Arthroscopic Reconstruction of the Anterior Tibiotalar Ligament Using a Free Tendon Graft

Investigation into the effect of deltoid ligament injury on rotational ankle instability using a three-dimensional ankle finite element model

Background

Injury to the lateral collateral ligament of the ankle may cause ankle instability and, when combined with deltoid ligament (DL) injury, may lead to a more complex situation known as rotational ankle instability (RAI). It is unclear how DL rupture interferes with the mechanical function of an ankle joint with RAI.

Purpose

To study the influence of DL injury on the biomechanical function of the ankle joint.

Methods

A comprehensive finite element model of an ankle joint, incorporating detailed ligaments, was developed from MRI scans of an adult female. A range of ligament injury scenarios were simulated in the ankle joint model, which was then subjected to a static standing load of 300 N and a 1.5 Nm internal and external rotation torque. The analysis focused on comparing the distribution and peak values of von Mises stress in the articular cartilages of both the tibia and talus and measuring the talus rotation angle and contact area of the talocrural joint.

Results

The dimensions and location of insertion points of ligaments in the finite element ankle model were adopted from previous anatomical research and dissection studies. The anterior drawer distance in the finite element model was within 6.5% of the anatomical range, and the talus tilt angle was within 3% of anatomical results. During static standing, a combined rupture of the anterior talofibular ligament (ATFL) and anterior tibiotalar ligament (ATTL) generates new stress concentrations on the talus cartilage, which markedly increases the joint contact area and stress on the cartilage. During static standing with external rotation, the anterior talofibular ligament and anterior tibiotalar ligament ruptured the ankle's rotational angle by 21.8% compared to an intact joint. In contrast, static standing with internal rotation led to a similar increase in stress and a nearly 2.5 times increase in the talus rotational angle.

Conclusion

Injury to the DL altered the stress distribution in the tibiotalar joint and increased the talus rotation angle when subjected to a rotational torque, which may increase the risk of RAI. When treating RAI, it is essential to address not only multi-band DL injuries but also single-band deep DL injuries, especially those affecting the ATTL.

Safe Talar Tunnel Placement During Reconstruction of the Deep Layer of the Deltoid Ligament: A Comparison of 4 Different Anatomic Landmarks on the Lateral Malleolus

Background

Deltoid ligament reconstruction of the ankle can be considered when the ruptured ligament is insufficient for direct repair.

Purpose

To compare the safety of talar tunnels oriented toward 4 different anatomic landmarks on the lateral malleolus during reconstruction of the deep layer of the deltoid ligament (DDL).

Study Design

Descriptive laboratory study.

Methods

A total of 30 computed tomography scans of the ankle joint in healthy adults were collected to generate 3-dimensional models. Virtual talar tunnels with a diameter of 5 mm and with different lengths (20.0, 25.0, and 30.0 mm) were created from the talar insertion of the DDL and were oriented toward the talar neck as well as the most anterior, the most distal, and the most posterior points of the distal fibula. The minimal safe distance (MSD) of a drilling route was calculated for the tunnels, and the safe distance from the end of the tunnel to the bone surface was measured for each tunnel. The nonpaired Student t test was used to detect differences among the safe distances of the 4 different bone tunnels.

Results

For the 20.0-mm tunnels, the safe distance of the tunnel oriented toward the talar neck (5.90 ± 1.16 mm) did not meet the MSD (6.0 mm). For the 25.0-mm tunnels, the safe distances of the tunnels oriented toward the talar neck (4.53 ± 1.13 mm) and the anterior point of the fibula (5.91 ± 1.52 mm) did not meet the MSD (6.9 mm).

Conclusion

Tunnels that were 5 mm in diameter and 20.0 and 25.0 mm in length, oriented toward the most distal or most posterior point of the distal fibula, were safe for DDL reconstruction.

Clinical Relevance

Knowledge of safe talar tunnel placement is important, especially to avoid bone surface penetration during DDL reconstruction.

Anatomical study of the bone morphology of the anterior talofibular ligament attachment

Anterior talofibular ligament (ATFL) injuries are the most common cause of ankle sprains. To ensure anatomically accurate surgery and ultrasound imaging of the ATFL, anatomical knowledge of the bony landmarks around the ATFL attachment to the distal fibula is required. The purpose of the present study was to anatomically investigate the ATFL attachment to the fibula with respect to bone morphology and attachment structures. First, we analyzed 36 feet using microcomputed tomography. After excluding 9 feet for deformities, the remaining 27 feet were used for chemically debrided bone analysis and macroscopic and histological observations. Ten feet of living specimens were observed using ultrasonography. We found that a bony ridge was present at the boundary between the attachments of the ATFL and calcaneofibular ligament (CFL) to the fibula. These two attachments could be distinguished based on a difference in fiber orientation. Histologically, the ATFL was attached to the anterodistal part of the fibula via fibrocartilage anterior to the bony ridge indicating the border with the CFL attachment. Using ultrasonography in living specimens, the bony ridge and hyperechoic fibrillar pattern of the ATFL could be visualized. We established that the bony ridge corresponded to the posterior margin of the ATFL attachment itself. The ridge was obvious, and the superior fibers of the ATFL have directly attached anteriorly to it. This bony ridge could become a valuable and easy-to-use landmark for ultrasound imaging of the ATFL attachment if combined with the identification of the fibrillar pattern of the ATFL.

