Knee Replacement Surgery Techniques

Introduction

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Knee Replacement Boosts Mobility, and Physical Ability in Patients

A study published in a recent issue of Arthritis and Rheumatism found that knee replacement is effective at restoring the mobility and physical functioning of the knee and relieving patients of the irrepressible pain and significant restrictions on quality of life caused by osteoarthritis.

South Nassau Communities Hospital's Center for Advanced Orthopedics offers a comprehensive line of advanced knee replacement treatment options that are tailored to address the specific needs of the patients and repairing the damage caused by osteoarthritis.

The study, conducted by a team of researchers from Duke University, is based on data culled from Medicare Current Beneficiary Surveys from 1992-2003 that focused on the outcomes of 259 patients who received knee replacements and 1,816 patients with osteoarthritis who did not receive a knee replacement.

The study grouped patients according to baseline level of functioning (the joint's normal level of functioning prior to medical treatment, therapy, and/or surgery), demographics, and co-morbidities and used the Nagi Disability Scale (a widely accepted permutation of the World Health Organization's approach to classifying disabilities), Instrumental Activities of Daily Living Scale (IADL), and the Activities of Daily Living Scale (ADL) to assess their physical ability. Nagi Scale is based on the performance of tasks deemed the highest level of physical functioning, such as walking and strength training. IADL tasks, such as shopping, cooking, housework, are at the intermediate level of difficulty. The ADL gages the ability to do basic level tasks, such as getting dressed or showering.

Knee replacement patients showed improvement in one basic function of self care (bathing), three intermediate tasks (light housework, heavy housework, and shopping), and two high level tasks (walking 2-3 blocks and lifting weights at least 10 pounds). The patients who did not receive a knee replacement continued to decline in overall physical functioning.

"Our approach is to provide the most effective and efficient options that will allow patients to return to the lifestyle and activities or their choice," said Craig Levitz, MD, Chief of Orthopedic Surgery and Director of the Center of Advanced Orthopedics.

Whether 35, 45, 55, 65 or older, osteoarthritis of the knee is a debilitating, painful disease that can bring life to a literal standstill. Osteoarthritis affects more than 21 million individuals in the United States. When it takes hold in the knee, the disease causes deterioration of cartilage between the femur (thigh bone) and tibia (shin bone). Without cartilage, which covers the ends of the each bone and acts like a cushion or shock absorber, the femur and tibia rub and grind against each other, causing steady decay, chipping and jagged surfaces.

South Nassau is one of just a handful of hospitals in the United States to combine minimally-invasive knee replacement with a revolutionary image guided medical technology system. This combination simplifies total knee replacement surgery and significantly improves the short- and long-term patient benefits of the operation.

Image guided surgical technology is used to determine the precise alignment of the replacement parts, improves the surgeon's view of and feel for the surgical field and reduces the size of the incisions to perform a replacement. By integrating multiple medical technologies and computerization, image-guided surgery outlines the precise alignment of the replacement components. It combines digital images of the shin bone and thigh bone with knee replacement-specific computer programming. The system puts together all of the information coming in from the patient and the instruments and tells the surgeon where the cuts should be made.

In standard knee replacement surgery, the surgeon must implant the replacement components - a metal and plastic platform atop the shinbone and a metal surface on the bottom of the thighbone - so that they rub together at precise angles to prevent premature or excessive wear of the implant. Surgical cutting blocks and acumen are used to determine where best to remove bone for the implant. Once the cut is made, the natural bone cannot be replaced.

The Mobile-Bearing Knee System is another proven knee replacement treatment provided by the Center. The system is one of the devices with the longest history in total knee replacement. Since 1977, more than 400,000 mobile-bearing knees have been implanted in the US and internationally. "A host of studies on the long-term clinical success of the system has demonstrated that average lifespan of the system is approximately 20 years in more than 96% of the patients," said Bradley Gerber, MD, Chief of Joint Replacement.

In the late 1990s, the Mobile-Bearing Knee System was updated to include additional primary and revision implant options as well as new instrumentation. "Benefits of the system include minimal incidence of patellar-femur complications (a common cause for revisions to a knee replacement) and consistent maximum contact while diffusing torsional and shear forces that can lead to implant loosening," said Dr. Gerber.

Under the direction of Dr. Levitz and Dr. Gerber South Nassau was one of the first hospitals in New York to introduce the minimally-invasive Uni-Knee® System. The Uni-Knee is a partial knee replacement that requires a two- or three-inch incision and uses precision surgical instrumentation and guides to remove the damaged bone and cartilage. Implants, which are shaped and sized to mimic and function exactly as the bone and cartilage that has been removed, are then inserted. They are secured to the bones using a solution known as bone cement.

"Benefits of the Uni-Knee System are recognized almost immediately," said Dr. Gerber. "The minimally invasive approach generally results in a shorter hospital stay (24 hours or fewer on the average), minimal blood loss, a smaller incision and, in some instances, an increase in range of motion."

Completing the prescribed rehabilitation following surgery is vital to the success of the knee replacement or transplant surgery. "This is not a stopgap, short-term solution," said Dr. Levitz. "Knee replacement is a long-term solution to restore the knee's functions. That can be achieved as long as the patient makes an inviolable commitment to physical rehabilitation."

Reference: South Nassau Communities Hospital in Oceanside, NY, provides cardiac, oncologic, orthopedic, bariatric, pain management, mental health and emergency services. It is a Stroke Center, offers the Gamma Knife and performs emergency or elective angioplasty.