Last Updated on October 27, 2023
This article focuses on Knee Osteoarthritis. For details on Osteoarthritis, read Osteoarthritis Symptoms, Diagnosis and Treatment
Knee osteoarthritis is can result in severe pain and disability, and affect activities like walking even for short distances or climbing stairs.
Like all other osteoarthritides, knee osteoarthritis takes a quite some time to develop and worsens gradually.
Earlier detection and intervention is important to lessen its impact on life. It cannot be cured but treatment can help the patients manage pain and stay active. Most people with osteoarthritis of the knee can be managed without surgery.
Knee osteoarthritis can be primary or secondary.
Primary osteoarthritis of the knee is said to occur when there is no antecedent cause. In secondary osteoarthritis, there is a preceding cause like old trauma.
It occurs most often in people 50 years of age and older, though it may occur in younger people, too.
Relevant Anatomy
The knee is the largest joint in the body and has to be strong enough to take our weight and must lock into position so we can stand upright. Being weight bearing joint, it is constantly subjected to load during walking, running or other activities that put twisting forces on it,
The knee joint is formed by the lower part of femur [thigh bone] and the upper end of tibia [shin bone] along with patella on anterior aspect.
Articular cartilage covers the articulating ends of the three bones and two wedge-shaped pieces of fibrocartilage between femoral and tibial articulations called meniscus act to cushion the joint and keep it stable.
Causes and Risk Factors of Knee Osteoarthritis
The detailed pathophysiology of osteoarthritis is given here.
The changes occur in the knee joint, partly the result of the inflammation and repair bid by the body.
As the effect of osteoarthritic changes, the cartilage of the knee becomes damaged, rough and thin. It could involve either patellofemoral articulations or femorotibial articulations or both.
The bone underneath the cartilage reacts by growing thicker and becoming broader and at the edges, bony spurs called osteophytes form. There may be thickening of the joint capsule and contraction of ligaments. The synovium may swell giving an effused look [swollen] to the joint.
Osteoarthritis develops slowly and the pain it causes worsens over time.
Risk factors for Knee Osteoarthritis
Following factors can increase the risk of knee osteoarthritis
- Age> 40 years
- Female gender
- Overweight
- Parents or siblings with osteoarthritis
- Knee injury, for example, a torn meniscus
- History of meniscus removal
- A hard, physically demanding job like farming
- rheumatoid arthritis or gout.
Presentation of Knee Osteoarthritis – Symptoms and Signs
The main symptoms of osteoarthritis of the knee are pain and stiffness. Pain particularly occurs at the movement of the knee or by end of the day. Pain may cause a feeling of weakness or buckling in the knee.
Vigorous activity may cause pain to flare up. Many people report increased pain with a change in the weather.
Stiffness is usually encountered after rest.
The knee may swell due to fluid accumulation in the joint. Sometimes patients may report hard protrusion from joint [osteophytes]
The muscles around joint may get wasted and over a very long period, the varus deformity may develop.
The symptoms of osteoarthritis are not constant and may wax and wane in severity over the time
The examination of the knee may reveal [Not all findings would be present in all the patients. In fact, the physical examination may be essentially normal in an early period of knee osteoarthritis]
- Warm, swollen knee joint
- Tenderness
- Decreased range of and movements, especially in extremes of the range
- Instability of the joint
- Crepitus (a grating sensation inside the joint) with movement
Imaging
X-rays are often not needed but are most useful to confirm a diagnosis of osteoarthritis.
X-rays of a knee with osteoarthritis may show
- Narrowing of the joint space
- Bone spurs or osteophytes
- Dense bone below cartilage [subchondral sclerosis]
The severity of the x-ray changes is not an indicator of pain or disability the patient is likely to have. While some people have a lot of pain from minor joint damage, others have little pain from severe damage.
Other imaging tests are rarely required.
Lab Studies
Not required for the diagnosis of osteoarthritis but may help to rule out other causes like rheumatoid arthritis, blood tests will help with a proper diagnosis.
