From The African Violet Factsheet, this source gives hope:
Repot violets about once a year, or when the leafless portion of the stem is about 1 to 1 1/2 inches long. Gently remove the plant from the pot with a paring knife. Remove all lateral crowns, leaving only the center crown. Trim off one or two rows of leaves, leaving a wheel of leaves around the crown. With the paring knife, scrape the neck as you would a carrot until all the brown plant material is removed and the neck is firm and green. Break or cut off the bottom half of the root. Have a clean pot ready for the pruned violet. Gently firm in new soil around the plant and water well. The pot should be one-third the diameter of the plant; a 4-inch pot is usually adequate.
Similarly, from Gardening Guide:
When it is time to repot, remove all crowns from your African violet except for the central one. Also, trim leaves from the plant, leaving a circle of leaves around the crown. Use a paring knife to scrape through the brown plant matter on the neck of your plant. When you see green, break off half the root and set your pruned African Violet into the pot, placing the crown just above the surface. Press the mixture firmly around the crown and water your plant well.
Alrighty, let's see what happens. Here is a picture of the sickly African Violet before, and after, transplantation into fresh potting soil especially designed 
for this delicate little guy.
Time will tell if these efforts of paring down the root and repotting the pruned plant will bring it back to better health. More pictures to follow in the future ... let's hope it survives.
for this delicate little guy.
Time will tell if these efforts of paring down the root and repotting the pruned plant will bring it back to better health. More pictures to follow in the future ... let's hope it survives.
The final replanted violet, the crown pruned, its roots tamped into fresh soil, re-watered, but still in need of its bottom leaves pared down to a circle:
