The relationship between OA and osteoporosis may surprise you. Some studies show that women with low bone mass from osteoporosis may be less likely to have OA. But once OA is found, a higher bone mass density (no osteoporosis) means a milder case of OA. Just what all this means and what the actual connections are between OA and osteoporosis remains unclear.

One important risk factor for knee OA (such as your mother had) is a previous knee injury. Men and women are both more likely to develop knee OA after an anterior cruciate ligament (ACL) tear. And women are twice as likely to develop an ACL injury compared with men.

All in all, it looks like osteoporosis may have a protective effect. It may actually prevent OA from developing. Scientists are studying this phenomenon carefully. It's possible they may discover something that could help prevent either or both of these conditions.