There is some evidence that strontium ranelate (patented and sold as Protelos on prescription in some countries) can benefit people with with OA - this is an example; http://www.ncbi.nlm.nih.gov/pubmed/25888851 .

However, use of it is a risk factor for adverse cardiovascular events - see https://www.gov.uk/drug-safety-updat...ovascular-risk . I doubt that the anion (ranelate) is important but the strontium probably is.

There is no evidence that I can find that strontium citrate (available OTC) is of any benefit. See http://www.4bonehealth.org/do-you-re...-osteoporosis/ .