Background and Etiology
The knee is the largest joint in the body. It is built for weight bearing, stability and mobility. The knee complex is composed of four bones and three osseous bone-to-bone joints. These are the patellafemoral joint, tibiofemoral joint and the tibiofibular joint.
Bone and Joint
The tibiofemoral joint is a hinge joint, located between the largest bone in the body (the femur) and the larges bone in the lower leg (the tibia.) When these two bones are joined together they form a medial and lateral compartment.
The second joint in the knee complex, called the patellafemoral joint, is located between the patella (knee cap) and the femur. The patella glides up and down a groove on the anterior distal aspect of the femur. There is also a joint between the small lateral bone of the lower leg (fibula) and the larger tibia.
At each joint the ends of the bones have a smooth shiny surface called joint articular cartilage that allows them to slide freely over each other.
Arthritis is the wearing, degeneration or loss of articular cartilage in a joint. The three most common types of joint arthritis are osteoarthritis, rheumatoid arthritis, and traumatic arthritis. The joints in the knee affected most often by arthritis are the tibiofemoral joint (located between the femur and tibia) and the patellofemoral joint (located between the patella and the femur).
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 people who are middle age and 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.
Symptoms of Osteoarthritis
- Pain and achiness in the knee joint.
- Loss of motion during knee extension (straightening) and/or flexion (bending) of the knee. Stiffness may improve with movement.
- 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.
Unlike other forms of arthritis, rheumatoid arthritis is a systemic autoimmune disease that is not caused by common wear and tear on the joint. This condition usually affects joints symmetrically (for example, both knees, both wrists, both shoulders). Rheumatoid arthritis causes degeneration of the articular or joint cartilage. It can also affect the tissue that surrounds and lubricates the joint (synovium). If the joint surfaces and cartilage are not lubricated they can start to rub, causing wear.
Rheumatoid arthritis can affect other parts of the body including organs like the heart and lungs, and can even cause fatigue. The cause of Rheumatoid arthritis is not fully known. It is considered an autoimmune disease where the cells of the body attack themselves. Although it is a chronic condition, individuals can have periods of little to no symptoms mixed with acute or symptomatic periods. There can be a genetic component to this disease.
- Pain is present over the knee joint often affecting both right and left.
- Swelling and inflammation of the joint.
- The joint will feel hot or warm to the touch.
- Stiffness and loss of motion of the knee when bending and/or straightening the joint.
- Weakness, which may be manifested as difficulty walking, getting up from a sitting position, kneeling, squatting and climbing stairs.
- Fatigue or tiring easily when performing normal daily activities.
Treatment of Knee Arthritis
Treatment of knee arthritis will depend on the severity of the condition. Some important guidelines should be followed at the onset:
Rheumatoid Arthritis Considerations
The ideal treatment involves a combination of medication, rest, joint range of motion and strengthening exercises, joint protection strategies such as bracing and splinting and patient education. Restoring range of motion and strength is paramount to maintaining function. Protecting the joint through education about movement, bracing and splinting when necessary can help reduce further joint damage. Treatment is customized depending on the individual’s age, level of function, acute versus chronic flare up, pain level and general health.
- Rest: avoid the activities that produce the pain. Avoid jumping, running, going up and down stairs, kneeling, squatting and walking for extended periods of time.
- Ice or moist heat: apply ice to the joint or area of pain or inflammation. It is one of the fastest ways to reduce swelling, pain and inflammation. Individuals with Rheumatoid arthritis may not tolerate ice well. The application of moist heat may be helpful with stiff joints. The application of ice or heat should be done at intervals for about twenty minutes at a time. Do not apply directly to the skin.
- Compression: when using ice, apply light compression. This is especially helpful if swelling is present.
- Elevation: elevate the area to help reduce swelling.
- Movement: keep your joints moving whenever possible. When pain occurs the tendency is not to move, but this will only result in further loss of motion and lead to increased pain and loss of function.
Mild: In mild cases rest, ice and medication may be all that is needed to reduce the pain. Once the pain is reduced physical therapy is recommended to develop a series of stretching and strengthening exercises to prevent loss of motion, weakness and function. Individuals are advised to avoid becoming sedentary; however return to full activity should be gradual to prevent a flare up of symptoms.
Moderate to Severe: If the problem persists, consulting your health care provider should be the next step. Your physician and/or physical therapist will perform a thorough evaluation to determine the severity of the condition and the best course of treatment.
Physical Therapy Interventions
Physical Therapists are professionals, educated and trained to administer interventions. As defined by The Guide to Physical Therapist Practice, interventions are the skilled and purposeful use of physical therapy methods and techniques to produce changes consistent with the diagnosis, prognosis and the patient or client’s goals.
Your physical therapist will perform a thorough evaluation to assess and determine the following:
- Joint: a series of measurements will be performed to determine which joint is involved and the extent to which the inflammation is acute
- Strength: resisted testing is performed to determine if there is associated weakness or strength imbalances
- Flexibility: range of motion measurements will be taken to determine if there is reduced joint movement
- Technique and ADL: the therapist will review what activities you have difficulty with and will help you make modifications in technique to reduce stress on the involved joint.
- Gait, Balance and Alignment: the therapist will assess your gait and balance on even and uneven surfaces. An assistive device such as a cane or walker may be indicated to improve safety, gait and reduce stress on the effected joint.
