Sounds like quite an accomplishment to get through that race. It makes adventure racing seem downright tame. I hope your knee will recover quickly.
Yeh, it was pretty neat event being the first time ever held. It is a lot trickier than adventure racing as you have not the luxury of extra gear. Likely it is time I had my knees looked at. The right one gets sore as I hurt my left one 3 years ago but continued to race and train at a slower speed putting all the stress on the right one.