title: Comparative analysis of visual field and image distortion in 30° and 70° arthroscopes.
abstract: OBJECTIVE
  There have been very few attempts to compare the visual fields and image distortion in arthroscopes. To better understand the images generated using existing arthroscopes, we performed image-mapping experiments to assess field of view and image distortion. The purpose of this study was to quantify and compare the visual fields obtained using 30° and 70° arthroscopes and assess image distortion in each arthroscope.
  
  
  METHODS
  A complete arthroscopy system was used in this study. To perform this quantitative analysis, we created a customized measurement device that consisted of three parts: (1) distance marker, (2) chessboard pattern, and (3) angle marker. Three observers collectively assessed the appropriate position of the arthroscope during simulation. For each scope, ten simulations were performed at distances between 1 and 3 cm. Using the obtained arthroscope images, field of view and image distortion were measured and calculated.
  
  
  RESULTS
  The field of view of the 70° arthroscope was 5, 10, and 15 mm wider in diameter in comparison with the 30° arthroscope at 1, 2, and 3 cm, respectively. Moreover, the 70° arthroscope had less 0.66, 0.13, and 0.26 pixels of root-mean-square distance than the 30° arthroscope at 1, 2, and 3 cm, respectively. The 70° arthroscope also contained 0.78 pixels less at the maximal error than the average 30° arthroscope. Therefore, the 70° arthroscope demonstrated less distortion than the 30° arthroscope. There was no significant difference between the two scopes with respect to median curvature measurement at 1-cm distance.
  
  
  CONCLUSIONS
  The 70° arthroscope demonstrates technical advantages over the 30° arthroscope, including a wider field of view and a less image distortion at the periphery. A wide angle and less image distortion can help better orient the surgeon within the joint cavity when a panoramic picture is needed to repair rotator cuff tears, in case of hip arthroscopy, or while treating the lesions of posterior horn of medial meniscus.
authors.affiliation: Department of Orthopaedic Surgery, Asan Medical Center, School of Medicine, University of Ulsan, 86 Asanbyeongwon-gil, Songpa-gu, Seoul, 138-736, Korea.
authors.forename: Aashay L
authors.initials: AL
authors.lastname: Kekatpure
authors.affiliation: Department of Orthopaedic Surgery, Asan Medical Center, School of Medicine, University of Ulsan, 86 Asanbyeongwon-gil, Songpa-gu, Seoul, 138-736, Korea.
authors.forename: Arnold
authors.initials: A
authors.lastname: Adikrishna
authors.affiliation: Department of Orthopaedic Surgery, Asan Medical Center, School of Medicine, University of Ulsan, 86 Asanbyeongwon-gil, Songpa-gu, Seoul, 138-736, Korea.
authors.forename: Ji-Ho
authors.initials: JH
authors.lastname: Sun
authors.affiliation: Department of Orthopaedic Surgery, Asan Medical Center, School of Medicine, University of Ulsan, 86 Asanbyeongwon-gil, Songpa-gu, Seoul, 138-736, Korea.
authors.forename: Gyeong-Bo
authors.initials: GB
authors.lastname: Sim
authors.affiliation: Department of Orthopaedic Surgery, Asan Medical Center, School of Medicine, University of Ulsan, 86 Asanbyeongwon-gil, Songpa-gu, Seoul, 138-736, Korea.
authors.forename: Jae-Myung
authors.initials: JM
authors.lastname: Chun
authors.affiliation: Department of Orthopaedic Surgery, Asan Medical Center, School of Medicine, University of Ulsan, 86 Asanbyeongwon-gil, Songpa-gu, Seoul, 138-736, Korea. jeonchoi@gmail.com.
authors.forename: In-Ho
authors.initials: IH
authors.lastname: Jeon
mesh_terms: D020679:Arthroscopes; D001182:Arthroscopy / Q000379:methods*; D006621:Hip Joint / Q000601:surgery; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D008592:Menisci, Tibial / Q000601:surgery; D000070636:Rotator Cuff Injuries / Q000601:surgery; D012785:Shoulder Joint / Q000601:surgery; D014794:Visual Fields
keywords: Arthroscope; Comparative analysis; Field of view; Image distortion