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

Prone Lachman with Ultrasound: A Literature Review and Description of the Technique

ABSTRACT

Magnetic resonance imaging is the current gold standard imaging modality for diagnosing anterior cruciate ligament (ACL) tears. However, ultrasound has grown in popularity for detecting ACL injuries because of its low cost, portability, and dynamic assessment capabilities. Recent studies demonstrate high sensitivity and specificity for diagnosing isolated ACL tears via ultrasound, but tremendous heterogeneity remains for optimal technique including patient positioning, transducer placement, and dynamic versus static ultrasound usage. As ultrasound becomes ubiquitous in clinics, training rooms, and on the sidelines, identifying objective and sensitive measurements to appropriately screen athletes for significant knee injuries is imperative. This article aims to review the current role of diagnostic ultrasound in ACL injuries and propose a standardized version of the Prone Lachman with Ultrasound test, which is an objective, reliable, and easily reproducible technique to evaluate ACL competency. Developing a standardized protocol will expand the use of point-of-care ultrasound, which may reduce cost and improve efficiency in care.

Evaluating the diagnostic pathway for acute ACL injuries in trauma centres: a systematic review

Objective

This review sought to evaluate the literature on the initial assessment and diagnostic pathway for patients with a suspected Anterior Cruciate Ligament (ACL) tear.

Methods

MEDLINE, EMBASE, and CINAHL were systematically searched for eligible studies, PRISMA guidelines were followed. Studies were included if they used at least one assessment method to assess for ACL injury and participants were assessed at an acute trauma centre within 6-weeks of injury. Article quality was evaluated using the QUADAS-2 checklist.

Results

A total of 353 studies were assessed for eligibility, 347 were excluded for the following reasons: injuries were not assessed in an acute trauma setting, injuries were not acute, participants had previous ACL injuries or chronic joint deformities affecting the knee, participants were under 18, or participants included animals or cadavers. A total of six studies were included in the review. Common assessment methods included: laxity tests, joint effusion, inability to continue activity, and a history of a ‘pop’ and ‘giving way’ at the time of injury. Diagnostic accuracy varied greatly between the assessment method and the assessing clinician. Gold standard diagnostics were MRI and arthroscopy. A weighted meta-mean calculated the time to reach diagnosis to be 68.60 days [CI 23.94, 113.24]. The mean number of appointments to reach diagnosis varied from 2–5. Delay to surgery or surgical consultation ranged from 61 to 328 days.

Conclusion

Clinicians in the Emergency Department are not proficient in performing the assessment methods that are used for diagnosis in acute ACL injury. Reliance on specialist assessments or radiological methods inevitably increases the time to reach a diagnosis, which has repercussions on management options. There is an ever-growing demand to improve diagnostic accuracy and efficiency; further exploration into quantitative measures of instability would aid the assessment of peripheral joint assessment.

Role of point-of-care ultrasonography (POCUS) in the diagnosing of acute medial meniscus injury of knee joint

BACKGROUND

In recent years, musculoskeletal ultrasound has increasingly become the common method for diagnosis for many medical specialties. Therefore, the present study was performed to evaluate the diagnostic value of point-of-care ultrasonography (POCUS) as a primary triage tool in the diagnosis of the acute medial meniscus injury of the knee.

MATERIALS AND METHODS

The present cross-sectional study was performed on patients with a suspected medial meniscus injury of the knee in the emergency department (ED). After history taking and primary physical examination, radiographic imaging of the knee was done. If there was no fracture in the knee X-ray, the POCUS examination on the knee was carried out. All the patients were asked to refer to an orthopedic clinic 2 weeks after discharge from ED for the Magnetic Resonance Imaging (MRI) evaluation. Finally, the POCUS findings were compared with the MRI findings in diagnosing medial meniscus injury.

RESULTS

Fifty-five patients with a mean age of 35.48 ± 11.58 years were analyzed in the study (69.1% male). In comparison with MRI scan, the sensitivity and specificity of POCUS in the detection of medial meniscus injury were 85.0 [95% confidence interval (CI), 54.0 to 98.9] and 65.7% [95% CI 42.2 to 85.7], respectively. Its positive and negative predictive values were 58.6% [95% CI 33.8 to 81.5] and 88.5% [95% CI 62.1 to 99.3], respectively. (Area under the ROC curve = 0.726, P value = 0.003).

