Although aging itself is a risk factor for OA and decreases the ability of cartilage to heal itself, it's not the sole cause.
Other factors include:
- Genetics and genderIn a study of female twins, heredity contributed to 39 to 65% of the hand and knee OA that developed. And OA of the knee is twice as common in women as in men.
- Obesity/overweightExcessive weight can stress cartilage and alter body mechanics.
- InjuriesPrior injuries to knee cartilage or ligaments or a fracture of the joint can lead to knee OA years later.
- Repetitive overuse of the jointFor example, kneeling or squatting repeatedly over time can damage the knee.
- Other causesMuscle weakness, poor bone alignment, poor aerobic fitness and the impact of nutritional imbalances are all being investigated.