Cuboid Stress Fracture
So the ankle "sprain" I had turns out to be/have become a cuboid stress fracture.
"Patients with a cuboid stress fracture experience sharp pain at the plantar and lateral cuboid area of the foot. The pain is noted during heel lift and toe off while walking or running, however in some it is noted during minimal weightbearing. Pain on palpation of this area may be minimal, and no erythema oedema or rise in temperature may be found. However there were cases where there was pain on palpation over the cuboid and the peroneal tendons along the lateral aspect of the foot with passive inversion causing pain. Differential diagnosis include cuboid syndrome, peroneal longus tendinitis, fifth metatarsal base irritation and ligamentous strain.
That's that for running a marathon this year. This is my first stress fracture. I will have a lot of time to reflect on this one... I suspect that when I get back to running the memories of this experience will keep me in check and force me to be very conservative. I will try to improve my swimming and biking skills to get rid of this focus on running. Time will tell...