Lateral subtalar joint capsuloligamentous instability: A review and proposed repair technique

Highlights

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    Persistent instability after Broström may reflect lateral subtalar joint laxity.

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    Novel IER-based retinacular repair technique reinforces lateral subtalar capsule.

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    Dynamic fluoroscopy enhances diagnosis of subtalar vs ankle instability.

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    Foot and ankle surgeons should assess subtalar laxity in failed ankle repairs.

Abstract

Lateral subtalar joint (STJ) instability is an underrecognized contributor to persistent lateral hindfoot symptoms, especially among patients who continue to feel unstable after anatomically successful anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) repair. Emerging cadaveric, biomechanical, and imaging work suggests a key stabilizing role for the lateral STJ capsule and the inferior extensor retinaculum (IER) complex. We provide a narrative review of the lateral STJ capsuloligamentous anatomy, relevant biomechanical data, and diagnostic considerations including MRI/ultrasound and dynamic fluoroscopic stress assessment. We then describe a practical operative approach for capsuloligamentous reinforcement of the lateral STJ using a flap of the medial band of the IER, with anchor fixation to the lateral talar process, and outline postoperative management. In the senior author’s experience, targeted subtalar capsuloligamentous repair can restore lateral stability in patients with isolated or residual STJ laxity after lateral ankle stabilization. The technique leverages local retinacular tissue to augment the lateral talocalcaneal ligament (LTCL) region and the lateral capsule while maintaining anatomic relationships. Lateral STJ capsuloligamentous laxity may drive persistent symptoms despite ATFL/CFL reconstruction. Surgeons should consider explicit subtalar assessment and, when indicated, capsular plication with IER augmentation. Prospective studies and standardized imaging/stress tests are needed to validate indications, outcomes, and durability.

Level of evidence: LEVEL V

Introduction and background

Lateral subtalar joint (STJ) instability is a clinically underrecognized cause of persistent lateral hindfoot instability, particularly in patients who fail to improve despite anatomically successful anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) repairs. Traditional approaches to lateral ankle instability have historically centered on the lateral ankle ligaments, while the subtalar joint has received less attention. Recent biomechanical, cadaveric, and imaging evidence points to an important role of the lateral subtalar capsule and associated ligaments as key stabilizers, particularly in dynamic or recurrent instability. This study explores the anatomy, biomechanical evidence, diagnostic considerations, and current surgical repair techniques involving these structures. Additionally, we discuss and provide a step-by-step outline of a novel technique for repair of lateral subtalar joint capsuloligamentous instability used by the author.

Relevant Anatomy of Lateral Subtalar Joint Ligaments:

The lateral subtalar joint capsule is reinforced by several poorly described ligamentous structures, often variably named and inconsistently defined in literature. Key structures include:

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    Lateral capsular ligaments of the subtalar joint

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    The lateral root of the inferior extensor retinaculum (IER)

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    The medial and deep bands of the IER

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    Contributions from the lateral talocalcaneal ligament (distinct from the CFL)

Sarrafian’s Anatomy of the Foot and Ankle describes a fibrous reinforcement of the lateral STJ capsule as a discrete structure. These ligaments are often disrupted in the setting of lateral ankle sprains, but are not routinely repaired during Broström-type reconstructions unless specifically addressed ( Figs. 1 and 2 ) .

Fig. 1

Articulating surfaces of the subtalar joint showing anterior, middle, and posterior facets. The lateral talocalcaneal ligament is visualized connecting talus and calcaneus laterally. Source: educational atlas.

Fig. 2

Lateral calcaneal view illustrating the lateral talocalcaneal ligament (LTL), interosseous ligament (IOL), and bifurcate ligament (B). Adapted from: Daftary A et al., Radiographics 2005;25:1215–1226.

Cadaveric and Biomechanical Evidence:

Studies such as those by Golanó et al. and Vega et al. have shown that the lateral STJ capsule and surrounding fibrous structures contribute significantly to varus stability of the subtalar joint. Disruption of these capsular components can allow for persistent varus instability, even in the presence of intact ATFL/CFL structures. Biomechanical data have shown that isolated lateral subtalar instability can occur, particularly in cases of chronic instability or failed Broström repairs.

Diagnostic Imaging and Under recognition:

MRI, T2 mapping, and high-resolution ultrasound can aid in identifying subtalar capsular laxity, but these findings are frequently subtle or misinterpreted. Dynamic fluoroscopy or stress views targeting the subtalar joint can provide additional value. Lateral subtalar instability is often underdiagnosed because clinical testing primarily evaluates tibiotalar structures, and subtalar-specific stress maneuvers are infrequently performed.

Surgical Repair Techniques Involving the IER:

Some surgeons have described subtalar capsular plication techniques or augmentation with the IER. Of particular interest are the medial and deep bands of the IER, which attach to the calcaneus and provide a lateral sling effect to the STJ. Incorporating these bands into lateral ankle reconstructions may improve subtalar stability ( Table 1 ).

Table 1

Summarizing key lateral subtalar joint ligaments relevant to instability patterns and surgical repair.

Structure Biomechanical Role Imaging Appearance Surgical Access/Repair
Lateral Subtalar Capsular Ligaments Resist subtalar varus and posterior talar subluxation Difficult to visualize; may show capsular thickening or effusion Direct repair or plication
Lateral Talocalcaneal Ligament Stabilizes subtalar joint against inversion Occasionally visible on MRI Can be reinforced with IER or grafts
Deep Band of Inferior Extensor Retinaculum Lateral sling support to the subtalar joint Not routinely visualized Incorporated in modified Broström repair
Medial Band of IER Stabilizes STJ by anchoring to calcaneus Rarely visualized Used as augmentation flap
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Sep 5, 2026 | Posted by in ORTHOPEDIC | Comments Off on Lateral subtalar joint capsuloligamentous instability: A review and proposed repair technique

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