The knee joint capsule is complex made of bones, cartilage, ligaments and tendons.
- The knee joint is comprised of 3 bones: the thigh bone (the “femur”) and the shin bone (the “Tibia”), and the patella or (the “kneecap”). The patella is a small piece of bone that covers and protects the knee joint. It sits in a groove in the femur and moves up and down when the knee is bent and straightened.
- All knee bones are covered with articular cartilage which allows the bones to slide and rotate with low friction. The cartilage also helps to better distribute the loads across the joint.
- The menisci are two cartilage structures vital for normal knee function, stability and the long-term health of the knee. The menisci sit between the femur and the tibia and function as shock absorption and distribute the load across the tibiofemoral joint.
- The collateral ligaments are located on the sides of the knee. The medial collateral ligament (MCL), and the lateral collateral ligament (LCL). They function to prevent excessive rotation of the knee.
- The cruciate ligaments are the Anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL) are knee stabilizers that prevent excessive anterior and posterior motion.
Knee stability is a function of the interaction between the bones, cartilage, ligaments, muscle forces, and menisci. While walking the forces on the knee are 3-7 times your body weight.
Common knee conditions
OA is called wear and tear arthritis which destroys the articular cartilage that lines the bone surfaces in the knee. The result is the bones rub together causing significant pain and dysfunction and bone spurs. Knee OA makes it difficult to do everyday activities like walking and climbing stairs. Initial treatment is nonsurgical. There is a 57% increased risk of post-traumatic OA after a knee injury. When pain and disability destroy quality of life, the most common treatment is joint replacement.
Anterior Cruciate Ligament (ACL) injury
Injuries to the ACL are common. ACL injuries send more athletes to the bench for longer periods than almost any other acute injury. ACL injuries occur most often in people who participate in high impact sports like tennis, basketball, football, skiing and soccer, which requires abrupt changes in direction. Treatment depends on the individual patient’s needs and whether there is a complete rupture or a partial tear. Young athletes typically need surgery in order to resume normal activities and sports. Older, less active individuals may be able to restore function with physical therapy. Complete ruptures usually require surgery. About 50% of ACL injuries also damage other ligaments, the meniscus, and articular cartilage. Combined injuries usually require surgery. Chronic instability causing knee buckling will damage the meniscus and OA.
Posterior cruciate ligament (PCL) injury
The PCL can be injured by a blow to the front of the knee. Tears tend to be partial and have the potential to heal on their own with conservative treatment. Injury to the PCL is often accompanied by other injuries to the knee. In this case, surgery may be recommended.
Patellar (kneecap) conditions
- The patellofemoral pain syndrome describes pain in the front of the knee and around the kneecap. It is commonly referred to the runner or jumper’s knee, caused by repetitive stress involves with squatting, jogging and climbing, and by abnormal tracking of the kneecap. Treatment is designed to relieve pain and restore range of motion and strength.
- The most common bone broken in the knee is a patellar fracture, usually caused by high energy trauma such as a fall or auto accident. A patellar fracture may also be accompanied by fracture of the ends of the tibia or femur. Simple fractures can be treated with a cast, but complex fractures may require surgery to restore and stabilize the kneecap.
- Patellar dislocation occurs when the knee bones are misaligned causing the patella to slip out of its groove. The cause may be abnormal bone structure or trauma. The result is instability.
Meniscus injuries are among the most common athletic injuries, cause functional impairment and can lead to other joint problems. Repair is crucial for pain relief and to prevent degenerative joint disease or osteoarthritis (OA). Small meniscus tears can be repaired surgically. When meniscus damage is severe the meniscus may be removed, but that causes OA in the long run. Thus, the most common option is a meniscus transplant.
The quadriceps and patellar tendons are commonly injured in middle age from running and jumping sports, falls, an awkward landing from a jump, and direct impact to the front of the knee.
Tears may be partial or complete. A complete tear separates the kneecap and prevents the ability to straighten the knee. Often a tear also breaks off a piece of bone from the kneecap. Small tears can be treated without surgery. However, in order to regain knee function, surgery to reattach the tendon is necessary. Surgery works best if done soon after the injury.
When you have knee pain, it’s time to schedule a consultation with Grossmont Orthopedics in San Diego, CA. Our board-certified, fellowship trained orthopedic surgeons can help you restore you quality of life so that you can return to the things that make life enjoyable.