Evaluating posterior cruciate ligament injury by using two-dimensional ultrasonography and sonoelastography

The use of ultrasonography as an effective screening tool for chronic posterior cruciate ligament injuries

PURPOSE

We aimed to explore the applicability and validity of ultrasonography for diagnosing chronic posterior cruciate ligament (PCL) injuries.

METHODS

PCL thickness was measured at 2 cm proximal to the tibia insertion site. Using the same ultrasonography image, the angle tangent to the PCL from the tibia insertion site was also measured. These data were analyzed by plotting the receiver operating curve (ROC), and the sensitivity and specificity were calculated according to the optimal cut-off point. Ultrasonography data from the PCLinjured knee were compared with those from the contralateral uninjured knee of the same patient.

RESULTS

Twelve men and six women, with a mean age of 28.8 ± 14.0 years, were included in this study. The mean time from injury to medical examination was 10.0 ± 6.7 months. The mean thickness of the PCL was 8.1 ± 1.9 mm on the affected side and 5.8 ± 1.2 mm on the uninjured side, with the affected side being significantly thicker. ROC analysis revealed that the optimal cut-off value for the thickness of chronic PCL injuries was 6.5 mm (sensitivity 83.3%, specificity 77.8%, area under the curve [AUC] = 0.87). The optimal cut-off value for the angle was 20° (sensitivity 88.9%, specificity 94.4%, AUC = 0.96).

CONCLUSION

Ultrasonography is useful as a screening tool for chronic PCL injuries. The optimal cut-off point was 6.5 mm for thickness and 20° for angle.

LEVEL OF EVIDENCE

IV.

Point-of-Care Ultrasound for the Evaluation and Management of Posterior Cruciate Ligament Injuries: A Systematic Review

Posterior cruciate ligament (PCL) injuries, though less common than other knee ligament injuries, pose significant management challenges. This study aimed to systematically review and analyze the current evidence on the use of point-of-care ultrasound (POCUS) for the evaluation and management of PCL injuries. It was hypothesized that POCUS has comparable diagnostic accuracy to magnetic resonance imaging (MRI) and that the use of POCUS improves patient outcomes and reduces healthcare costs. A comprehensive systematic review of articles published up to April 2023 was conducted using PubMed, Web of Science, Cochrane, and Scopus databases and adhered to the PRISMA guidelines. Studies were selected based on relevance to the research question, with a focus on diagnostic accuracy, reliability, clinical utility, and cost-effectiveness of POCUS in PCL injuries. Seven studies, analyzing a total of 242 patients with PCL injuries, were included. The reported sensitivity and specificity of POCUS for diagnosing PCL injuries ranged from 83.3% to 100% and 86.7% to 100%, respectively, across the studies. In one study, POCUS demonstrated a positive predictive value (PPV) of 87.9% and a negative predictive value (NPV) of 82.4%. Additionally, three studies reported 100% accuracy in PCL injury detection using POCUS, suggesting a substantial potential for cost savings by eliminating the need for MRI. This systematic review supports the use of POCUS in the evaluation and management of PCL injuries, suggesting that POCUS is a reliable, cost-effective tool with high diagnostic accuracy comparable to that of MRI, offering the potential to improve patient outcomes and reduce healthcare costs. The data collated in this review can inform clinical practice and guide future research in the field.

The effect of thickness and elastic modulus of the anterior talofibular ligament on anterior ankle joint stiffness: A subject-specific finite element study

Ankle sprain is a frequent type of sports injury leading to lateral ligament injury. The anterior talofibular ligament (ATFL) is a primary ligamentous stabilizer of the ankle joint and typically the most vulnerable ligament injured in a lateral ankle sprain (LAS). This study aimed to quantitively investigate the effect of the thickness and elastic modulus of ATFL on anterior ankle joint stiffness (AAJS) by developing nine subject-specific finite element (FE) models under acute injury, chronic injury, and control conditions of ATFL. A 120 N forward force was applied at the posterior calcaneus leading to an anterior translation of the calcaneus and talus to simulate the anterior drawer test (ADT). In the results, the ratio of the forward force to the talar displacement was used to assess the AAJS, which increased by 5.85% in the acute group and decreased by 19.78% in the chronic group, compared to those of the control group. An empirical equation described the relationship between AAJS, thickness, and elastic modulus (R-square 0.98). The equation proposed in this study provided an approach to quantify AAJS and revealed the effect of the thickness and the elastic modulus of ATFL on ankle stability, which may shed light on the potential diagnosis of lateral ligament injury.

