OrthoDx: Scapholunate Ligament Injury

Slideshow

  • Figure 1. Bilateral clenched fist radiograph shows a symmetric scapholunate interval compared with the opposite side.

  • Figure 2. Coronal MRI of the wrist shows synovitis throughout and a partial tear of the scapholunate ligament.

A 46-year-old man presents with a 1-week history of left wrist pain. The patient tripped and fell on his outstretched arm at work, landing directly on his hand with his palm up. A few hours after the injury he noticed pain when lifting objects and swelling developed over the dorsal aspect of his hand. On physical examination of the wrist, the patient has mild synovitis to the wrist joint and dorsal tenderness to palpation over the scapholunate interval. He has limited range of motion of the wrist with 30 degrees of flexion and 40 degrees of extension. Bilateral clenched fist radiography (Figure 1) shows a symmetric scapholunate interval compared with the opposite side. Wrist magnetic resonance imaging (coronal MRI image, Figure 2) shows synovitis throughout the wrist and a partial tear of the scapholunate ligament.

The scapholunate ligament is an interosseous structure that stabilizes and connects the scaphoid and lunate bones during wrist motion. The scapholunate ligament has 3 parts: dorsal (strongest part of ligament), intermediary, and volar. Injury to the scapholunate ligament is commonly...

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The scapholunate ligament is an interosseous structure that stabilizes and connects the scaphoid and lunate bones during wrist motion. The scapholunate ligament has 3 parts: dorsal (strongest part of ligament), intermediary, and volar. Injury to the scapholunate ligament is commonly caused by a fall on an outstretched hand, which may cause dorsal wrist pain and swelling.1,2

Tears of the scapholunate ligament are often missed on anteroposterior (AP) radiography. A clenched fist view is a dynamic radiographic study to help diagnose a scapholunate injury and will show widening of the scapholunate interval. Bilateral clenched fist views are recommended as they consistently pick up scapholunate gaps (if present) and subtle changes. A scapholunate gap of more than 3 mm is considered abnormal and unstable. The best imaging study to diagnose scapholunate ligament tears is MRI, which can determine the extent of injury ranging from partial, complete repairable, and complete irreparable tears. Missed scapholunate ligament injuries can progress from a partial tear to complete tear without timely treatment, leading to wrist instability and progressive arthritis.1,2

Nonoperative treatment for nondisplaced scapholunate injuries is recommended and may include casting or splinting the wrist. Complete tears found on MRI and scapholunate widening found on dynamic radiography should be treated operatively.1,2

Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopedics for Physician Assistants.

References

1. Schmitz MW, Morrell NT, Jacobs RC. Diagnosis and surgical treatment of acute scapholunate ligament injuries. JBJS JOPA. 2021;9(2):e20.00039. doi:10.2106/JBJS.JOPA.20.00039

2. Pappou IP, Basel J, Deal DN. Scapholunate ligament injuries: a review of current concepts. Hand. 2013;8(2):146-156. doi:10.1007/s11552-013-9499-4

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