TDK conference 2024

A common lesion in horses with lameness is subchondral cystic lesion (SCL) under the articular surface. In this study, we have collected cases where the cyst cavity was not surgically accessible through the articular surface. None of the surgical treatments described so far in similar cases has provided a perfect solution. A new surgical procedure, which was first published as oral presentation at the ECVS (European Collage of Veterinary Surgeons) annual meeting in July 2024, has been used to treat these patients. This technique has been developed by the Equine Research Group of the University of Veterinary Medicine Budapest. A retrospective analysis of these cases is presented in this TDK thesis.

Nine horses were operated at the Department of Equine Medicine at our University Equine Clinic between 2008 and 2024 and one at the University of Berlin Equine Clinic in August 2024. Cillindrical cancellous bone grafts were harvested from the external iliac crest of the same horse and then implanted by extra-articular minimally invasive exploration using the so called "press-fit" technique. The grafts were harvested and implanted under the same general anaesthesia. In 2/10 horses, previously applied lag screw fixation through the cyst has been unsuccessful, that is why has the above mentioned procedure was performed as a second treatment option. The horses suffered from 2-4/5 degrees of lameness before the operations. Clinical signs, radiological examination and intra-articular anaesthesia were necessary to establish the diagnosis. The localization of SCLs was as follows: 5/10 in the first phalanx, 2/10 in the hock (os tarsale tertium, distal intertarsal joint), 2/10 in the condyle of the third metacarpal bone, one cyst in the proximal radius and one in the second phalanx. These figures included one case where a cyst in the first phalanx and the distal condyle of the metacarpus on the same limb was treated. Of the 13 grafts implanted, 10 were 8.5mm grafts, one was 6.5mm and two were 4.5mm grafts. Following surgery, the horses were box rested for four weeks, followed by hand walking (2x5 minutes per day for the first two weeks), and then were let out in small paddocks two months after the surgery. After 6-8 months, owners were allowed to start working the horses again. In general, 9 out of 10 horses were successful in the cases described. Of these horses, 6/10 performed on pre-operative or higher activity level (defined as success), 3/10 horses showed a large improvement (defined as improved), while one case (1/10) showed no improvement (defined as unchanged). The three improved cases are currently undergoing rehabilitation, so it is possible that they will eventually be placed in the successful category later.