Deltoid ligament injury and repair

The deltoid ligament is the primary stabilizer of the medial side of the ankle joint. It is a complex structure with an origin at the medial malleolus from where it spreads fan shaped distally with an insertion into the medial side of the talus, calcaneus and navicular bone. This chapter gives an overview of the anatomy, function, and pathology of the deltoid ligament.The deltoid ligament can become insufficient as a result of an ankle injury or prolonged strain. In the acute setting, deltoid insufficiency often coincides with multi ligament injury the ankle joint; syndesmosis injury, or ankle fractures. Management in the acute phase remains a subject of debate. Some orthopedic surgeons have a tendency towards repair, whereas most trauma surgeons often treat the deltoid nonoperatively. In the chronic setting the ligament complex is often elongated as a result of prolonged strain. It often coexists with a hindfoot valgus, as is the case in planovalgus feet. In such a case a realignment procedure should be combined with the deltoid repair.

Prediction of anterior tibiotalar ligament injury: measurement of the angle between the deep posterior tibiotalar ligament and talus on MRI

Background

Identification of anterior tibiotalar ligament (aTTL) injury is essential because it influences the surgeon's treatment option and patient prognosis.

Purpose

To assess the diagnostic accuracy of the angle measurement between the talus and posterior tibiotalar ligament (talus-pTTL) on magnetic resonance imaging (MRI) in patients with arthroscopically proven aTTL injuries.

Material and Methods

Ankle MRI scans of 67 patients who underwent arthroscopic examination were retrospectively reviewed. The talus-pTTL angle on axial T2-weighted MRI and the medial clear space (MCS) on mortise ankle radiograph were measured. Inter-observer agreement of the measurements was calculated. Also, sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve (AUC) were the metrics of diagnostic accuracy.

Results

AUC was 0.90 for observer 1 with 78.6% sensitivity, 97.4% specificity, 88% accuracy, and 54.7° cutoff value for the talus-pTTL angle. AUC was 0.87 for observer 2 with 85.7% sensitivity, 84.6% specificity, 85.2% accuracy, and 53.7° cutoff value for the talus-pTTL angle. AUC was 0.86 with 82.1% sensitivity, 79.5% specificity, and 80.8% accuracy for observer 1 and 0.79 with 57.1% sensitivity, 92.3% specificity, and 74.7% accuracy for observer 2 for the MCS. Different MCS values and additional capabilities when complemented with the angle measurement showed an increase in diagnostic performances. Intra-observer reliability of MCS and talus-pTTL angle of the two radiologists was excellent. Inter-observer reliability of the two radiologists was excellent for both the talus-pTTL angle (0.95) and the MCS (0.85).

Conclusion

Measurement of the talus-pTTL angle showed good sensitivity, specificity, and accuracy for the evaluation of aTTL injury with excellent inter-observer reliability.

A Review of Recent Advances in Natural Polymer-Based Scaffolds for Musculoskeletal Tissue Engineering

The musculoskeletal (MS) system consists of bone, cartilage, tendon, ligament, and skeletal muscle, which forms the basic framework of the human body. This system plays a vital role in appropriate body functions, including movement, the protection of internal organs, support, hematopoiesis, and postural stability. Therefore, it is understandable that the damage or loss of MS tissues significantly reduces the quality of life and limits mobility. Tissue engineering and its applications in the healthcare industry have been rapidly growing over the past few decades. Tissue engineering has made significant contributions toward developing new therapeutic strategies for the treatment of MS defects and relevant disease. Among various biomaterials used for tissue engineering, natural polymers offer superior properties that promote optimal cell interaction and desired biological function. Natural polymers have similarity with the native ECM, including enzymatic degradation, bio-resorb and non-toxic degradation products, ability to conjugate with various agents, and high chemical versatility, biocompatibility, and bioactivity that promote optimal cell interaction and desired biological functions. This review summarizes recent advances in applying natural-based scaffolds for musculoskeletal tissue engineering.

Role of Arthroscopy in Various Ankle Disorders

INTRODUCTION

Ankle arthroscopy has come a long way since it was thought, it is not feasible because of tight joint and anatomical characteristics of ankle joint. The same anatomical features like capsular attachment and safe accessory portals are used to access the whole joint even with a rigid arthroscope. Ankle distraction method was routinely used to access the anterior ankle. However, nowadays, anterior arthroscopy is done in dorsiflexion as this increases the anterior ankle joint volume, and thereby easy access to various anatomical structures. On the other hand, intermittent traction is used to access the posterior ankle. Initially used as a diagnostic tool, ankle arthroscopy is now used extensively as a therapeutic and reconstruction tool. New evidence is published for all inside ligament reconstructions, effective management of impingement syndromes, and osteochondral lesions. The indications are being extended to fracture management and arthrodesis.

METHODOLOGY

This narrative review was performed following a literature search in the Pubmed database and Medline using the following keywords: ankle arthroscopy, portals, ankle OCD, functional outcome. Related articles were then reviewed.

CONCLUSION

Complications rate is reduced with a better understanding of the relative anatomy of surrounding neurovascular structures and tendons with regard to the position of ankle joint. This review on ankle arthroscopy focuses on anatomy, indications, and complications. Ankle arthroscopy is a safe and elegant tool as any other joint arthroscopy.