I hold a bit different viewpoint than some other people in this thread.
Let me show an example: Jujimmufu
He is extremely muscular...but also flexible.
It seems most in this thread consider any level of muscular hypertrophy will automatically make someone less flexible. And this would be true...unless you also emphasize stretching while focusing on muscular hypertrophy and neuro-muscular effectiveness (aka strength).
The main thing going for you if you have muscle already is this special phenomenon within the body refered to as mTOR. In simplest terms, mTOR is essentially how our body is able to replicable protein-dense cells aka muscles and soft tissues.
So that means if you develop a strong base of muscularity for many months or ideally years prior to surgery, while always emphasizing flexibility to the same degree of intensity (perhaps even greater intensity and effort given to flexibility, and THEN stop lifting/hypertrophy-focused exercise ~3 months prior to surgery to allow de-training to take affect leading to decreased muscle size from decrease in contractile size (thus easier time stretching them out), you essentially create a hyper-anabolic environment for your body post-surgery.
With the end effect of "muscle memory" allowing you to spring back much quicker post-op.
Speaking with Dr. Robbins (Paley's fellow Dr. he does the surgery with), the absolute best patient outcomes had consistently been long-time athletes who dropped the heavy sports a few months prior to surgery to hyper-focus on flexibility (he mentioned a football player, a crossfit guy, and a skier/outdoorsman I think who had a journal on this forum already).
AKA exactly what my hypothesis is regarding this question.
TL/DR: be fit and flexible. Not just one or the other.