Anatomy & Background
As the largest joint in the body, the knee is designed for both mobility and stability. It is a weight-bearing joint comprised of three joints, as well as four bones. The osseous joints in the knee include the tibio-femoral joint, patella-femoral joint and tibio-fibular joint.
Bones and Joints
To understand the joint complex in the knee, each joint and the bones that are connected within joints, must be considered individually. These include:
- Tibio-femoral joint – This is a hinge joint situated between the tibia (the large bone in the lower leg) and the femur (the large bone in the upper leg and the largest bone in the body). There is a medial (closer to the middle) and lateral (closer to the outside) section of the joint.
- Patella-femoral joint – This joint is situated between the patella (“knee cap”) and the femur in the upper leg. The patella-femoral joint allows the patella to glide along a groove in the anterior distal section of the femur.
- Tibio-fibular joint – This joint is situated between two bones from the lower leg – the tibia (larger bone) and the fibula (smaller bone) – where they meet at the knee.
At the end of each bone that meets within the knee joints, joint articular cartilage covers the bone. This smooth and spongy substance is what allows the bones in the joints to move and slide freely over one another. Synovial fluid, a slippery fluid that helps limit friction, fills the joint.
The most common form of knee arthritis, Osteoarthritis is a gradual wearing and degeneration of the joint surfaces or articular cartilage. Osteoarthritis is most common in adults over the age of 50. Women are more likely to develop osteoarthritis, and it can affect one knee or both. Knee osteoarthritis is the most common cause of disability.
Common causes of knee osteoarthritis include:
- Genetics and family history can predispose individuals to developing osteoarthritis and joint degeneration.
- Ligament or meniscus damage can affect the stability and integrity of the knee joint placing more stress on the joint or articular cartilage. The increased stress and force placed on the joint surfaces can lead to wear-and-tear on the joint.
- Repetitive strain injuries to the knee can damage and accelerate wear on joint surfaces.
- Obesity causes increased weight and pressure on the knee joints, when performing everyday activities. This puts added stress on the knees, increasing forces on the joint cartilage.
- Diseases of the joint cartilage.
- Excessive use of steroids or steroid medication can result in degeneration of the joint and cartilage.
- Previous trauma to a joint can increase wear-and-tear and the likelihood of developing osteoarthritis.
- Pain and achiness in the knee joint.
- Loss of motion during knee extension (straightening) and/or flexion (bending) of the knee.
- Noticeable swelling around the joint.
- Increased size or deformity of the joint.
- Weakness may be present, making it difficult to get out of chair, squat, kneel, or climb stairs.
- Cracking, crunching or joint noise called “crepitus” when moving the knee.
Symptoms of Osteoarthritis
When it comes to treating osteoarthritis of the knee, treatment generally depends on the severity of the condition, as well as other factors unique to the individual, such as his/her age, physical condition, activity level, pain threshold and overall health.
Treatment should address a variety of factors, including acute pain and inflammation, joint protection, and maintaining or improving the range of motion and strength of the joint.The best treatment often involves a combination of RICE (rest, ice, compression and elevation), range of motion (stretching) and strengthening exercises, and joint protection strategies such as splinting, taping, strapping or bracing. Medication may also be an integral part of knee osteoarthritis treatment and patient education is the key to providing patients with the information needed to avoid further joint damage.
Although ongoing or advanced treatment of knee osteoarthritis will depend on a number of factors, general guidelines for treating knee arthritis at the onset of symptoms typically begin with the RICE method, and other simple steps that an individual can do on his or her own. These include:
- Rest – Avoid the activities that cause pain or that place too much strain on the knee joint, such as kneeling, jumping, squatting, walking up and down stairs, running, or any other activity that requires repetitive movement of the knee for long periods of time.
- Ice – Applying ice to the affected joint for 20 minutes at a time can help reduce swelling, inflammation and pain. Ice should not be applied directly to the skin and should not be used for more than 20 minutes consecutively. If the knee joint is stiff, moist heat (like a hot/warm wash cloth) can also be used to reduce stiffness, although it will not reduce swelling and inflammation.
- Compression – Light compression of the knee joint can help reduce swelling and can be used in conjunction with ice.
- Elevation – If pain and swelling persists, elevating the leg can help to reduce swelling.
