The pending $50 million sale of Physician Associates, Central Florida's largest medical practice, to Orlando Health marks a giant shift in the local healthcare landscape. When the expected merger takes effect Dec. 31, each of the group's 95 physicians will receive about $500,000. Physician Associates dominates the local primary-care market. Collectively its physicians, who are part of the 28-year-old practice of mostly primary-care doctors, care for about 340,000 patients. At that moment, all the physicians will go from being independent practitioners to hospital employees.