There is one side effect they may not warn you about, and that is opposite hip pain following total knee replacement. It’s probably usually not too severe, but surf on “opposite hip pain after knee replacement” and you’ll get a lot of hits.
It was and still is a problem for my wife after surgery last April, but the situation is somewhat unusual. She had a very severe knee injury 50 years prior and it pulverized the tibial plateau. She had already had three surgeries on it within the first year and a half, but over the years her functional leg length had way shortened due to lateral wobble in the joint. Over the years she developed significant lumbar scoliosis, I’m presuming because of the shorter leg and changed pelvic angle. The knee prosthesis straightened and tightened the knee, and it is fine, but a week and a half after the knee replacement, she developed excruciating pain in her opposite hip (thankfully not as bad any more), but she still has significant sciatic issues in both hips and thighs. The orthopedic doc and staff were supposed to be controlling her pain, but all they cared about was her knee pain.