Robotic assisted partial knee replacement

What the procedure involves

The operation is performed with a surgeon-controlled robotic arm system, which offers more accurate resurfacing of the diseased portion of the knee.

As a partial knee procedure it can be performed on the medial (inside) compartment, the patellofemoral (top) compartment, or the lateral (outside) portion of the knee. It can also be done as a bicompartmental procedure on both the medial and patellofemoral portions.

In many cases patients are able to walk soon after surgery, drive within about two weeks, and return to normal daily activities shortly afterwards.

Why the robotic arm helps

The system provides patient-specific three-dimensional modelling for planning before surgery. During the procedure, the robotic arm combined with stereo tracking gives the surgeon real-time visual, tactile and auditory feedback, allowing reproducible precision in positioning the implant. That accuracy is what supports optimal implant positioning and alignment, and a more natural knee motion afterwards.

The potential benefits are accurate resurfacing of the arthritic portion while preserving healthy tissue and bone, optimal implant positioning, a more rapid recovery and shorter hospital stay than traditional total knee replacement, and rapid relief from pain.

Who is a candidate

The right treatment has to be determined individually, but typical candidates share these characteristics: knee pain with activity, usually on the inner knee, under the kneecap or the outer knee; start-up pain or stiffness when getting going from a seated position; and failure to respond to non-surgical treatment or anti-inflammatory medication.

Like other knee replacement procedures, it is typically covered by most Medicare-approved and private health insurance plans. Speak with Dr. Seneviratne about whether it is the right option for you.

What to expect

The procedure can be done as an inpatient or outpatient, depending on what Dr. Seneviratne determines is right for you. Hospital stays average one to three days; ambulatory patients return home the same day.

All implants have a life expectancy that depends on weight, activity level, quality of bone stock and how well you follow your surgeon's instructions. Proper implant alignment and precise positioning during surgery are also important factors. Because very little bone is actually removed during a partial knee procedure, the implants can be replaced later with another procedure, such as a total knee replacement, if necessary. With single-compartment disease, a second compartment can be treated in future if the arthritis spreads.

About osteoarthritis of the knee

Osteoarthritis is a degenerative joint disease characterized by the breakdown and eventual loss of joint cartilage. Cartilage cushions the bones of a joint; as the top layer wears away, the bones underneath begin to rub together.

The root cause is unknown, but risk is influenced by age, sex and inherited traits affecting the shape and stability of your joints, along with previous knee injury, repetitive strain, improper joint alignment, being overweight, and stress placed on the knee through exercise or sport.

Symptoms include pain while standing or walking short distances, climbing stairs, or getting in and out of chairs; start-up pain or stiffness from a seated position; joint stiffness after getting out of bed; swelling in one or more areas of the knee; and a grating or crunching sensation during use.

Diagnosis begins with your medical history and symptoms. Dr. Seneviratne will observe the knee's natural movement, evaluate knee and ankle alignment, and check reflexes, muscle strength, range of motion and ligament stability. X-rays show how much joint or bone damage has occurred and whether bone spurs are present. CT or MRI may be ordered to determine exactly where the damage is. Blood tests may be used to rule out other causes, or a joint aspiration performed to draw fluid from the joint for examination.

Whatever the severity, treatment usually starts with lifestyle changes to reduce stress on the knee. Other strategies include physical therapy, steroid injections, over-the-counter pain medication such as acetaminophen, NSAIDs, or topical pain-relieving creams. If symptoms stop responding to non-surgical measures, or pain can no longer be controlled with medication, surgery becomes an option.

The most common surgical intervention for knee osteoarthritis is total knee replacement, where the natural joint is removed and replaced with an artificial implant. That is usually offered to patients with advanced arthritis. For patients with early to mid-stage arthritis in only one or two compartments, total knee replacement is not always the best answer, and partial knee resurfacing may be more appropriate.