SYMPOSIUM: PAPERS PRESENTED AT THE ANNUAL MEETINGS OF THE KNEE SOCIETY Total Knee Arthroplasty With a Computer-navigated Saw A Pilot Study

Background Computer-aided surgery aims to improve implant alignment in TKA but has only been adopted by a minority for routine use. A novel approach, navigated freehand bone cutting (NFC), is intended to achieve wider acceptance by eliminating the need for cumbersome, implant-specific mechanical jigs and avoiding the expense of navigation. Questions/Purposes We determined cutting time, surface quality, implant fit, and implant alignment after NFC of synthetic femoral specimens and the feasibility and alignment of a complete TKA performed with NFC technology in cadaveric specimens. Methods Seven surgeons prepared six synthetic femoral specimens each, using our custom NFC system. Cutting times, quality of bone cuts, and implant fit and alignment were assessed quantitatively by CT surface scanning and computational measurements. Additionally, a single surgeon performed a complete TKA on two cadaveric specimens using the NFC system, with cutting time and implant alignment analyzed through plain radiographs and CT. Results For the synthetic specimens, femoral coronal alignment was within ± 2 of neutral in 94% of the specimens. Sagittal alignment was within 0 to 5 of flexion in all specimens. Rotation was within ± 1 of the epicondylar axis in 97% of the specimens. The mean time to make cuts improved from 13 minutes for the first The institution of four authors (KLG, AB, CWH, HH) has received, during the study period, funding from DePuy Orthopaedics Inc (Warsaw, IN, USA) and contract research funding from Arthrex Inc (Naples, FL, USA), Biomet Inc (Warsaw, IN, USA), Naval Health Research Center (San Diego, CA, USA), Empirical Testing Corp (Colorado Springs, CO, USA), Exactech Inc (Gainesville, FL, USA), Exponent Inc (Philadelphia, PA, USA), ESKA (Lübeck, Germany), Gruppo Bioimpianti (Milan, Italy), Kyocera Medical Corp (Osaka, Japan), Implanet (Martillac, France), Ortho Development (Draper, UT, USA), Otis Glebe Medical Research Foundation (Omaha, NE, USA), Renovis Surgical Technologies (Redlands, CA, USA), Smith & Nephew Inc (Memphis, TN, USA), SoftJoint (Iowa City, IA, USA), Stryker Orthopaedics (Mahwah, NJ, USA), Spine Medica (Atlanta, GA, USA), and Tornier (Montbonnot, France). The institution of one of the authors (CRM) has received, during the study period, funding from Smith & Nephew. One of the authors (KLG) certifies that he, or a member of his immediate family, has received or may receive payments or benefits, during the study period, an amount of $100,001 to $1,000,000 from Biomet Inc. One of the authors (HH) certifies that he, or a member of his immediate family, has received or may receive payments or benefits, during the study period, an amount of $10,000 to $100,000 from AMTI (Watertown, MA, USA), an amount of less than $10,000 from Arthrex, an amount of $10,000 to $100,000 from Biomet Inc, an amount of less than $10,000 from Orthopedic Surgical Manufacturers Association (Rockville, MD, USA), an amount of less than $10,000 from SoftJoint, and an amount of less than $10,000 from SI-BONE (San Jose, CA, USA). All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. Each author certifies that his or her institution approved or waived approval for the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research. This work was performed at the Orthopaedics Biomechanics & Advanced Surgical Technologies Laboratory, University of Nebraska Medical Center, Omaha, NE, USA. K. L. Garvin, A. Barrera, C. W. Hartman, H. Haider (&) Department of Orthopaedic Surgery and Rehabilitation, University of Nebraska Medical Center, 981080 University of Nebraska Medical Center, Omaha, NE 68198-1080, USA e-mail: [email protected] C. R. Mahoney Iowa Orthopaedic Center, Des Moines, IA, USA 123 Clin Orthop Relat Res DOI 10.1007/s11999-012-2521-2 Clinical Orthopaedics and Related Research® A Publication of The Association of Bone and Joint Surgeons®