I am glad to hear, MoFirmer, you have come through your cancer, and I wish you well as you get back your strength.
I recently went to a spine specialist because I have had some SI joint pain. [I also have mild osteopenia.] I feared arthritis, and the good news is that there is no sign of it! In fact, the doctor didn't find anything wrong with my spine and hips--my husband, who has had a hip replacement, drooled over my x-ray.
My doctor did tell me to avoid moves that involved weights and twisting -- he said to definitely use weights, but in straight forward motions. I was surprised, however, that he also advised against squats and deadlifts. I asked if that was just because of my SI pain, and he said these moves were hard on the hips and spine in general and he advises against them.
He told me I could, and should, keep lifting weights and doing high impact as long as I didn't use weights and twist at the same time. He also approved of my recent addition of yoga. For me, getting the okay to continue high impact was a huge relief, even if the squats/deadlift advice was disappointing. I've been doing more of my straight forward Hiit workouts (Cathe's Imaxes and Hiit in particular) and less of the "functional" moves with weights in my hand. One of the "don't" moves he showed me seems (twisting to side with heavy weight) to be in every workout these days. This doctor was a young doctor, and he seemed pretty up to date on things.
[I have to admit that I have actually continued doing squats and deadlifts, but I am extremely careful about form and I don't use heavy weight. With the deadlifts, I use very light weight (a 12 lb bar).]
My point is not to be a rebel like me
or even to follow my particular doctor's advice; it is to say that I have had similar, surprising, medical advice.
The doctor also gave me a list of exercises to strengthen the hip and lower back. These included: bird dog move (extend opposite arm and leg out straight), pelvic tilt, bridge, prone extension (looks like cobra pose in yoga), child's pose, and partial curls (instead of sit-ups). He also recommended hamstring stretches.