From the viewpoint of a clinician, the knee is one of the most interesting joints. This can be confirmed by taking a casual look at any orthopaedic or physiotherapy book, I have found that a considerable volume of these books is dedicated to injuries or diseases of the knee as compared to any single joint.
The reasons why the knee is at risk of injury or disease, and the preventive steps to save the knees are discussed below-
1. Location: The knee is located between the hip and the foot. Seen in this way, it is jammed between two very mobile joints, and an involvement of the hip or foot will affect the knee.
- Transmission of the force from the hip or the foot is one of the many reasons for a knee problem. To control this, it is essential to strengthen the muscles at the hip and foot.
- Hip muscles link the lower back to the leg, in this way they provide postural control of the lower back and the leg. Strengthening the hip gives stability to the knee as it aligns the knee posture, keeping the risk of injury to the knee at the minimum. Shown below is an exercise for the hip:
- The exercise shown above is called bridging. Raising the pelvis up this way uses the muscles of the hip, the muscles in the back of the thigh, and the lower back. This is a great exercise for posture and hip strength.
- Leg exercises are very important to stabilize the joints of the foot and the ankle and keep the stress off the knee. There have been numerous scientific studies which have documented that exercises of the leg and foot provide a better posture and save the risk of a sprain, and even improve balance.
- The picture above shows a wobble board exercise. These exercises a performed on a wobble board with a narrow base, the motion performed is that of rocking side to side, and back to front keeping the hands on the pelvis. This exercise is commonly used to strengthen the muscles of the legs.
2. The muscles around the knee: The knee is surrounded by some of the most powerful muscles of the human body. These muscles also contribute to the stability of this joint. Neglecting the strength of these muscles or their divisions compromises the knee.
- Most people feel that doing squats is the exercise which will work the muscles around the knee. This neglects the calf muscles and the hamstrings at the back of the thigh. An appropriate strength of these muscles contributes to preventing ligament injuries, and injury to the deep structures of the knee. The pictures below demonstrate hamstrings and calf exercises.
- The exercise above is a simple variation of bridging exercise. Placing a gym ball below the feet and lifting the pelvis shifts the strain of this exercise to the hamstrings.
3. Forces which the knee bears: The knee must deal with a lot of activity testing its strength, it has been measured that in some of the activities a force of 3 or 4 times the body weight is placed on the knee.
- One of the ways to counteract the forces which can damage the knee during regular activity is to do a warm-up before any exercise. This will prepare the muscles around the joint for activity and reduce the risk of injury. Cooling down and stretching the muscles around the knee helps to take the tension off after activities.
- A sure shot way to guard the knee against excessive forces is to keep weight under control. There is a previous article which I have written addressing weight loss. However, there are ways to protect your knee if you are overweight.
- A person with excessive weight needs to do exercises on soft surfaces which cushion the weight.
- Some exercises such as squats place excessive stress on the knee, an overweight person should not do stressful exercises such as squats.
- Take frequent rests by sitting while standing or doing exercises. This will take the weight off the knees.
4. Aging and development: As we age we lose muscle strength, there is a loss of bone mineral density, and this causes widespread changes in the knee and the muscles around it making the knee more prone to injury. The figure below shows changes of the skeleton with ageing.
As the figure shows the loss of bone mineral density causes the shifting of weight forward, also there is a loss of muscle tissue. Aging causes the increase of stress which is placed on the knee.
- Taking calcium supplementation and exercise can prevent the development of the weakening of the muscles and bones.