The CFL fails before the ATFL immediately after combined ligament repair in a biomechanical cadaveric model

Biomechanical evaluation of the anterior talo-fibular and calcaneo-fibular ligaments using shear wave elastography in young healthy adults

BACKGROUND

The objective of this study was to evaluate the stiffness of the anterior talo-fibular ligament (ATFL) and calcaneo-fibular ligament (CFL) using shear wave elastography (SWE) with the ankle in the neutral position and in varus, in young healthy adult volunteers. We also evaluated the reliability and reproducibility of the SWE measurements.

HYPOTHESIS

The stiffness of both ligaments increases with increasing ankle varus. SWE may be a reliable tool for evaluating the lateral collateral ligament complex of the ankle.

MATERIAL AND METHODS

We used SWE to evaluate both ankles of each of 20 healthy volunteers (10 females and 10 males). For each test, the foot was placed on a hinged plate and tested in the neutral position and in 15° and 30° of varus. Stiffness was evaluated based on shear wave velocity (SWV).

RESULTS

Stiffness of both the ATFL and CFL was minimal in the neutral position (2.06m/s and 3.43m/s, respectively). Stiffness increased significantly for both ligaments in 15° of varus (2.48m/s and 4.11m/s, respectively; p<0.0001) and was greatest in 30° of varus (3.15m/s and 4.57m/s, respectively; p<0.0001). ATFL stiffness was greater in males than in females in 15° (p=0.04) and 30° (p=0.02) of varus. For the CFL, in contrast, stiffness was not different between males and females. Stiffness of the ATFL and CFL was not associated with age, dominant side, height, or foot morphology. No correlations were found between stiffness of the two ligaments in any of the positions. Repeating each measurement three times produced excellent concordance for both ligaments in all three positions.

CONCLUSION

The ATFL and CFL are the main lateral stabilisers of the ankle, and each exerts a specific function. Their stiffness increases with the degree of varus. This study describes a protocol for evaluating ATFL and CFL density by SWE, which is a reliable and reproducible technique that provides a normal range.

LEVEL OF EVIDENCE

IV.

Reconstruction of the interosseous talocalcaneal ligament using allograft for subtalar joint stabilization is effective

PURPOSE

The aim of this study was to assess the biomechanical effects of subtalar ligament injury and reconstruction on stability of the subtalar joint in all three spatial planes.

METHODS

Fifteen fresh frozen cadaveric legs were used, with transfixed tibiotalar joints to isolate motion to the subtalar joint. An arthrometer fixed to the lateral aspect of the calcaneus measured angular displacement in all three spatial planes on the inversion and eversion stress tests. Stress manoeuvres were tested with the intact joint, and then repeated after sequentially sectioning the inferior extensor retinaculum (IER), cervical ligament (CL), interosseous talocalcaneal ligament (ITCL), arthroscopic graft reconstruction of the ITCL, and sectioning of the calcaneo-fibular ligament (CFL).

RESULTS

Sectioning the ITCL significantly increased angular displacement upon inversion and eversion in the coronal and sagittal planes. Reconstruction of the ITCL significantly improved angular stability against eversion in the axial and sagittal planes, and against inversion in the axial and coronal planes, at the zero time point after reconstruction. After sectioning the CFL, resistance to eversion decreased significantly in all three planes.

CONCLUSION

Progressive injury of ligamentous stabilisers, particularly the ITCL, led to increasing angular displacement of the subtalar joint measured with the inversion and eversion stress tests, used in clinical practice. Reconstruction of the ITCL using tendon graft significantly stabilised the subtalar joint in the axial and sagittal planes against eversion and in the axial and coronal planes against inversion, immediately after surgery.

Stepwise decision making for CFL repair in addition to arthroscopic ATFL repair yields good clinical outcomes in chronic lateral ankle instability regardless of the remnant quality

BACKGROUND

Although arthroscopic anterior talofibular ligament (ATFL) repair for chronic lateral ankle instability (CLAI) has been widely performed, there are several issues such as the efficacy of the isolated ATFL repair for the ATFL and calcaneofibular ligament (CFL) injury and the influence of the poor remnant on the clinical outcomes to be discussed. This study aimed to evaluate clinical outcomes of the arthroscopic ATFL repair with the stepwise decision regarding the requirement of CFL repair and the influence of remnant qualities on clinical outcomes.

METHODS

Forty-four ankles underwent arthroscopic surgery to repair the lateral ankle ligament for CLAI. After arthroscopic ATFL repair, CFL repair was performed if instability remained. Clinical outcomes including the Karlsson-Peterson (KP) scores, Japanese Society for Surgery of the Foot (JSSF) scale, and the Self-Administered Foot Evaluation Questionnaire (SAFE-Q) were assessed at the final follow-up. ATFL remnants were classified into excellent, moderate, and poor according to the arthroscopic findings, and the clinical outcomes of each remnant group were compared.

RESULTS

Twenty-five ankles were required for CFL repair after ATFL repair. K-P score was significantly improved from 66.1 ± 5.3 to 94.8 ± 6.5 points (p < 0.01). JSSF scale was significantly improved from 70.5 ± 4.5 to 95.9 ± 6.0 points (p < 0.01). The SAFE-Q was also significantly improved on all subscales. There were no significant differences in clinical outcomes among excellent, moderate, and poor remnants.

CONCLUSIONS

Stepwise decision for CFL repair in addition to arthroscopic ATFL repair gave satisfactory clinical outcomes in CLAI regardless of the remnant quality.

Current Concepts on Subtalar Instability

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

Safe angles of ATFL and CFL anchor insertion into anatomical attachment of fibula in a lateral ankle ligament repair

BACKGROUND

Lateral ankle ligament repair for chronic lateral ankle instability is common, and arthroscopic repair of the anterior talofibular ligament (ATFL) has been widely performed. However, it is desirable to repair of calcaneofibular ligament (CFL) combined with arthroscopic ATFL repair to obtain good long term clinical outcomes. Repairing CFL through small skin incision, there is the possibility to interfere with ATFL and CFL anchors because of close attachment of ATFL and CFL at fibula. The purpose of this study is to determine the safety anchor insertion angles for ATFL and CFL on CT images and to achieve ATFL and CFL repair with minimally invasive technique.

METHODS

Fifty ankles in 50 patients were included in this study. On a sagittal CT image, the anchor drill hole angles for ATFL and CFL were measured to avoid interference with these anchors. Then, arthroscopic ATFL repair combined with CFL repair was performed on 15 patients according to the safety insertion angles obtained by CT. CFL repair was performed through 1.5 cm length of accessory anterolateral portal. Clinical outcome was evaluated using the Japanese Society for the Surgery of the Foot (JSSF) ankle hindfoot scale and the Karlsson score before surgery and at final follow-up.

RESULTS

On the CT image, the mean angles between the ATFL drill hole and anterior border of the fibula was 59.4 ± 6.5°, and those between the longitudinal axis of the fibula and ATFL drill hole, and the CFL drill hole were 34.6 ± 5.0°, and 15.1 ± 5.7°, respectively. Postoperative CT after arthroscopic ATFL repair combined with CFL repair showed that no interference with 2 anchors, and JSSF scale and the Karlsson score were significantly improved from preoperative to final follow-up.

CONCLUSIONS

This study showed how safety ATFL and CFL anchor insertion angles comprise a minimally invasive anatomical repair technique.