Scapholunate dissociation: an overview of the clinical entity and current treatment options

The tangential view described by Moneim to demonstrate scapholunate dissociation: an update

PURPOSE

Scapholunate dissociation is a common and significant injury to the wrist. Radiographs are important in the diagnosis of this injury and in the planning of treatment. The tangential radiograph view was described almost 40 years ago as a method for accurately measuring scapholunate gaps. The hand is positioned on a 20° foam rubber block and the thumb on the cassette, which positions the scaphoid and lunate articular surfaces parallel, without patient discomfort or effort. The goal of this study was to review this method with more recent data and in a larger group of patients.

METHODS

Radiographs of 31 patients who had scapholunate interosseous ligament tears and surgical repair over a 9 year period were retrospectively evaluated. Each of the four authors independently measured scapholunate gaps for posteroanterior and tangential views.

RESULTS

The tangential view gaps were significantly greater than the posteroanterior gaps overall. Similar results were found for borderline cases where the posteroanterior gap was less than 3 mm. Every tangential view gap measurement was greater than its respective posteroanterior gap with good inter-rater reliability.

CONCLUSION

The tangential view is a reliable radiographic method to identify scapholunate gaps. It should be obtained when there is clinical concern for scapholunate dissociation, especially in patients with borderline posteroanterior gaps.

The role of arthroscopy in carpal instability

Carpal instability is predominantly caused by trauma and presents as a painful wrist with signs and symptoms of weakness, clicking, clunking and a sense of giving way. Wrist arthroscopy is widely regarded as the 'gold standard' in diagnosing and understanding carpal instability. This article is based on an extensive literature search to evaluate the evidence behind the use of wrist arthroscopy in the assessment and management of these patients. There is convincing evidence supporting the role of arthroscopy in diagnosis and assessment of factors involved in the development of carpal instability, but weak evidence for the effectiveness of arthroscopic techniques in the actual treatment of this condition. The article reviews mechanisms behind, and the role for arthroscopy in the management of scapholunate, lunotriquetral, midcarpal and radiocarpal instability. It also presents how the author incorporates the 'evidence-base' into an 'experience-based' clinical practice.