Limited intrarater and interrater reliability of acute ligamentous ankle injuries on 3 T MRI

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.

Arthroscopic Quantitative Measurement of Medial Clear Space for Deltoid Injury of the Ankle: A Cadaveric Comparative Study With Stress Radiography

BACKGROUND

The deltoid ligament (DL) is an important stabilizer of the ankle. DL injury of varying severity can occur alone or with syndesmotic injury and fibular fracture. Limited diagnostic tools are available to assess DL injury quantitatively.

PURPOSE

To establish an arthroscopic quantitative assessment of DL injury and to compare its performance with that of external rotation stress (ERS) and gravity stress (GS) radiography.

STUDY DESIGN

Controlled laboratory study.

METHODS

In total, 24 cadaveric lower extremities were divided into 4 groups: group 1 consisted of intact DL, group 2 of superficial DL disruption, group 3 of deep DL disruption, and group 4 of complete DL (superficial and deep) disruption. All specimens underwent sequential sectioning of syndesmotic ligaments, and medial clear space (MCS) was measured with ankle arthroscopy, ERS radiography, and GS radiography at different stages of syndesmotic sectioning.

RESULTS

For noninjured deltoid (group 1) and injured deltoid (groups 2-4), area under the receiver operating characteristic curve (AUC) of measurement of MCS was 0.939 for arthroscopy, 0.932 for ERS radiography, and 0.874 for GS radiography, with a significant difference between arthroscopy and GS radiography (P = .014). For incomplete deltoid injury (groups 1-3) and complete deltoid injury (group 4), the AUC of MCS was 0.811 for arthroscopy, 0.656 for ERS radiography, and 0.721 for GS radiography, with a significant difference between arthroscopy and ERS radiography (P < .001) and between arthroscopy and GS radiography (P = .035). For all stages of syndesmotic sectioning, cutoff values of arthroscopic MCS with intact fibula were ≤2.5 mm for intact DL, between 2.5 and 3.5 mm for partial DL injury (superficial or deep), and ≥3.5 mm for complete DL injury. Arthroscopy was unable to detect a difference between superficial deltoid injury (group 2) and deep deltoid injury (group 3) in partial DL injury, with a measured MCS between 2.5 and 3.5 mm. The intraclass correlation coefficient of interrater reliability was 0.975 for arthroscopy, 0.917 for ERS radiography, and 0.811 for GS radiography.

CONCLUSION

Arthroscopic MCS measurement can differentiate intact DL, partial DL injury, and complete DL injury. Compared with ERS and GS radiography, arthroscopic MCS measurement has greater accuracy with excellent interrater reliability.

CLINICAL RELEVANCE

For patients with suspected DL injury, arthroscopic MCS is useful for determining deltoid lesion severity based on defined cutoff values for consideration in preoperative planning to improve surgical outcomes.

The Role of Diffusion Weighted MR Imaging in the Diagnosis of Tendon Injuries of the Ankle and Foot

Background and objectives: Our aim is to determine the diagnostic performance and utility of Diffusion Weighted MR Imaging (DWI) against the routine Magnetic Resonance Imaging (MRI) for the evaluation of patients with tendon injuries of the ankle and foot. Materials and Method: After institutional review board approval and informed consent taken from all the patients, ankle and foot MR imaging and DWI-Apparent Diffusion Coefficient (ADC) mapping were performed on the 81 injured tendons of 50 patients. All tendon injuries were named as Rupture (R), Partial tear (PT), and Tenosynovitis (T). Diagnostic interpretation was based on the MRI-DWI and ADC mapping, verified by either open surgery, diagnostic arthroscopy, or conservative procedures-splint application. Statistical analysis of this research was assessed by Fischer’s exact test, variance analysis test between dependent groups, Receiver Operating Characteristics (ROC) curve, and Pearson chi square statistics. Results: MRI depicted all tendon injuries with 70% sensitivity and 100% specificity, and showed a significant statistical relationship to surgical and arthroscopic references with high agreement (p < 0.05, k: 0.609). DWI had 100% sensitivity and 83–90% specificity for the visualization of tendon injuries with certain agreement and a significant statistical relationship to the gold standard (p < 0.05, k: 0.890–0.899). For all those injured tendons, DWI had 100% sensitivity for the diagnosis of R, and 92–97% sensitivity corresponding to PT and T over routine ankle MR imaging. The specificity of DWI to MRI ranged from 75 to 44% for all the injured tendons. DWI had significant statistical superiority over MRI for the visualization of R, PT, and T of all tendons included in this research (p < 0.05). Conclusions: DWI is a good imaging modality for the visualization of ankles with tendon injuries, possibly further improving the sensitivity of the classical ankle and foot MRI, and supplying more beneficial and diagnostic information than routine MR imaging on the basis of R, PT, and T of tendons at the ankle and foot.

Acute clinical evaluation for syndesmosis injury has high diagnostic value

PURPOSE

To determine the diagnostic value of injury history, physical examination, six syndesmosis tests and overall clinical suspicion for syndesmosis injury.

METHODS

All athletes (> 18 yrs) with an acute ankle injury presenting within 7 days post-injury were assessed for eligibility. Acute ankle injuries were excluded if imaging studies demonstrated a frank fracture or 3 T MRI could not be acquired within 10 days post-injury. Standardized injury history was recorded, and physical examination was performed by an Orthopaedic Surgeon or Sports Medicine Physician. Overall clinical suspicion was documented prior to MRI. Multivariate logistic regression was used to determine the association between independent predictors and syndesmosis injury.

RESULTS

Between September 2016 and July 2019, a total of 150 acute ankle injuries were included. The median time from injury to acute clinical evaluation was 2 days (IQR 2). Prior to clinical evaluation, the median patient reported Visual Analog Scale for pain was 8/10 (IQR 2). Syndesmosis injury was present in 26 acute ankle injuries. An eversion mechanism of injury had a positive LR 3.47 (CI 95% 1.55-7.77). The squeeze tests had a positive LR of 2.20 (CI 95% 1.29-3.77) and a negative LR of 0.68 (CI 95% 0.48-0.98). Overall clinical suspicion had a sensitivity of 73% (CI 95% 52-88) and negative predictive value of 89% (CI 95% 78-95). Multivariate regression analyses demonstrated significant association for eversion mechanism of injury (OR 4.99; CI 95% 1.56-16.01) and a positive squeeze test (OR 3.25; CI 95% 1.24-8.51).

CONCLUSIONS

In an acute clinical setting with patients reporting high levels of ankle pain, a negative overall clinical suspicion reduces the probability of syndesmosis injury. Eversion mechanism of injury and a positive squeeze test are associated with higher odds of syndesmosis injury.

LEVEL OF EVIDENCE

Level III.