Use of a Custom-Made Patellar Groove Replacement in an American Staffordshire Terrier Puppy with a Severe Bone Defect in the Femoral Trochlea Caused by Hematogenous Osteomyelitis

Simple Summary Osteomyelitis is a bone infection disease causing progressive inflammation. Bone lysis, periosteal reactions and ischemic regions of infected necrotic and devitalized tissue are likely secondary abnormalities. A prolonged antibiotic therapy, an abundant lavage of the affected region and several revision surgeries to debride infected and necrotic bone are paramount treatments for osteomyelitis. The treatment of extensive bone defects and functional damage may require the use of prosthetic surgery, allowing the anatomical and functional recovery of the affected area, and in some cases, it is necessary to use a customized prosthesis for a better anatomical and functional adaptation. In veterinary medicine, the implementation of 3D-printing technologies and the application of custom-made surgical implants and prosthetics have enabled the management of intricate orthopedic conditions that were previously only addressed through salvage procedures, such as arthrodesis or amputations. The purpose of this report is to describe the surgical technique and outcome of a custom-made patellar groove replacement in a puppy with a severe bone defect in the femoral trochlea caused by hematogenous osteomyelitis. This surgery showed excellent short-, medium- and long-term outcomes, and it is the first report on a custom-made patellar groove replacement available in the literature.Abstract An 8-month-old male American Staffordshire terrier was referred for a no-weightbearing lameness of the right pelvic limb, hyperthermia, lethargy and inappetence. Two months before, endocarditis was diagnosed and treated in another veterinary hospital. Orthopedic, radiographic and tomographic examinations revealed a bone sequestrum of 4 x 1.4 cm and active periosteal reaction of the caudo-lateral cortical in the metaphysis and the distal third of the right femoral diaphysis, medullary osteolysis and interruption of the cranio-medial cortical profile, with involvement of the femoral trochlea leading to a secondary medial patella luxation. Hematogenous osteomyelitis was the suspected diagnosis. Once skeletally mature, after 4 months from surgical debridement and aggressive antibiotic therapy against Klebsiella oxytoca revealed by a bacteriological exam, the patient underwent prosthetic surgery for the application of a custom-made patellar groove replacement (PGR) to fill the bone defect and restore the femoral trochlea surface. Despite the serious injury that afflicted the right pelvic limb, the surgery had satisfactory outcomes until the last 18-month postoperative follow up.