MODULE SUPPLEMENT: MUSCULO-SKELETAL SYSTEM
Differences in Cartilage Between Aging and Osteoarthritis
Differences between age related changes and osteoarthritis are listed in the following table. The exact effects of age related changes on functioning are currently not well studied. However, complaints of pain and disability should not be attributed to aging. In addition, maintaining muscle and bone health can potentially minimize the impact of aging on joint cartilage and has been shown to be assistive in minimizing the impact of osteoarthritis.
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Aging
|
Osteoarthritis |
|
Occurrence |
Occurs with age |
Group of diseases with various etiologies; does not affect all older adults; does not affect all joints; varies in symptomatology |
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Cartilage Hydration
(water content) |
Decreased |
Increased |
|
Proteoglycans |
Normal quantity but a decrease in their size |
Decreased quantity as well as a decrease in their size |
|
Collagen |
Normal quantity with increased stiffness and cross linking |
Decreased quantity with decreased stiffness and loss of cross links with degradation |
|
Chondrocytes |
No change in metabolic activity; no or reduced proliferation |
Increased metabolic activity and proliferation |
|
Subchondral Bone |
No change |
Increased thickness |
Adapted from: Hammerman (1989) and Loeser & Delbono (1999)
Tendons and ligaments also appear to undergo changes with age that appear to be similar to those experienced by cartilage. These changes reduce their strength, weaken their attachments, and predispose to injury (Loeser & Delbono, 1999). Thus activity interventions, including exercise, need to be planned carefully so that extra stress is not exerted on tendons and ligaments. Consistent activity that maintains the strength of these tissues is safer over the long run that sudden bouts that may add excessive stress.
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