Info

Cure Arthritis Naturally

Cure Arthritis Naturally

Get Instant Access

A Model for Understanding the Pathomechanics of Osteoarthritis in Aging

Thomas P. Andriacchi and Annegret M√ľndermann

Osteoarthritis occurs in the majority of adults and is often described as ''wear and tear'' arthritis, or a disease of aging resulting from the structural and biochemical breakdown of articular cartilage in synovial joints. The causes of degenerative osteoarthritis with aging are complex and involve interrelated biological, mechanical, and structural pathways. This chapter examines the interrelationship or coupling of these pathways that converges at an in vivo systems level in humans. Using the knee as an example, an integrated in vivo framework for understanding the various factors that influence the initiation and progression of osteoarthritis is described. This framework provides a basis for explaining the role of kinematics and load on the progression of osteo-arthritis. The framework helps to explain the integrated effect of biological, morphological, and neuromuscular changes to the musculoskeletal system during aging or during menopause on the increased rate of idiopathic osteoarthritis with aging.

Introduction

Arthritis is the most common type of joint disease and comprises a heterogeneous group of conditions that cause common histopathological and radiological changes. Osteoarthritis, often described as wear-and-tear arthritis, occurs in the majority of adults. It is a disease of aging resulting from the structural and biochemical breakdown of articular cartilage in synovial joints. The "itis" in osteoarthritis implies inflammation; however, most people with this condition do not have inflamed joints. Osteoarthrosis, defining a condition where the joints are affected by degeneration without inflammation, is probably a more accurate overall description of the condition. Nevertheless, as most people refer to the condition as osteoarthritis, this is the term used here. Osteoarthrosis and osteoarthritis are terms that are used virtually interchangeably.

The causes of degenerative osteoarthritis with aging are complex and involve interrelated biological

(Lohmander et al, 1999; Maniwa et al, 2001; Otterness et al., 2001), mechanical (Beaupre et al., 2000; Carter et al., 1998; Grodzinsky et al., 2000; Mow and Guo, 2002; Mow and Wang, 1999), and structural (Eckstein et al., 2002; Koff et al., 2003; Peterfy et al., 1994) pathways. The interrelationship or coupling of these pathways converges at an in vivo systems level in humans (see Figure 77.1).

In vivo function influences the mechanical environment of articular cartilage and the mechanobiology (Arokoski et al., 2000; Sweet et al., 1992; Thonar et al., 1985) of the tissue. Thus, in vivo function is coupled to the structure and health of the joint. Patients can functionally adapt to pathological joint changes such as ligament injury or degeneration of the articular cartilage. For example, it has been observed from in vivo studies (Mundermann et al., 2004; Prodromos et al., 1985; Wang et al., 1990) that some patients with knee osteoarthritis can adopt patterns of locomotion that lower the load at the knee and reduce the rate at which osteoarthritis progresses. Variations in the soft tissue properties or structure (Ateshian et al., 1991; Cicuttini et al., 2002) of the joint can influence the congruency and laxity of the joint and produce substantial variations in contact stress and joint motion that impact the mechanical environment of the cartilage. Cartilage adapts to mechanical stimuli (Smith et al., 1995) and ultimately becomes dependent on the maintenance of that mechanical stimulus for normal tissue function (Carter and Wong, 2003). In vitro studies (Smith et al., 1995) have shown that isolated cartilage cells (chondro-cytes) can adapt to changes in their mechanical environment by changing metabolic activity in response to increased levels of certain types of stress (Beaupre et al., 2000; Carter et al., 1998; Grodzinsky et al., 2000; Guilak and Mow, 2000). Cartilage health depends on the body's ability to maintain the equilibrium between degeneration and synthesis of cartilage constituents including collagen fibrils and proteoglycans. Chondrocytes, the cells of cartilage, retain this equilibrium by controlling enzymatic processes.

Handbook of Models for Human Aging

Copyright © 2006 by Academic Press All rights of reproduction in any form reserved.

Types Human Gait Patterns

Figure 77.1 Understanding the in vivo response of articular cartilage to its physical environment requires an integrated view of the problem that considers functional, anatomical, and biological interactions. Gait analysis, quantitative MRI, and assays of biomarkers provide a basis for understanding the interaction between the various pathways that lead to the initiation and progression of osteoarthritis (from Andriacchi et al., 2004).

Figure 77.1 Understanding the in vivo response of articular cartilage to its physical environment requires an integrated view of the problem that considers functional, anatomical, and biological interactions. Gait analysis, quantitative MRI, and assays of biomarkers provide a basis for understanding the interaction between the various pathways that lead to the initiation and progression of osteoarthritis (from Andriacchi et al., 2004).

Was this article helpful?

0 0
Arthritis Relief and Prevention

Arthritis Relief and Prevention

This report may be oh so welcome especially if theres no doctor in the house Take Charge of Your Arthritis Now in less than 5-Minutes the time it takes to make an appointment with your healthcare provider Could you use some help understanding arthritis Maybe a little gentle, bedside manner in your battle for joint pain relief would be great Well, even if you are not sure if arthritis is the issue with you or your friend or loved one.

Get My Free Ebook


Post a comment