THE MAIN hospital in Prince George's County is a cramped, badly outdated money drain that has required tens of millions of dollars in public subsidies in this decade on its way to obsolescence. Most of the structure, in Cheverly, just beyond the District's northeast border, is 50 or 60 years old and has not been renovated; its age and layout make modernization all but impossible. Little wonder that top doctors, as well as privately insured patients, have fled the place in favor of better-rated hospitals in the District and elsewhere.

The decay at the Prince George's Hospital Center has left the county of more than 900,000 people with a shortage of high-quality health care — not just an inconvenience, but a competitive disadvantage in terms of regional economic development. For years, county elected officials lobbied for an upgrade while at the same time they sought to explain away a track record of woeful management at the existing hospital, which made investment in a new one a tough sell.

That hurdle, among others, was finally overcome last year when state regulators approved a new hospital. And last week, construction finally began on a modern, full-service health center of 205 beds just beyond the Beltway at the Largo Town Center Metro stop, due east of the District.

The construction, expected to take more than two years, should correct what amounted to an injustice for Prince George's — if the new center's manager, University of Maryland Medical Systems, which runs a network of 13 hospitals around the state, lives up to its promises.

The new teaching hospital, to be known as the Prince George's County Regional Medical Center, was scaled down from the original proposal to meet state regulators' concerns about cost and need. Planners shaved more than $100 million off the $654 million price tag foreseen in 2013. The facility also will have a slightly smaller bed capacity than the existing hospital, although it will provide a state-of-the-art cancer center, stroke center and pediatric hospital, as well as programs in neuroscience, orthopedic medicine and women's health.

It didn't help matters for the existing hospital that Dimensions Healthcare, the private nonprofit organization that managed it for 30 years, was notoriously inefficient, inept at collecting bills and subject to political meddling. Under pressure from state regulators, Dimensions was folded into UMMS as a precondition of the new center's approval. It won't be missed.

Key to the new center's success will be the reality and appearance of providing quality health care, without which it is unlikely to lure back thousands of insured patients who gave up on seeking in-county medical treatment. That has saddled the existing hospital with an unusually high proportion of indigent patients, weighing on its balance sheet and forcing it to charge higher rates to patients who do pay. Unless UMMS can convince insured patients and top doctors that the new facility is on a par with its competitors in the region, it too will be forced to charge high rates, imperiling the project's market share and success.