Hi Cemc,

I've read a number of papers that suggest that degenerative changes in the SI joints are not that uncommon. Here is a short quote from one website:

"Many problems can cause degenerative arthritis of the SI joints. It is often hard to tell exactly what caused the wear and tear to the joints. One of the most common causes is an injury. The injury can come from a direct fall on the buttocks, a motor vehicle accident, or even a blow to the side of your pelvis. The force from these injuries can strain the ligaments around the joint. Ligaments are the tough bands of connective tissue that hold joints together. Tearing of these ligaments can lead to too much motion in the joint. The excess motion can lead to wear and tear of the joint and pain from degenerative arthritis. Injuries can also cause direct injury of the cartilage lining the surfaces of the joint where motion occurs. Over time, this will also lead to degenerative arthritis in the joint."

Note the link between tearing of ligaments, loose joints and degenerative arthritis. My understanding is falling onto your butt can be enough to do this - it doesn't necessarily mean a serious trauma like a car accident. I've fallen on my backside a number of times in my life and I'm sure many people have. If you're unlucky, I believe torn or stretched ligaments can be the result.

Wendy

Rheumatoid Arthritis
Methotrexate, Celebrex, Plaquenil