Chinese Journal of Tissue Engineering Research ›› 2013, Vol. 17 ›› Issue (17): 3109-3116.doi: R318

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Biomechanical changes in the acetabular dome region to knee joint varus and valgus

Tang Min-sheng1, Bai Bo2, Xie Shi-juan3, Long Hao4, Liu Qi2, Chen Yi2   

  1. 1 Department of Orthopedics, Liwan Hospital of Guangzhou Medical College, Guangzhou 510170, Guangdong Province, China
    2 Department of Orthopedics, The First Affiliated Hospital of Guangzhou Medical College, Guangzhou 510120, Guangdong Province, China
    3 Department of Orthopedics, First People’s Hospital of Huaihua, Huaihua 418000, Hunan Province, China
    4 Department of Orthopedics, the Fourth Affiliated Hospital of Guangzhou Medical College, Guangzhou 510182, Guangdong Province, China
  • Received:2012-12-31 Revised:2013-03-05 Online:2013-04-23 Published:2013-04-23
  • Contact: Bai Bo, Chief physician, Professor, Department of Orthopedics, The First Affiliated Hospital of Guangzhou Medical College, Guangzhou 510120, Guangdong Province, China drbobai@yahoo.com
  • About author:Tang Min-sheng★, Maser, Associate chief physician, Department of Orthopedics, Liwan Hospital of Guangzhou Medical College, Guangzhou 510170, Guangdong Province, China tom239@163.com

Abstract:

BACKGROUND: Knee joint varus and valgus can change the morphology of the knee joint, influence the function of the knee joint and can change the biomechanical behavior of adjacent articular hip which is the mechanics conduction between the acetabulum and femoral head. 
OBJECTIVE: To investigate the effect of different varus and valgus angle on the biomechanics of acetabular dome region.
METHODS: Three lower limb specimens were collected from adult male fresh cadaver. All muscles and connective tissues were dissected while hip and knee periosteum, joint capsules and ligaments were preserved. The high tibial osteotomy was operated to simulate different degrees of knee varus and valgus. The specimens were divided into neutral position group, knee varus 10° group, knee varus 20° group, knee valgus 20° group and knee valgus 10° group. During the experiment, the pelves were in the single-leg standing neutral position. The specimens were loaded with 50 kg by biomechanical testing machine. The loading area, mean stress, and the peak stress in the acetabular dome region were measured with pressure sensitive film system.
RESULTS AND CONCLUSION: The loading area of tibiofemoral articular surface in the acetabular dome region under the neutral position was (6.33±0.12) cm2, the mean stress was (3.62±0.33) MPa and the peak stress was (4.58±0.20) MPa. When the knee joint varus and valgus for 10°, the loading area in the acetabular dome region was decreased, while the mean stress and peak stress were significantly increased, but the difference between varus and valgus 10° was no significant (P > 0.05); when the knee joint varus and valgus for 20°, loading area in the acetabular dome region was significantly decreased, while the mean stress and peak stress were significantly increased, and there was significant difference between varus and valgus 20° (P < 0.01). The loading area, mean stress and the peak stress distribution in hip dome region were changed with the tendency of knee varus and valgus increasing. When the knee joint varus and valgus for 20°, the loading area in the acetabular dome region was significantly decreased, while the mean stress and peak stress were significantly increased, this may be one of the factors of hip osteoarthritis caused by knee varus and valgus. Therefore, we should pay attention on the early intervention to the patients with knee osteoarthritis varus and valgus deformity in clinic.

Key words: bone and joint implants, biomechanics of bone and joint, knee varus, knee valgus, acetabular dome region, arthrodial cartilages, loading area, biomechanics, stress, provincial grants-supported paper

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