From the Guidelines
The Watson test is the primary clinical test for scapholunate ligament injury, and it should be performed in conjunction with other diagnostic tests such as the scaphoid shift test and the DISI test to assess for dorsal intercalated segment instability. To perform the Watson test, the examiner stabilizes the scaphoid bone with their thumb while applying pressure to the lunate with their other hand, creating a shearing force across the scapholunate joint. Pain or a clunking sensation during this maneuver suggests scapholunate ligament disruption. These physical examination findings should be correlated with the patient's history of wrist trauma, complaints of dorsal wrist pain, clicking sensations, or weakness with gripping activities.
Diagnostic Approach
While these clinical tests are valuable for initial assessment, they should be followed by imaging studies such as X-rays (including clenched fist views to look for scapholunate gap widening), MRI, or wrist arthroscopy for definitive diagnosis, as scapholunate ligament injuries can lead to progressive wrist instability and degenerative arthritis if not properly diagnosed and treated. According to the most recent study 1, MR arthrography has a higher sensitivity and specificity for the detection of scapholunate ligament injury, lunotriquetral ligament injury, and TFC injury.
Imaging Studies
The study also suggests that wrist traction improves detection of cartilage, TFC, and intrinsic ligament injuries 1. An interdisciplinary group of hand surgeons and radiologists consensus statements concluded that “MR arthrography provides better diagnostic accuracy for the determination of scapholunate interosseous ligament tears than MRI” and “MR arthrography or CT arthrography are generally recommended for the diagnostic workup for ligamentous and early cartilage defects” 1. However, another study 1 found that CT arthrography has the highest sensitivity, specificity, and accuracy for detecting scapholunate ligament tears, with nearly 100% sensitivity, specificity, and accuracy.
Recommendation
Based on the most recent and highest quality study, MR arthrography is recommended for the diagnostic workup of scapholunate ligament injuries. However, CT arthrography may also be considered as a diagnostic tool, especially for detecting partial ligament tears and articular cartilage defects 1. It is essential to note that the choice of imaging study should be based on the individual patient's needs and the clinical question being addressed.
Clinical Considerations
In clinical practice, it is crucial to consider the patient's history, physical examination findings, and imaging results when diagnosing and treating scapholunate ligament injuries. A comprehensive approach that includes clinical tests, imaging studies, and correlation with the patient's symptoms and history is necessary to ensure accurate diagnosis and effective treatment. As stated in the study 1, MR arthrography provides better diagnostic accuracy for the determination of scapholunate interosseous ligament tears than MRI, and it is generally recommended for the diagnostic workup for ligamentous and early cartilage defects.
From the Research
Clinical Tests for Scapholunate Ligament Injuries
- The scaphoid shift test is a commonly used clinical examination for scapholunate ligament pathologies, but its diagnostic value is limited, with a low sensitivity of 0.50 in a large cohort of patients 2.
- In a subgroup of patients specifically referred for suspected scapholunate ligament injury, the sensitivity of the scaphoid shift test was higher (0.61), but the specificity was low (0.62) 2.
- The scaphoid shift test demonstrated higher sensitivity (0.66) in detecting more serious lesions (Geissler 3 + 4) 2.
Diagnostic Approaches
- A noninvasive clinical tool can be developed to predict scapholunate interosseous ligament injury using kinematic and three-dimensional measurements, with a high accuracy rate of 93% 3.
- Conventional X-ray imaging, including static and dynamic radiographs, can be used to diagnose scapholunate ligament injuries, with the scapholunate distance (SLD) and carpal angles being useful parameters 4.
- A combination of SLD in ulnar inclination, SLD in PA projection, and scapholunate angle (SLA) can be used to diagnose scapholunate ligament injuries, with a high area under the curve (AUC) of 0.822 4.
Management Strategies
- Treatment of scapholunate ligament injuries is based on injury factors, patient factors, and surgeon preference, with options including nonsurgical, arthroscopic, repair, reconstruction, pain relieving measures, and salvage procedures 5.
- Classification systems, such as the Geissler grade, can be used to guide treatment decisions 5.