Knee pain is often linked with aging, but more people in their 30s and 40s are now experiencing this issue.

With a rise in high-intensity sports participation and higher average body mass index (BMI), younger adults are increasingly facing knee problems—some even opting for surgery.

Between 2000 and 2017, inpatient knee replacements for patients ages 45 to 64 increased by 240%, according to the Department of Health and Human Services (HHS).

Early Signs of Knee Damage

A recent study in the journal Osteoarthritis and Cartilage revealed that structural changes in the knee can appear as early as age 30, often before any symptoms develop.

Researchers at Finland’s University of Oulu examined 297 participants, most without symptoms, and found joint damage in more than half. Minor cartilage defects—mainly between the kneecap and thigh bone—were present in over half the group, while a quarter showed defects between the shin and thigh bones. Small bone spurs were also detected in more than half of participants.

The study concluded that higher BMI was the strongest factor linked to these knee changes.

Obesity’s Role in Knee Problems

According to the CDC, more than 40% of U.S. adults are obese. Dr. Ran Schwarzkopf, professor of orthopedic surgery at NYU Grossman School of Medicine, agreed that higher BMI among younger Americans is a key driver of knee issues.

“[For] patients who are obese and have a high BMI, it’s a high load on their joints,” Schwarzkopf told Fox News Digital. “That’s more load constantly on the knees, so there’s more wear and tear.”

He added that the intensity of high school and college sports in the U.S. also contributes to more knee injuries compared to many other countries. Even when treated, some injuries—especially those affecting cartilage—cannot fully heal, leading to lasting damage.

“As cartilage disappears, osteoarthritis may develop,” Schwarzkopf noted. “That can cause pain and disability, sometimes requiring knee replacement as the ultimate treatment.”

Preventing Knee Pain and Surgery

For younger adults, prevention is key. Schwarzkopf emphasized maintaining a healthy weight as the most important step, since it can significantly reduce knee pain.

He also advised staying active, strengthening surrounding muscles like the hamstrings and quadriceps, and avoiding long hours of sitting without breaks. People in desk jobs should aim for at least an hour of daily activity and take frequent breaks to stand, stretch, and walk.

Proper footwear is another important factor, especially for those who spend long hours on their feet.

For those already experiencing discomfort, seeking professional orthopedic care is crucial. Treatments such as physical therapy and minimally invasive arthroscopic surgery can help restore function and reduce pain long before knee replacement becomes necessary.

“We don’t want to do knee replacements on people in their late 20s and 30s,” Schwarzkopf stressed.