Bilateral Femoral Intraosseous Transcutaneous Amputation Prosthesis (ITAP) in a Cat

Abstract

Background: Intraosseous transcutaneous amputation prosthesis (ITAP) is a limb-salvage technique that involves anchoring an implant to the bone, enabling external prosthetic attachment via osseointegration. This approach offers an alternative to traditional amputation by preserving skeletal support and functional integration. Despite its increasing use in human medicine, ITAPs have been scarcely studied in veterinary practice, and no standardized guidelines exist for implant selection, considering the anatomical variability among species and breeds. This case report describes the successful application of ITAP in a cat following severe complications from bilateral femoral osteosynthesis, with a 27-month follow-up.

Case: A 1-year-old male cat, missing for 54 days, returned home with bilateral Salter-Harris type I femoral fractures. The patient underwent multiple unsuccessful surgical attempts, leading to complications such as contamination, bacterial resistance, Rush pin migration, plate exposure, osteomyelitis, and the need for muscle and skin flap reconstruction. Given the failure of all limb-preserving options, ITAP placement in the bilateral femoral diaphysis was proposed as an alternative to total limb amputation, aiming to restore independence and mobility. Preoperative planning involved computed tomography (CT) imaging, with Radiant® software used for image segmentation, bone viability assessment, and osteotomy height determination. A custom-designed titanium intramedullary implant was developed using CAD software. The surgical procedure was uneventful, and the patient was hospitalized for three days for postoperative monitoring. Fifteen days postoperatively, skin dehiscence and implant exposure were observed in the left femur. A revision surgery was performed, including implant coverage, bacterial culture, copious Betadine® lavage, and wound closure with 2-0 nylon sutures for the musculature and 3-0 for the skin. Enterococcus faecium was identified, and a three-week course of compounded marbofloxacin was prescribed, leading to complete wound healing without further complications.   

Discussion: The failure of prior fracture management necessitated the use of ITAP as an alternative to bilateral femoral amputation, ultimately resulting in excellent adaptation and quality of life. This case highlights the potential of osseointegrated implants in veterinary patients, demonstrating that ITAP can provide a durable and functional limb-salvage solution. The implant was designed with a fully intramedullary titanium structure to promote osseointegration, ensuring long-term biomechanical stability. A key feature was the inclusion of an anti-rotational locking pin to counteract rotational forces that could compromise implant integrity and prosthetic function. One of the major challenges in ITAP application is dermal integration, which is crucial to preventing ascending infection and soft tissue breakdown. Poor skin adherence to the implant can lead to complications such as infection, retraction, implant exposure, and mechanical failure, as reported in similar cases. The necessity for surgical revision in this patient underscores the importance of meticulous implant design and strict postoperative wound management. Long-term implant success also relies heavily on owner compliance, as proactive care and infection monitoring are essential to maintaining functionality and preventing complications. ITAP offers a functional alternative to total limb amputation by preserving biomechanics, restoring mobility, and improving quality of life. After 27 months, the patient showed no signs of implant failure or mobility impairment. Continued advancements in implant technology and surgical techniques will be essential to optimizing ITAP outcomes and expanding its application in veterinary medicine.

Keywords: Osseointegration, limb sparing, orthopedics, endo-exo prosthesis, surgery.