Causes of Osteoarthritis
Osteoarthritis develops through a combination of mechanical stress, genetics, previous injury, aging, and biologic changes within the joint. It is often the final common pathway of several joint-damaging processes.
Primary risk factors
- Age: The risk increases significantly after age 45, with cartilage becoming less resilient over time.
- Obesity: Excess weight puts additional stress on weight-bearing joints like knees and hips.
- Joint Injury: Previous trauma, fractures, or ligament damage can accelerate cartilage breakdown.
- Repetitive Stress: Occupations or activities involving repetitive joint use (e.g., kneeling, heavy lifting) increase risk.
- Genetics: Family history plays a role, with certain genetic variations affecting cartilage quality.
Contributing factors
- Gender: Women are more likely to develop OA, particularly in the hands and knees.
- Muscle Weakness: Weak muscles around joints can lead to improper loading and increased wear.
- Joint Malalignment: Conditions like bowlegs or knock-knees can cause uneven stress distribution.
- Metabolic Factors: Conditions like diabetes may contribute to cartilage degradation.
More than simple wear and tear
While osteoarthritis was once thought to be purely "wear and tear," research shows it's a dynamic process involving inflammation, attempted repair, and eventual breakdown. Not everyone with risk factors develops symptomatic OA, and some individuals develop it without obvious causes.
