A 5-year-old Thoroughbred gelding presented to his primary veterinarian for acute onset of non-weight bearing lameness of his left forelimb. After further examination, a laceration was discovered just distal to the metacarpophalangeal (fetlock) joint. The gelding was referred to the Cornell University Equine Hospital with suspicion of digital flexor tendon sheath (DFTS) involvement. Surgery was elected, and the DFTS and 30% of the superficial digital flexor tendon (SDFT) were found to be involved. The wound was thoroughly lavaged and sutured, leaving the apex open for drainage. The gelding was discharged with a good prognosis for survival yet only a fair to guarded prognosis for return to athletic performance. Unfortunately, 11 days after elected stem cell therapy 7 weeks later, the gelding returned to Cornell with an infection of his DFTS and no healing seen of his SDFT. With a poor prognosis for return to soundness, euthanasia was elected. This report will describe the clinical findings, diagnostics, and surgical treatment of a horse with a laceration to his fetlock region involving the SDFT and DFTS.