Yukimasa Higano1, Tadashi Hayami2, Go Omori3, Yoshio Koga4, Kazuo Endo5, Naoto Endo6. 1. Department of Orthopedic Surgery, Tsuruoka Municipal Shonai Hospital, Yamagata, Japan; Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medicine and Dental Science, Niigata, Japan. Electronic address: higanoy@msn.com. 2. Department of Orthopedic Surgery, Saiseikai Niigata Daini Hospital, Niigata, Japan. 3. Center of Transdisciplinary Research, Niigata University, Niigata, Japan. 4. Department of Orthopedic Surgery, Niigata Medical Center, Nigata, Japan. 5. Department of Physical Therapy, Niigata University of Health and Welfare, School of Medical Technology, Niigata, Japan. 6. Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medicine and Dental Science, Niigata, Japan.
Abstract
BACKGROUND: Relationship malalignment of the knee and the onset of knee OA are unclear. Moreover, it has not been clarified whether malalignment of the knee affects the morphological change of the proximal tibia. The purpose of current study was to investigate whether varus knee alignment and morphological change of the proximal medial tibia influence the onset of medial knee OA and to clarify the relationship between them. METHODS: The subjects comprised 736 knees from 390 women that went under both the first survey in 1979 and the fourth survey in 2000 in the Matsudai district in Niigata Prefecture in Japan. None of the subjects demonstrated radiographic knee OA at the first survey. OA was graded according to the Kellgren-Lawrence classification and the subjects were divided according to the OA grades in the forth survey into the 3 groups (non-OA, early OA, and advanced OA). Age, BMI, Femorotibial angle (FTA), the tibial plateau angle and medial tibial cortical bone thickness (MTCBT) were measured. We performed multivariate logistic regression analysis using the stepwise method to identified the risk factors regarding onset of knee OA and calculated the odds ratio (OR) and 95% confidence intervals (95% CI). RESULTS: Advanced OA had a significantly higher OR compared to non-OA in 1979 with the tibial plateau angle (OR: 1.15) and MTCBT (OR: 2.11). And also advanced OA had a significantly higher OR compared to early-OA in 1979 with the tibial plateau angle (OR: 1.17) and MTCBT (OR: 1.62). CONCLUSIONS: In the advanced OA, varus alignment of the proximal tibia had already existed before the onset of knee OA. In addition, we thought that varus alignment due to the proximal tibia had influenced the morphologic alterations of proximal medial tibia.
BACKGROUND: Relationship malalignment of the knee and the onset of knee OA are unclear. Moreover, it has not been clarified whether malalignment of the knee affects the morphological change of the proximal tibia. The purpose of current study was to investigate whether varus knee alignment and morphological change of the proximal medial tibia influence the onset of medial knee OA and to clarify the relationship between them. METHODS: The subjects comprised 736 knees from 390 women that went under both the first survey in 1979 and the fourth survey in 2000 in the Matsudai district in Niigata Prefecture in Japan. None of the subjects demonstrated radiographic knee OA at the first survey. OA was graded according to the Kellgren-Lawrence classification and the subjects were divided according to the OA grades in the forth survey into the 3 groups (non-OA, early OA, and advanced OA). Age, BMI, Femorotibial angle (FTA), the tibial plateau angle and medial tibial cortical bone thickness (MTCBT) were measured. We performed multivariate logistic regression analysis using the stepwise method to identified the risk factors regarding onset of knee OA and calculated the odds ratio (OR) and 95% confidence intervals (95% CI). RESULTS: Advanced OA had a significantly higher OR compared to non-OA in 1979 with the tibial plateau angle (OR: 1.15) and MTCBT (OR: 2.11). And also advanced OA had a significantly higher OR compared to early-OA in 1979 with the tibial plateau angle (OR: 1.17) and MTCBT (OR: 1.62). CONCLUSIONS: In the advanced OA, varus alignment of the proximal tibia had already existed before the onset of knee OA. In addition, we thought that varus alignment due to the proximal tibia had influenced the morphologic alterations of proximal medial tibia.