Physical therapy for knee arthritis must remain conservative at the onset to avoid aggravating the condition. Emphasis will be placed on rest, reducing the inflammation, protecting the joint and increasing the blood circulation for healing. Once the initial inflammation has reduced, a program of stretching and strengthening will be initiated to restore flexibility and improve strength to reduce stress on knee joint. Taping, bracing or strapping to rest and protect the joint while promoting healing may be indicated.
Physical Therapy Interventions
Common Physical Therapy interventions in the treatment of Knee Arthritis include:
- Manual Therapeutic Technique (MTT): hands on care including soft tissue massage, stretching and joint mobilization by a physical therapist to improve alignment, mobility and range of motion of the knee. The use of mobilization techniques also helps to modulate pain.
- Therapeutic Exercises (TE) including stretching and strengthening exercises to regain range of motion and strengthen muscles of the knee and lower extremity to support, stabilize and decrease the stresses place on joint cartilage and the knee joint.
- Neuromuscular Reeducation (NMR) to restore stability, retrain the lower extremity and improve movement techniques and mechanics (for example, running, kneeling, squatting and jumping) of the involved lower extremity to reduce stress on the joint surfaces in daily activities. Taping, strapping or bracing may be indicated for joint protection and promote healing. Gait and balance training may be indicated in those that have issues with walking.
- Modalities including the use of ultrasound, electrical stimulation, ice, cold, laser and others to decrease pain and inflammation of the involved joint.
Avoiding the activities that produce the pain or stress the involved tendon is the first line of treatment.
- RICE: Rest, Ice, Compression, Elevation should be used to reduce the stress on the bursa.
- NSAIDS (Non steroidal anti-inflammatory drugs) to reduce pain and inflammation.
- Immobilization, strapping or bracing may be beneficial to rest, protect the joint and promote healing.
- Injection of steroids may be indicated to reduce inflammation of the involved joint.
- Joint injections of hyaluronic acid preparations (synvisc or suparz) to facilitate joint cartilage repair and regeneration.
- In severe recurrent conditions surgery may be indicated. In less severe cases arthroscopic surgery to clean the joint surfaces (debridement) may be indicated. In cases of severe arthritis or joint degeneration a partial or total knee replacement may be recommended.
Medical Management of Rheumatoid Arthritis
Early aggressive medical care is recommended for individuals with Rheumatoid Arthritis. Interventions may include the following:
- The use of DMARD (disease modifying anti-rheumatic drugs).
- The use of NSAIDS (nonsteroidal anti-inflammatory drugs)
- When indicated steroids in low doses will be prescribed to reduce joint inflammation.
- Physical and Occupational Therapy to develop a stretching and strengthening program.
- Bracing and splinting to protect and rest the involved joints
- Surgery may be indicated in severe cases. An arthroscopic procedure to remove an inflamed synovial lining is one surgical option. In the case of severe joint and cartilage degeneration a total knee replacement is the preferred procedure.
Outcomes and prognosis for individuals with osteoarthritis will depend on the severity of the joint degeneration, motion loss, weakness and age of the individual.
Mild: Individuals with mild degeneration respond well to conservative treatment including medication for pain and inflammation and a program of exercises for stretching and strengthening of the knee joint and surrounding muscles. Most patients show improvement in pain and function in 4-6 weeks.
Moderate: Individuals with moderate degenerative changes usually experience greater loss of motion, pain, weakness and loss of function. In some cases arthroscopic surgery may be required to clean or debride the knee joint. Recovery may take from 6-9 weeks following surgery with emphasis on reduction of swelling, restoration of range, strength and function.
Severe: Individuals with severe joint degeneration have significant pain, stiffness, loss of motion and function. The cartilage on the joint surfaces has been eroded and X-rays reveal a loss of joint space and “bone on bone” contact. Joint replacement is the treatment of choice. At this point quality of life becomes a concern. Following a joint replacement the artificial knee will be different from the natural joint and there will be some limitations in motion and function. However, a patient’s quality of life is usually significantly improved following a total joint replacement. Recovery following knee replacement can take 3-4 months of intensive physical therapy and rehabilitation. Improvements and functional gains can continue to develop for up to a year following the procedure.
Once the pain and inflammation is reduced, and motion and strength are improved it is important that the patient returns to full activity gradually. Instruction in daily activities and a comprehensive home program are helpful for reducing a reoccurrence of flare-ups and slowing the degenerative process. As a preventive measure individuals should:
- Movement: keep moving and avoid a sedentary lifestyle. Joints are meant to move and depend on movement for lubrication. Sitting and remaining sedentary will reduce the joint’s available range of motion.
- Stretching: stretching regularly in addition to before and after activity will reduce the chances of developing joint stiffness and pain. Stretching will also improve and maintain the elasticity and flexibility of muscles and tendons of the joint. Hold stretches for 20 seconds and do not bounce. Remember, as joints age flexibility is lost. It is part of the aging process.
- Strength: performing a regular strength program will keep muscles strong enough to absorb the stresses placed on the joints. Weak muscles allow the stress and forces of every day activities to be transferred to the joint surfaces. Remember, as people get older weakness increases.
- Protection: Avoid activities that place increased stress on the knees. This includes kneeling, squatting, running or high impact activities.