gnarled and knotty

The early Vikings colonized much of Europe over 1,000 years ago and discovered America long before Columbus, but Christopher had a better PR firm. However, the longboats carried more than just oarsmen. They carried a remarkable genetic disease producing contracture of the fingers on either hand, and which was later called Dupuytren’s Contracture after Baron Guillaume Dupuytren, who was once Napoleon’s surgeon.

Dupuytren’s contracture generally affects the fourth and fifth fingers of the hands and slowly flexes the fingers towards the palm of the hand. Eventually the fingers cannot be straightened out and the sufferer cannot put his hand in his pocket, without catching the finger(s) and it also becomes difficult to shake hands, as the flexed fingers make it difficult to open the hand.

TSC gnarled... adjective
knobbly, rough, and twisted, especially with age.