When Mildred Romans, a retired dentist, fell and broke her hip at age 80, she was lucky to have a sister living nearby who cared whether she ever walked again. Already frail and confused from a series of small strokes, Romans is a textbook case of those seniors most at risk after fracturing a hip.

"I made up my mind that I would go with her to every physical therapy session, to make sure she wasn't palmed off on someone who didn't care," said her sister, Vera Glaser, a retired national correspondent for Knight-Ridder.

Glaser said her sister, a small woman with thin bones that are the hallmark of osteoporosis, became one of the 300,000 people in the United States who break a hip each year when she "just fell to the floor" last year at her assisted-living facility in Friendship Heights. She fractured the femoral neck of her right hip, one of the more common breaks. The neck and head of the femur were replaced with a metal prosthesis.

After the surgery, Glaser accompanied her sister each day to rehabilitation sessions in Rockville, even though it is an exhausting regime for her as well.

"Mildred is now moving again with the assistance of a walker, but she has to be watched. Her cognition has suffered and she could easily forget and put one of her hands out, lose her balance and fall," Glaser said shortly after her sister's surgery. "Looking out for her is a perpetual job."

Romans is not alone. Nearly 90 percent of those who fracture a hip are 65 or over, said David Lewellan, an orthopedic surgeon specializing in adult reconstructive and trauma work at the Mayo Clinic in Rochester, Minn. And complications are common and often fatal among this group.

The reasons for this poor survival rate vary, according to Lewellan. Many elderly go back to institutions with little or no physical therapy or go home to less-than-ideal situations. "Family support is critical to psychological and physical recovery," Lewellan said.

The majority of hip fractures occur from the force of a fall, Lewellan said, although some happen from the sudden weight load on the bone when an elderly person with osteoporosis gets out of a chair or twists the hip abruptly.

Seniors are at higher risk for hip fractures because their bones tend to be weakened by decades of diets lacking in vital minerals and calcium, Lewellan said. What would be a minor spill in a younger person often results in a debilitating fracture in an older person that may require months of rehabilitation, particularly if he or she has not been doing weight-bearing exercise on a daily basis.

"Older people may already be largely immobile. They may have cataracts or otherwise impaired vision or diabetic neuropathy in their feet, all of which affect balance and increase the risk of falling," he said. The hip operation itself may be traumatic and cause disorientation. Urinary or prostate problems, which necessitate frequent nighttime trips to the bathroom, also increase the risk of falling, he said.

"A hip fracture in a healthy younger person presents an entirely different recovery scenario," Lewellan said. A high-injury trauma, like an automobile or motorcycle accident, is often the only way a person under 45 breaks a hip. In the young, recovering from a hip fracture takes hard work to regain full mobility, but the surgery is not life-threatening.

"In an older person with multiple underlying illnesses, it is often the first domino in a cascading decline," Lewellan said.

John B. Cohen, a physician who is a consulting member of the medical staff at the National Rehabilitation Hospital in Washington, agrees. Recovery is much more complicated in a dementia patient or even a mildly confused one, he said. "Part of the problem is they don't remember the instructions."

Cohen said he is treating several patients with Alzheimer's disease. "We put them in leg braces so they won't move their leg or dislocate their hip prosthesis before the preliminary healing process has had a chance."

In recent years, changes have taken place in postoperative care to improve the long-term survival rate in hip fractures, Cohen said.

"In the olden days, we used to immobilize patients in traction and in bed for three months. Now we know that even three or four days in bed severely weakens an elderly person."

Today, he said, "we want them sitting in a chair within 36 hours of surgery," to try and halt the rapid deconditioning cycle that happens when older people are inactive.

Jay Magaziner has studied 2,000 hip patients over more than 15 years as a professor and director of the division of gerontology in the University of Maryland School of Medicine's Department of Epidemiology and Preventive Medicine. "Shorter, more active hospital stays are a given today," he said. That's partly due to cost-cutting, he said, but also because "we have more tools like swing beds and home health services to support patients than we did 10 years ago."

Results from the Maryland hip studies, Magaziner said, show that seniors, especially men, with the fewest social contacts before and after a hip fracture and/or surgery do far worse after they leave the hospital than those people with a good network of family and friends.

"Only the very healthiest go home. But even they need backup," said Magaziner. In the Maryland studies, people without a long-term care and exercise plan died in greater numbers than those with a daily regime.

"Those who come to the hospital at the time of their fracture in a state of delirium or confusion also do more poorly," he said, adding that in the future doctors should look more closely at these patients for other underlying illness.

Typically, a demented or confused person is excluded from rehab programs unless a family member takes an active role, Magaziner said. "The demented person cannot always be responsive or follow directions," even with a family advocate, he said.

Magaziner and others worry about the effect new Medicare reimbursement regulations may have on stays in sub-acute centers and on physical therapy, home care and other forms of rehabilitative care.

Indeed, insurance plans are cutting back on coverage, said Julie Kinn, a physical therapist at the Fox Chase Rehabilitation and Nursing Center in Silver Spring.

"Two years ago, hip fracture patients were our main clients. Now, most of them go directly home from the hospital and are seen by visiting nurses, if they are seen at all," she said.

Kinn's own father broke his hip recently when he fell off a ladder at age 64. Even though he was healthy and had good physical stamina, the surgery that replaced the ball of his femur "really took a lot out of him. It's seven months later and he's finally recovered," she said.

Anatomy of a Hip Fracture

Most hip fractures, according to the Mayo Clinic, occur in one of two locations: the femoral neck just below the ball part of the hip's ball-and-socket joint, or in the part of the hip that juts out and is known as the intertrochanteric region.

If the break is in the latter area, a compression hip screw is inserted across the fracture to repair the break and keep the bone stable while it heals.

A fracture in the femoral neck area can be repaired in one of three ways, depending on the type of break and the damage to the ends of the bone:

Metal screws may be inserted into the bone in a procedure known as internal fixation.

The head and neck of the femur may need to be replaced with a metal prosthesis. This is called hemi-arthroplasty.

Total hip replacement is the third option. It is called for most often if there is arthritis or if an earlier injury has damaged the joint. The older you are, the more likely it is that you will receive a prosthesis.