Chloe Kim, Red Gerard, and soon, Mikaela Shiffrin are representing the USA well in Pyeongchang, South Korea. So, let’s have a look at a winter sports case!
This 17-year-old female fell during a winter-related sporting accident, and now presents with right thumb pain. You are shown three finger coil images. Image 1 uses a coronal 3D data set.
Q1 – When falling, the patient attempted to brace herself using the sporting equipment in hand. What do you think the sport was?
Q2 – What is the name of the entity?
Q3 – What is the abnormality?
Q4 (BONUS QUESTION) – Why does a Stener lesion occur more frequently on the medial than the lateral side of the thumb?
A1 – Skiing.
A2 – Skier’s thumb.
A3 – Avulsion fracture to include the distal insertion of the ulnar collateral ligament (UCL) involving the base of the medial proximal phalanx.
A4 – While this is not a Stener lesion (folded entrapment of the proximal retracted UCL ensconced by the adductor aponeurosis), the reason is simple:
(a) The aponeurosis on the radial side of the thumb is more vertical, or oriented straight and parallel to the collateral ligament. This parallel course does not permit the deeper radial collateral ligament from transgressing the radial aponeurosis.
(b) On the other hand, the adductor aponeurosis has an oblique course allowing the UCL to retract underneath it, flap backwards, and then flip over the top.
The pink and blue arrows on images 4 and 5 highlight the avulsion fracture. On image 6, the oblique course of the adductor aponeurosis is indicated with a red line demarcated by a green arrow. The UCL will get caught in a small notch proximal to this (image 6, yellow arrow). The straighter course of the radial aponeurosis is highlighted with a purple line. You can see how much more oblique the adductor aponeurosis is by tracing the red line.
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