CONCLUSION

The present study demonstrated that POCUS can reasonably be applied in comparison with MRI to evaluate medial meniscus injury. POCUS is an effective initial diagnostic modality in patients with suspected medial meniscus injuries.

Superb microvascular imaging (SMI) detects increased vascularity of the torn anterior cruciate ligament

PURPOSE

Ultrasound with superb microvascular imaging (SMI) is a novel microvascular imaging technology which may be useful to assess the vascularity of the torn anterior cruciate ligament (ACL) as a potential measure of healing potential following surgery. This study aimed to quantify the vascularity of the torn and intact ACL using ultrasound with SMI.

METHODS

23 patients (mean age ± standard deviation, 27.1 ± 12.8 years), who were diagnosed with an ACL tear with an intact contralateral ACL were enrolled (ACL injury group). Ten healthy volunteers (36.1 ± 4.9 years) who had intact ACLs in both knees were also recruited (ACL healthy controls). The vascularity of the ACL was assessed using SMI within 15 mm from the tibial insertion in both knees. The amount of the vascular signal was assessed using a semi-quantitative grading scale (vascularity grade: grade 0-3) and a quantified ratio of vascularized area with respect to total area of the region of interest (vascularity ratio).

RESULTS

In the ACL injury group, a significantly higher vascularity grade and ratio were observed in the torn ACL (vascularity grade 0-3: 1, 8, 7, and 7 patients, respectively; vascularity ratio: 1.3 ± 1.4%) than the contralateral intact ACL (vascularity grade 0-3: 21, 1, 1, and 0 patients, respectively; vascularity ratio: 0.1 ± 0.5%) (P < 0.001), whereas no significant difference was observed between both ACLs in the ACL healthy control group.

CONCLUSIONS

SMI was useful to assess the increased vascularity in torn ACL, which may reflect the potential for, or state of, ACL maturation following reconstruction or repair.

LEVEL OF EVIDENCE

Level III.

Ultrasound-based examination of the medial ligament complex shows gender- and age-related differences in laxity

PURPOSE

Ultrasound (US) examination of the medial joint space of the knee has played a subordinate diagnostic role up till now. The purpose of the present study was to describe mean values of medial joint width and to investigate the impact of gender, age, and body mass index (BMI) on medial joint laxity in healthy knees using modern, dynamic US in a standardized fashion in unloaded and standardized loaded conditions.

METHODS

A total of 65 subjects with 79 healthy knees were enrolled in this study. All volunteers underwent clinical examination of the knee. The medial knee joint width was determined using US in a supine position at 0° and 30° of knee flexion in unloaded and standardized loaded (= 15 Dekanewton, daN) conditions using a specific device. Mean values were described and correlations between medial knee joint width and gender, age, and BMI were assessed.

RESULTS

Thirty-two females and 33 males were enrolled in this study. The mean medial joint width in 0° unloaded was 5.7 ± 1.2 mm and 7.4 ± 1.4 mm loaded. In 30° of knee flexion, the mean medial joint width was 6.1 ± 1.1 mm unloaded and 7.8 ± 1.2 mm loaded. The average change between unloaded and loaded conditions in 0° was 1.7 ± 1.0 mm and in 30° 1.7 ± 0.9 mm. A significant difference between genders was evident for medial joint width in 0° and 30° of flexion in unloaded and loaded conditions (p < 0.05). With rising age, a significant increased change of medial joint space width between unloaded and loaded conditions could be demonstrated in 0° (p = 0.032). No significant correlation between BMI and medial joint width in US could be found.

CONCLUSION

Mean values of medial joint width in unloaded and standardized loaded conditions using a fixation device could be demonstrated. Based on the results of this study, medial knee joint width in US is gender- and age-related in healthy knees. These present data may be useful for evaluating patients with acute or chronic pathologies to the medial side of the knee.

LEVEL OF EVIDENCE

III.