Have you ever taken issue with how your body works? Or more to the point, how it doesn’t work like it used to? You can experience that most often with your knees. The knee is the joint that connects your femur, or thigh bone, with the tibia, or shin bone. The little bone at the front of the knee is called the patella, or kneecap. The knee is the joint that helps us jump, squat and kneel. When it works properly, the knee will move primarily in one plane—forward to back. Unfortunately, it is commonly injured in sports as well as in everyday living.
As a human, you are biped. In other words, you walk upright. When you stand, walk, run and jump, your body weight is born by your two lower limbs. So the stresses on your legs, especially the joints, are quite significant. For instance, with each step you take, your patella experiences a force of nearly three times your body weight. The average person takes between 7,000 and 12,000 steps per day. The stress on your patella increases to almost four times your weight on stairs, eight times on a run and 12 times on a landing after a jump. By doing the math, it becomes painfully clear what a 10-pound weight gain will do to increase the pressure your knee experiences. At 12,000 steps per day, a 10-pound weight increase will equal 360,000 pounds of force per day—OUCH! No wonder your knees hurt.
The bones make up only a part of the important structures in the knee. Ligaments, meniscus and tendons are critical to the proper functioning of a knee.
Ligaments are the gristly strands or cords that connect bones to each other. Ligament tears are called sprains. When the ligament is mildly stretched, it's a low-grade sprain. Ligament tears are considered high-grade sprains.
ACL Injuries
The most familiar sprain or tear is of the anterior cruciate ligament (ACL). It is the knee’s “sexy ligament” because we hear so much about ACL tears in athletes. The ACL lies in the very center of the knee with its counterpart, the posterior cruciate ligament (PCL). Together these two ligaments keep the tibia from sliding too far forward or backwards on the femur.
The most common ways to injure the ACL are stopping suddenly to change directions when running, falling backwards while skiing, or being hit in the back of the knee while your foot is planted. Most athletes will state that their knee just buckled or that they felt a pop, but often there's not a lot of pain. Overnight there is usually a great deal of swelling. After an ACL tear, your knee may feel like it buckles or might buckle with simple activities. If your knee swells or buckles as a result of this type of injury, you should wrap and ice your knee. And to avoid further injury, you should see your Orthopedic surgeon right away.
Another interesting fact about the ACL is that in some sports, such as soccer, volleyball or basketball, women are much more likely to injure their ACLs than men. Why the unbalanced predisposition? Women typically have wider hips and narrower knees than men, and they tend to land jumps with straight legs rather than with bent knees. Also, women tend to develop stronger quadriceps muscles in relationship to their hamstring muscles. Hormones have also been suggested as a possible factor. Training programs have been developed to help people, especially women and girls, decrease the risk to their ACLs. These programs have shown promise when properly implemented, and they are available at our office.
The PCL is rarely injured, but when it is, the injury is usually caused by striking the front of the knee in a car accident or fall.
MCL and LCL Injuries
The other two ligaments in your knees are the medial collateral ligament (MCL) and the lateral collateral ligament (LCL). The MCL is located on the inside of your knee and the LCL is on the outside. Both connect the femur to the tibia. LCL sprains occur when your knee is forced into a bow-legged position. If you sprain your LCL, seek medical attention. This injury will require at least bracing, if not surgery. The MCL is injured when the knee is forced into a knock-kneed position. Interestingly, it rarely requires surgery. The MCL is commonly injured and does require bracing for best recovery.
Meniscal Tears
Although not quite so exciting, the most common knee injury requiring surgery is the meniscus tear. A knee has two menisci (plural of meniscus). The one on the inside of the knee is the medial meniscus and the one on the outside is the lateral meniscus. These C-shaped structures cushion the tibia and the femur. Meniscal surgery is the most common orthopedic surgery performed. In fact, of all surgeries performed anywhere on the body, it is second only to childbirth. Fortunately, meniscal surgery is performed with an arthroscope and is minimally invasive. Recovery is very short, and the arthroscope is usually very well tolerated.
Why is the meniscus injured so often? It sees a lot of force, especially when you twist, and its inside edge is wafer-thin. The meniscus also has a very poor blood supply. In fact, only the outside 30% has a blood supply at all. This is important because when a part of the body is injured, it requires the healing properties found in blood to repair it. If there is poor—or no—blood flow to the injured area, it has no way to heal and remains injured. In the case of the meniscus, it remains torn.
How do you know if you have a meniscal tear? Typically, the symptoms are pain, swelling, popping or catching in the knee. You may experience all or just a few of these symptoms. The funny thing is that you can tear a meniscus without a specific trauma, twisting injury or fall. Many tears simply develop over time, and because they don't heal on their own, you will eventually notice the symptoms.
The real problem lies in waiting too long before you do something about a meniscal tear. Studies have shown that waiting more than three months can lead to damage to the white, shiny cartilage at the end of the femur and tibia. This damage is known as arthritis. It's very important to have your meniscal tears seen by an Orthopedic surgeon in order to prevent the possibility of further damage to your knee.
New Advancements in Treatment
A recent and very exciting development in the treatment of ligament and tendon injuries is called platelet-rich plasma, or PRP. A concentration of the healing properties in your own blood is injected at the site of injury and actually speeds the healing process. In many cases, PRP can even heal the injury well enough that surgery isn't necessary. Using PRP in the treatment of MCL injuries has yielded excellent results, and athletes can return to sports in three weeks instead of the usual four- to six-week healing period. We are currently using PRP in the treatment of ligament sprains, patella tendonitis, tennis elbow and even for arthritis.
As you can see, knees are tricky little joints. Staying strong is a good defense against injury, but when injuries do arise and you feel “knee-dy,” be sure to have them properly treated in order to prevent additional problems down the road.