As if a raft of social problems weren’t enough for teenagers, many adolescents also deal with the physical pain of a skeleton that’s a tad too eager to grow up. Joint pain is most common, and knee pain even more so, and a recent study from Aarhus University finds that what we call “growing pains” don’t always stop when the growing does.

Untreated knee pain presents a far greater challenge than many people anticipate, argue the researchers. Over time the pain won’t only persist, but worsen. Chronic knee pain among adolescents can cause their quality of life to equal that of kids waiting for surgery to repair torn anterior cruciate ligaments (ACL) or 75-year-olds six months after receiving a knee replacement, and the risks only increase as kids enter adulthood.

"If knee pain is not treated there is a high risk of the pain becoming chronic. And this clearly has a big consequence for the individual's everyday life and opportunities,” said physiotherapist and co-author Dr. Michael Skovdal Rathleff in a statement.

Rathleff and his colleagues collected data on nearly 3,000 adolescents between 12 and 19 years old, asking them about their experiences with pain in terms of frequency, site, intensity, and duration. Knee pain and lower back pain were obvious standouts. In total, 61 percent reported daily pain in at least one region. Worse, said Rathleff, “more than half still have problems after two years, so it is not something they necessarily grow out of.”

Among chronic knee pain sufferers — roughly one in three respondents for general pain, seven percent for localized pain in the front of the knee — competing in sports upped the overall risk for prolonged discomfort. “This is, of course, extremely unfortunate,” Rathleff said, “because we know that it is very difficult to start again once you have stopped.” Given the adult rate of osteoarthritis, which itself reflects a history of adolescent knee pain in about 25 percent of cases, the team encouraged strong treatment options, if not preventive efforts altogether.

A silver lining to the study, according to Rathleff, is that just about half of all knee pain cases tended to subside with the right training. Starting early is preferable, despite the ostensible difficulties of fitting in physiotherapy with a teenager’s already hectic schedule, from school to homework to other extracurricular obligations. But personal health may not make such high demands, Rathleff admits.

“This does not necessarily mean that all adolescents with bad knees must visit a physiotherapist. A closer cooperation between physiotherapists and general practitioners about how to best help these young people could also be a solution.”

Of the 3,000 participants, 153 suffered from Patellofemoral Pain Syndrome, or PFPS. The condition is the most common knee injury among athletes, even more so than the dreaded ligament tear, and involves sharp pain on the back of the knee cap. Fifty-five percent of PFPS sufferers said their pain had lasted more than two years.

Adult chronic pain, especially in the knees, is already recognized as a serious health condition. But adolescent chronic pain isn’t seen in the same light, the team argues, and their study should offer proof that managing adolescent injury and pain could prevent a great deal of adult cases from ever happening.

“To improve quality of life during adolescence and reduce chronic pain during adulthood,” they concluded, “we should increase our focus on adolescents experiencing musculoskeletal and other pain.”

Source: Rathleff M, Roos E, Olesen J, Rasmussen S. High prevalence of daily and multi-site pain – a cross-sectional population-based study among 3000 Danish adolescents. BMC Pediatrics. 2014.