Imaging Review of the Posterior Cruciate Ligament

Posterior cruciate ligament (PCL) injuries can often be missed on physical examination, especially in multiligament knee injuries. Therefore, a comprehensive approach to imaging the PCL should be implemented whenever history and examination findings indicate relative risk. Radiography, including a posterior-stress view, and magnetic resonance imaging, when available, provide consistently accurate diagnosis of PCL pathology and common knee comorbidities. Computed tomography and ultrasonography can be useful modalities with potential advantages with respect to availability and access, specific comorbidities, and/or cost-effectiveness.

ACR Appropriateness Criteria® Acute Trauma to the Knee

Acute trauma to the knee is a common presentation seen in the emergency department. After a routine clinical examination, imaging is frequently performed to facilitate the diagnosis and almost always starts with radiographs. If clinically indicated, advanced cross-sectional imaging may then be performed for further evaluation. CT is often performed for preoperative planning of the complex tibial plateau and distal femur fractures. Currently, MRI is the study of choice for evaluation of bone marrow, internal derangements, and other soft-tissue injuries about the knee joint. In patients with knee dislocations, MR angiography may be performed simultaneously with MRI for evaluation of internal derangements and vascular injuries with less morbidity compared to conventional angiography. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Efficiency of knee ultrasound for diagnosing anterior cruciate ligament and posterior cruciate ligament injuries: a systematic review and meta-analysis

OBJECTIVE

To evaluate the diagnostic performance of knee ultrasound for anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) injuries.

MATERIALS AND METHODS

PubMed and EMBASE databases were searched for diagnostic accuracy studies that used ultrasound for diagnosing ACL and PCL injuries. Bivariate and hierarchical summary receiver operating characteristic modeling was used to evaluate diagnostic performance. Subgroup analysis was performed by assessing studies conducted using the ultrasound technique (functional ultrasound versus conventional ultrasound) for diagnosing ACL injury. We performed meta-regression analyses for a potential source of heterogeneity.

RESULTS

Eleven (938 ultrasound/878 patients) and six articles (281 ultrasound/237 patients) were included for ACL and PCL injuries respectively. The summary sensitivity, summary specificity, and area under the hierarchical summary receiver operating characteristic for ACL and PCL injuries were 0.88 (95% confidence interval [CI], 0.81-0.93) and 0.99 (95% CI, 0.49-1.00), 0.96 (95% CI, 0.91-0.98) and 0.99 (95% CI, 0.73-1.00), and 0.97 (95% CI, 0.96-0.98) and 1.00 (95% CI, 0.99-1.00) respectively. In subgroup analysis, there was no significant difference between sensitivity (p = 0.63) and specificity (p = 0.72) of functional and conventional ultrasound. Among the various potential covariates, patient enrollment, patient position, and ultrasound performer were associated with heterogeneity in terms of sensitivity, and proportion of the ACL injury was associated with heterogeneity in terms of specificity.

CONCLUSION

Knee ultrasound demonstrates high diagnostic performance for ACL and PCL injuries, particularly when performed by experienced musculoskeletal radiologists. Future prospective studies to compare the cost- and time-effectiveness between ultrasound and magnetic resonance imaging and to determine the optimal ultrasound parameters are warranted.

Feasibility of point-of-care knee ultrasonography for diagnosing anterior cruciate and posterior cruciate ligament tears in the ED

OBJECTIVE

To evaluate the feasibility of point-of-care knee ultrasonography (POCUS) compared with knee magnetic resonance imaging (MRI) for diagnosing anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) tears in patients with acute knee trauma.

MATERIAL AND METHODS

A prospective study was conducted in a tertiary hospital emergency department; acute (within 1-week) knee trauma patients with suspected ACL or PCL tear were recruited. Two POCUS performers (a board-certified emergency physician and a musculoskeletal radiologist) independently evaluated the ACL and PCL using POCUS. Findings were classified as normal appearance or ligament tear. Final radiology reports of knee MRI were used as the reference standard. We calculated the diagnostic values (sensitivity, specificity, and accuracy) for POCUS obtained by both POCUS performers. Kappa values (k) were calculated for inter-observer agreement between the two POCUS performers.

RESULTS

Sixty-two patients were enrolled. Compared with the reference standard, POCUS showed acceptable sensitivity (90.6-100%), specificity (90.0-97.7%), and accuracy (91.9-96.8%). Inter-observer agreement between the two POCUS performers was excellent (k = 0.853-0.903).

CONCLUSION

POCUS demonstrates excellent precision as compared to MRI in the diagnosis of ACL and PCL tears. The findings of POCUS could be used for immediate diagnosis and further pre-operative imaging in patients with acute knee trauma.