An unusual complication following partial lateral splint bone ectomy is described. Four weeks following the surgery, the horse fell onto the surgery site and from that point on showed a lameness on that limb. Despite a positive local anesthesia, the re-evaluation did not reveal any abnormal ultrasonographic and radiographic findings. The local steroid injection reduced the lameness only slightly. The clinical evaluation at our clinic revealed the potential presence of a fracture in the lateropalmar cortex. The horse was scheduled for surgery and the special fluoroscopic examination prior to surgery confirmed the tentative diagnosis. The origin of the fracture turned out to be the horizontal saw cut in the lateropalmar cortex of McIII, which occurred accidentally during the osteotomy of the fractured splint bone. The fall of the horse onto the partially amputated splint bone in association with the horizontal cut in the lateropalmar cortex of McIII, resulted in this avulsion fracture associated with significant pain. The splint bone and the fracture were stabilized with the help of a 9-hole 3.5 mm DCP applied over the splint bone and with the screws traversing the entire lateropalmar cortex of McIII. The horse responded positively to this treatment and 10 weeks postoperatively the plate was removed. An additional reason for this relatively early plate removal was the presence of an additional suspensory problem, which demanded a prolonged recovery period.