Try an MFR therapist! They are really great after surgeries. Don’t quite adequately repair the bones. It’s probably the muscles and the nerves. You will need to be under guided rehabilitation and you need to give your recovery a couple years for your body to heal. I had one hip replaced then the other two years later and then my lumbar. You will need to rebuild your core. When you have fusion your tiny pair of spinal muscles have to be exercised in a different way. You need to return to your orthopedic surgeon and get his comments and create a plan of care. It takes like three months for postoperative swelling to go down and it takes another quarter of a year to start working on your muscles and it can take 4 to 10 years for your nerves to regrow and remodel themselves, so don’t look at this a short term but rather long-term and make sure you tap into your doctors. A great orthopedic surgeon and a great MFR therapist working in tandem along with your proper exercising will help you recove completely at 42. Sometimes nerves and scar tissue get in the way and have to be dealt with later but that’s usually a year or two out so make sure you are getting MFR therapy to help that along.