Image-free navigation in ACL replacement with the OrthoPilot system

Abstract

In many areas of surgery, ever smaller approaches are being sought to reduce soft tissue traumatisation in minimally invasive operating techniques. This is associated with the danger that the surgeon will lose an overview of the topography of the structures as a whole. Computerassisted navigation promises to remedy this. Computer- assisted surgery began in the 1990s with intracranial neurosurgical operations and the implantation of pedicle screws in spinal surgery, using CT and MRI imaging. Today however, there are other solutions which do not require pre- and intra-operative X-rays. One of these solutions is offered by the OrthoPilot navigation system (. Fig. 39.1). One problem in cruciate ligament surgery has arisen because, whilst it is certainly true that the number of cruciate ligament operations has substantially increased, there has at the same time been an over proportional rise in the number of surgeons performing these operations. In fact, approximately 85% of cruciate ligament operations are conducted by surgeons or orthopaedic surgeons who perform fewer than 10 cases a year, and who can thus gather relatively little experience. Responsible government departments and insurance companies are therefore now thinking out loud about establishing process and quality controls similar to those which exist for osteosynthesis. According to such a scheme, the operation may only be performed if the site of the tunnels, and therefore the site of the ACL replacement, is documented. Monitoring the tunnel site with an image converter is now being recommended at the various cruciate ligament congresses. However, there are problems associated with image converter monitoring: the patients are exposed to a not inconsiderable dose of radiation, and the position of the image converter must be altered several times in order to obtain an image in two planes. The main problem in cruciate ligament surgery is correct tunnel placement. Computer-assisted navigation can represent a solution to this problem, as it can determine and document the tunnel site without CT scans or intraoperative X-rays. For this reason, software was developed for OrthoPilot to allow the optimum tunnel sites to be defined by navigation. © 2007 Springer Medizin Verlag Heidelberg.