Sunday, October 19, 2008

Skier's Thumb and Partial Stener Lesions

Skiing in the crisp mountain air, beneath a blue sky, is one of life's true pleasures.

Photo by Spatial Mongrel
Eventually, every skier falls backward in a fall, and hyperabducts the thumb MCP joint. That places them at risk for "skier's thumb", the eponym for a tear of the ulnar collateral ligament. Historically, the UCL was often chronically injured in gamekeepers, who killed rabbits and other small game by breaking their necks between the ground and their thumbs and index fingers.

Bertil Stener was a Swedish hand surgeon who elucidated the cause of chronic instability in patients with ulnar collateral ligament tears:

Stener noted that in some patients with UCL tears, the torn ligament would retract superficial to the aponeurosis of the overlying adductor pollicis muscle. The interposed adductor aponeurosis prevented healing of the torn UCL.

In most cases, a Stener lesion represents a complete rupture of the UCL. This is not always true however, as pointed out by Romano et al. (Can Assoc Radiol J 2003;54(4):243-8) in an excellent article on the spectrum of ulnar collateral ligament injuries. They observed that in some patients, "a large component of the redundant ligament was displaced proximally and dorsally, as would be found in a Stener’s lesion, but the distal end remained beneath the aponeurosis, which distinguished it from a classic Stener’s lesion".

This article goes on to note that "this contradicts previous claims that adductor aponeurosis interposition cannot occur in partial ruptures".

Twenty-seven year old patient with trauma to the thumb, and clinical evidence of a thumb UCL tear, who was referred for an MRI, to rule out a Stener lesion:

Coronal T2-weighted images with fat saturation reveal a torn, retracted UCL (red arrows), superficial to the adductor aponeurosis (yellow arrows). Note that although the majority of the UCL is retracted proximally, there remains a portion of the ligament (white arrow) that remains underneath the aponeurosis.

Thus, although a Stener lesion typically reflects a complete tear of the UCL, in a minority of cases one can have partial tears of the UCL leading to a Stener configuration.



Vic David MD
Orthoradiology.com

1 comment:

P. said...

is there a way to upload or email images for a second opinion on your blog

thanks p albert winrad at yahoo.com