Is knee pain in teens common or cause for concern?
When knee pain is associated with swelling, locking, instability or disruption of daily activities, it’s time to see a doctor. Here are four common causes of knee pain in teens.
Did you know that our knees are the largest and strongest joints in our bodies? For teenagers, they’re often a common source of pain.
While I stress with my patients that regular exercise is good for teens, knee pain is usually caused by overuse. In those cases, rest will often lead to a full recovery. But when knee pain is associated with swelling, locking, instability or disruption of daily activities, it’s time to see a doctor. Below, are four common causes of knee pain in teens.
But first, let’s take a quick refresher in knee anatomy:
The knee is made up of the lower end of the femur (thighbone), the upper end of the tibia (shinbone) and the patella (kneecap). The patella protects the front of the knee. As the knee bends and straightens, the patella slides up and down the femur in a groove.
The ends of the bones behind the patella are covered with cartilage, which protects the bones during knee movement. Just below the patella is a small pad of fat that acts as a shock absorber.
The ends of children’s and adolescents’ bones also have cartilage known as growth plates, where the bones lengthen as kids grow. A bony bump called the tibial tubercle covers the growth plate at the end of the tibia. When a child is fully grown, the growth plates harden into solid bone.
Ligaments act like strong ropes that connect bones, and tendons connect muscles to bones.
When teens experience knee pain, it is usually located in front and center.
Patellofemoral pain syndrome (PFS), a common cause of knee pain in young athletes, is an overuse injury that results from activities that cause pressure or friction on the cartilage behind the patella. The pain is usually dull and achy and the patient may also feel pain at night and after sitting for a long time. The affected knee may also make popping sounds when the patient climbs stairs. PFS frequently occurs in athletes who participate in sports that involve running or jumping, such as basketball, volleyball, track or cross-country. It often starts after there has been a recent increase in training intensity or volume. People with flat feet, intoeing (pigeon toes) or knock knees may be at higher risk for PFS because these conditions may affect how the patella tracks in its groove. Athletes with tight or weak hamstring and quadriceps muscles may also be at risk because these conditions can interfere with normal patellar tracking.
Osgood-Schlatter disease (OSD) is another common cause of knee pain in teenagers. OSD typically occurs in girls aged 10 to 13 and boys aged 12 to 15. Up to 20 percent of children in these age groups are affected. OSD is an inflammation of the area just below the knee where the patellar tendon attaches to the tibia. With activity, the quadriceps muscle pulls on the patellar tendon. In turn, the tendon pulls on the tibial tubercle covering the growth plate. This repetitive traction leads to inflammation of the growth plate. The main symptom of OSD is pain at this spot during activities involving running, jumping and kneeling, or after a fall. About one third of patients have symptoms in both knees. The condition usually goes away after the athlete finishes growing.
Patellar tendonitis, a.k.a. “jumper’s knee,” is an injury or inflammation of the tendon that connects the patella to the tibia. It is a frequent injury of athletes, especially those who play volleyball and basketball. Over time, the pain may worsen and interfere with daily movements such as climbing stairs or rising from a chair.
Not always front-and-center … Iliotibial band friction syndrome (ITBS) is the most common cause of knee pain on the outer (lateral) side of the patella. ITBS usually affects athletes who are involved in sports that require continuous running or repetitive knee flexion and extension like long-distance runners and cyclists.
The first step in treatment is avoiding activities that cause pain. A doctor will often determine a diagnosis based on the patient’s symptoms and a physical exam. An X-ray or MRI is occasionally needed. Next steps depend on the diagnosis. For most problems due to overuse, such as PFS or OSD, patients may recover with rest, ice and low-impact activities such as swimming and low-resistance cycling. If the symptoms are more severe, or not improving, you may be referred to an orthopedist or sports medicine specialist. Time to kick that knee pain outta here!
Rima Himelstein, MD, is a Crozer-Keystone Health System pediatrician and adolescent medicine specialist.