Dr Chew Tec Hock Jeffrey
For many people, arthritis is generally associated with old age. This is because the most common form of arthritis is osteoarthritis in the knee, when the knee cartilage is worn out due to wear and tear over the years. However, this is no longer restricted to the elderly, as there are more and more young people diagnosed with arthritis. The irony here is that this rising trend is the result of an increasingly active population.
The 2007 National Health Surveillance Survey conducted by the Ministry of Health found that 23.7% of Singaporean adults between the age of 18 and 50 are reported to be suffering from arthritis or chronic joint problems. This is a startling increase compared to the previous survey conducted in 2001, where only 7.4% of adults between the age of 18 and 64 were reported to be suffering from arthritis.
'With the rising interest in sports in Singapore,' says Dr Jeffrey Chew, an orthopaedic surgeon in Mount Elizabeth Hospital, 'we are seeing a rise in the number of patients with premature osteoarthritis from sporting injuries.' Dr Chew, who has over 20 years of experience in treating arthritis, added, 'It is inevitable that some of them will eventually require knee replacement in the future to mitigate their pain from osteoarthritis in their knees and regain mobility.'
According to a study published in Annals, a journal of the Academy of Medicine, Singapore, 96% of knee replacements performed in Singapore are caused by osteoarthritis, and 4.8% of people who receive total knee replacements are below the age of 50.
The knee joint is made up of 3 main compartments, and there is cartilage on each of these compartments to ensure smooth movement of the joint. Osteoarthritis occurs when this cartilage is worn down due to wear and tear, usually in old age. However, knee injuries can damage the cartilage and result in premature wear and tear.
Dr Chew says that more often than not, premature arthritis tends to involve only one compartment of the knee at the outset. This is unlike the usual osteoarthritis seen in the elderly, where the majority of the cartilage in all 3 compartments is damaged.
Normally, osteoarthritis is treated through a total knee replacement. This is a procedure where the entire knee joint is removed and replaced by a special implant made from metal and high density plastic. However, this may not be the best course of treatment for younger patients whose osteoarthritis in the knee is caused by sporting injuries.
'Usually in sporting injuries, one compartment of the knee tends to deteriorate faster than the rest,' says Dr Chew. 'Conventional total knee replacements where the entire knee is replaced is not recommended for these younger patients as only one compartment of their knee is damaged.'
With the advent of minimally invasive surgery and robotic technology, it is now possible to perform a partial knee replacement that resurfaces only one compartment of the knee. 'This is a new method that allows the surgeon to resurface only the damaged portion of the knee, sparing the remainder of the knee,' Dr Chew explains. Using robotic technology, the surgeon is able to place the implant into the affected portion of the knee with high precision. The use of robotic technology results in greater accuracy compared to conventional manual techniques, and accuracy is especially important in this procedure to ensure that healthy segments of the bone are not affected.
Only through detailed scans will the orthopaedic surgeon be able to determine whether your condition requires a total knee replacement or a partial knee replacement. Either way, multiple studies have shown that knee replacements are very effective in stopping chronic knee pain due to osteoarthritis and regaining mobility for the patient. The implants tend to last between 15 – 20 years on average, and the newer implants tend to use more durable material and are designed to work similar to a normal knee.
'For a total knee replacement, patients are usually able to regain 70 – 80% of their mobility after 6 weeks, and attain full recovery after 3 months,' Dr Chew says. Patients should be able to return to low impact activities such as walking and golf, although high impact activities are usually not advised so as to reduce wear and tear on the new joint and the risk of the implants loosening.
'In a total knee replacement, the knee ligaments are removed. In a partial knee replacement, however, the knee ligaments are preserved,' Dr Chew explains. This, together with the fact that the majority of the original knee is preserved, means that the knee feels more natural to the patient as opposed to a total knee replacement.
After partial knee replacements, most patients are able to return to sports, Dr Chew says. For many of them, their knee feels no different from before their injury, and as a result many of them are able to return to the sports they have done before. They are also able to participate in much more vigorous exercises compared to those who have gone through total knee replacements.