Augmented reality (AR) or virtual reality is used in many fields, including medicine, education, manufacturing, and entertainment. With technical advances in optics, computer systems, and surgical instruments, AR applications to medicine are being vigorously researched. In particular, as surgeries using laparoscopy, endoscopy, or catheterized intervention have increased, AR plays an important role in many medical applications. AR is defined as a technique to combine the real world and virtual objects, which are digital content artificially generated by a computer. As another aspect of AR is the registration between the real world and virtual objects, it aims at an accurate estimation of the three-dimensional (3D) position and orientation of virtual objects related to the real world. Essentially, AR can allow users to see 3D virtual objects superimposed upon the real world. With the help of AR, a surgeon can view invisible organs during the surgery and improve the accuracy and safety of treatment procedures. After a brief description of the technical issues of medical AR, its applications will be introduced in this article.

Augmented reality is popular in various fields, and the importance of this technology has been increasing. Its medical application has also been widely studied. Particularly, augmented reality can be a more promising technique of a surgery which requires great precision. This paper introduces an overview of augmented reality and reviews the recent applications in medicine. After describing the basic concepts, brief characteristics of the three components that comprise augmented reality are provided. Various applications implemented in the authors' laboratory are reviewed.

Augmented reality is popular in various fields, and the importance of this technology has been increasing. Its medical application has also been widely studied. Particularly, augmented reality can be a more promising technique of a surgery which requires great precision. This paper introduces an overview of augmented reality and reviews the recent applications in medicine. After describing the basic concepts, brief characteristics of the three components that comprise augmented reality are provided. Various applications implemented in the authors' laboratory are reviewed.

PURPOSE: The intraoperative version of the femoral component is usually determined by visual appraisal of the stem position relative to the distal femoral condylar axis. However, several studies have suggested that a surgeon's visual assessment of the stem position has a high probability of misinterpretation. We developed a computed tomography (CT)-based navigation system with a patient-specific instrument (PSI) capable of three-dimensional (3D) printing and investigated its accuracy and consistency in comparison to the conventional technique of visual assessment of the stem position. MATERIALS AND METHODS: A CT scan of a femur sawbone model was performed, and pre-experimental planning was completed. We conducted 30 femoral neck osteotomies using the conventional technique and another 30 femoral neck osteotomies using the proposed technique. The femoral medullary canals were identified in both groups using a box chisel. RESULTS: For the absolute deviation between the measured and planned values, the mean two-dimensional anteversions of the proposed and conventional techniques were 1.41° and 4.78°, while their mean 3D anteversions were 1.15° and 3.31°. The mean θ 1, θ 2, θ 3, and d, all of which are parameters for evaluating femoral neck osteotomy, were 2.93°, 1.96°, 5.29°, and 0.48 mm for the proposed technique and 4.26°, 3.17°, 4.43°, and 3.15 mm for the conventional technique, respectively. CONCLUSION: The CT-based navigation system with PSI was more accurate and consistent than the conventional technique for assessment of stem position. Therefore, it can be used to reduce the frequency of incorrect assessments of the stem position among surgeons and to help with accurate determination of stem anteversion.
Arthroplasty, Replacement, Hip ; Femur ; Femur Neck ; In Vitro Techniques* ; Osteotomy ; Printing, Three-Dimensional ; Surgeons ; Surgery, Computer-Assisted ; Tomography, X-Ray Computed