I have to wonder if unwanted calcium deposition in the cartilage isn't part of the problem, or if calcium metabolism somehow contributes to cartilage loss. I've had some relief from muscle and hip pain after taking a dosage of vitamin K2-MK4 that's a bit higher than typically used -- 10 mg/day (still quite a bit under the 45 mg/day used in the study of Japanese post-menopausal women.
Calcium pyrophosphate crystals form in the synovial fluid when there is a boron deficiency. These crystals can erode joint tissues contributing to cartilage loss in the inflammatory spiral that is part of the cycle that produces arthritis. (Note that most older people have arthritic hands that show their age, gnarled knuckles, etc..., which I suspect generally occurs because of long-term boron deficiency.)
I have taken 500+ mcg/day of the superior form of vitamin K2 (MK-7) for a long time (several years) and noticed no improvement in my right-hand middle finger arthritis. Please note that vitamin K2 (MK-7) is effective in several hundred microgram doses and lasts in the body for three days, where MK4 requires 15 mg three times a day as it is undetectable in the body in about eight hours.
It was only after I had taken 12 mg/day of calcium fructoborate, a highly absorbable form of boron, that the knuckle began to shrink and eventually over a four-month period, stopped aching. It also has shrunken to be almost the same size as my unaffected left-hand middle finger, for comparative purposes.
Boron supplementation, generally above six mg a day, but is quite safe at much higher doses, has been shown in numerous studies to improve arthritis. I chose 12 mg/day after considerable reading.
I apologize for not providing references, but I am traveling and the laptop I have doesn't have my files fully loaded.