Knee Pain in Children: Causes, Symptoms & Treatment Guide

What Causes Knee Pain in Children and Teenagers?

Knee pain in children and teenagers can be caused by growth-related conditions (Osgood-Schlatter disease, anterior knee pain), overuse injuries from sports, acute injuries like sprains, or occasionally underlying conditions like juvenile arthritis. The most common causes are related to rapid growth and physical activity.

Knee pain is one of the most frequent musculoskeletal complaints in pediatric medicine, affecting approximately 18-33% of children and adolescents at some point during their development. Unlike adult knee pain, which often stems from degenerative changes, childhood knee pain typically relates to the unique challenges of growing bodies engaged in physical activity.

The knee joint is particularly vulnerable during growth spurts because the bones, muscles, tendons, and growth plates develop at different rates. When a child is rapidly growing, the tendons may temporarily become tighter relative to the lengthening bones, creating stress at their attachment points. This biomechanical imbalance explains why many pediatric knee conditions cluster around periods of accelerated growth, particularly between ages 8-15.

Understanding the underlying cause of your child's knee pain is essential for appropriate management. While most causes are benign and self-limiting, some conditions require specific treatment to prevent long-term problems. The location of pain, its timing relative to activity, associated symptoms like swelling, and your child's age all provide important clues about the underlying cause.

Common Causes by Location and Age

Different knee conditions tend to present at specific ages and affect particular parts of the knee. Anterior knee pain (pain at the front of the knee) is extremely common in adolescents and often relates to the patellofemoral joint or the structures just below the kneecap. Pain below the knee, at the tibial tubercle, frequently indicates Osgood-Schlatter disease, while pain at the bottom of the kneecap suggests Sinding-Larsen-Johansson syndrome.

Younger children under age 7 may develop a Baker's cyst – a fluid-filled swelling behind the knee that typically resolves spontaneously. Older adolescents are more susceptible to ligament injuries, particularly if involved in cutting and pivoting sports. The pattern of pain, whether it occurs during activity, after activity, or at rest, also helps differentiate between various causes.

What Are the Symptoms of Knee Problems in Children?

Symptoms of knee problems in children include pain during or after activity, swelling around the knee joint, stiffness or difficulty bending the knee fully, pain when climbing stairs or squatting, limping, and occasionally a sensation of the knee "giving way" or locking in one position.

The symptoms your child experiences depend largely on the underlying cause of their knee pain. However, several common patterns help parents and healthcare providers identify when knee symptoms warrant concern versus when they represent typical childhood complaints that will resolve with time and simple measures.

Pain is the most common symptom, but its character varies significantly between conditions. Growth-related conditions like Osgood-Schlatter typically cause pain that worsens with specific activities – running, jumping, kneeling, or climbing stairs – and improves with rest. The pain is usually localized to a specific spot and may be accompanied by visible swelling or a bony prominence. In contrast, inflammatory conditions may cause more diffuse pain that persists even at rest and may be worse in the morning.

Swelling around the knee provides important diagnostic information. Localized swelling at the tibial tubercle (the bump below the kneecap) is characteristic of Osgood-Schlatter disease. Generalized joint swelling (effusion) may indicate injury, infection, or inflammatory conditions. A cyst at the back of the knee is typically a Baker's cyst. The timing of swelling – whether immediate after injury or gradual – also helps determine the cause.

Pain During Different Activities

Understanding when your child's knee hurts provides valuable diagnostic information. Many pediatric knee conditions cause activity-related pain that follows predictable patterns. Pain with jumping, running, and high-impact sports suggests conditions affecting the extensor mechanism – the quadriceps muscle, patellar tendon, and their attachments to the kneecap and shin bone.

Pain with prolonged sitting, often called "movie theater sign" or "theater sign," is characteristic of anterior knee pain syndrome (patellofemoral pain). Children may complain that sitting in class, during long car rides, or at the movies makes their knees ache. They often feel relief when they can stretch their legs out straight.

Pain when climbing or descending stairs is another common complaint, particularly in anterior knee pain. The forces across the patellofemoral joint increase significantly during stair climbing, making this a sensitive indicator of conditions affecting this area. Some children may avoid stairs entirely or take them one at a time to minimize discomfort.

