Causes of knee pain in adolescents

Your bone, muscles and its surrounding structures all assist you to move and perform various activities.

However, the right amount of pressure enhances performance and too much stress may cause an injury.

Osgood-Schlatter (OS) (knee pain) results from repeated damage around the knee joint. Frequently, a lump or growth may be seen just below the kneecap.

The condition may develop when there is too much stress placed on the top or front aspect of the knee joint during a growth spurt- period of rapid bone growth.

Adolescents usually have the most rapid rate of bones growth and hence are commonly affected.

What is it?

Osgood-Schlatter disease arises when there is a lot of stress or pressure on the top or front part of the shin bone, at the point where the tough cords from the shin bone join the kneecap.

When there are high levels of stress placed at that point, for example due to increased participation in sports or increased activity levels of the adolescent.

As your child goes through adolescence, you would realise a lot of rapid changes in his/her body. These changes also include rapid bone growth so they become bigger and taller.

During the growth spurt, the bones grow faster than muscles and the tough cords-connects muscles and bones.

Increased stress in the tough cords in the knee joint results in the tough cords pulling away from the bone which may cause a tear to occur.

Most girls experience this development between 11 to 12 years, while the boys have theirs between 13 and 14 years.

However, boys experience this condition frequently due to their increased activity levels.

The condition may begin as a slight discomfort or soreness at the knee joint but may develop into intense pain and restrict movement if it’s not resolved correctly and early.

How does it occur?

Every structure in the body can accommodate specific amount of stress or pressure when the level or amount of stress is too much for the structure to accommodate an injury may occur.

This condition comes about when there is repeated stress at the knee joint – front or top aspect. It frequently occurs in adolescents who are usually engaged in running or jumping activities.

The increased activity levels, coupled with the rapid growth, places too much stress on the knee joint causing pain. When the activity levels – amount and frequency of exercise - are not altered, sometimes a bony outgrowth may form on the front aspect of the shin bone.

There are other various factors which also contribute to the development of the condition.

These factors include;

• Knee or hip joint stiffness

• An abrupt increase in an activity or sports

• Inappropriate footwear

• Thigh muscle tightness or weakness

• Improper training

• Inappropriate foot placement

What are the signs and symptoms?

Your child may experience various symptoms such as:

• An outgrowth of bone may be observed at the top aspect of the shin bone

• The pain becomes worse each time the child exerts him/herself in sports

• There is swelling just below the knee joint

• Increased tightness in the thigh muscles

• Progressive increase in pain just below the knee or at the top aspect of the shin bone.

• Movement in the knee joint is reduced considerably. Activities that involve knee-bending such as kneeling or squatting become painful.

• Decrease strength in the thigh muscles

How is it diagnosed?

The Physical Therapist (PT) assesses the adolescents’ flexibility, strength, sensation through various tests specific to the foot, knee and hip joints.

The PT will observe how your child’s knee moves as he/she walks, jogs, climbs stairs etc.

Your child may also be required to perform specific movements to ascertain the painful parts of the affected leg.

The hip joint will be examined, as well as the thigh muscles to find out whether there is tightness in the muscles during movement. Further investigations such as X-ray or MRI may be conducted to confirm the diagnosis.

After the assessment, appropriate management is commenced to restore movement and function of the knee joint.

The writer is a Senior Physiotheropists at the 37 Military Hospital