Computer navigation in knee and hip prosthetic surgery: an option for haemophilic patients

Computer Assisted Surgery has been employed in orthopaedics since the beginning of 1990ies with the aims of improving the precision, reducing surgical aggressiveness and improving the tracing of the operation. Among the proposed approaches, the most tested and useful seems to be the computer navigation not based on previous CT, like that named Orthopilot, by which more than 5000 knee replacements in more than 100 centres all over the world have been performed. Incorrect leg axes and inexact alignment of prostheses are known to reduce the longevity of prostheses (misleading, wear, synovitis, loosening). Computer navigation in prosthetic surgery may improve precision concerning geometry of axes, resection planes and implant alignment, by the determination of joint centres (actual axis), amount of bone resection, size of prostheses and check of ligament balance. At our Orthopaedic Department, Orthopilot has been used since March 2001, and more than 100 patients underwent hip/knee replacement. Follow-up of these patients shows good results: no complications, benefit for mechanics and ligament balance, great capacity of corrections of deformities. Due to the early-onset severe arthropathy, haemophiliacs undergo prosthethic surgery at younger age than general population; therefore, to ensure a longer duration of implantations is a major objective to be reached in this setting. We have planned to employ Orthopilot for knee/hip replacements in six haemophiliacs (age range 45–52 years) over the next 3 months. A long-term follow-up of these and larger samples of patients is needed for testing cost/risk-benefit ratio of Orthopilot in prosthetic surgery of haemophiliacs.