• Activity-related pain: Worse during or after sports, especially jumping activities; common in Osgood-Schlatter and patellofemoral pain
• Rest pain: May indicate inflammation, infection, or more serious conditions; warrants medical evaluation
• Night pain: Growing pains typically occur at night, but persistent night pain may need investigation
• Morning stiffness: Lasting more than 30 minutes suggests inflammatory conditions like juvenile arthritis
• Pain with kneeling: Direct pressure on the tibial tubercle is particularly painful in Osgood-Schlatter

Mechanical Symptoms

Some knee conditions cause mechanical symptoms – sensations related to the physical movement and stability of the joint. These include locking (the knee getting stuck in one position and requiring manipulation to straighten), catching (a sensation of something catching or clicking within the joint), and giving way (a feeling of instability or the knee buckling).

Locking is an important symptom that may indicate a loose body within the joint, a meniscus tear, or osteochondritis dissecans where a piece of cartilage and bone has partially or completely separated. True locking should be distinguished from stiffness; with locking, there is a mechanical block that prevents movement until the loose piece shifts position.

A sensation of giving way or instability may follow ligament injuries, particularly to the anterior cruciate ligament (ACL). While ACL injuries are less common in younger children, they are increasingly recognized in adolescents involved in cutting and pivoting sports like soccer, basketball, and skiing.

When Should You See a Doctor for Your Child's Knee Pain?

You should see a doctor if your child's knee pain doesn't improve with rest after several days, if there is persistent swelling, if your child cannot bear weight on the leg, if the knee locks or gives way, if there is fever with knee pain, or if the pain is severe following an injury. Seek immediate care if the knee appears deformed or if there was a significant trauma.

Most childhood knee pain resolves with rest, ice, and time. However, certain features indicate the need for professional evaluation. Understanding these warning signs helps parents make appropriate decisions about seeking care while avoiding unnecessary emergency visits for minor issues that will improve at home.

The nature and severity of any precipitating injury is an important consideration. High-energy injuries – falls from height, direct blows to the knee, or twisting injuries during sports – are more likely to cause structural damage requiring medical attention. A child who cannot bear weight immediately after an injury should be evaluated promptly. Similarly, visible deformity, severe swelling within hours of injury, or an audible pop at the time of injury suggest significant damage.

Pain that persists despite appropriate rest is another indication for evaluation. While some conditions like Osgood-Schlatter may cause intermittent pain over months, the symptoms should improve when the aggravating activity is avoided. Pain that continues or worsens despite rest suggests a diagnosis that may require specific treatment.

Concerning Signs That Need Evaluation

Several features should prompt a non-urgent but timely medical evaluation. Persistent swelling of the knee joint itself (as opposed to localized swelling over the tibial tubercle in Osgood-Schlatter) may indicate injury to internal structures, inflammatory conditions, or infection. A healthcare provider can determine whether imaging or other tests are needed.

Pain that interferes significantly with daily activities or sleep deserves evaluation. While some discomfort with vigorous activity may be acceptable during a child's recovery, pain that prevents normal walking, disturbs sleep, or causes significant distress warrants professional assessment to ensure nothing is being missed.

Systemic symptoms accompanying knee pain – fever, weight loss, fatigue, or pain in other joints – suggest the possibility of inflammatory or infectious conditions that require specific treatment. Juvenile idiopathic arthritis, for example, can present with knee pain and swelling, and early treatment improves outcomes.

• See a doctor within a few days if: Knee pain persists beyond 1-2 weeks despite rest, there is mild but persistent swelling, or home treatments are not helping
• See a doctor within 24-48 hours if: Your child cannot bear weight normally, swelling is moderate to significant, or there is warmth and redness around the joint
• Seek immediate care if: There is severe pain after injury, visible deformity, inability to move the knee, or signs of infection (fever, severe redness, spreading warmth)

How Are Knee Problems in Children Diagnosed?

Diagnosis begins with a thorough medical history and physical examination assessing pain location, mobility, strength, and stability. X-rays may be ordered to evaluate bones and growth plates. MRI is used when soft tissue injuries (ligaments, meniscus, cartilage) are suspected. Blood tests may be needed if inflammatory conditions are considered.

