fb-pixel Skip to main content

Timing knee and hip replacements

A new registry that tracks knee and hip replacements can help patients choose the best time for an effective surgery

Lorenzo Gritti for The Boston Globe

Walking has long been one of Janet Golden’s passions, but her knees were so shot by her mid-50s that the fifth-grade teacher was limping everywhere. Over-the-counter medications didn’t touch the pain, and fluid injections at her doctor’s office to help lubricate and cushion her deteriorated joints didn’t help much either.

So at 58, Golden had her right knee replaced. That surgery went so well, she opted to have her left knee replaced a year later, even though it wasn’t as cranky as her right had been.

“I love being able to not be in pain and limping all over,” said the now-retired Westborough resident who, at 63, is able to cycle and walk as much as she wants.


Physicians often suggest that patients with knee and hip problems try a variety of less invasive treatments before resorting to artificial joints, because surgery carries risks and rehabilitation can be arduous. But new research led by Massachusetts scientists suggests some patients can wait too long.

After studying knee and hip replacement surgery outcomes in 17,000 patients — Golden is among those studied — the scientists concluded that patients who wait until they are severely hobbled may not fully benefit from joint replacement, and are likely to find less-than-expected function in the joint after surgery.

With surging numbers of Americans replacing worn-out hips and knees, and the money spent on the surgeries climbing exponentially, a growing number of researchers are working to quantify the effects of treatments and surgeries by building databases that track patients over the long term. Their aim is to help doctors and patients make more informed choices.

“We can actually measure where [patients] were before the surgery, how limited they were, and how much pain they had, and we can look a year after surgery,” said Dr. David Ayers, who heads the department of Orthopedics and Physical Rehabilitation at University of Massachusetts Medical School, and is a lead researcher on the federally-funded project called FORCE-TJR.


The FORCE researchers are creating a registry that collects detailed information from patients before and after hip or knee surgery about their overall health, pain levels, and ability to perform very specific tasks, such as climbing stairs, getting in and out of a car, or putting on socks. It also tracks problems with implants and surgeries.

More than 130 orthopedic surgeons across 23 states are contributing patient information (with the patients’ consent), and the goal is to include at least 30,000 patients that researchers intend to track for years. They’ve already enrolled 20,000 patients, Ayers said.

Ayers’s team recently compared the surgery results from 17,000 of these patients, ranging in age from their 40s to over 80, with similar patients who didn’t have severe knee or hip problems.

A national scoring system routinely used by physicians to assess patient health pegs people without joint problems at a “level 50.” Ayers’s team discovered that the typical patient in its database had deteriorated to a level 32 before opting to undergo surgery for an artificial joint, suggesting the patients had severe limitations but were not entirely hobbled by worn out joints.

They also found that their typical patient experienced a 12-point improvement after surgery, bringing them near the function of patients without deteriorated joints. But they also discovered that patients who waited until their ability to function was scored at 25 or lower — in other words, they were severely disabled — generally didn’t get the full 12-point improvement from surgery. Roughly 40 percent of these patients only improved to a level that most patients were at just before they had surgery.


Precisely why this group did not show as much improvement is not clear, but the researchers suspect it’s because many of the patients were disabled for such a protracted length of time that the muscles around their joints severely deteriorated, as did their heart and lung capacity.

“It’s a harder road back for recovery,” said Dr. Patricia Franklin, director of clinical research at UMass Medical School’s department of Orthopedics and Physical Rehabilitation, and a co-investigator in the FORCE project.

Franklin said researchers intend to dig deeper into their database to tease out whether specific health problems may be contributing to these poorer outcomes and also if more targeted rehab might improve results.

“We would like to give best practice ideas to the surgeons,” she said, “So they can tailor the rehabilitation process to that.”

Dr. Tony DiGioia, medical director of the Bone and Joint Center at the University of Pittsburgh Medical Center, has been contributing patient outcomes to the FORCE database for 18 months. He said he receives detailed, quarterly reports from the registry that include information about his patients’ outcomes compared with the outcomes of other surgeons’ patients in the database.

DiGioia, who has been doing knee and hip surgeries for 22 years, said the data has helped him and his patients select the optimum time when surgery should be considered.


The information in the database has also highlighted a considerable disconnect between patients and surgeons regarding expectations from surgery, and has helped DiGioia more clearly communicate expectations, he said.

“If you talk to any surgeon, we may have a patient that we think had a fantastic outcome,” he said, “and if you go and ask the patient about their outcome, it doesn’t match up.”

The American Joint Replacement Registry , a much larger database that is affiliated with the American Academy of Orthopaedic Surgeons, receives information from 1,800 surgeons across 48 states, and is tracking outcomes from more than 100,000 surgeries a year.

But unlike FORCE, it is not collecting detailed patient information, with yearly follow-ups. It has primarily focused on how the many implant devices on the market have fared, and tracks whether patients have needed follow-up surgeries to fix faulty implants. It started as a small pilot program in 2010.

Dr. William Maloney, who chairs the registry’s board of directors and orthopedic surgery at Stanford University Medical Center, said he started planning the joint replacement registry in 2000 when implant failure was happening frequently.

The technology has improved considerably since then, Maloney said, but researchers still lack sufficient data to know whether today’s devices are sturdy enough to reliably last for 20 years or more, as growing numbers of patients under age 65 are opting for joint replacement surgeries.


“That’s the advantage of a registry,” Maloney said. “We will have that data.”

A decade ago, younger patients who replaced deteriorating joints often faced the prospect of their implants wearing out.

Golden, who had both her knees replaced in the past four years isn’t worried.

“I keep my weight down, and I exercise,” she said. And, she added, she was diligent about doing her rehabilitation exercises after each surgery. “People I have known who had [replacement surgery] and who didn’t do the therapy, it doesn’t work out for them.”

Kay Lazar can be reached at Kay.Lazar@
. Follow her on Twitter @Globe