Knee pain rising among younger adults as obesity and intense sports take toll

Knee pain and structural knee changes are appearing more frequently in people in their 30s and 40s, researchers and orthopedic specialists say, with higher body mass index and more intense sports participation cited as the main drivers.

Federal and academic data point to a notable rise in procedures and early joint damage. The U.S. Department of Health and Human Services reported a 240% increase between 2000 and 2017 in inpatient knee replacements among patients ages 45 to 64. A study published in the journal Osteoarthritis and Cartilage by researchers at the University of Oulu in Finland found early structural knee changes were common by age 30, often without symptoms. In scans of 297 primarily asymptomatic participants, investigators detected minor articular cartilage defects in more than half of the group, most frequently between the kneecap and thighbone; defects between the shin and thighbone were present in roughly a quarter of participants. Small bone spurs were noted in more than half, and the study identified higher body mass index as the key factor linked to those defects.

"For patients who are obese and have a high BMI, it's a high load on their joints," said Dr. Ran Schwarzkopf, a professor of orthopedic surgery at NYU Grossman School of Medicine. "That's more load constantly on the knees, so there's more wear and tear." Schwarzkopf, who was not involved in the Finnish study, said increased participation in high-school and college sports in the United States — often at higher intensity levels than in other countries — has also led to more traumatic knee injuries among younger people.

Orthopedic specialists said traumatic injuries can create damage that does not fully recover, particularly in cartilage, and that accumulated damage combined with excess load on the joint can accelerate the development of osteoarthritis. "Even if these injuries are treated surgically or non-surgically, some elements of the knee, such as cartilage, cannot be restored, causing a long-lasting effect," Schwarzkopf said. He added that the long-term deterioration can lead some patients to require knee replacement as the ultimate treatment for severe cartilage loss.

Clinicians and public health officials point to obesity trends as amplifying the problem. The Centers for Disease Control and Prevention estimates that more than 40% of U.S. adults are obese, a condition that increases mechanical stress on weight-bearing joints. Specialists advise preventive measures for younger adults who are experiencing knee pain or want to reduce future risk.

Maintaining a healthy weight is the most commonly recommended step to reduce joint load. Strengthening the muscles that support the knee, particularly the quadriceps and hamstrings, can improve stability and reduce strain. For people with sedentary jobs, clinicians recommend regular breaks to stand and walk, and aiming for about an hour of physical activity on most days. Proper footwear matters for those who spend long hours on their feet, and targeted physical therapy can restore function and reduce pain. When nonoperative approaches are insufficient, arthroscopic procedures can address some injuries in people in their late 20s and 30s, helping delay or avoid knee replacement, physicians said.

The convergence of rising obesity rates and persistent high-intensity youth sports participation poses a public health challenge as health systems see more younger patients with knee problems. Experts emphasize early evaluation and conservative management to preserve joint function and potentially reduce the need for joint-replacement surgery later in life.

The Finnish study and U.S. treatment trends underscore that structural knee changes may begin decades before severe symptoms or the need for replacement, prompting calls from clinicians for greater focus on prevention, early diagnosis and rehabilitation among younger adults at risk.