The diagnostic process for pediatric knee pain begins with a detailed conversation about your child's symptoms. The healthcare provider will ask about the onset of pain (sudden versus gradual), its location and character, factors that make it better or worse, any precipitating injury, and your child's activity level and sports participation. Previous episodes, treatments tried, and the impact on daily activities are all relevant.

Physical examination is central to diagnosis. The provider will observe your child walking and may ask them to squat, hop, or climb stairs. They will examine the knee for swelling, warmth, tenderness, and deformity. Specific tests assess the stability of the ligaments, the tracking of the kneecap, the integrity of the meniscus, and the range of motion. Comparison with the unaffected knee helps identify subtle abnormalities.

For many common pediatric knee conditions, history and physical examination provide sufficient information for diagnosis without additional testing. Osgood-Schlatter disease, for example, typically has such characteristic findings – tenderness and swelling at the tibial tubercle in an active adolescent with activity-related pain – that imaging is often unnecessary.

When Imaging Is Needed

X-rays are commonly the first imaging study ordered when further evaluation is needed. They effectively visualize bones, can identify fractures, show the status of growth plates, and may reveal characteristic changes of conditions like Osgood-Schlatter disease (fragmentation of the tibial tubercle) or osteochondritis dissecans (changes in the bone and cartilage surface).

MRI (magnetic resonance imaging) provides detailed images of soft tissues including ligaments, tendons, meniscus, and articular cartilage. It is particularly useful when ligament injury, meniscus tear, or advanced osteochondritis dissecans is suspected. Because MRI does not use radiation, it is particularly appropriate for children when detailed soft tissue imaging is needed.

Ultrasound can be useful for evaluating superficial structures and is particularly good for assessing Baker's cysts. It has the advantages of being quick, radiation-free, and allowing comparison with the other side. However, it cannot visualize deep structures within the joint as well as MRI.

What Are the Common Types of Knee Pain in Growing Children?

The most common types include Osgood-Schlatter disease (pain below the knee in athletic youth), anterior knee pain syndrome (pain behind or around the kneecap), Sinding-Larsen-Johansson syndrome (pain at the bottom of the kneecap), Baker's cyst (swelling behind the knee in young children), and osteochondritis dissecans (cartilage and bone separation in the joint).

Osgood-Schlatter Disease

Osgood-Schlatter disease is one of the most recognized causes of knee pain in adolescents, affecting approximately 10-20% of athletic teenagers. It occurs when repetitive stress from the quadriceps muscle, transmitted through the patellar tendon, causes irritation and inflammation at the tibial tubercle – the bony prominence just below the knee where the patellar tendon attaches.

The condition is most common during growth spurts, typically affecting children between ages 8-15. During rapid growth, the tibial tubercle (which contains a growth plate) is particularly vulnerable to stress. The repetitive pulling of the tendon causes microtrauma, leading to pain, swelling, and sometimes fragmentation of the growth plate that creates a visible and tender bump.

Children with Osgood-Schlatter typically report pain during and after activities involving running, jumping, kneeling, or climbing stairs. The pain is localized to the tibial tubercle, which is tender to touch and often visibly enlarged. Symptoms may affect one or both knees and tend to fluctuate with activity levels.

The good news about Osgood-Schlatter disease is that it resolves in nearly all cases once skeletal maturity is reached – when the growth plate closes and becomes solid bone. The enlarged tibial tubercle may persist as a permanent but usually painless bump. During the active phase, management focuses on activity modification, stretching, and pain control to maintain quality of life while the condition runs its course.

Anterior Knee Pain (Patellofemoral Pain Syndrome)

Anterior knee pain syndrome, also called patellofemoral pain, is perhaps the most common cause of knee pain in adolescents. It refers to pain at the front of the knee, typically around or behind the kneecap. The condition results from abnormal forces or movement patterns affecting the patellofemoral joint – where the kneecap meets the thighbone.

Multiple factors can contribute to anterior knee pain, including muscle imbalances (particularly weakness of the inner quadriceps muscle), tightness of surrounding structures, overuse, and biomechanical issues such as flat feet or knock knees. Girls are affected more often than boys, possibly due to differences in hip anatomy and muscle development.

Children with anterior knee pain often describe a diffuse aching pain around the kneecap that worsens with prolonged sitting, stair climbing (especially descending), squatting, or kneeling. They may report grinding or clicking sensations and a feeling of stiffness after sitting. Unlike Osgood-Schlatter, there is typically no visible abnormality, though the knee may be tender when the kneecap is compressed against the thighbone.

