Cathy Branta of Wisconsin.... finished 2nd at World Cross in '85 (behind Zola Budd and ahead of Ingrid Kristiansen). Her career was ended in '86 when a knee scope determined she had 40% erosion of the medial meniscus and 5 stress fractures of the medial condyle (according to the book "Silence of Great Distance"). Very sad.
Also throw in Erica Palmer, '99 NCAA XC Champ, whose career was cut short by compartment syndrome. She did one of the most heart-wrenching interviews ever several years ago:
http://www.fast-women.com/athletes/interviews/ericapalmercordes.html
You could throw Julia Stamps in there (forgot her married name). Shattered her leg from a freak skate boarding accident. Still has managed to comeback and run well in the marathon.