Chondromalacia

What is chondromalacia?

In chondromalacia, the cartilage that lines the back of the kneecap or patella, becomes softened and damaged.

As the cartilage softens it becomes more vulnerable as the kneecap glides over the leg during movement. Small areas of cartilage may break down, allowing the kneecap to rub against the femur or thigh-bone, aggravating the damage.

One knee only is usually affected. Typically the knee feels stiff after sitting down and may click when moved. Any action where the knee is bent and straightened, running or going up and down the stairs, for example, will bring the pain on.

The condition is also known as chondromalacia patella or patellofemoral pain syndrome, and it is the commonest cause of chronic knee pain.

Causes and risk factors

The kneecap is normally pulled over the thigh bone (femur) in a straight line but in those with chondromalacia, there may be abnormal tracking of the patella towards the outer side of the femur. This can put abnormal stress on the tissues, triggering a sequence of damage, inflammation, and pain.

It's still not fully understood why the condition develops but several groups seem to be at particular risk.

Teenagers (especially girls) may be especially predisposed top chrondromalacia due to changes in the tissues during their growth spurt. Strenuous exercise, where there may be excessive strain on the muscles and ligaments (particularly if the person has knock knees or is flat-footed) can be the trigger for the damage to start, as can repeated injuries to the knee. Osteomalacia is more common in the very active, especially among people who play sports such as running, cycling, skiing and football.

Older adults may also be affected as part of the process of osteoarthritis that can affect all joints.

Treatment and recovery

Over time, the condition tends to improve. Physiotherapy helps to strengthen the supporting muscles and ligaments around the knee joint (especially the inner parts of the quadriceps muscle) which straightens the tracking movement of the patellar and prevents future recurrences.

When the knee is uncomfortable, painkillers, anti-inflammatory medication, an elastic knee support, cold or heat packs will bring relief.

In severe cases, it's sometimes necessary for an orthopaedic specialist to look inside the knee joint with a fibre-optic camera and remove the damaged cartilage.