It is very rare to go into solo practice now. I know of only one individual who went directly into solo practice and he is having a hard time getting any block surgical time at the hospital, so he operates late afternoons, nights, and weekends. He also gets some stuff dumped on him in the ER. I think if you went solo in a small town with no orthopod, the hospital would probably do anything for you and the local FPs would probably refer to you, but if you try a solo practice in a major town, it will be incredibly hard.
I think the hardest part of orthopedics is the business side, which most of us have absolutely no training in. I had no clue how billing, coding, scheduling, etc...was done and after four years, I'm still clueless on a lot of things. This things would make solo practice hard unless you buy someone out who has an experienced office staff.
The other downside to solo practice is being on call all of the time, unless you find some other orthopod or group to share call with. Everytime you leave town, you must arrange for someone to watch your patients and be available for phone calls.
Also, with solo practice you don't have any experienced partners to bounce things off of in clinic, or help you out with difficult cases.
As for developing a referral base with a group and then going solo: This is very difficult since most contracts will have a "no compete" clause excluding you from the surrounding market areas unless you pay some ridiculous penalty. Although, you may battle this and win in a court room. However, the money spent on lawyers may bankrupt you.
These are just my thoughts, maybe others out there will shed a more optomistic light on solo practice.