Five lakh people undergo TKR (Total Knee Replacement) in India every year which is 2.5 times the number of such procedures conducted annually about 5 years ago, says Dr. Rajesh Malhotra, head of AIIMS Orthopaedics division. The prevalence at 50 years of age was 0.68% and increased to 2.92% at 60 years, 7.29% at 70 years, 10.38% at 80 years and 8.48 at 90 years of age.
The number of joint replacements in India is set to grow at the highest rate from 2020 to 2026. It is high time that we should ponder why this number is increasing at a faster rate and how we can cure the same and prevent the patients from undergoing surgery. Generally TKR is performed for destruction of joint cartilage either from osteoarthritis, rheumatoid arthritis/inflammatory arthritis,posttraumatic degenerative joint disease, or osteonecrosis/joint collapse with cartilage destruction.
Knee osteoarthritis is the most common type of arthritis diagnosed, and its prevalence will continue to increase as life expectancy and obesity rises. Depending on the source, roughly 13% of women and 10% of men 60 years and older have symptomatic knee osteoarthritis. Among those older than 70 years of age, the prevalence rises to as high as 40%. The prevalence of knee osteoarthritis in males is also lower than in females. Interestingly, not everyone who demonstrates radiographic findings of knee osteoarthritis will be symptomatic. One study found that only 15% of patients with radiographic findings of knee OA were symptomatic. Not factoring in age, the incidence of symptomatic knee osteoarthritis is roughly 240 cases per 100,000 people per year.
Articular cartilage is composed primarily of type II collagen, proteoglycans, chondrocytes, and water. Healthy articular cartilage constantly maintains an equilibrium between each of the components so that any degradation of cartilage is matched by synthesis. Healthy articular cartilage is thus maintained. In the process of osteoarthritis, matrix metalloproteinases (MMPs), or degradative enzymes, are overexpressed, disrupting the equilibrium and resulting in an overall loss of collagen and proteoglycans.
In the early stages of osteoarthritis, chondrocytes secrete tissue inhibitors of MMPs (TIMPs) and attempt to increase the synthesis of proteoglycans to match the degradative process. However, this reparative process is not enough. The loss in equilibrium results in a decreased amount of proteoglycans despite increased synthesis, increased water content, the disorganized pattern of collagen, and ultimately loss of articular cartilage elasticity. Macroscopically these changes result in cracking and fissuring of the cartilage and ultimately erosion of the articular surface.
Although knee osteoarthritis is closely correlated with aging, it is important to note that knee osteoarthritis is not simply a consequence of aging but rather its own disease. This is supported by the differences seen in cartilage with both osteoarthritis and aging. Furthermore, the enzymes responsible for cartilage degradation are expressed in higher amounts in knee osteoarthritis, whereas they are at normal levels in the normal aging cartilage.
Osteoarthritis is being developed at early ages and the most common cause for the same is our lifestyle. As we have more of a sedentary job profile (more of sitting) or overuse of body due to prolonged standing/walking , it leads to weakening of spinal and lower limb muscles especially quadriceps and gluteus which leads to overload on knee and hip joint which leads to early wear and tear in knee joint hence leading to pain and deformity that eventually results in reduced functional capacity in standing, walking, stair climbing and squatting.
To avoid early degenerative changes the only thing that can help is lifestyle changes that involve walking in daily routine, strengthening of lower limb and spinal muscles for prevention and following good nutrition. Consulting specialist in case of grade 1 or 2 OA that can help in reducing fast progression by improving functional capacity and reducing load on the knee joint hence delaying the surgery.