Duque’s recovery is not only a success story but also the inspiration for EquiPhysics.

He was injured in a pasture accident, likely fighting over the fence with another gelding. Initial radiographs showed no fracture, which is not uncommon—fractures can take time to become visible. Meanwhile, a small cut at the site of the wound became infected, leading to cellulitis. He was put on oral antibiotics, and new radiographs revealed a fracture of the lateral splint bone in his right hind leg.

Duque went for surgery in Phoenix. Because of the cellulitis and location of the fracture, the procedure included the removal of the entire splint bone, including the section forming part of the hock joint. He remained in the clinic for a week of IV antibiotics, where the infection was stabilized. He then went to Miller Equine Rehab in Cave Creek for three months of intensive therapy, including cold saltwater spa treatments, shockwave therapy, and pulsed electromagnetic field (PEMF) therapy. The prognosis was poor. Because the entire splint bone was removed and complicated by infection, several veterinarians told me that Duque might never return to soundness.

Conflicting opinions left me searching for answers. As a mathematician who studies how animals move, my background had been in jellyfish propulsion and insect flight. But faced with Duque’s injury, I turned my academic skills toward horses. I began reading veterinary literature directly and came across Baxter et al. (1992), which reported good outcomes after complete removal of the fourth metatarsal bone in eight horses. This gave me a scientific basis to hope for Duque’s recovery and guided me to pursue rehabilitation cautiously.

Duque’s rehabilitation was long and structured. Nine months of stall rest and hand-walking in Tucson gradually gave way to short sessions of free trotting, lunging, and eventually mounted walking and trotting. Step by step, we designed his exercise program the way I would design an experiment: carefully increasing load, documenting responses, and validating progress with objective gait analysis.

Duque’s recovery was the work of his veterinary surgeon, his rehabilitation team, and months of careful, patient care. What mathematics contributed was evidence and confidence: a 1992 study by Baxter and colleagues of eight horses documenting good outcomes after complete splint-bone removal, and later, motion-sensor data confirming what his team could see — his right hind now moves through the same range as his left, about 56–60° on either side. In the data, you cannot pick out the operated leg.

Today Duque is sound, in work, and employed as a teacher. His electrocardiogram anchors a university mathematics lab on modeling the heartbeat, and his gait data appears in our classroom examples. The horse the literature helped save now helps students fall for the mathematics that helped save him — which is EquiPhysics in one story.