Computer-assisted navigational orthopedic procedures use navigational systems during musculoskeletal surgery to provide additional information and to further integrate preoperative planning with how the surgery is being performed. Navigational systems are typically used to improve placement and positioning of a prosthetic and/or surgical instrument during the procedure. Computer-assisted navigational orthopedic procedures can also be used as an adjunct to fixation of pelvic, acetabular, or femoral fractures, and as an adjunct to hip or knee arthroplasty procedures.
The navigational systems require three steps to gather information: data acquisition, registration, and tracking. Data acquisition is obtained in one of three ways: fluoroscopic imaging, computer tomography (CT), magnetic resonance imaging (MRI), or through an imageless system. The data is then used for registration and tracking. Registration refers to how the images (e.g., X-rays, CT, MRI) relate to the anatomical position in the surgical field. Surface-matching techniques are often used for matching shapes of bones before surgery to surface data points during surgery. Tracking refers to the sensor and measurement devices that report the position and orientation of the instruments and/or the placement and orientation of the implants relative to the bone anatomy during surgery.
In a meta-analysis, Bauwens et al. (2007) evaluated the available peer-reviewed literature on computer-navigated knee arthroplasties. Thirty-three studies, including 11 randomized trials were reviewed, representing 3,423 individuals with a mean age of 67.3 years. The authors noted that there was no evidence of publication bias, though there was strong statistical heterogeneity in the studies. The alignment of the mechanical axes did not differ between the navigated or conventional surgery groups, though participants managed with navigated surgery had a lower risk of malalignment at critical thresholds of greater than 3 degrees. The authors concluded that computer-navigated knee replacement offered few advantages over conventional surgery and that the clinical benefits were unclear and remained to be determined on a larger scale.
In a prospective randomized controlled trial, Mueffels et al. (2012) evaluated the effectiveness of computer-assisted anterior cruciate ligament (ACL) reconstruction. One hundred individuals eligible for ACL reconstruction with a transtibial technique were randomized to either conventional or computer-navigated surgery. Measurement of femoral and tibial tunnel placement with use of three-dimensional computed tomography was used as the primary outcome measurement. The placement of either the femoral or tibial tunnels did not have a statistically significant difference between the groups. The authors concluded that there was no significant difference in either the accuracy or precision of tunnel placement between conventional and computer-navigated ACL reconstruction.
In an updated Cochrane systematic review, Eggerding et al. (2014) evaluated the effectiveness of computer-navigated surgery for knee ligament reconstruction. Five randomized controlled trials were included, representing 366 participants. All studies involved ACL reconstructions. The authors found moderate-quality evidence of no clinically relevant difference between computer-navigated and conventional surgery when reviewing the International Knee Documentation Committee subjective scores (i.e., self-reported measure of knee function). Pooled data from two of the studies showed a small but clinically irrelevant difference favoring computer-navigated surgery. The authors concluded that based on the available evidence, they were unable to demonstrate a favorable effect of computer-navigated surgery for cruciate ligament reconstructions of the knee when compared to conventional reconstructions.
Computer-assisted navigation systems used in musculoskeletal surgical orthopedic procedures have been proposed to facilitate alignment and reduce the chance for malposition. While there are numerous devices approved by the US Food and Drug Administration (FDA) for surgical navigational systems, these systems are typically only subject to 510(k) approval because they serve as an adjunct to surgery rather than actually performing the surgery. In addition, the available published peer-reviewed literature has not demonstrated improved health outcomes for individuals.