Pain felt at the front of the knee, in the region of the knee cap (the “patella”) is one of the most common joint pains seen in children, and whilst it can be troublesome, it is rarely due to a serious problem with the knee itself.
Problems with the hip can actually cause pain to be felt in the knee, so we always ask about and examine the hip in children complaining of knee pain. We also often perform x-ray imaging of the hip as well as the knee in such cases.
Osgood-Schlatter disease
What is it?
Osgood-Schlatter disease is the name given to a condition in which localised inflammation occurs where the ligament from the kneecap (patella) attaches to the the top of the leg-bone (the tibia). The condition presents as a localised distinct painful bony swelling on the top of the front of the shin. Pain is usually related to activity.
This condition almost always gets better over time without any specific intervention other than activity modification. Occasionally, physiotherapy as detailed below is required. Very rarely, we will advise a brace or plaster for pain management.
Patellofemoral Pain Syndrome (PFP) or Anterior knee pain
What is it?
This is the most common cause of pain around the kneecap in children, most often during the teenage growth spurt.
Girls are affected more than boys
It affects about 7% of young male athletes and 10% of young female athletes; it can affect non-active kids too.
Symptoms are usually felt in both knees, but one maybe more affected than the other.
Pain is usually felt during and after activities, (eg. weight bearing sports, stairs (worse coming down) and squatting).
Sitting with the knees bent for prolonged periods of time can also cause pain and stiffness.
It can feel as though the knee “gives way”, particularly during stair walking and walking along inclines, because of pain or weakness causing problems with the functioning of the quadriceps muscles.
Why does it occur?
The pain is thought to be due to problems with the way in which the kneecap (the “patella”) sits and glides within its groove on the front of the lower part of the thigh bone (the “femur”). This space between the kneecap and the femur is called the “patellofemoral joint”. There are a number of different things that can interfere with the way the kneecap glides in its groove (“tracking”), such as:
Muscle imbalance:
- Weakness of the quadriceps muscle, or a relative imbalance between its inner and outer parts (vastus medialis and vastus lateralis respectively) may cause PFP.
- Weakness of the vastus medialis causes problems with patellar gliding as the knee is fully straightened (terminal 30 degrees), with the patella being pulled outwards increasing the stress through the joint.
Muscle tightness:
- Around the knee, (quadriceps, hamstrings, calf muscles)
- Around the hip (the gluteal muscles)
Abnormalities of the bones:
- Bowlegs or knock-knees
- Excessive inward twists of the femur bone or excessive outward twists of the tibia bone
- Abnormal formation of the groove in the femur for the patella (“patellofemoral dysplasia”)
Treatment
These pains will usually gradually improve and get better over time.
To help things along, we may suggest modifying activities to reduce the forces affecting the patellofemoral joint.
We also often refer patients to physiotherapy for exercises to:
- stretch tight muscles and ligaments (quadriceps, hamstrings, iliotibial band, gastrocnemius)
- strengthen the weak muscles
Physiotherapy for these problems generally follows a schedule similar to that detailed in this table:
If a structural problem with the bones is identified, this may require further investigation, and then possibly corrective surgery. However, even in these cases, physiotherapy would be the first-line treatment.