Quantitative Analysis of Deltoid Ligament Degradation in Patients With Chronic Ankle Instability Using Computed Tomographic Images

Bone marrow edema at ligament insertion is an accurate MRI sign of deltoid ligament injury

BACKGROUND

Magnetic resonance imaging (MRI) is effective in diagnosing deltoid ligament (DL) injury but its sensitivity in chronic cases is low. Additional diagnostic signs are required to reduce the risk of a false negative diagnosis.

PURPOSE

To evaluate the added diagnostic value of bone marrow edema at the ligament insertion (BMELI) of DL to the MRI assessment of chronic DL injury.

MATERIAL AND METHODS

One hundred patients who consecutively came to our institution between November 2018 and December 2021 and underwent arthroscopic surgery for chronic ankle instability (CAI) were enrolled in the present study. Preoperative MR images were retrospectively reviewed by two orthopedic surgeons to evaluate the sensitivity, specificity and interobserver reliability of three MRI signs in diagnosing chronic DL injury, namely, abnormal ligamentous morphological characteristics (ALMC), BMELI and medial clear space (MCS).

RESULTS

Taking arthroscopy as the reference standard, there were 34 patients with and 66 without DL injury. ALMC had 64.71% (22/34; 46.47-79.70) sensitivity and 83.33% (55/66; 71.71-91.00) specificity, BMELI had 70.59% (24/34; 52.33-84.29) sensitivity and 95.45% (63/66; 86.44-98.82) specificity and MCS had 26.47% (9/34; 13.51-44.65) sensitivity and 92.42% (61/66; 82.50-97.18) specificity. Compared with ALMC, BMELI had similar efficacy in superficial cases (P = 0.06) and greater efficacy in deep cases (P = 0.04). All three signs showed good interobserver agreement (kappa values all above 0.7).

CONCLUSION

BMELI can reliably indicate concomitant injury to the DL in CAI patients. Using BMELI as a sign of chronic DL injury when ALMC is unclear may reduce the risk of a false negative diagnosis.

Multidirectional Chronic Ankle Instability: What Is It?

Not all ankle sprains are the same and not all ankles behave the same way after an injury. Although we do not know the mechanisms behind an injury producing an unstable joint, we do know ankle sprains are highly underestimated. While some of the presumed lateral ligament lesions might eventually heal and produce minor symptoms, a substantial number of patients will not have the same outcome. The presence of associated injuries, such as additional medial chronic ankle instability, chronic syndesmotic instability, has been long discussed as a possible reason behind this. To explain multidirectional chronic ankle instability, this article aims to present the literature surrounding the condition and its importance nowadays.

Ankle Instability Update

Sprains are the most frequent injuries of the ankle, especially in sports. Up to 85% of cases affect the lateral ligament complex. Multi-ligament injuries with associated lesions of the external complex, deltoid, syndesmosis, and sinus tarsi ligaments are also common. Most ankle sprains respond to conservative treatment. However, up to 20 to 30% of patients can develop chronic ankle pain and instability.New concepts have been recently developed, based on arthroscopic advances, such as microinstability and rotatory ankle instability. These entities could be precursors of mechanical ankle instability and at the origin of frequently associated ankle injuries, such as peroneus tendon lesions, impingement syndromes, or osteochondral lesions.Imaging methods, especially magnetic resonance (MR) imaging and MR arthrography, are key in precisely diagnosing ligament lesions and associated injuries, facilitating an adequate therapeutic approach.

A Preliminary Study to Assess the Relevance of Shear-Wave Elastography in Characterizing Biomechanical Changes in the Deltoid Ligament Complex in Relation to Ankle Position

BACKGROUND

The purpose of this study was (1) to evaluate the biomechanical properties of the different bundles of the deltoid ligament in various ankle positions in a cohort of healthy adult volunteers; (2) describe the impact of demographic and hindfoot morphology characteristics on their stiffness; (3) to assess the reliability and reproducibility of these measurements.

METHODS

Deltoid ligament complex of both ankles were assessed by shear-wave elastography (SWE) in 20 healthy patients resting on hinge support. The propagation shear-wave speed (SWS) in ligaments was measured, which is related to the tissue's elastic modulus. The following ligaments were analyzed in a neutral position and then in varus, valgus, dorsal, and plantar flexions: tibionavicular ligament (TNL), tibiocalcaneal ligament (TCL), the superficial posterior tibiotalar ligament (SPTL), the anterior tibiotalar ligament (ATTL), and the deep posterior tibiotalar ligament (DPTTL).

RESULTS

The mean SWS increased between neutral and 20 degrees valgus position for TCL (4.08 ± 0.78 m/s vs 5.56 ± 0.62 m/s, respectively; P < .0001) and for DPTTL (2.58 ± 0.52 m/s vs 3.59 ± 0.87 m/s, respectively; P < .0001). The mean SWS increased between neutral and 30 degrees plantarflexion for ATTL (2.11 ± 0.44 m/s vs 3.1 ± 0.5 m/s, respectively; P < .0001) and TNL (2.96 ± 0.66 m/s vs 4.99 ± 0.69 m/s, respectively; P < .0001). The mean SWS increased between neutral and 20 degrees dorsal flexion for SPTL (4.2 ± 1 m/s vs 5.45 ± 0.65 m/s, respectively; P < .0001).Women had less DPTTL SWS than men in the neutral position (2.37 ± 0.35 m/s vs 2.71 ± 0.49 m/s, respectively; P = .007). Other demographics had no impact on the SWS value of other ligaments. All inter- and intraobserver agreements were good to excellent.

CONCLUSION

This study presents a reliable and reproducible SWE measurement protocol to describe the physiological function of all bundles of the medial collateral ligament in healthy adults.

CLINICAL RELEVANCE

This examination technique can be available to orthopaedic surgeons, allowing reliable and reproducible monitoring of the SWS of the various ligaments constituting the medial collateral plane. The biomechanical values described in this study may give insight into in what position medial ankle ligament reconstruction should be tensioned.