Treatment
There is no cure for osteoarthritis, there are treatment options that relieve pain and improve mobility. Most of the patients do well with nonsurgical treatment.
Lifestyle modification
Lifestyle modification aims to reduce the stress on the knee joint. Reduce activities that aggravate the condition, such as climbing stairs, squatting and sitting cross-legged. Curtail activities that transmit the high load to the knee. Switching to swimming or cycling is an option.
Change of job, if required, can be considered if the current job is too demanding for the knees.
Weight Reduction
Overweight increases the strain on your knees. It increases the risk of developing osteoarthritis. It also increases the chances of progression of osteoarthritis.
Losing even a small amount of weight can make a big difference to the strain on weight-bearing joints.
Exercises
Exercises strengthen muscles and increase a range of motion and flexibility of the joint.
It is better to do small exercises at a higher frequency than doing strenuous exercises at a stretch.
Little and often is usually the best approach.
There are two types of exercise that you’ll need to do:
Aerobic exercise: These exercises are good for overall health, endurance and stamina building
Strengthening exercises: These exercises improve the strength and tone of the muscles providing better muscle control and help in the reduction of pain. Swimming is a good exercise for osteoarthritis without putting much strain on the joints.
Aids
Walking supports like a cane, crutches, or a walker can improve mobility and independence. Using devices such as a cane, wearing shock-absorbing shoes or inserts, or wearing a brace or knee sleeve can be helpful. A brace may be especially helpful if the arthritis is centered on one side of the knee.
Similarly to avoid bending a long-handled reacher to pick up low-lying things will help.
Leg-length inequalities can be managed with a shoe lift.
Drugs
Drugs may be added for those who are not relieved by non-pharmaceutical means and pain is affecting daily routine, or is not relieved by other nonsurgical methods.
Acetaminophen [Paracetamol] is the first drug to be used. NSAIDs like ibuprofen and diclofenac can also be used. Prolonged use of pain relievers have side effects and should be judiciously used under the supervision of a doctor.
Glucosamine and chondroitin are helpful to some patients although the literature is equivocal about their use.
Intra-articular steroids are also used to relieve pain. These are prescribed and injected by a qualified doctor.
The injection of hyaluronic acid in the joint is also called viscosupplement injection. Hyaluronic acid which is a component of the normal joint fluid.
Disease-modifying anti-rheumatic drugs (DMARDs) are used to slow the progression of rheumatoid arthritis if osteoarthritis coexists. Drugs like methotrexate, sulfasalazine, and hydroxychloroquine are commonly prescribed.
Other remedies
Applying heat or ice, using pain-relieving ointments or creams, or wearing elastic bandages could ease pain.
Surgical Treatment
Total Knee replacement is the most common and very successful surgery for painful knee osteoarthritis.
Apart from this, sometimes, osteotomy, removal of osteophytes or other required surgeries might be done in selected cases.
General Tips for Reducing Strain on the knee
Apart from keeping weight in check, there are other measures that a person with knee osteoarthritis can take.
- Spread your physical jobs at an easy maintainable pace. Instead of doing everything together, plan spread and segregate.
- Avoid high heels as they put extra strain by changing the angle.
- Footwear with better and thicker sole
- Walking stick to reduce the load on a painful knee
- Use a better leg first when climbing stairs. Use a handrail if available for support.
- Make the necessary changes to your home/vehicle/workplace that would reduce the strain on your joints.
- Use heat/ice packs to help ease pain and stiffness.
Prognosis of Osteoarthritis
The progression of osteoarthritis cannot be predicted. Usually, the progression is slow but sometimes it can develop over just a year or two and cause damage to joints.
In a few people, the disease reaches a peak after a few years and thereafter, the symptoms remain the same or get better.
Lifestyle changes and other nonpharmaceutical measures can reduce the chances of osteoarthritis getting worse.
