Yukihide Minoda1, Shigeru Nakagawa2, Ryo Sugama3, Tessyu Ikawa4, Takahiro Noguchi5, Masashi Hirakawa6, Hiroaki Nakamura7. 1. Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan. Electronic address: yminoda@msic.med.osaka-cu.ac.jp. 2. Department of Orthopaedic Surgery, Osaka Rosai Hospital, 1179-3, Nagasone-cho, Kita-ku, Sakai, Osaka 591-8025, Japan. 3. Department of Orthopaedic Surgery, Osaka General Hospital, 3-1-56 Mandaihigashi, Sumiyoshi-ku, Osaka 558-8558, Japan. 4. Hanwa Joint Reconstruction Center, 3176 Fukaikitamachi, Naka-ku, Sakai, Osaka 599-8271, Japan. 5. Department of Orthopaedic Surgery, Shinbeppu Hospital, 3898 Tsurumi, Beppu, Oita 874-0833, Japan. 6. Department of Orthopaedic Surgery, Oita University Faculty of Medicine, Graduate School of Medicine, 1-1 Idaigaoka, Hazama-cho, Yufu, Oita 879-5593, Japan. 7. Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
Abstract
BACKGROUND: Soft-tissue balancing of the knee is fundamental to the success of a total knee arthroplasty (TKA). In posterior-stabilized TKA, there is no stabilizer of the anterior-posterior translation in the midflexion range in which the cam-post mechanism does not engage yet. Therefore, instability in the midflexion range is suspected to occur in posterior-stabilized TKA. The purpose of this study was to measure the joint gap throughout a full range of motion and to analyze the joint gap laxity in the midflexion range after implantation of a mobile-bearing posterior-stabilized total knee prosthesis. METHODS: Joint gap kinematics in 259 knees with varus osteoarthritis were measured during TKAs using a tensor device with the same shape of a total knee prosthesis of the same design was used. After the implantation of a mobile-bearing posterior-stabilized prosthesis and the reduction of the patellofemoral joint, the joint gap was measured at 0°, 30°, 60°, 90°, 120°, and 145° of flexion. RESULTS: The center size of the joint gap was tight in extension and deep flexion and loose at midflexion ranges, especially at 30° of flexion (p<0.001). The symmetry of the joint gap was varus at 0° and 145° of flexion (p<0.001). CONCLUSIONS: Our results showed the joint gap laxity in the midflexion range after the implantation of a mobile-bearing posterior-stabilized prosthesis. Our new tensor device, which can attach the polyethylene insert trial, will provide the important information about the joint gap kinematics after implantation of total knee prostheses. LEVEL OF EVIDENCE: IV.
BACKGROUND: Soft-tissue balancing of the knee is fundamental to the success of a total knee arthroplasty (TKA). In posterior-stabilized TKA, there is no stabilizer of the anterior-posterior translation in the midflexion range in which the cam-post mechanism does not engage yet. Therefore, instability in the midflexion range is suspected to occur in posterior-stabilized TKA. The purpose of this study was to measure the joint gap throughout a full range of motion and to analyze the joint gap laxity in the midflexion range after implantation of a mobile-bearing posterior-stabilized total knee prosthesis. METHODS: Joint gap kinematics in 259 knees with varus osteoarthritis were measured during TKAs using a tensor device with the same shape of a total knee prosthesis of the same design was used. After the implantation of a mobile-bearing posterior-stabilized prosthesis and the reduction of the patellofemoral joint, the joint gap was measured at 0°, 30°, 60°, 90°, 120°, and 145° of flexion. RESULTS: The center size of the joint gap was tight in extension and deep flexion and loose at midflexion ranges, especially at 30° of flexion (p<0.001). The symmetry of the joint gap was varus at 0° and 145° of flexion (p<0.001). CONCLUSIONS: Our results showed the joint gap laxity in the midflexion range after the implantation of a mobile-bearing posterior-stabilized prosthesis. Our new tensor device, which can attach the polyethylene insert trial, will provide the important information about the joint gap kinematics after implantation of total knee prostheses. LEVEL OF EVIDENCE: IV.
Authors: Sami Shalhoub; Jeffrey M Lawrence; John M Keggi; Amber L Randall; Jeffrey H DeClaire; Christopher Plaskos Journal: Arthroplast Today Date: 2019-08-13
Authors: Michel P Bonnin; Arnoud de Kok; Matthias Verstraete; Tom Van Hoof; Catherine Van Der Straten; Mo Saffarini; Jan Victor Journal: Knee Surg Sports Traumatol Arthrosc Date: 2016-09-26 Impact factor: 4.342