Treatment centers on physical therapy to strengthen the muscles that support and stabilize the kneecap, particularly the quadriceps (especially the vastus medialis obliquus) and hip muscles. Stretching tight structures, activity modification, and sometimes taping or bracing are also helpful. Most cases improve significantly with a consistent rehabilitation program.

Sinding-Larsen-Johansson Syndrome

Sinding-Larsen-Johansson syndrome is similar in mechanism to Osgood-Schlatter disease but affects the bottom of the kneecap (inferior pole of the patella) rather than the tibial tubercle. It results from repetitive traction at the origin of the patellar tendon where it attaches to the kneecap.

This condition primarily affects active children between ages 10-14, with a particular prevalence among those who participate in jumping sports – hence the common name "jumper's knee" or "high-jumper's knee." However, it can affect any child engaged in repetitive running and jumping activities, including those playing soccer, basketball, or participating in track and field.

The pain is localized to the inferior pole of the patella and worsens with activity, especially jumping, running, and stair climbing. Physical examination reveals tenderness at this specific location. Like Osgood-Schlatter, this is a self-limiting condition that resolves as the child reaches skeletal maturity. Management involves activity modification, stretching and strengthening exercises, and symptomatic treatment.

Baker's Cyst (Popliteal Cyst)

A Baker's cyst is a fluid-filled swelling that develops in the popliteal fossa – the area at the back of the knee. In children, these cysts typically arise from the bursa (a fluid-filled sac) between two muscles at the back of the knee. Unlike Baker's cysts in adults, which often result from knee joint problems, pediatric Baker's cysts are usually primary lesions that develop independently.

Baker's cysts are most common in children younger than 7 years old. Parents typically notice a soft, smooth swelling at the back of their child's knee. The cyst is usually painless, though very large cysts may cause a sense of tightness or mild discomfort behind the knee, particularly with full bending or straightening.

The reassuring aspect of childhood Baker's cysts is that they typically resolve spontaneously over months to years without treatment. They rarely cause significant problems and do not usually require intervention. However, it is important to have a healthcare provider confirm the diagnosis, as other conditions can cause swelling behind the knee.

Osteochondritis Dissecans

Osteochondritis dissecans (OCD) is a condition where a segment of cartilage and the underlying bone separates from the surrounding surface, potentially creating a loose fragment within the joint. In children, OCD most commonly affects the knee, typically the medial femoral condyle (inside part of the thighbone at the knee).

The exact cause of OCD is not fully understood, though repetitive microtrauma, impaired blood supply to the area, and genetic factors likely play roles. The condition is most common in adolescents between ages 12-19, particularly those involved in sports. Boys are affected more often than girls.

Symptoms of OCD include activity-related pain, often diffuse within the knee, and mechanical symptoms such as catching, locking, or giving way if the fragment becomes unstable or loose. Swelling may occur after activity. In some cases, a loose fragment can move within the joint, causing intermittent mechanical symptoms.

The treatment and prognosis of OCD depend on the child's skeletal maturity and the stability of the lesion. In younger children with stable lesions, the cartilage and bone often heal with activity modification and time – the growth potential allows for repair. Older adolescents and those with unstable or loose fragments may require surgical intervention to stabilize or remove the fragment and promote healing.

What Can You Do at Home for Your Child's Knee Pain?

Home care includes rest from aggravating activities (not complete bed rest), ice application for 15-20 minutes several times daily, over-the-counter pain relievers as needed, gentle stretching exercises, and activity modification to avoid movements that cause pain. Children can often continue low-impact activities like swimming while recovering.

Most childhood knee pain responds well to conservative home management. The key principle is relative rest – avoiding activities that provoke pain while maintaining overall fitness and function. This approach allows healing while preventing the deconditioning and psychological effects of complete inactivity.

The RICE principle (Rest, Ice, Compression, Elevation) provides a good framework for initial management of knee pain, particularly following an acute injury or flare-up. Rest from the specific aggravating activity – whether that's basketball, running, or jumping – is essential. Ice applied to the affected area for 15-20 minutes several times daily helps reduce inflammation and provides pain relief. Compression with an elastic bandage can help control swelling, and elevation of the leg reduces fluid accumulation.

