An overview of muscles and problems with the knee

You talked about knees being a potential joint problem for people.  What muscles and exercises can help?

The knees are the most easily injured part of the body. It’s the largest and most complicated joint. The knee is used for so many things. Standing up, sitting, walking, running, just about anything that comes to mind. The knee is a weight bearing joint that can straighten, bend, twist and rotate. All this mobility increases the risk of acute or overuse knee injuries. 

How is the knee designed?

The knee joint is made up of three parts. The thigh bone (femur) which meets the shin bone (tibia). This forms the main joint. The joint has an inner (medial) and outer (lateral) part. The kneecap (patella) joins the femur to form the patellofemoral joint. The knee joint is surrounded by ligaments strapping the inside and outside of the joint as well as ligaments crossing the joint. All these ligaments provide stability and strength to the knee joint. The meniscus is a cartilage pad between the two joints formed by the femur and tibia. It acts as a smooth surface for motion and absorbs the load of the body above the knee when standing. It also aids in dispersing joint fluid for joint lubrication. The knee joint is surrounded by fluid filled sacs called bursa. These serve as gliding surfaces that reduce friction of the tendons. The knee function allows movement of the leg and is critical to normal walking.

Common knee injuries

Knee pain is usually caused by doing too much too soon. This is especially true when you haven’t exercised for a while and with high impact activities like aerobics, walking, running, jumping etc. (Walking upstairs puts pressure on the knees four times your body weight. When running upstairs it can be as much as eight times your body weight.) 

Acute knee injuries including torn ligaments and torn cartilage are often caused by twisting the knee or falling. Sports involving running, jumping, sudden stopping and turning increase the risk of acute knee injuries. More commonly sudden knee injuries are due to overuse or overload. 

Overuse knee injuries including muscle strain, tendonitis and bursitis may develop gradually over days or weeks. Pain often is mild and intermittent in the beginning and worsens over time. When muscles and tendons are stressed even slightly beyond their capabilities microscopic tears occur. These tears must be given the chance to heal before doing the same activity again to over reinjure. Inflammation which is part of the healing process is what causes the pain. 

A common cause of knee pain is knee osteoarthritis. This risk of these increases with age. This is a form of arthritis that involves degeneration of the cartilage. Exercise is vital to maintain strength and flexibility of muscles supporting the knee which will reduce the stress on the knee joint. 

Runner’s knee or patellofemoral pain or anterior knee pain is a common form of knee pain in young people (and runners). The pain is usually behind the kneecap. Symptoms worsen after climbing stairs, jumping, running, or after sitting for a time. This is caused by poor tracking of the kneecap. 

Knee pain is usually treated conservatively. However, in some situations surgery is required. Athletes are at a greater risk for sudden injuries, such as torn ligaments in the centre of the knee or certain types of fractures that may require surgery. People with advanced knee osteoarthritis may need replacement surgery. However, most knee conditions respond to non-invasive treatments and pain and inflammation medications. Non-invasive treatments can be applying heat or cold, taking a break from activities that can aggravate the pain. Exercises that strengthen the muscle that support the knee can help reduce stress on the knee joint and reinjure. 

Knee pain can be prevented by keeping the muscles that support your knees strong and flexible. Proper footwear is important especially for walking and running on hard surfaces