Total knee replacement surgery is growing in popularity and efficacy. It was first performed in 1968, while modern techniques began in earnest in the 1970s. In the last few decades, major improvements in surgical materials and techniques have greatly increased its efficacy. Total knee replacement, also known as total knee arthroplasty, is one of the most common procedures in orthopaedic surgery and one of the most successful in all of medicine. The number of people undergoing total knee replacement surgery is increasing, which researchers theorize is due in part to rising obesity rates. A study published in the June 2014 issue of Journal of Bone and Joint Surgery, showed that total knee replacements more than tripled between 1993 and 2009. The researchers found that knee replacements were far more prevalent among patients who were overweight or obese. Being overweight puts an increased burden on joints, raising the risk of developing knee pain and osteoarthritis.
The statistics vary on the number of procedures performed, potentially due to different criteria used for analysis as well as fluctuations from year to year. The National Center for Health Statistics at the Centers for Disease Control and Prevention noted that there were 719,000 inpatient knee replacement surgeries performed in the U.S. in 2010. The Agency for Healthcare Research Quality states a lesser number of more than 600,000 knee replacements performed each year in the U.S., with 393,345 women and 237,896 men undergoing this procedure in 2012. A 2014 prevalence study by Mayo Clinic researchers showed that an estimated 4.7 million Americans have already undergone total knee arthroplasty. Prevalence was higher in women than in men with 3 million women versus 1.7 million men living with implants. They also found that prevalence increased with age; by ages 80 to 89, about 10% of the entire population had undergone a total knee replacement procedure.
In the EU, there is considerable variation across countries in the rate of knee replacement surgery. Germany, Switzerland, and Austria have the highest rates, with Germany’s rate rivalling that of the U.S. Experts attribute these disparities to reasons such as differences in osteoarthritis prevalence, the ability to deliver and pay for procedures, and varying clinical treatment guidelines and practices.
Osteoarthritis: The #1 Reason for Knee Replacement Surgery
Recent studies estimate that symptomatic knee osteoarthritis (confirmed through radiological imaging) impacts 3.8% of the population worldwide. Studies estimate that 90% of all knee replacement surgeries are due to late-stage osteoarthritis, the most common cause of musculoskeletal pain and disability related to the knee. The complex knee joint, which is the largest joint in the body, connects the bones in the upper and lower leg, comprised of muscle, ligaments, tendons, and the meeting of four bones: the thigh bone (femur), shin bone (tibia), calf bone (fibula), and kneecap (patella). The end of the femur and tibia are covered in smooth articulate cartilage. Two concave pads of cartilage called menisci are located between the femur and tibia, functioning as shock absorber pads.
Osteoarthritis is a chronic condition in which cartilage (the material that cushions the joints) breaks down, potentially causing serious impairment. Pain and stiffness generally progress over a period of time, so in the early stages, low-grade aching and stiffness may be periodic. Symptoms of osteoarthritis can include joint pain with activity, night pain, morning stiffness, limited motion, joint inflammation, a noise from the knee, and in severe cases – deformity. The pain may be more pronounced when you put weight on it, climb stairs, bend, kneel, squat, walk, or participate in sports. In addition, about 20 to 30% of patients with rheumatoid arthritis have knee symptoms related to this disease. In most cases, nonsurgical treatment is administered before surgery is considered, including anti-inflammatory medications, physical therapy, cortisone injections, joint fluid injections, icing, and moist heat.