From Workbasket Magazine:

Damp weather, arthritis, sports strain and strenuous workouts cause most of us to suffer muscle and joint aches at least once in a while. If you are bothered with an ache in the knee, you know it can be as annoying as the proverbial pain in the neck.

Knee warmers, worn in bed at night, keep the joints warm to stimulate natural muscle healing and soothing relief. Knit a pair and see for yourself.

Finished Measurements:

Small: 8.5” long; 6” across widest point
Medium: 8.5” long; 6.5” across widest point
Large: 8.5” long, 7” across widest point

Measurements given are for the unstretched knee warmer prior to wear.

Pattern calls for optional elastic thread.