Strong knees and the muscles around them keep our bodies erect. ‘Weak in the knees’ is just a phrase for strong emotions due to a certain incident, usually in the young. In old age, weak knees might mean having to move around in a wheelchair. So, who likes to sit in a wheelchair?

Knee pain is a common condition in the young, especially in the sporty ones and those in uniform, but as one grows old, there can be many conditions which cause knee pain or weakness in the knees. So, keep knees pain-free, strong and agile, even while growing old. Let’s first learn more about the structure of the knee, else we will keep having a knee-jerk reaction to the many issues of the knee.

A Complex Construction

The knee is one of the most vulnerable joints because it is involved in bearing body weight, walking and kneeling. It is under stress if a person is lifting heavy objects, running or playing games which need twisting movement such as football, basketball, boxing or wrestling. Understanding the structure of the knee is important to know the cause of the pain.

Bones. The knee’s infrastructure is built by strong long bones of the thigh (femur) which glides over an equally strong leg/ shin bone (tibia). Their joint is covered by a small bone, the patella, which in turn is held by a strong muscle, above and a ligament below.

Cartilage. The bones at the joint are covered by a ‘shock absorber layer of cartilage. An example of cartilage is the material of the ear under the skin. Hard but not bony. It is well-oiled by a greasy liquid called the synovial fluid. Interestingly, the more the joint moves, the better this fluid gets.

Ligaments. are non-muscle fibres that attach two long bones together, both, inside the joint and on the sides of the joint. The patellar ligament attaches the patella to the tibia. They provide stability and limit the range of movements.

Muscles. The muscles behind the joint, the hamstrings are responsible for bending the knee. Those on the front are the quadriceps which straighten the knees. The muscles end up as rope-like tendons and attach themselves to bones.

The Pain

Acute knee pain is mostly due to injuries, sports or other accidents. Acute infections, tumours, ligament strains, meniscus tears and certain other conditions can also cause acute pain. Such acute pains need emergent/ early treatment and hence are not being discussed here. Weakness and pain in the knees can be due to various causes which also include post-injury chronic pain. Wear and tear due to ageing is, of course, the commonest cause of weakness and pain. Let us examine the causes, one by one.

Cartilage deterioration

This is very common in those who exert more but exercise less. The cushioning effects become less. It is also common in sports people who give up sports. The muscles around the knee, if strengthened may delay the process.

Muscle weakness

After the age of 30 years, there is a 5% loss in the strength of the muscles with every passing decade. This weakness is called Sarcopenia. The weakness becomes very rapid in those who are bedridden due to disease or injury, especially in older age.

Bone density

Our bones, on a daily basis, get broken down and new bone forms in the same place. As we age, especially after 45-50 years, the new bone formation is slower than what is breaking down. After a period of time, the bone becomes less dense and weak. This is called Osteoporosis. Such bones have a higher chance of breaking with the same kind of injury. The lesser dense bones are also the cause of pain. In ladies, hormonal changes at menopause are also responsible for loss of bone density.

Sedentary lifestyle

Bad news for the couch potatoes and workaholics who keep sitting for hours at an end on their sofa/chair. Their muscles slacken and the movement of synovial fluid in the joint becomes less. Thus their joint becomes creakier and weaker. Those in the elderly age group find difficulty in doing their day-to-day jobs.

Gaining weight

The more body weight we gain, the more stress on our knees and ankles. Initially, the additional load may be compensated by the strong muscles. However, if the person is sedentary, the muscular support becomes less. In those who are obese, the chances of metabolic and inflammatory changes may initiate degenerative joint diseases like osteoarthritis in the knee.

Arthritis

The knee joint may be affected by Osteoarthritis as we age. It may, however, affect earlier in life in an injured knee. The cushioning cartilage begins to break up and the bones may begin to grind with each other. Everyone suffering from Osteoarthritis may not have pain. Other, uncommon arthritis of the knee are Rheumatoid arthritis, Gout and Reactive arthritis. Advanced diabetes can lead to skeletal as well as muscular weaknesses causing pain in any joint.

When To Consult a Specialist?

If we have Acute pain or dull pain for the following reasons

• There is swelling in the knee causing pain at bending.
• The knee becomes unstable or gets locked.
• There is infection – as seen by redness and warmth around the joint and fever.
• The joint looks deformed.
• There is a grinding or popping sound at the knee.
• The affected knee cannot bear body weight.
• Deteriorated knees due to ageing

Self Care

Avoid sitting for longer than 45 minutes or so. Depending on the age and disability, one should walk for at least half an hour every day. Many hospitals have enforced walking schedules for admitted patients so that sarcopenia doesn’t set in. Do as many different activities as possible at home while in a standing position. Loose weight to gain health. It will reduce the burden on the knees as well. If possible, visit a physiotherapist to learn exercises for strengthening not just the muscles around the knee but also those of the hip and lower leg. Stronger muscles take care of weaker joints and provide better balance to the body.

Low-impact exercises will and full-body activity are a must for every human. It is especially true for preventing Osteoporosis in those having knee problems. Those suffering from knee pain may not be able to walk briskly. Switch to low-impact exercises like swimming or cycling. Yoga and Tai chi are excellent but should be done till we sweat and our breathing becomes noticeable.

Tobacco, especially cigarette smoking is responsible for more quantum of pain in those suffering from Osteoarthritis. It also causes osteoporosis faster. Hence, give up tobacco or suffer more from knee pain.

Those who work in kneeling positions may wear knee pads. Diet and supplements. A balanced, home-cooked diet is ideal. Fruits, vegetables and salads are a must. A cocktail of nuts, not necessarily an expensive one, be taken to get trace elements. The elderly and ladies in menopausal/post-menopausal need extra calcium, potassium and importantly more protein. Vegetarians need to consume more paneer (not cheese). Supplements – protein and vitamins should be taken on the advice of a physician. Sunlight exposure for vitamin D is extremely important as we age. Activities can be undertaken in sunlight.

Pain relievers (tablets, creams /sprays/ massage oils), knee caps or knee braces may be used for limiting pain during walks or exercising. These should be used in consultation with a doctor. Surgery, if advised, maybe the cure for those with advanced disability. Keep comorbidities under control. Diabetes, High cholesterol, Rheumatoid arthritis, Gout and other rare diseases in those having knee pain require adequate treatment. These comorbidities may also contribute to excessive pain in the knee.

Conclusion

Knees are essential for our mobility. They need to be kept pain-free. Paradoxically, the more we use our knees, the less wear and tear occurs in the joints. Of course, injuries to the knees need urgent treatment but pain in the knees should always be investigated and cause(s) found. Staying active, eating a balanced diet and enjoying free sunlight have been told to us since we were knee-high! The same holds good even today.

Disclaimer: The views and opinions expressed by the author do not necessarily reflect the views of the Government of India and Defence Research and Studies

Image Courtesy: Soflete