I was playing around in an historical database and came across this article from the British Medical Journal, 1984:

Fly fisher's finger

I want to report a new sign associated with fly fishing. At the height of the fly fishing season last year-a patient in his 40s developed severe pain and swelling in his left middle finger. The finger was particularly painful and swollen the morning after a full day's boat fishing on Rutland Water. The proximal interphalangeal joint was red, swollen, and had limited movement. Within 48 hours this had settled with no specific treatment other than rest. It occurred on two further occasions after similar expeditions.

Over the past few years there has been a dramatic change in fly fishing techniques, particularly on large reservoirs. The traditional lightweight tackle approach of catching surface fish has been replaced in many instances by fishermen adopting deep sea trawler like tactics. This entails using heavily loaded lines which sink rapidly to the bottom, where monster trout may He waiting. Indeed, trout of 10 lb or more are often caught at Rutland Water. Many metres of line lie out behind the boat, which is moving with the wind on the rudder. This line is then rapidly retrieved, usually by the left hand in a right-handed person, and trauma results to the fingers.

This technique has many rewards for the aficionados of this style but is abhorred by the traditionalists. It is likely to increase, particularly as more specimen trout are being caught in the deeper waters.

A. C. B. Wicks, physician, Leicester."