Schlatter Knee (Osgood-Schlatter Disease): Symptoms, Causes, and Treatment

What is Schlatter Knee?

Schlatter knee, clinically known as Osgood-Schlatter Disease (OSD), is a common cause of knee pain in growing adolescents, characterized by inflammation of the patellar ligament at the point where it attaches to the tibial tuberosity, a bony bump just below the kneecap.

Understanding Osgood-Schlatter Disease

Osgood-Schlatter Disease is an overuse injury or traction apophysitis, affecting the growth plate (apophysis) located at the top of the shin bone (tibia). Specifically, it impacts the tibial tuberosity, the insertion point for the patellar tendon, which connects the quadriceps muscle to the tibia via the kneecap (patella). During periods of rapid growth, this area is particularly vulnerable to repetitive stress from activities involving powerful quadriceps contractions, leading to microtrauma, inflammation, and pain.

Who Is Most Affected?

OSD primarily affects active adolescents undergoing growth spurts, typically:

• Boys: Aged 10-15 years
• Girls: Aged 8-13 years This age difference reflects the typical timing of growth spurts in each gender. Athletes involved in sports that demand frequent running, jumping, and rapid changes in direction are at higher risk. These include basketball, soccer, volleyball, gymnastics, and track and field. While it can affect one knee, it is bilateral (affects both knees) in 20-30% of cases.

Key Symptoms and Presentation

The hallmark symptoms of Osgood-Schlatter Disease include:

• Pain: Localized pain and tenderness just below the kneecap, specifically over the tibial tuberosity. The pain typically worsens with activity, especially running, jumping, squatting, kneeling, and climbing stairs, and often improves with rest.
• Swelling: Mild to moderate swelling around the tibial tuberosity.
• Tenderness: Significant tenderness to the touch over the affected area.
• Prominent Bump: In some cases, a noticeable bony lump or enlargement may develop at the tibial tuberosity due to chronic inflammation and new bone formation. This lump may persist even after the pain resolves.
• Tightness: Associated tightness in the quadriceps and hamstring muscles may contribute to or exacerbate symptoms.

The Underlying Biomechanics and Causes

The primary mechanism behind OSD is repetitive stress on the immature growth plate. During activities, the powerful quadriceps muscles pull on the patellar tendon, which in turn pulls on its attachment point at the tibial tuberosity. In adolescents whose bones are still growing, this attachment point is a weaker cartilaginous growth plate rather than fully ossified bone.

• Repetitive Traction: Repeated forceful contractions of the quadriceps, common in athletic activities, create traction forces on the vulnerable growth plate.
• Microtrauma: This repetitive pulling can lead to micro-avulsions (tiny separations) of cartilage or bone fragments from the tibial tuberosity.
• Inflammation and Repair: The body responds to this microtrauma with inflammation and attempts at repair, often leading to increased bone formation and the characteristic painful bump.
• Growth Spurt Vulnerability: The rapid growth during adolescence makes the growth plates more susceptible to injury because they are still soft and haven't fully hardened into bone.

Diagnosis: How Is It Confirmed?

Diagnosis of Osgood-Schlatter Disease is primarily clinical, based on the patient's age, symptoms, and a physical examination.

• Physical Examination: A healthcare professional will palpate (feel) the area below the kneecap, looking for tenderness, swelling, and the presence of a bony prominence. They will also assess range of motion and quadriceps flexibility.
• Imaging (X-rays): While not always necessary for diagnosis, X-rays may be performed to:
  • Confirm the diagnosis by showing fragmentation or prominence of the tibial tuberosity.
  • Rule out other conditions that can cause knee pain, such as fractures, infections, or tumors.

Management and Treatment Strategies

Treatment for OSD is typically conservative and focuses on pain management, reducing inflammation, and modifying activity until the growth plate matures.

• Rest and Activity Modification: This is the cornerstone of treatment. Reducing or temporarily stopping activities that aggravate the pain is crucial. Complete rest is rarely necessary, but high-impact activities should be limited.
• Ice Application: Applying ice packs to the affected area for 15-20 minutes several times a day can help reduce pain and inflammation.
• Pain Relief: Over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen can help manage pain and inflammation.
• Stretching and Strengthening: A physical therapist or trainer can guide specific exercises to improve flexibility and strength.
• Supportive Devices: A patellar tendon strap or knee brace may help distribute forces and reduce tension on the tibial tuberosity during activity.
• Gradual Return to Activity: Once pain subsides, activities should be gradually reintroduced, closely monitoring symptoms.

Rehabilitation and Exercise Considerations

A structured rehabilitation program is vital for managing OSD and preventing recurrence.

• Flexibility: Focus on stretching the quadriceps, hamstrings, and hip flexors to reduce tension on the patellar tendon.
  • Quadriceps Stretch: Standing or lying, gently pull the ankle towards the glute.
  • Hamstring Stretch: Seated or standing, reach for toes with a straight leg.
• Strengthening: Strengthen the surrounding musculature to improve knee stability and support.
  • Quadriceps Strengthening: Leg presses, wall sits, straight leg raises (non-aggravating).
  • Hamstring Strengthening: Hamstring curls, glute bridges.
  • Gluteal Strengthening: Clamshells, side-lying leg raises, glute bridges, to improve hip stability and kinetic chain efficiency.
• Core Stability: Strengthening the core muscles can improve overall movement mechanics and reduce stress on the lower limbs.
• Proprioception: Balance exercises can help improve neuromuscular control around the knee joint.

Prevention Strategies for Athletes

While OSD cannot always be prevented, certain strategies can reduce the risk, particularly in young athletes:

• Proper Warm-up and Cool-down: Ensure adequate warm-up before activity and cool-down stretches afterward.
• Gradual Increase in Training Load: Avoid sudden increases in intensity, duration, or frequency of training. Follow the "10% rule" (do not increase training load by more than 10% per week).
• Cross-Training: Encourage participation in a variety of sports or activities to reduce repetitive stress on a single joint.
• Appropriate Footwear: Wear supportive athletic shoes that are appropriate for the sport and replaced regularly.
• Listen to the Body: Teach young athletes to recognize and report pain early, rather than playing through it.
• Maintain Flexibility: Regular stretching, especially of the quadriceps and hamstrings, is crucial.

When to Seek Professional Medical Advice

While OSD often resolves on its own with conservative management, it's important to consult a healthcare professional if:

• Pain is severe or does not improve with rest and home care.
• Swelling or redness around the knee is significant or worsens.
• There is a fever or other signs of infection.
• The pain interferes significantly with daily activities or sleep.
• The bony prominence is causing significant functional issues.

Prognosis and Long-Term Outlook

Osgood-Schlatter Disease is generally a self-limiting condition, meaning it resolves on its own once the growth plate at the tibial tuberosity matures and fuses, typically by the end of adolescence. For most individuals, symptoms disappear completely, and they can return to full activity without limitations. In some cases, a prominent, painless bony lump may persist at the tibial tuberosity, and a small percentage of individuals may experience residual pain or discomfort into adulthood, especially with kneeling or direct pressure on the area. Surgical intervention is rare and usually only considered for persistent, severe symptoms in skeletally mature individuals.