Total Knee Replacement BRINA, PAIGE, TYLER, & EMANUEL

Did you know…?Walking generates a force

of up to 3x the body weight upon the knee.

Running can produce a force of 10x the body weight upon the knee.

Going down stairs can put 5x the force of normal body weight on knees.

The Knee

The knee is the largest and most complex joint in the human body.

Hinge joint- only one direction of movement.

Some rotation is also permitted.

Bony Anatomy Knee joint

Femur Tibia Fibula Patella

Soft Tissue Anatomy

Articular Cartilage Menisci- absorb shock Lateral Collateral Ligament & Medial

Collateral Ligament- stability Anterior Cruciate Ligament & Posterior

Cruciate Ligament- stability Synovial Fluid- lubricates the joint to

eliminate friction

Cartilage Breakdown

Intact cartilage allows knee to function with smooth motion.

Breakdown results in narrowing of joint space, bone spurs, and/or damage to surrounding soft tissue structures.

What caused the joint to become diseased? Osteoarthritis

Rheumatoid arthritis

Osteoarthritis Normal wear and tear of

a joint. Causes:

Age Injury Weight Stress on joint Poorly formed joint

Rheumatoid Arthritis Chronic inflammatory

disorder that affects the joints.

Autoimmune Risk factors:

Age Sex Family History

What can be done for the knee? Indications for a total

knee arthroplasty are: To eliminate or reduce

pain Improve functional

activities Correct deformity

Contraindications include:

Active or recent septic arthritisA “nonfunctioning extensor mechanism or severe neurologic dysfunction that prevents extension or control of the kneeNeuropathic joint

Preparing for surgery

o Pre-Operative Evaluationo Pre-Admission Testingo Scheduling of Surgeryo Medication Adjustmentso X-Rays, possibly an MRIo Anesthesiology Preparationo Option for Blood Bankingo Education on TKRo Muscle Strengtheningo Mental Preparation

Surgical Procedure A vertical incision is

made down the knee to gain access to the surgery site.

For a traditional surgery = 8-10 inches long

The patella is exposed The surgeon rotates

the patella away from the knee to enable admission to the inner tissue of the knee.

Surgical Procedure Femur is exposed and surgeon is able to

carefully remove the area of damaged bone and cartilage.

Once the bone is resurfaced, the surgeon fits the metal femoral component of the implant. Cementless = porous-coated and allows

surrounding bone to grow into and adhere to prosthesis (direct biologic fixation).

Cement = most common due to better survival = ~15 years

Hybrid = advancing approach- cemented tibial component, noncemented femoral component Young, active patients at highest risk for

component loosening.

Surgical Procedure The tibia is rid of all

damaged bone and cartilage. The surgeon fits the plastic

and metal tibial components. The tibial tray is fitted to the

tibia (usually using bone cement).

Polyethylene insert is placed between femur and tibia to act as a buffered articulating surface and to provide support.

Surgical Procedure Before replacing

the original patella, the surgeon may cement an additional component to the backside of it in order to ensure a proper fit with the rest of the implant.

Total Knee Replacement= Total Knee Arthroplasty

Possible ComplicationsSide effects from anesthesiaBlood clotsInfectionComplications from a transfusionAllergy to metal componentsWound and bleeding complicationsNerve or neurovascular damageKnee stiffness or loss of motionProsthesis problems and implant failure

Outcomes of Surgery 99.96% of patients

survive this surgery. 84% are living 10

years after the surgery.

1% get a postoperative infection.

Less than 2% acquire blood clots.

About 85% of implants still work after 20 years.

Prognosis Most people who undergo a

TKR are between the ages of 50-80 years, with the average being about 70 years of age.

Short-term results are excellent. Most patients can stand, with limited weight-bearing, the day after surgery.

With exercise, maintaining a healthy weight, protection against infection, and avoidance of high impact sports, long-term results are optimal.