title: How deep can straight instruments be inserted into the femoral canal: a simulation study based on cadaveric femora.
abstract: Determining how deep instruments can be inserted into the femoral canal without touching adjacent structures is a fundamental necessity for navigating instruments in primary and revision total hip arthroplasty. The aim of the study was to determine the reachable depth of a straight instrument inserted into the femur canal during primary and revision total hip arthroplasty. Based on the three-dimensional data of twenty-six femurs, obtained from a CT scan, the insertion depth of a virtual, straight instrument was accessed by a simulation. The effect of the diameter of the virtual instrument and the extension of the osteotomy were evaluated. Without extending the osteotomy, 100% of the femoral canal was reachable to a depth of 5.1-6.3 cm for instruments with a diameter of 10 mm. The depth was measured from the lower edge of the osteotomy. A maximum lateral extension of the osteotomy by 1 cm enlarges the access to a depth of 8.8 cm. The results provide a theoretical basis for the limitations of guiding instruments used for the preparation of the femoral canal. Bone preserving methods need the development of angulated instruments to reach deep areas in the femoral canal.
authors.affiliation: a Department of Orthopaedic Surgery , Experimental Orthopaedics, Medical University Innsbruck , Innsbruck , Austria.
authors.forename: David
authors.initials: D
authors.lastname: Putzer
authors.affiliation: a Department of Orthopaedic Surgery , Experimental Orthopaedics, Medical University Innsbruck , Innsbruck , Austria.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Klug
authors.affiliation: b Stryker IMT , Freiburg , Germany.
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Moctezuma
authors.affiliation: c AKH Celle, Klinik für Unfallchirurgie, Orthopädie und Neurotraumatologie , Celle , Germany.
authors.forename: Eckart
authors.initials: E
authors.lastname: Mayr
authors.affiliation: a Department of Orthopaedic Surgery , Experimental Orthopaedics, Medical University Innsbruck , Innsbruck , Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Nogler
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D002102:Cadaver; D004867:Equipment Design; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D010027:Osteotomy; D012086:Reoperation; D065287:Robotic Surgical Procedures / Q000379:methods*; D013525:Surgical Instruments; D014057:Tomography, X-Ray Computed
keywords: Femoral canal; handling straight instruments; hip revision; lateral extension of the osteotomy; navigation of instruments; robotic guided surgeries