Koji Takayama1, Kazunari Ishida2, Hirotsugu Muratsu3, Yuichi Kuroda4, Masanori Tsubosaka4, Shingo Hashimoto4, Shinya Hayashi4, Takehiko Matsushita4, Takahiro Niikura4, Ryosuke Kuroda4, Tomoyuki Matsumoto4. 1. Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan. kojitakayama1978@gmail.com. 2. Department of Orthopaedic Surgery, Kobe Kaisei Hospital, Kobe, Hyogo, Japan. 3. Department of Orthopaedic Surgery, Steel Memorial Hirohata Hospital, Himeji, Hyogo, Japan. 4. Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
Abstract
PURPOSE: The purpose of this study was to examine the relationship between medial tibial joint line elevation and the improvement of range of motion (ROM) in unicompartmental knee arthroplasty (UKA). The hypothesis was that limited elevation of tibial joint line will improve knee range of motion in UKA. METHODS: Forty-six consecutive medial UKAs were enrolled in this study. Medial tibial joint line elevation was defined as the polyethylene insert and tibial tray thickness minus the tibial osteotomy and sawblade thickness. Positive values indicated an elevation of the tibial joint line. A component gap between the femoral trial prosthesis and the medial tibial osteotomy surface was also examined. Joint loosening was also calculated based on the joint component gap minus insert and tibial tray thickness. The correlation of the medial tibial joint line elevation with joint looseness and postoperative range of motion were analyzed. RESULTS: The mean medial tibial joint line elevation was 4.9 ± 1.1 mm. The medial tibial joint line elevation reduced the improvement of knee extension (R = - 0.43, p < 0.01). The medial tibial joint line elevation was also correlated with reduced loosening of the joint knee extension (R = - 0.42, p < 0.01). This, in turn, resulted in limited improvement of the knee extension angle. Moreover, joint line elevation under 5 mm significantly improved knee extension angle compared to joint line elevation over 5 mm. CONCLUSIONS: The medial joint line elevation of the tibia in UKA reduced the improvement of knee extension angle, due to a reduced joint looseness at knee extension. A tibial joint line elevation greater than 5 mm in UKA should be avoided to prevent postoperative flexion contracture. For the clinical relevance, this study clarified that the medial joint line of the tibia is an important factor to prevent postoperative flexion contracture in UKA. LEVEL OF EVIDENCE: II.
PURPOSE: The purpose of this study was to examine the relationship between medial tibial joint line elevation and the improvement of range of motion (ROM) in unicompartmental knee arthroplasty (UKA). The hypothesis was that limited elevation of tibial joint line will improve knee range of motion in UKA. METHODS: Forty-six consecutive medial UKAs were enrolled in this study. Medial tibial joint line elevation was defined as the polyethylene insert and tibial tray thickness minus the tibial osteotomy and sawblade thickness. Positive values indicated an elevation of the tibial joint line. A component gap between the femoral trial prosthesis and the medial tibial osteotomy surface was also examined. Joint loosening was also calculated based on the joint component gap minus insert and tibial tray thickness. The correlation of the medial tibial joint line elevation with joint looseness and postoperative range of motion were analyzed. RESULTS: The mean medial tibial joint line elevation was 4.9 ± 1.1 mm. The medial tibial joint line elevation reduced the improvement of knee extension (R = - 0.43, p < 0.01). The medial tibial joint line elevation was also correlated with reduced loosening of the joint knee extension (R = - 0.42, p < 0.01). This, in turn, resulted in limited improvement of the knee extension angle. Moreover, joint line elevation under 5 mm significantly improved knee extension angle compared to joint line elevation over 5 mm. CONCLUSIONS: The medial joint line elevation of the tibia in UKA reduced the improvement of knee extension angle, due to a reduced joint looseness at knee extension. A tibial joint line elevation greater than 5 mm in UKA should be avoided to prevent postoperative flexion contracture. For the clinical relevance, this study clarified that the medial joint line of the tibia is an important factor to prevent postoperative flexion contracture in UKA. LEVEL OF EVIDENCE: II.
Entities:
Keywords:
Gap; Joint line; Range of motion; Unicompartmental knee arthroplasty
Authors: Benedict U Nwachukwu; Frank M McCormick; William W Schairer; Rachel M Frank; Matthew T Provencher; Martin W Roche Journal: J Arthroplasty Date: 2014-04-05 Impact factor: 4.757
Authors: Shaw Akizuki; John K P Mueller; Hiroshi Horiuchi; Daigo Matsunaga; Atsuyuki Shibakawa; Richard D Komistek Journal: J Arthroplasty Date: 2008-08-12 Impact factor: 4.757