Current Concepts on Subtalar Instability

Abstract

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.

Relationship between Joint and Ligament Structures of the Subtalar Joint and Degeneration of the Subtalar Articular Facet

“…Recently, subtalar joint instability was reported to occur in 10–80% of patients with chronic lateral ankle instability [ 1 ], but the problem is very difficult to diagnose [ 1 , 2 ]. Reasons for this include that the subtalar joint comprises anatomically complex structures, and subtalar joint instability is similar to chronic ankle instability [ 2 , 3 ].…”

“…Recently, subtalar joint instability was reported to occur in 10–80% of patients with chronic lateral ankle instability [ 1 ], but the problem is very difficult to diagnose [ 1 , 2 ]. Reasons for this include that the subtalar joint comprises anatomically complex structures, and subtalar joint instability is similar to chronic ankle instability [ 2 , 3 ]. In a report on a mouse model of combined injury to the talocrural and subtalar joints, cartilage degeneration of the talocrural and subtalar joints was observed at 12 weeks after the ligament was cut, suggesting the possibility of progression to osteoarthritis [ 4 ].…”

Role of the intrinsic subtalar ligaments in subtalar instability and consequences for clinical practice

“…Recent literature clarifies the local anatomical and biomechanical characteristics of the subtalar ligaments. This allows to improve the understanding of kinesiology and pathophysiology (Michels et al, 2020a;Michels et al, 2021b;Pereira et al, 2021). This improved understanding has some consequences for clinical practice.…”

Relationship between Joint and Ligament Structures of the Subtalar Joint and Degeneration of the Subtalar Articular Facet

“…Recently, subtalar joint instability has been reported to occur in 10-80% of patients with chronic lateral ankle instability [1], but the problem is very difficult to diagnose [1,2]. Reasons for this include that the subtalar joint comprises anatomically complex structures and subtalar joint instability is similar to chronic ankle instability [2,3].…”

“…Recently, subtalar joint instability has been reported to occur in 10-80% of patients with chronic lateral ankle instability [1], but the problem is very difficult to diagnose [1,2]. Reasons for this include that the subtalar joint comprises anatomically complex structures and subtalar joint instability is similar to chronic ankle instability [2,3]. In a report on a mouse model of combined injury to the talocrural and subtalar joints, cartilage degeneration of the talocrural and subtalar joints was observed at 12 weeks after the ligament was cut, suggesting the possibility of progression to osteoarthritis [4].…”