A Pictorial Review Of Wrist Injuries In The Elite Golfer (P4)
Dorsal ganglion cysts of the wrist are the most common focal lesions in the hand and wrist in the general adult population and are also common in elite golfers. They are not true cysts as they have no epithelial lining, but instead have a pseudocapsule of compressed loose areolar tissue. Although the pathogenesis remains unclear, a commonly held view is that they are mucin filled lesions which arise from defects or tears in tendon sheaths and joint capsules. These defects lead to mucin extravasation through the damaged collagen bundles. The tight nature of the defects results in a one way valve system whereby the extravasated fluid can no longer return into its original space. Volar wrist ganglions are more common but tend to be asymptomatic. 60% of wrist ganglia that present clinically occur on the dorsal side typically as a 1-2cm painless soft tissue mass but they can cause be associated with a dull ache in the dorsum of the wrist which is more likely to irritate rather than debilitate. In elite golfers the majority occur in the leading wrist. The exact cause of pain is also controversial but compression of the terminal branches of the posterior interroseus nerve has been implicated as a potential cause. Dorsal ganglia tend to originate from the scapholunate joint or ligament and can also cause paraesthesia from compression of the ulnar or median nerves (or their branches).
On MR imaging ganglia are typically fluid signal being low signal on T1 weighted images and high signal on T2 weighted images, but a high proteinaceous content or haemorrhage can result in lesions appearing isointense or hyperintense on T1 weighted images. A narrow stalk connecting the ganglion to the joint is often visualised. The sonographic findings mirror MR, typically a hypoechoic fluid filled mass is seen with a narrow stalk extending towards the joint. An elongated neck can cause the ganglion to surface at distance from the joint and appear at an apparent atypical location. Complex ganglions can contain septations or display commet-tail artefacts and they are typically larger than simple ganglia. Ganglia are usually not compressible and the surrounding soft tissues are not hyperaemic except when there has been recent ganglion rupture or leakage when the surrounding tissues may be mildly hyperaemic and oedematous. Sonographically solid appearing ganglions have also been reported in the literature. Solid appearing ganglion are characteristically collapsed and can demonstrate increased central and peripheral colour doppler flow. There characteristics are non specific and the differential diagnosis can include proliferative synovitis, nodular fasciitis, giant cell tumor of the tendon sheath or a focal granulomatous process.