Over-the-counter pain relievers such as ibuprofen (Advil, Motrin) or naproxen (Aleve) can help manage pain and inflammation. Acetaminophen (Tylenol) addresses pain but has less anti-inflammatory effect. Follow age-appropriate dosing guidelines and use these medications for short periods rather than continuously. If regular medication is needed for more than a week or two, consult a healthcare provider.

Stretching and Strengthening

Many pediatric knee conditions benefit from stretching and strengthening exercises, even when started at home before formal physical therapy. Tight quadriceps and hamstring muscles contribute to several knee problems, and gentle stretching can provide relief and reduce the risk of recurrence.

For Osgood-Schlatter disease and anterior knee pain, stretching the quadriceps and hamstrings is particularly helpful. These stretches should be done gently, holding each position for 30 seconds and repeating several times. Stretching is most effective when muscles are warm, such as after a warm shower or light activity.

Strengthening exercises for the quadriceps, particularly the inner part of the muscle (vastus medialis obliquus), help stabilize the kneecap and improve patellofemoral mechanics. Simple exercises like straight leg raises, wall sits, and mini-squats can be started at home. However, if your child's pain persists or these exercises cause increased discomfort, professional guidance from a physical therapist is valuable.

Activity Modification

Complete cessation of all activity is rarely necessary and may even be counterproductive. Instead, the goal is to identify and avoid the specific activities that provoke pain while allowing your child to remain active. This approach maintains fitness, preserves muscle strength, and supports psychological well-being.

Children with Osgood-Schlatter or patellofemoral pain may need to temporarily avoid running, jumping, and kneeling. However, they can often continue swimming, cycling (with the seat adjusted to limit knee bending), or other low-impact activities that don't aggravate symptoms. Sometimes simply reducing the intensity or duration of the problematic activity is sufficient.

A gradual return to full activity is important once symptoms improve. Returning too quickly often leads to recurrence. A good rule of thumb is to increase activity by no more than 10% per week and to stop if pain returns. Adequate warm-up before activity and stretching afterward help prevent recurrence.

How Is Knee Pain in Children Treated?

Treatment depends on the cause but typically includes activity modification, physical therapy for stretching and strengthening, over-the-counter pain medications, and sometimes bracing or taping. Most growth-related conditions resolve with maturity. Surgery is rarely needed but may be required for unstable osteochondritis dissecans lesions, some meniscus tears, or recurrent patellar dislocations.

The treatment approach for pediatric knee pain is guided by the specific diagnosis, the severity of symptoms, and the child's activity goals. Fortunately, most childhood knee conditions respond to conservative (non-surgical) treatment, and the vast majority of children return to full activity without lasting problems.

For growth-related conditions like Osgood-Schlatter and Sinding-Larsen-Johansson syndrome, the primary treatment is supportive care while awaiting skeletal maturity. The knowledge that the condition will resolve is reassuring for families, though the timeframe of 1-2 years can feel long. During this period, treatment focuses on managing symptoms through activity modification, stretching, and pain control to allow the child to maintain as much activity as possible comfortably.

Anterior knee pain responds particularly well to physical therapy. A structured rehabilitation program focusing on strengthening the quadriceps (especially the vastus medialis), hip abductors, and core muscles, combined with stretching of tight structures, produces significant improvement in most patients. The exercises must be performed consistently over weeks to months for optimal benefit.

Over-the-Counter Pain Relief

Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen are effective for managing pain and inflammation associated with many pediatric knee conditions. They can be used on an as-needed basis for acute flare-ups or for short periods when symptoms are particularly troublesome.

When using these medications, follow age and weight-appropriate dosing instructions. NSAIDs should be taken with food to minimize stomach upset. For children who cannot tolerate NSAIDs or prefer an alternative, acetaminophen provides pain relief though with less anti-inflammatory effect.

If your child needs regular pain medication for more than 1-2 weeks, consult a healthcare provider. Persistent pain requiring ongoing medication warrants evaluation to ensure the diagnosis is correct and to consider whether additional treatments are needed.

Physical Therapy

Physical therapy is a cornerstone of treatment for many pediatric knee conditions. A physical therapist can provide a personalized exercise program, hands-on treatments to address muscle tightness or joint stiffness, and education about activity modification and injury prevention.

