title: Custom-fit total knee arthroplasty (OtisKnee) results in malalignment.
abstract: We report on 4 patients who underwent total knee arthroplasty with OtisKnee system (OtisMed, Hayward, Calif). An image-free computer navigation system was used to evaluate the deformities and the recommended cuts. The recommended custom cuts were as follows: valgus/varus cuts on the femur (5.5 degrees valgus to 0.5 degrees varus) in reference to the mechanical axis, flexion cuts on the femur (4 degrees -9 degrees of flexion); femoral rotation was within 1 degrees of the epicondylar axis; valgus/varus cut on the tibia (3 degrees of valgus to 7.5 degrees of varus); tibial slope (5.5 degrees of anterior slope to 0.5 degrees of posterior slope). The custom OtisKnee system guides recommended alignment of the components that was more than 3 degrees off of mechanical axis. The potential for malalignment with this system places implants at high risk of early failure.
authors.affiliation: Department of Orthopaedics, Rothman Institute and Thomas Jefferson University, Philadelphia, PA 19107, USA.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Klatt
authors.forename: Nitin
authors.initials: N
authors.lastname: Goyal
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Austin
authors.forename: William J
authors.initials: WJ
authors.lastname: Hozack
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D017760:Bone Malalignment / Q000209:etiology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007720:Knee Prosthesis / Q000009:adverse effects*; D011474:Prosthesis Design; D011475:Prosthesis Failure