More Patients Weighing Cause, Effects Of Total Knee Replacement

CARMEL, N.Y. — Total knee replacement has become one of the most common orthopedic procedures performed on older persons. According to the American Academy of Orthopaedic Surgeons, there are about 270,000 knee replacement operations performed each year in the United States, about 70 percent of them on people over the age of 65.

From 1979 to 2002, the rate of knee replacement procedures in that age group increased eightfold. A growing number of knee replacements are being done on younger patients as well.

Changing attitudes toward aging and expectations of an active life after retirement have made more people unwilling to endure years of discomfort or resign themselves to a restricted level of activity.

“For people with severe knee damage, total knee replacement can relieve debilitating pain and allow them to be more active,” said Dr Douglas Fauser of Somers Orthopaedic Surgery & Sports Medicine Group in Carmel, N.Y. “Advances in surgical techniques and improvement in the prostheses we use have improved outcomes and reduced recovery time. In fact, among patients with two damaged knees, many are now electing simultaneous total knee replacement, avoiding a second surgery, hospital stay, and rehabilitation.”

A significant number of patients with degenerative joint disease have severe symptoms in both knees and need bilateral total knee replacement. The surgical options available for these patients include a staged procedure with a time interval (generally several months) between two surgeries and a simultaneous replacement of both knees in a single surgery.

“The advantages of simultaneous bilateral total knee replacement are well known,” said Dr Fauser. “The patient undergoes a single surgery and anesthesia, a single hospital stay, and a single rehabilitation period. Studies have also shown that simultaneous replacement is associated with a lower risk of postoperative infection and mechanical malfunction compared to two separate procedures.”

These advantages make simultaneous replacement an attractive option for patients. In one study, 95 percent of those who had undergone simultaneous replacement would elect to do so again.

However, simultaneous replacement may not be appropriate for all patients. In most studies, the rates of cardiac, pulmonary, and neurological complications have been reported to be greater for simultaneous bilateral replacement, particularly in patients over 80 years old.

“Advances in surgical technique, anesthesia, and recovery management have made total knee replacement a safe and effective option for more elderly patients than ever before,” said Dr Fauser. “But those patients who are older are also likely to be sicker and at higher risk for cardiovascular and respiratory complications. Clearly, every patient, along with his or her doctor, must carefully weigh all the factors and risks in deciding between simultaneous and staged knee replacement.”

Normal knee function is required to perform most everyday activities. The knee, the largest joint in the body, acts as a hinge to provide motion where the thigh meets the lower leg.

The thigh bone (femur) meets the large bone of the lower leg (tibia) at the knee joint, protected in the front by the kneecap (patella).

The joint surfaces where these three bones touch are covered with cartilage, a smooth substance that cushions the bones and enables them to move easily. All remaining surfaces of the knee are covered by a thin, smooth tissue liner called the synovial membrane that releases synovial fluid that lubricates the knee, reducing friction to nearly zero in a healthy knee.

Normally, all of these components work in harmony. But disease or injury can disrupt this harmony, resulting in pain, muscle weakness, and reduced function.

The most common cause of chronic knee pain and disability is arthritis, usually osteoarthritis, rheumatoid arthritis, or traumatic arthritis:

*Osteoarthritis usually occurs as people age and the cartilage that cushions the bones of the knee softens and wears away. The bones then rub against one another, causing knee pain and stiffness. A study published by the Centers for Disease Control (CDC) reports that nearly half (46 percent) of American adults and two out of three obese adults will develop painful knee osteoarthritis at some point.

*Rheumatoid arthritis is a disease in which the synovial membrane becomes chronically inflamed, eventually causing cartilage loss, pain, and stiffness.

*Traumatic arthritis can follow a serious knee injury such as a fracture or severe tears of the ligaments that may damage the cartilage over time, causing knee pain and limiting knee function.

When the surface of the joint is worn away, walking and daily activities become very difficult. Standardized treatment such as weight loss, anti-inflammatory medication, braces, orthotics, steroid injections, and physical therapy are generally tried and may be effective. In many cases, however, nonsurgical treatments fail to correct functional limitations and relieve progressive pain, leading people to consider knee replacement.