title: How to drill the talar tunnel in ATFL reconstruction?
abstract: OBJECTIVE
  Reconstruction of the anterior talofibular ligament may be indicated in cases of residual instability after conservative treatment. Often, a bone tunnel is used for fixation in the talar bone. The purpose of this study is to evaluate possible routes for drilling the talar tunnel.
  
  
  METHODS
  Virtual tunnels were generated in a 3D bone model, oriented towards the following external landmarks: the talar neck, the most anterior point of the medial malleolus (MM), the most distal point of the MM, the most medial point of the MM, and the most posterior point of the MM. The parameters analysed for tunnels with lengths of 20, 25, and 30 mm were the maximum distance inside the bone and the distance from the tunnel to the bone surface. A minimal safe distance (MSD) was calculated for a tunnel with a diameter of 5 mm.
  
  
  RESULTS
  The shortest measured distance before arriving outside the talar bone was 16.7 mm. The longest distances were obtained in the tunnels oriented towards the talar neck (mean value of 36.6, SD 2.8) and towards the most posterior point of the MM (mean value of 35.8, SD 0.3). Only one tunnel, measuring 20 mm in depth and oriented towards the most posterior point of the MM, revealed no individual values below the MSD.
  
  
  CONCLUSIONS
  External landmarks are useful for drilling a talar tunnel during reconstruction of the anterior talofibular ligament. Only one tunnel, oriented towards the most posterior point of the MM, measuring 5 mm in diameter and with a maximum depth of 20 mm, was safe in all individuals. Surgeons should be aware of these limits when treating patients with ankle instability.
authors: Orthopaedic Department, AZ Groeninge Kortrijk, Burg Vercruysselaan 5, 8500, Kortrijk, Belgium. frederick_michels@hotmail.com.
authors: Frederick
authors: F
authors: Michels
authors: Orthopaedic Department, Mérignac Sport Clinic, 2, Rue Georges Negrevergne, 33700, Mérignac, France.
authors: Stéphane
authors: S
authors: Guillo
authors: Radiology Department, AZ Groeninge Kortrijk, Burg Vercruysselaan 5, 8500, Kortrijk, Belgium.
authors: Frederik
authors: F
authors: Vanrietvelde
authors: Radiology Department, AZ Groeninge Kortrijk, President Kennedylaan 4, 8500, Kortrijk, Belgium.
authors: Eddy
authors: E
authors: Brugman
authors: Orthopaedic Department, AZ Groeninge Kortrijk, Loofstraat 43, 8500, Kortrijk, Belgium.|Department of Development and Regeneration, Faculty of Medicine, University of Leuven Campus Kortrijk, Etienne Sabbelaan 53, 8500, Kortrijk, Belgium.
authors: Filip
authors: F
authors: Stockmans
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks; D016512:Ankle Injuries / Q000000981:diagnostic imaging / Q000601:surgery*; D000843:Ankle Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007593:Joint Instability / Q000601:surgery; D008023:Ligaments, Articular / Q000000981:diagnostic imaging* / Q000293:injuries / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D010027:Osteotomy / Q000379:methods*; D036542:Tomography, Spiral Computed; D055815:Young Adult
keywords: Ankle instability; Anterior talofibular ligament; Bone tunnel; Interference screw; Ligament reconstruction