Normally, all of the parts of the knee joint work together and the joints move easily and without pain. Disease, arthritis, or injury can disturb the normal functioning of the knee joint resulting in knee pain, muscle weakness, and limited movement. Longer life expectancies and greater activity levels lead to joint replacements being performed in greater numbers of patients.

How does the knee work? 
The knee joint functions like a hinge at the junction of two bones, the femur (thigh bone) and tibia (shin). The ends of the bones are covered with a thick cushion of hard, white cartilage. You are given only one coating of this cartilage in your lifetime. Knee cartilage damage or worn cartilage causes the underlying bones to rub together producing knee pain and inflammation typical of knee arthritis.  

Why the Rothman Orthopaedic Institute Joint Replacement Team?

Rothman Orthopaedic Institute’s Joint Replacement Program is one of the nation’s top joint replacement centers performing more than 17,000 surgeries annually. The surgeons of Rothman Orthopaedic Institute joint replacement team are experienced and skilled in total joint replacement. In addition to their extensive residency training, each physician has undergone advanced subspecialty training and acquisition of skills in programs known as Fellowships. Fellowships provide each surgeon with superior knowledge and expertise in their chosen area of subspecialization. 

Knee Arthritis

Arthritis is the breakdown of the cartilage of a joint, which can cause pain, swelling, stiffness, instability and often deformity. Severe arthritis interferes with a person’s activities and limits his or her lifestyle. Osteoarthritis or Degenerative Joint Disease – This is the most common type of arthritis. Osteoarthritis is also known as "wear and tear arthritis," since the cartilage simply wears out. When cartilage wears away, bone rubs on bone causing severe pain and disability. Inflammatory Arthritis – This arthritis presents as swelling and heat (inflammation) of the joint lining, which causes a release of enzymes that soften and eventually destroy the cartilage. Rheumatoid arthritis, lupus, gout and psoriatic arthritis are inflammatory in nature.

Causes and Risk Factors

The most frequent reason for osteoarthritis is genetic, since the durability of each individual’s cartilage is based on genetics. If your parents have arthritis, you may also get it. Trauma can also lead to osteoarthritis. A bad fall or blow to the knee at any point in your life can injure the joint. If the injury does not heal properly, extra force may be placed on the joint, which may cause the cartilage to wear away over time. Patients who have previously torn the meniscus cartilage or a ligament in their knee may be at increased risk for developing arthritis.


Pain is the most frequent symptom for patients with knee osteoarthritis. The pain from knee arthritis is usually described as being in the front or sides of the knee. The pain is frequently worsened with activity and relieved by rest. It may occur at night and, in severe cases, prevent sleep. Patients with knee arthritis also tend to have stiffness and often limp when they walk. They may have difficulty going up and down stairs and walking long distances.


Doctors diagnose arthritis by taking a medical history, performing a physical exam and reviewing x-rays of the knee. Sometimes, additional blood tests are added to this to diagnose inflammatory arthritis. It is typically unnecessary to get an MRI to diagnose arthritis, since x-rays almost always reveal the presence and extent of the problem .

How Do I Know If Joint Replacement Is Right For Me?

When joint pain is severe and interferes with daily activities, work and sleep, joint replacement may be an option. The decision to replace your knee is made by you and your orthopedic surgeon mainly based on the degree to which the pain is affecting your life.

Knee pain and the stiffness of joint degeneration may be worse during certain times of the day, or after certain activities such as:

  • Walking
  • Bending
  • Going up and down stairs
  • Kneeling or squatting
  • Getting in and out of a chair
  • Getting in and out of a car
  • Dressing (e.g. putting socks and shoes on) Joint degeneration can eventually make it extremely difficult for individuals to work and enjoy themselves. It can also make it difficult for individuals to care for themselves.

Links to Societies

American Association of Hip and Knee Surgeons ( - Established in 1991, the American Association of Hip and Knee Surgeons (AAHKS) is committed to its mission of providing educational opportunities to its members. For the past several years, Annual Fall meetings have addressed an increasingly broad array of scientific topics, such as implant design, results, surgical techniques and complications of primary and revision total hip replacements, as well as the latest information available on socioeconomic issues affecting the specialty.

The American Academy of Orthopaedic Surgeons ( - The American Academy of Orthopaedic Surgeons is an organization of orthopaedic surgeons that provides comprehensive information on hip issues. This information can be found here:


There are a variety of treatments that may be considered for knee arthritis.

1. Non-surgical
a. Diet and exercise – Weight reduction can reduce pressure across the knees, which results in less pain.
b. Medication – Non-steroidal anti-inflammatory drugs can help relieve inflammation inside the joint. There are non-prescription and prescription medications that can help relieve pain.
c. Injections – Injections with corticosteroids can reduce inflammation in the joint. Other injections, such as viscosupplementation, may help lubricate the joint. However, these injections are often performed over a series of 3-5 injections and need insurance clearance. Injections are most effective in early stages of arthritis.

2. Surgical
a. Arthroscopic surgery – Arthroscopy is rarely helpful in a patient with knee arthritis. However, if a patient with mild-to-moderate knee arthritis develops acute sharp stabbing knee pain and has mechanical symptoms (locking and catching) due to a torn meniscus, cleaning up the knee using arthroscopic tools may occasionally be helpful. However, arthroscopy can also lead to increased swelling and pain in a patient with knee arthritis and may not be recommended by your surgeon depending on the extent of your arthritis.
b. Total or partial knee replacement.
If non-surgical treatments fail, a partial or total knee replacement may be the best way to replace the damaged cartilage with metal and plastic. Please click on the following links to learn more:
i. Total knee replacement
ii. Partial knee replacement

Knee Programs

  • Cartilage Restoration Institute

    This is a center where patients can go to have their disabled joint biological resurfaced, realigned, and stabilized without having the joint replaced by artificial materials such as metal and plastic. It is well known that the outcomes of patients under the age of 50 undergoing artificial joint replacement are not as good as we would like. Therefore we feel the future of Orthopaedics is to try to restore a joint back to its original anatomy by realignment, ligament reconstruction, and cartilage restoration.
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