ASHLEE E. WATTS, DVM, Diplomate ACVS 1 , LISA A. FORTIER, DVM, PhD, Diplomate ACVS 1 , ALAN J. NIXON, BVSc, MS, Diplomate ACVS 1 , and NORM G. DUCHARME, DVM, MSc, Diplomate ACVS 1 1 Cornell University Hospital for Animals, Cornell University, Ithaca, NY Veterinary Surgery February 2010 39 2 244 - 253 Objective—To report a technique for laser-facilitated, minimally invasive proximal interphalangeal joint (PIJ) arthrodesis in horses. Study Design—Case series. Animals—Horses (n=6); 5 thoracic and 2 pelvic limb PIJ. Methods—PIJ osteoarthritis (OA) diagnosis was confirmed by radiography. A diode laser was used to apply 2000 J of energy to the joint followed by insertion of 3 parallel 5.5 mm screws in lag fashion through stab incisions to achieve PIJ arthrodesis. After anesthetic recovery, limbs were maintained in bandages (n=2) or bandage casts (5) for 3 weeks. Horses were allowed exercise or turnout by 3 months. Results—Three horses (4 limbs) were sound throughout follow-up (6–18 months). One horse remained lame the 1st month, another had mild lameness at pasture at 6 weeks, and another had persistent low-grade lameness and delayed joint fusion (1 year). Within 6 months, 5 horses were sound, 4 had radiographic evidence of successful joint fusion, and 5 had returned to intended use. Conclusion—Diode laser-facilitated, 3 parallel screw arthrodesis for PIJ OA costs less and is associated with less pain compared with standard, open PIJ arthrodesis using 3 parallel screws inserted in lag fashion. Clinical Relevance—In horses with advanced PIJ OA, this technique appears to be a viable alternative for PIJ arthrodesis. Further study including characterization of the effects of the laser, ideal case selection indications, and optimal laser dose is indicated before this technique is recommended for routine PIJ arthrodesis.