Chondromalacia, also known as “runner’s knee,” is a condition where the cartilage on the undersurface of the patella (kneecap) deteriorates and softens. This condition is common among young, athletic individuals, but may also occur in older adults who have arthritis of the knee.
Chondromalacia is often seen as an overuse injury in sports, and sometimes taking a few days off from training can produce good results. In other cases, improper knee alignment is the cause and simply resting doesn’t provide relief. The symptoms of runner’s knee are knee pain and grinding sensations, but many people who have it never seek medical treatment.
Your kneecap normally resides over the joint of your knee. When you bend your knee, the movement causes the backside of your kneecap to glide over the bones of the knee, specifically the femur or thigh bone. Tendons and ligaments attach your kneecap to your shinbone and your thigh muscle to the kneecap. When any of these components fails to move properly, it can cause your kneecap to rub up against your bone. This rubbing can lead to deterioration in the patella, and then chondromalacia or runner’s knee.
Improper kneecap movement may result from:
- poor alignment due to a congenital condition
- weak hamstrings and quadriceps (the muscles in the back and front of your thighs)
- muscle imbalance between the adductors and abductors (the muscles on the outside and inside of your thighs)
- repeated stress to your knee joints, such as from running, skiing, or jumping
- a direct blow or trauma to your kneecap
There are a variety of risk factors for developing chondromalacia.
Adolescents and young adults are at high risk for this condition. During growth spurts, the muscles and bones develop rapidly, which may contribute to short-term muscle imbalances.
Females are more likely than males to develop runner’s knee, as they typically possess less muscle mass than males. This can cause abnormal knee positioning, as well as more lateral (side) pressure on the kneecap.
Flat feet may place more stress on your knee joints than in people who have higher arches in their feet.
A prior injury to the kneecap, such as a dislocation, can increase your risk of developing runner’s knee.
High Activity Level
If you have a high activity level or engage in frequent exercises that place pressure on your knee joints, this can increase the risk for knee problems.
Runner’s knee can also be a symptom of arthritis, a condition causing inflammation to the joint and tissue. Inflammation can prevent the kneecap from functioning properly.
Chondromalacia will typically present itself with pain in the knee region, known as patellofemoral pain. You may feel sensations of grinding or cracking when bending or extending your knee. Pain may worsen after sitting for a prolonged period of time or during activities that apply extreme pressure to your knees, such as standing for an extended period or exercising.