In vivo hip joint contact distribution and bony impingement in normal and dysplastic human hips
Department of Orthopaedic Surgery, Osaka Kosei Nenkin Hospital, 4-2-78, Fukushima, Fukushima-ku, Osaka, 553-0003, Japan. Journal of Orthopaedic Research
(Impact Factor: 2.99).
10/2013; 31(10). DOI: 10.1002/jor.22414
Our objectives were to clarify the 3D articular contact areas of the in vivo normal hip joint and acetabular dysplasia during specific positions using magnetic resonance imaging (MRI), voxel-based registration, and proximity mapping. Forty-two normal and 24 dysplastic hips were examined. MRI was performed at four positions: neutral; 45° flexion; 15° extension; and the Patrick position. Femur and pelvis bone models were reconstructed at the neutral position and superimposed over the images of each different position using voxel-based registration. The inferred cartilage contact and bony impingement were investigated using proximity mapping. The femoral head translated in the anterior or posteroinferior, anterosuperior, and posteroinferior direction from neutral to 45° flexion, 15° extension, and the Patrick position, respectively. Multiple regression analyses showed age, femoral head sphericity, and acetabular sphericity to be associated with higher hip instability. The present technique using subject-specific models revealed the in vivo hip joint contact area in a population of healthy individuals and dysplastic patients without radioactive exposure. These results can be used for analyzing disease progression in the dysplastic hip and pathogenesis of acetabular labral tear. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res XX:XXX-XXX, 2013.
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- "Further, our results support clinical observations of OA progression for relatively young patients with acetabular dysplasia versus older patients. In patients with traditional dysplasia and early OA, labral tears and peripheral damage to the acetabular cartilage and delamination are the most common findings (Akiyama et al., 2013; Dorrell and Catterall, 1986; Fujii et al., 2009; Hartig-Andreasen et al., 2013; McCarthy et al., 2003, 2001a, 2001b; Tamura et al., 2012; Thomas et al., 2013). In contrast, older patients with early OA typically exhibit progressive joint space narrowing (Conrozier et al., 1998; Franklin et al., 2011; Goker et al., 2000). "
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ABSTRACT: The mechanics of contacting cartilage layers is fundamentally important to understanding the development, homeostasis and pathology of diarthrodial joints. Because of the highly nonlinear nature of both the materials and the contact problem itself, numerical methods such as the finite element method are typically incorporated to obtain solutions. Over the course of five decades, we have moved from an initial qualitative understanding of articular cartilage material behavior to the ability to perform complex, three-dimensional contact analysis, including multiphasic material representations. This history includes the development of analytical and computational contact analysis methods that now provide the ability to perform highly nonlinear analyses. Numerical implementations of contact analysis based on the finite element method are rapidly advancing and will soon enable patient-specific analysis of joint contact mechanics using models based on medical image data. In addition to contact stress on the articular surfaces, these techniques can predict variations in strain and strain through the cartilage layers, providing the basis to predict damage and failure. This opens up exciting areas for future research and application to patient-specific diagnosis and treatment planning applied to a variety of pathologies that affect joint function and cartilage homeostasis.
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ABSTRACT: The geometry of acetabular cartilage surface plays an important role in hip joint biomechanics. The aim of this study was to analyze the morphology of acetabular articular cartilage surface in elderly donated bodies to science using a 3D-digitizer.
Twenty hemipelves from 12 subjects (mean ages 85 years) were scanned with 3D-digitizer. Each acetabular surface model was divided into four regions: anterosuperior (AS), anteroinferior (AI), posterosuperior (PS), and posteroinferior (PI). In the global acetabulum and each region, the acetabular sphere radius and the standard deviation (SD) of the distance from the acetabular sphere center to the acetabular cartilage surface were calculated. In the global acetabulum, the distance between the acetabular surface model and the maximum sphere which did not penetrate over the acetabular surface model was calculated as the inferred femoral head, and then the distribution was mapped at intervals of 0.5 mm.
The SD in AS was significantly larger than that in AI (p = 0.006) and PI (p = 0.001). The SD in PS was significantly larger than that in PI (p = 0.005). The closest region (0-0.5 mm) tended to be distributed at anterior or posterosuperior acetabular edge.
The contact between the femoral head and acetabulum might start at the periphery of the lunate surface, especially in the anterior or posterosuperior region. From viewpoint of acetabular morphology, the acetabular articular cartilage in the anterior or posterosuperior edge could be more vulnerable due to direct contact mechanism.
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ABSTRACT: This paper provides evidence that the onset and development of osteoarthritis can redistribute the loads over the joint and subsequently alter the mechanism of bone resorption or deposition, leading to the formation of cysts (geodes), ivory-like areas (eburnation), or both. A two-dimensional model of the proximal half of the human femur was implemented from X-ray images. Finite element analysis was performed for four scenarios with normal and altered loading of the femoral head. Strain, maximum principal strain, and strain energy density (SED) were computed and their distributions were analyzed. The results show that osteoarthritis is associated with marked abnormal remodeling conditions. In particular, the low-SED areas in trabecular bone can experience bone resorption with a subsequent formation of geodes, whereas overstimulation at the interface between trabecular and subchondral bone can result in anomalously high bone deposition.
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