For anterior knee pain, physical therapy typically focuses on strengthening exercises for the muscles that control the kneecap, stretching tight structures, and sometimes techniques to improve kneecap tracking. For Osgood-Schlatter and Sinding-Larsen-Johansson, therapy emphasizes flexibility, particularly of the quadriceps and hamstrings, which can reduce tension at the tendon attachment sites.

Following an acute injury or surgery, physical therapy guides the rehabilitation process to restore strength, range of motion, and function. The therapist can help determine when it is safe to return to sports and guide a graduated return-to-activity program.

Bracing and Supportive Devices

Various braces, sleeves, and straps may be helpful for certain knee conditions. For Osgood-Schlatter, a patellar tendon strap (infrapatellar strap) can help distribute force and reduce stress on the tibial tubercle. Some children find these provide relief during activity.

Knee sleeves provide compression and proprioceptive feedback (awareness of joint position) that some children find helpful. For anterior knee pain, patellar stabilizing braces or taping techniques can help improve kneecap tracking. Custom orthotics may be beneficial if foot mechanics contribute to knee symptoms.

Bracing is typically used as an adjunct to other treatments rather than as the sole intervention. The goal is to allow comfortable participation in activity while other aspects of treatment (rest, physical therapy) address the underlying problem.

When Surgery Is Needed

Surgery is rarely required for pediatric knee conditions but is indicated in certain circumstances. Osteochondritis dissecans lesions that are unstable, detached, or fail to heal with conservative treatment may require surgical stabilization or removal of the fragment. The specific procedure depends on the size and location of the lesion and whether the cartilage surface can be preserved.

Meniscus tears, while less common in children than adults, sometimes require surgical repair, particularly if they cause locking or persistent symptoms. When possible, surgeons prefer to repair rather than remove the torn meniscus, as the meniscus provides important cushioning and stability.

Recurrent patellar dislocation that does not respond to physical therapy may benefit from surgical procedures to stabilize the kneecap. These can include repair or reconstruction of the ligaments that hold the kneecap in place, procedures to realign the patella, or a combination of approaches.

How Can You Help Prevent Knee Problems in Active Children?

Prevention strategies include proper warm-up before activity, regular stretching of quadriceps and hamstrings, strength training for leg and core muscles, appropriate footwear, gradual increases in training intensity, cross-training to avoid overuse, and ensuring adequate rest between sports seasons.

While not all knee problems can be prevented, several strategies can reduce the risk of common pediatric knee conditions, particularly those related to overuse. These measures are especially important for children involved in organized sports and intensive training.

Proper conditioning is fundamental to injury prevention. Children should develop good base levels of strength, flexibility, and cardiovascular fitness before progressing to intensive sport-specific training. Strong leg muscles, particularly the quadriceps and hamstrings, help absorb forces and protect the knee joint. Core and hip strength contributes to good lower limb mechanics.

A thorough warm-up before activity prepares the body for exercise and reduces injury risk. This should include light aerobic activity to increase blood flow and body temperature, followed by dynamic stretching. Static stretching is better reserved for after activity, when muscles are warm.

Training Considerations

Overuse injuries, including many common pediatric knee problems, result from the cumulative effects of repetitive stress without adequate recovery. Training errors – increasing intensity or duration too quickly, inadequate rest, year-round participation in the same sport – are significant risk factors.

The "10% rule" provides a useful guideline: increases in training volume (duration, distance, or frequency) should not exceed 10% per week. This allows the body to adapt to increasing demands gradually. Rest days are essential for recovery and should be built into training schedules.

Sport specialization – focusing on a single sport year-round from a young age – has been linked to increased overuse injuries in children. Experts recommend that children participate in multiple sports or take breaks between seasons to allow recovery and develop varied movement skills. The American Academy of Pediatrics recommends against single-sport specialization before age 15-16 for most sports.

• Proper footwear: Shoes appropriate for the activity, properly fitted, and replaced when worn
• Surface considerations: Training on appropriate surfaces; varying surfaces when possible
• Equipment: Properly fitted protective gear when indicated for the sport
• Technique: Proper instruction in sport techniques, particularly landing and cutting mechanics
• Listen to the body: Encouraging children to report pain early rather than "playing through" discomfort