Aging adults face many problems from osteoarthritis and osteoporosis. Osteoarthritis (OA) is a disease of the joints that causes slow destruction of the joint surfaces and underlying bone. Osteoporosis means “porous bones.” With osteoporosis, there is less bone mass with many open spaces within the bone. People with osteoporosis are more likely to fracture or break their bones than the average person.
There is some question about why these two diseases occur together. Many reports have tried to explain the connection between them, but nothing has been proven. Doctors in Japan compared two groups of 42 women ranging in age from 64 to 83 years. One group included women with OA who had total knee replacement. A second group was made up of women with a break at the top of the thighbone (femoral neck fracture).
This study looked at how fragile the bones in the spine were for both groups. The researchers measured bone mineral density and used X-rays to examine the bones in the low back area. Specifically, they looked at how much bone had been destroyed, how much space was left between bones, and how much the bones had been pressed down.
Compared to women with osteoporosis, women with OA of the knee had more severe back problems. Women with OA had more fractures, were much heavier, and showed more bone changes in the joints and back. Doctors suspect these differences occur because women with OA have fragile bones all through the body. Women with osteoporosis may only have thinning bones in some areas.
This study shows that women with knee OA who had total knee joint replacement tended to be heavier and have less bone mass in the spine. This new information raises the question whether women who end up needing knee joint replacement surgery have a greater risk for fractures of the spine than women with osteoporosis.