was greater in young men with generalized joint laxity than in those without generalized joint laxity

PURPOSE

This study aimed to evaluate the relationship between generalized joint laxity (GJL) and stress ultrasonographic (US) findings of the anterior talofibular ligament (ATFL) of healthy young men.

METHODS

The ATFL lengths of healthy young men were consecutively measured in the stress and nonstress positions. The ATFL ratio was calculated as an indicator of lateral ankle laxity. GJL was evaluated using the Beighton score (BS), and a BS of ≥ 5 was considered GJL. The manual anterior drawer test (ADT) was also performed. The results of stress US and ADT were compared between subjects with and without GJL, and the correlation between GJL and US findings was examined.

RESULTS

A total of 13 subjects with GJL and 95 without GJL were included in the study. The mean BSs in the GJL and no-GJL groups were 5.9 ± 0.9 and 1.1 ± 1.3, respectively (p < 0.0001). The GJL group showed a higher grade of ADT than the no-GJL group (p < 0.0001). Significant differences were found in the stress ATFL length (23.6 ± 1.8 mm vs. 21.7 ± 1.8 mm, p = 0.002) and ATFL ratio (1.15 ± 0.06 vs. 1.07 ± 0.03, p < 0.0001) between the GJL and no-GJL groups. Spearman's correlation coefficients showed a moderate correlation between the BS and ATFL ratio (r = 0.45, p < 0.0001).

CONCLUSION

The present study showed significant differences in the ATFL ratio and stress ATFL length between young men with and without GJL. The BS was moderately correlated with the lateral ankle laxity in this population.

LEVEL OF EVIDENCE

Level IV.

Association between the Beighton Score and Stress Ultrasonographic Findings of the Anterior Talofibular Ligament in Healthy Young Women: A Cross-Sectional Study

The Beighton score (BS) is widely used to evaluate generalized joint laxity. However, the association between the BS and lateral ankle laxity is unclear. This study compared the ultrasonographic (US) findings of the anterior talofibular ligament (ATFL) between high- (≥6) and low- (≤3) BS groups of healthy young women. The ATFL lengths of healthy young women were measured in the stress and nonstress positions using the previously reported technique from March 2021 to January 2022. The ATFL ratio (ratio of stress to nonstress ATFL length) was used as an indicator of lateral ankle laxity. The anterior drawer test (ADT) was performed. The correlation between the BS and US findings was also examined. A total of 20 (high-BS group) and 61 (low-BS group) subjects with a mean age of 23.8 ± 1.0 years were included. The high-BS group showed a higher grade of ADT than the low-BS group. No significant differences were found in the nonstress and stress ATFL lengths and ATFL ratio (1.10 ± 0.05 vs. 1.09 ± 0.05, p = 0.19) between the groups. No correlation was found between the BS and US findings. In conclusion, this study did not detect significant differences in the US findings of the ATFL between the high- and low-BS groups.

Statistical ankle-shape and pressure analysis for design of elastic tubular bandage

Ankles can benefit from the elastic tube bandage (ETB) by providing the ankle joint with compression, but partial high- or low-pressure leads to body discomfort. The aim of this paper is to propose a method for analyzing the ankle shape with the fabric compression which is basis on the comfortable pressure on human body. First, a standard model of ankle is established from the scanned data of 306 samples, and the mapping of the fabric shape curves on ankle were constructed by the U-direction convex curves of the model. The positions or areas of maximum and minimum pressure are then marked by extracting the curvatures of the fabric shape curves. According to the Laplace's Law, the sizes of ETBs can be calculated given that the value of comfortable pressure on human body is the maximum one. The data of calculation is approximate to the relevant previous studies which has the same parameters of ETBs. Nine groups of the ankle shapes from the database are discussed, each group has a proportional coefficient to the standard model, and the result shows that six sizes of ETBs with comfort pressure match for the nine groups. These can be applied to the comfort design, and the method proposed can boost size customization of ETBs, as well as will inspire the research on other elastic compression garments.