Total Knee Replacement (1)

1. Total Knee Replacement Brina , Paige, tyler , & Emanuel

2. 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.

3. 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.

4. Bony Anatomy Knee joint Femur Tibia Fibula Patella

5. 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

6. 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.

7. What caused the joint to become diseased? Osteoarthritis Rheumatoid arthritis

8. Osteoarthritis Normal wear and tear of a joint. Causes: Age Injury Weight Stress on joint Poorly formed joint

9. Rheumatoid Arthritis Chronic inflammatory disorder that affects the joints. Autoimmune Risk factors: Age Sex Family History

10. 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 arthritis A “nonfunctioning extensor mechanism or severe neurologic dysfunction that prevents extension or control of the knee Neuropathic joint

11. Preparing for surgery Pre-Operative Evaluation Pre-Admission Testing Scheduling of Surgery Medication Adjustments X-Rays, possibly an MRI Anesthesiology Preparation Option for Blood Banking Education on TKR Muscle Strengthening Mental Preparation

12. 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.

13. 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.

14. 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.

15. 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.

16. Total Knee Replacement= Total Knee Arthroplasty

17. Possible Complications Side effects from anesthesia Blood clots Infection Complications from a transfusion Allergy to metal components Wound and bleeding c omplications Nerve or n eurovascular damage Knee stiffness or loss of motion Prosthesis problems and implant failure

18. 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.

19. 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.