OA (osteoarthritis) of the knee joint

 

Anatomy of knee joint:

First, let us know the anatomy of knee joint.

Knee joint consists of two joints Tibiofemoral joint and Patellofemoral joint, which is made up of 3 bones: Femur(thigh bone), Tibia(leg bone) and Patella(Knee cap). There are different soft tissue in the knee joint that protects the joint like ligaments (ACL, PCL, medial and lateral), Bursae, meniscus (medial and lateral) and cartilage. Today, our main focus will be on the cartilage as it is the primary structure that gets damages in osteoarthritis of knee.

Cartilages are smooth and flexible substance covering the end of bones where they meet. It enables the bones in joint to move without rubbing against each other. When cartilage in the joint is healthy, it effectively allows bending/straightening motion and protects joint from weight bearing stresses. Cartilages does not have blood supply, thus, if cartilage is damages it cannot heal, exposing the underlying bone-ends and the joint looses its protective cushion. 

Osteoarthritis of knee:

Arthritis can be of various types but the most common arthritis, occurring in millions of people world wide, in knee joint is osteoarthritis. It is also called wear-and-tear arthritis of knee joint. It is a condition in which the natural cushioning between joints (cartilage) wears away. When this happens, the bones of the joints rub more closely against one another with less of the shock-absorbing benefits of cartilage. The rubbing results in pain, swelling, stiffness, decreased ability to move and, sometimes, the formation of bone spurs. While it can occur even in young people, the chance of developing osteoarthritis rises after age 45.

Cause of knee osteoarthritis:

The most common cause of osteoarthritis of the knee is age. Almost everyone will eventually develop some degree of osteoarthritis. However, several factors increase the risk of developing significant arthritis at an earlier age.

• Weight: It increases pressure on all the joints, especially the knees. Every pound of weight you gain adds 3 to 4 pounds of extra weight on your knees.
• Heredity: This includes genetic mutations that might make a person more likely to develop osteoarthritis of the knee. It may also be due to inherited abnormalities in the shape of the bones that surround the knee joint.
• Gender: Women ages 55 and older are more likely than men to develop osteoarthritis of the knee.
• Repetitive stress injuries: These are usually a result of the type of job a person has. People with certain occupations that include a lot of activity that can stress the joint, such as kneeling, squatting, or lifting heavy weights (55 pounds or more), are more likely to develop osteoarthritis of the knee because of the constant pressure on the joint.
• Other illnesses: People with rheumatoid arthritis, the second most common type of arthritis, are also more likely to develop osteoarthritis. People with certain metabolic disorders, such as iron overload or excess growth hormone, also run a higher risk of osteoarthritis.
• Joint injuries: Injuries, such as those that occur when playing sports or from an accident, can increase the risk of osteoarthritis. Even injuries that occurred many years ago and seemingly healed can increase your risk of osteoarthritis.

Symptoms

Osteoarthritis symptoms often develop slowly and worsen over time. Signs and symptoms of osteoarthritis include:

·         Pain. Affected joints might hurt during or after movement.

·         Stiffness. Joint stiffness might be most noticeable upon awakening or after being inactive.

·         Tenderness. Your joint might feel tender when you apply light pressure to or near it.

·         Loss of flexibility. You might not be able to move your joint through its full range of motion.

·         Grating sensation. You might feel a grating sensation when you use the joint, and you might hear popping or crackling.

·         Bone spurs. These extra bits of bone, which feel like hard lumps, can form around the affected joint.

·         Swelling. This might be caused by soft tissue inflammation around the joint.

 

How physiotherapy can help:

First of all a proper assessment is necessary to identify the exact cause of pain, joint mal-alignment, strength of muscle and to see whether any surrounding structures(soft tissues) are damaged.. Depending on the findings of assessment a physiotherapist will develop a customized treatment plan keeping in mind the goal of patient. Not all the people suffering from arthritis require same treatment protocol. Some can start high intensity exercises right away, where as, some has to start with low intensity exercises and progress accordingly. Severe cases of arthritis with exaggerated symptoms, that cannot be managed conservatively, may have to go for total knee replacement surgery.

To reduce pain, there are many modalities that can help for e.g. TENS, Interferential therapy, Ultrasound, cold or hot packs, etc. Along with that manual mobilization technique like Maitland, Mulligan are also found to be extremely helpful in managing pain. Also, manual releasing of muscle with technique such as Ischemic compression, Myofascial release, MET, Releasing of muscles with Garston tool have shown improvement in weight bearing pain in arthritis. Taping and using braces will also help to manage pain.

Exercise has been proven to be effective as pain management and also improves physical functioning in the short term. Exercises have to take place under the supervision of a physiotherapist initially and when properly instructed these exercises can be performed at home, though research has shown that group exercise combined with home exercise is more effective.

Movement or physical activity is the best medicine for people suffering from knee osteoarthritis. Performing physical activity may not only improve your joint mobility, it can also improve your overall quality of life and can help reduce depression. Individuals with knee OA commonly engage in strengthening their knee muscles, neglecting however hip muscle strengthening. On assessing patients with knee OA they would usually be presented with hip muscle weakness and are more prone to increase in medial compartment loading on the knee joint. Research has proven that patients with knee pain will benefit following hip strengthening exercises. Potential benefits includes quick pain relief and better hip strength. It is important to strengthen the hip in knee OA because hip strengthening exercises tend to improve the mechanics of your lower limb and reduce stress on the knee.

Here are some of basic strengthening exercises

1.       Isometric knee extension

Sit with your knee supported on a rolled towel. Contract your thigh muscle (quadriceps) to push your knee down on the towel without lifting your foot off the ground. Relax and repeat.

2.       Knee extension

Lie down on your back with a foam roller behind your thigh, just above the knee.Push your thigh down into the roller and lift your heel up off the floor as high as you can without lifting the leg from the roller.Lower your leg to the starting position and repeat.

3.       Straight leg raises

Lie on your back with one knee bent and the affected leg completely straight.  Lift your leg off the bed about one foot high off the surface, keeping it straight. Lower the leg to the starting position and repeat.

4.       Side SLR

Lay on your side with your head supported and lower leg bent. Lift the top leg up to about 30 degrees, keeping the foot parallel to the ground and the thigh aligned with the body (do not move it forward as you lift).

5.       Sitting knee extension

Sit straight in a chair with a weight tied around your ankle. Lift your foot as high as you can so as to straighten your knee as much as possible. Lower your leg slowly and repeat.

These are very basic low grade exercises to start with. Progression for this can be squatting, lunges and also to more complex exercise techniques which involves use of whole body such as jogging, Tai Chi, Propioceptive exercises, agility and balance training can also be useful in management of knee osteoarthritis.