Talonavicular ligament: prevalence of injury in ankle sprains, histological analysis and hypothesis of its biomechanical function

Abstract

Objective: To assess the prevalence of injury of the talonavicular ligament (TNL) in ankle sprains, its anatomy and the stability of the talonavicular joint (TNJ) before and after dividing the TNL in a cadaver. Methods: During a prospective study of 100 patients to assess the outcome of ankle injuries, we noted high incidence of TNL injuries; we will discuss here the TNL findings. Each patient had undergone ultrasound and cone beam CT examination of the ankle. Six TNLs were dissected off fresh-frozen cadaveric feet for histological analysis. In further six cadaveric feet, the stability of the TNJ was assessed by mechanical stress before and after division of the TNL; movement at the joint was assessed by measuring the distance between the talus and navicular bone [talonavicular distance (TD)] using ultrasound. The TD was measured on ten randomly selected ultrasound images by three independent observers and repeated twice by a single observer to determine the inter-and intraobserver reliability. Results: 21% of the patients had an injury to the TNL. Histological examination demonstrated a dense connective tissue composed of bundles of collagen in parallel arrangement along the ligament length. The interobserver and intraobserver reliability of the TD showed almost perfect agreement. Displacement at the TNJ after stress with the TNL intact measured 0.18 6 0.08 cm and 0.29 6 0.07 cm (p , 0.005) when divided. Conclusion: The TNL is surprisingly commonly injured in ankle sprains. Its anatomy and histology suggest a role in tensile force transmission during the windlass mechanism in gait. Advances in knowledge: Injury to the TNL is common and has not been described. Its anatomy suggests resistance to tensile forces and its injury allows excessive movement at the TNJ. INTRODUCTIONAcute ankle injuries account for approximately 10% of all emergency department attendances.1 Several publications cover the incidence of ligament injuries, especially the lateral ligamentous complex and deltoid ligament (DL). In one study, there were anterior talofibular ligament (ATFL) injuries in 75% of patients after acute inversion ankle sprain with a combined ATFL and calcaneofibular ligament (CFL) in 41%. 2 In another study, the prevalence of DL injury in patients with chronic lateral ankle instability was 36%.3 There are no studies to our knowledge investigating injury of the talonavicular ligament (TNL) in patients presenting with an ankle sprain.

Predicting poor outcome from simple ankle injuries: a prospective cohort study

“…Also, injury to the talonavicular ligament was surprisingly common and this has been the topic of a publication with an analysis of the ligaments biomechanical function. 13…”

Ultrasonography: Sports Injuries

“…Ligamentous injury of the small ligaments of the foot can be identified using diagnostic ultrasound, especially if they are superficial. Injury to the talonavicular ligament can occur in isolation or in association with lateral ligamentous injury [34]. This destabilises the midfoot allowing movement across the talonavicular joint which is vital in the normal windlass mechanism of walking; this is the dynamic tightening of the arch of the foot by long and short stabilisers prior to pushing off from the ball of the foot.…”

Ultrasound Imaging Guide for Assessment of the Intrinsic Ligaments Stabilizing the Subtalar and Midtarsal Joints

“…The dorsal talonavicular ligament plays a role in resisting these tensile forces dorsally and therefore is intrinsically predisposed to injury. 47,48 It can be evaluated by placing the probe in a sagittal plane on the dorsolateral aspect of the foot over the talonavicular joint. The ligament appears as a focal thickening of the joint capsule: its fibrillar echotexture can be better appreciated in plantar flexion (►Fig.…”

“…The dorsolateral CCL looks like a thin broad band connecting the anterolateral corner of the calcaneus with the dorsal surface of the cuboid, where it inserts 5 mm distal to the joint line. In a cadaveric series, 47 anatomical variants of this ligament were reported in almost 50% of cases including a V-shaped morphology, a meniscoid band, or two (i.e., dorsal and lateral) or more separate bands. 47 The dorsolateral CCL is best examined with the patient supine or seated keeping the knee flexed and the foot inverted with its plantar aspect flat on the examination bed.…”

“…In a cadaveric series, 47 anatomical variants of this ligament were reported in almost 50% of cases including a V-shaped morphology, a meniscoid band, or two (i.e., dorsal and lateral) or more separate bands. 47 The dorsolateral CCL is best examined with the patient supine or seated keeping the knee flexed and the foot inverted with its plantar aspect flat on the examination bed. The probe should be placed horizontally over the CCj on the lateral aspect of the midfoot, keeping its shaft parallel to the sole.…”