Knee replacements ‘truly phenomenal,’ study shows

A new study in the New England Journal of Medicine confirms what orthopedists have long known: Knee replacements are a marvel of modern medicine.

In the study, conducted at the University of Southern Denmark, 100 patients with moderate to severe knee arthritis either underwent total knee replacement paired with nonsurgical treatments or had only the nonsurgical treatments (physical therapy, diet advice for weight loss, shoe insoles and pain medication).

The surgical patients showed an improved quality of life and more improvement in walking, climbing stairs and other activities. They also were more likely to report significant reductions in pain.

“There are nearly 700,000 knee replacements done in the United States each year, but evidence of their benefit has been lacking,” the study’s lead author wrote.

“We have never before had a randomized controlled trial of knee replacement that permits a direct comparison of knee replacement versus physical therapy,” Dr. Jeffrey Katz, a professor of orthopedic surgery at Harvard Medical School, wrote in a New England Journal of Medicine editorial.

“For most patients, the dramatic pain relief associated with total knee replacement provides a compelling rationale to choose surgery,” he wrote. “Patients have a choice. Knee replacement is among the most successful interventions in modern medicine, but physical therapy is a reasonable choice for patients as well.”

The results of the Danish study were no surprise to orthopedic surgeon Leonard Remia, MD, of Cape Cod Orthopaedics.

“Knee replacement is the most common inpatient surgery,” he said. “It’s tried and true and has been well-tested since the 1960s.”

The average age of the knee-replacement recipients in the U.S. is 66.

“We see some younger patients with end-stage arthritis caused by sports injuries or a traumatic injury from a car accident,” said Dr. Remia. “We have to counsel them that joint replacements do not last forever.”

But the technology for replacement knees is still improving.

“The newer plastics introduced in 2001 are expected to last at least 20 years,” he said. “They have negligible wear, as shown through X-ray analysis. After 10 years, testing shows 97 percent are still functioning.”

In his NEJM editorial, Dr. Katz referred to knee surgery as “among the most significant advances of the 20th century.”

Dr. Remia agreed. “It’s not up there with heart transplants or penicillin or the polio vaccine, but knee replacements have given back quality of life to millions of patients,” he said. “In that way, it has been truly phenomenal.”

Knee-replacement surgery is an “excellent option” for those who qualify, Dr. Remia said.

“As long as your primary care doctor or cardiologist has cleared you for surgery, you’re a candidate if you have failed to improve with non-operative treatments like physical therapy, anti-inflammatory medications and cartilage supplements that can help lubricate knee joints.”

As with any surgical procedure, there are risks, in particular blood clots. But for those who qualify, Dr. Remia feels the benefits make a strong case for going ahead. “Patients can feel confident going ahead with knee-replacement surgery if they’ve failed non-operative options,” he said.