The RICE method can help to reduce swelling, pain and inflammation, but it is just one step in the process of treating arthritis of the knee. It is important to note that resting should not be confused with the tendency to not use the joint at all. Although a short period of rest may be necessary in handling pain and inflammation, and certain motions should be avoided during arthritis flare-ups, it is best to continue to move the joint as much as possible. Range of motion (stretching) and strengthening exercises will help avoid any further loss of motion and are critical to maintaining joint function.
Managing Your Pain
f you are experiencing persistent or chronic knee arthritis, pain management intervention can assist in managing both acute and chronic pain. Avoiding the activities that cause or exacerbate pain is the first line of treatment, as is using at-home methods such as RICE (rest-ice-compression-elevation) and temporary immobilization techniques such as bracing, taping, strapping or splinting.
Additional pain management interventions may include:
- Medication – The use of non-steroidal anti-inflammatory drugs (NSAIDs) can reduce pain, swelling and inflammation. If knee arthritis is caused by rheumatoid arthritis, the use of disease modifying anti-rheumatic drugs (DMARDs) may improve the your overall condition.
- Steroid injections – Low doses of steroids, injected into the knee joint, can reduce inflammation.
- Synvisc or Suparz injections -– Joint injections of hyaluronic acid preparations like Synvisc or Suparz help to facilitate the repair and regeneration of cartilage in the joint.
- Physical therapy – Following a thorough analysis of the affected joint, including assessing the level of inflammation, flexibility, strength, balance and gait, a series of stretching and strengthening exercises may be initiated to improve strength and flexibility of the knee joint. Changes to gait can also reduce stress on the joint, and other techniques including manual therapy, ultrasound, electrical stimulation, cold therapy and ice may be used to reduce pain and inflammation.
- Surgery – Surgery is a last-resort method for managing chronic and severe pain resulting from knee arthritis. In some cases, arthroscopic surgery can be performed to debride (clean out) the affected joint surfaces and synovial lining, with the goal of reducing inflammation and swelling. If severe joint degeneration has occurred and other methods of pain management have been unsuccessful, a partial or total knee replacement may be recommended.
The prognosis for individuals affected by arthritis of the knee will depend on a number of factors, including the type of arthritis that is causing symptoms (osteoarthritis, rheumatoid arthritis, traumatic arthritis), the severity of the joint damage and cartilage degeneration, the strength and flexibility of the joint, and other factors such as the age, weight, level of physical fitness and overall health of the individual. The timing and type of treatment utilized will also affect arthritis outcomes.
Typically, it is best to discuss outcomes and prognosis based on the level of severity of the condition. This can be the most important factor in affecting the outcome of treatment.
- Mild Cases – Patients experiencing mild forms of arthritis in the knee, associated with minimal degeneration and damage, generally respond well to short-term, conservative treatment when flare-ups occur. Using the RICE method (rest-ice-compression-elevation) at the onset of pain, coupled with non-steroidal anti-inflammatory medication (NSAIDs) if needed, and followed by a program of mild stretching and strengthening exercises is generally all that is required to experience improvement. Most patients can expect to see diminished or eliminated pain and improved function within 4 – 6 weeks.
- Moderate Cases – Patients that experience moderate degeneration due to arthritis may need more than just rest, medication and exercises to see marked improvement in symptoms. If there is increased degeneration or damage due to more serious or chronic arthritis, the patient may have more pain, weakness, and loss of mobility and functioning. Pain management techniques such as steroid injections or injections of hyaluronic acid preparations can help to reduce inflammation and repair or regenerate cartilage in the knee joint. Arthroscopic surgery may be required to debride (clean out) the knee joint. Following this procedure, recovery can be expected to take 6 – 9 weeks, and the surgery should be followed by an exercise or physical therapy regimen aimed at restoring strength, range of motion and function.
- Severe Cases – For patients that experience severe joint damage and degeneration due to knee arthritis, marked by significant pain, swelling and stiffness, as well as loss of strength, motion and function, traditional treatments that help those with mild to moderate knee arthritis may not be sufficient. Conservative treatments are generally tried first before attempting a more invasive technique, but if the cartilage is severely eroded and there is bone-on-bone contact in the joint, a partial or total knee replacement is typically the treatment of choice. Joint replacement surgery is usually followed by 3 – 4 months of physical therapy, although it can take up to a full year for recovery to be complete. Most patients that undergo joint replacement surgery see dramatic improvements in knee function, reduction in pain and the opportunity to return to a better quality of life. However, the artificial joint will still feel and operate differently than a natural joint and may result in some limitations.