From the Guidelines
To examine for ACL, PCL, and VA (varus/valgus) injuries, a comprehensive knee examination should be performed, starting with the Lachman test for ACL assessment, followed by the posterior drawer test for PCL evaluation, and varus and valgus stress tests for collateral ligament integrity, with positive findings warranting imaging studies like MRI for confirmation, as recommended by the American College of Radiology 1.
Key Examination Components
- Lachman test for ACL assessment: stabilize the femur with one hand while pulling the tibia forward with the other hand; excessive anterior translation indicates ACL injury
- Posterior drawer test for PCL evaluation: push the tibia posteriorly from a 90-degree flexed position; abnormal posterior movement suggests PCL damage
- Varus and valgus stress tests for collateral ligament integrity: apply medial and lateral force to the knee at 30 degrees of flexion
- Pivot shift test to detect rotational instability in ACL injuries
Importance of Early Detection
Early detection of these injuries is crucial as they can lead to joint instability and accelerated osteoarthritis if left untreated, as highlighted in a study by Koster et al 1, which found that the presence of a bone contusion on MRI after acute knee trauma is highly predictive of the development of focal osteoarthritis 1 year after trauma.
Role of Imaging Studies
Imaging studies like MRI are essential for confirming the diagnosis and assessing the severity of the injury, as they can detect patterns and severity of bone marrow contusions, meniscal tears, and ligament injuries, as reported by Magee and Williams 1, who found that 3T MRI has a high sensitivity and specificity for detecting meniscal tears.
Additional Considerations
The examination should also include assessment of joint effusion, range of motion, and neurovascular status to provide a complete clinical picture, and the Single Leg Hop and Crossover Hop tests may be useful in evaluating functional performance in individuals with ACL or meniscal injury, as suggested by a systematic review by the Optiknee Consensus 1.
From the Research
ACL and PCL Injuries Examination
- The examination for ACL and PCL injuries involves a combination of history, physical examination, imaging studies, and arthroscopic evaluation 2.
- For ACL injuries, the Lachman, anterior drawer, pivot shift, and lever sign tests are commonly used, with the lever sign test having the lowest LR- (0.21) and the pivot shift test having the highest LR+ (11.60) 3.
- A comprehensive clinical examination of the potentially ACL-deficient knee should include inspection, palpation, range of motion, varus and valgus stress, neurovascular status, and provocative maneuvers 4.
- The anterior drawer test, Lachman test, and pivot shift test are the most commonly used physical examination tests to evaluate cruciate ligament injury, with the Lachman test and pivot shift test being more difficult to perform 5.
- Non-invasive diagnostic methods, including the Anterior Drawer test, Lachman test, and magnetic resonance imaging (MRI), can be effective in detecting ACL tears, with MRI showing a sensitivity of 98.57%, specificity of 87.50%, and diagnostic accuracy of 96.51% 6.
Diagnostic Accuracy
- The diagnostic accuracy of physical examination tests for ACL injuries varies, with the Lachman test demonstrating a sensitivity of 90%, specificity of 87.5%, and diagnostic accuracy of 89.53% compared to arthroscopy 6.
- The anterior Drawer test exhibited a sensitivity of 88.57%, specificity of 87.50%, and diagnostic accuracy of 88.37% against the gold standard of arthroscopy 6.
- MRI is considered the gold standard imaging study for detecting ligament injuries, including ACL and PCL tears 2, 6.
Examination Techniques
- The "floppy ACL sign" and the posteromedial drive through sign are specific arthroscopic findings indicative of a PCL tear 2.
- Every knee scope should be preceded by an examination under anesthesia to ensure accurate diagnosis and treatment 2.
- Provocative maneuvers should be performed to evaluate the integrity of structures such as the posterolateral corner, posteromedial corner, and menisci, in addition to the ACL and PCL 4.