Causes of knee cartilage damage are varied and often interlinked, encompassing both acute injuries and long-term degenerative processes.
Understanding the causes of knee cartilage damage is essential for both prevention and effective care. Damage often happens because of trauma, overuse, ageing, swelling in the joints, or unusual body mechanics. Each of these adds extra strain on the knee cartilage. This includes both the smooth cartilage covering bones and the shock-absorbing menisci. These tissues don’t get much blood flow, so even small injuries often don’t heal well. Over time, they may cause long-term joint problems.
One major cause is sudden injury, especially during sports, falls, or accidents. A direct hit or a quick twist can tear or loosen cartilage. This happens often in contact sports like football, rugby, or basketball. These actions usually harm the meniscus or the smooth cartilage on the thigh and shin bones. People who play sports or stay very active face higher risks. These injuries often happen along with torn ligaments like the ACL or MCL. When ligaments tear, the knee becomes unstable, which wears out the cartilage faster.
Overuse and Ageing as Causes of Knee Cartilage Damage
Doing the same movement too often is another big cause. Jobs that involve kneeling, squatting, or lifting heavy items—like construction, farming, or military work—can wear out the knee over time. These motions strain the cartilage and joint surfaces, causing small damage that adds up. Runners and cyclists may also face cartilage wear due to repeated knee motion. While these sports are healthy overall, poor training or not enough rest raises the risk of injury.
Ageing adds more stress. As people get older, cartilage loses strength and becomes more brittle. This change makes it easier to wear down, even with normal activity. Weak muscles and less joint support in older adults also add more pressure to the knees. This wear and tear often leads to osteoarthritis. In that condition, cartilage slowly breaks down. This causes the bones to rub together, which leads to pain and stiffness.
Biomechanical and Weight-Related Causes of Knee Cartilage Damage
Body mechanics can also play a big role. If the legs are not straight—like with bow legs or knock knees—weight is not spread evenly across the knee. This extra pressure on one side causes faster cartilage loss in that area. Flat feet or ankles that roll inward also affect how you walk and move. This leads to odd joint motion and more wear on the cartilage. Leg length differences or bone structure problems may also add to this risk over time.
Being overweight puts a lot of pressure on the knees. Just walking or standing with extra weight pushes down on the joints. Every extra kilo of body weight adds about four kilos of force to the knee. This added strain wears out cartilage faster. Also, fat tissue makes chemicals that cause swelling in the joints. That swelling speeds up cartilage damage, combining both physical and chemical stress.
Inflammatory and Genetic Causes of Knee Cartilage Damage
Some illnesses that cause joint swelling also hurt cartilage. Rheumatoid arthritis makes the immune system attack the joints, including cartilage. This leads to constant swelling and faster damage. In gout, sharp crystals form inside the joint. These cause painful flare-ups and cartilage wear. Other diseases, like reactive arthritis or joint infections, also damage the cartilage. If not treated quickly, they can ruin the joint’s surface and lower its ability to move smoothly.
Genetics and hormones also matter. Some people are born with weak cartilage or odd joint shapes. For example, osteochondritis dissecans causes a piece of bone and cartilage to break off. This is more common in people with a family history of the condition. Hormone changes, especially after menopause, may also weaken cartilage. Oestrogen usually helps protect joints. In conditions like Ehlers-Danlos or Marfan syndrome, joints are too loose, making damage more likely.
Muscle Weakness and Previous Injuries as Causes of Knee Cartilage Damage
Old injuries or surgeries often lead to new cartilage problems. After an injury, the body may move in odd ways to avoid pain. These new movement patterns can stress parts of the knee that were once healthy. For example, surgery to fix a torn ACL may still leave the knee unstable. This can lead to a torn meniscus later on. A poorly healed break in the bone can also change how weight moves through the joint, wearing down cartilage faster.
Weak muscles around the knee can also cause trouble. Strong muscles—like the thighs, hamstrings, and calves—help support and protect the knee. When these muscles are weak, the knee has to absorb more shock on its own. This puts more stress on the cartilage. Tight muscles and tendons can also limit movement. This increases pressure in the joint and raises the risk of damage during activity.
Final Thoughts on Causes of Knee Cartilage Damage
In summary, the causes of knee cartilage damage include sudden injuries, repeated use, ageing, poor body mechanics, too much weight, swelling from disease, weak muscles, and genes. Knowing these causes helps people take action early. This means better prevention and smarter treatment. Simple habits—like keeping a healthy weight, staying strong, and fixing joint alignment—can go a long way in stopping damage. Preventing cartilage wear helps keep knees healthy and pain-free for the long term.
