Published in the Hong Kong Economic Journal
Just as machines can wear out, the human body's joints are also susceptible to deterioration. Knee osteoarthritis is a common problem that afflicts many middle-aged and elderly individuals. Among the various joints in the body, the knee is one of the most frequently affected by degenerative changes. Activities such as walking, running, and hiking all rely heavily on the knees. Knee problems can significantly impact a patient's daily life.
According to a 2001 survey by the Chinese University of Hong Kong, the incidence rate of knee osteoarthritis in Hong Kong is equally high as in Western countries. The prevalence of knee arthritis increases rapidly in women after menopause. Among men aged 50 or above, 17% have experienced persistent knee pain, and 7% have been diagnosed with knee arthritis. For women in the same age group, 24% suffer from persistent knee pain, and 13% have been diagnosed with knee arthritis.
Understanding the Knee
First, we need to understand the structure of the knee. The knee is primarily composed of three parts: the femur (thigh bone), the tibia (shin bone), and the patella (kneecap). The knee is surrounded by multiple soft tissues, including the joint capsule, tendons, and muscles. On the surfaces where the femur and tibia meet, there is a layer of 2-3 millimeters of articular cartilage. Additionally, there are two menisci (crescent-shaped cartilage discs) between the two bones, which are soft and smooth, serving to cushion and stabilize the knee. These cartilaginous structures are the primary areas affected in arthritis.
Types and Causes of Knee Arthritis
There are various causes of knee arthritis, such as degenerative osteoarthritis, rheumatoid arthritis, gouty arthritis and post-traumatic arthritis. Osteoarthritis is the most common type among all different type of arthritis. While the exact cause of osteoarthritis is still unknown to the medical community, most experts believe that factors such as aging and injury can lead to different degrees of cartilage wear and tear. Regarding risk factors, studies have shown that obese individuals are 5 times or more likely to develop knee arthritis compared to those with normal weight. If a patient has previously sustained a knee injury (e.g., cruciate ligament tear, meniscus injury, or fracture), the risk of developing knee arthritis increases 7-fold compared to those without prior injury.
This article was written by Dr. Cheung Man Hong, a consultant in Orthopaedics at the Hong Kong Adventist Hospital - Stubbs Road
Published in the Hong Kong Economic Journal
Knee Osteoarthritis
Osteoarthritis is the most common type of joint disease. Almost any joint can develop osteoarthritis, but it most often affects weight-bearing joints like the knees, hips, spine, first metatarsophalangeal joint (base of the big toe), and first carpometacarpal joint (base of the thumb). Among these, knee osteoarthritis is commonest type of osteoarthritis.
In the early stages, the cartilage on one side (medial or lateral) of the joint may start to wear down, and gradually progresses to the other side. Eventually, the cartilage lining the joint may become almost completely eroded. X-ray examinations can reveal that the normally smooth joint surface becomes uneven, with bone overgrowth, commonly known as bone spurs. Many people mistakenly think the pain is caused by the bone spurs rubbing against the soft tissue, but this is not the case. The main cause of the pain is actually the wear and tear of the cartilage. Even if the bone spurs are removed, the pain may not improve significantly.
Key Symptoms
In the early stage, patients may feel knee pain when going up/down stairs or walking on slopes, accompanied by joint swelling. Abnormal grinding noises may be heard when moving the joint. In the late stage, patients may experience joint stiffness, difficulty in bending/extending the joint, and even deformities like "bow legs." The range of motion decreases, making the patient difficult to climb stairs or squat. These symptoms not only cause inconvenience in work and daily life, but may also affect the patient's emotional well-being.
Osteoarthritis vs. Rheumatoid Arthritis
Many people confuse osteoarthritis with rheumatoid arthritis, as they share some similar symptoms like joint pain, redness, and swelling. However, the underlying causes and treatment approaches are completely different. There are also other conditions like gout or pseudogout, where uric acid or calcium crystals deposit in the joint, leading to acute, severe joint pain and swelling, which can resemble osteoarthritis symptoms. Therefore, if a patient experiences frequent joint pain and swelling, they should seek medical attention promptly to determine the root cause and receive appropriate treatment.
This article was written by Dr. Cheung Man Hong, a consultant in Orthopaedics at the Hong Kong Adventist Hospital - Stubbs Road
Published in the Hong Kong Economic Journal
How to diagnose?
The doctor will first inquire about the patient's medical history and family history, particularly asking about the timing and triggering factors of the joint pain. For example, if the patient has osteoarthritis, the pain usually worsens after using the joint (walking, moving, or climbing stairs), but improves with rest. In contrast, if the patient has rheumatoid arthritis, the joints are often more painful in the morning upon waking up, and the pain tends to ease after some movement. If the patient experiences knee joint swelling and pain after consuming seafood, internal organs, or alcohol, the possibility of gout should be considered. The doctor will also assess the severity of the arthritis based on the patient's mobility (e.g., whether a cane or walker is needed) and the frequency of pain medication use.
After the interview, the doctor will conduct a thorough physical examination, paying particular attention to the location of knee pain, the patient's mobility, joint deformities, range of motion, lower limb muscle strength (such as the quadriceps), joint stability, and the structure and tension of related ligaments. If the patient is considering knee replacement surgery, the doctor will also examine the lower limbs, especially the condition of the feet, to check for any fungal infections (Tinea Pedis), as this would make the patient unsuitable for knee replacement surgery.
The doctor will then arrange an X-ray examination. Usually, the patient will be asked to adopt a standing posture when taking the knee X-ray, as the cartilage loss are often more apparent when the patient is standing compared to lying down. The X-ray will be checked for narrowing of the joint space and soft tissue swelling.
This article was written by Dr. Cheung Man Hong, a consultant in Orthopaedics at the Hong Kong Adventist Hospital - Stubbs Road
Published in the Hong Kong Economic Journal
Bone Spurs?
"Degenerative Osteoarthritis " is a condition that not everyone may have heard of, but I believe every Hong Kong citizen has heard of the so-called "bone spur" ailment affecting themselves or someone they know. Many patients discover they have knee pain, and after a X-ray examination, they are told that their knee has developed bone spurs, which is actually a misunderstanding.
A normal joint has a smooth overlying surface is smooth, but when the joint degenerate its surface becomes uneven. One contributing factor for the surface irregularly is the presence of bony outgrowths, which are commonly known as bone spurs. The emergence of bone spurs is the result of knee's surrounding tissues attempting to repair the degenerating knee. Bone spurs are most commonly seen in the knee. From X-rays, the bone spurs in a degenerative knee are often rounded bony protrusions around the joint, so these bone spurs are not sharp "spurs", and they will not pierce the soft tissues or skin to cause pain.
The main cause of a patient's knee pain is due to the wear and tear of the cartilage, as well as the accompanying bone loss, ligament laxity, joint capsule instability, synovial inflammation and swelling. The appearance of bone spurs is only a partial symptom of the degenerative knee, and not the primary culprit. Therefore, even if the bone spurs are removed, the pain will not improve significantly, so doctors will not perform surgery just to remove the bone spurs without addressing the underlying knee disease. In fact, the medical term for "bone spurs" is actually "osteophytes", meaning redundant bone growth.
However, the discovery of osteophytes on a knee X-ray does have its significance. If the patient has symptoms of knee arthritis, the presence of osteophytes is one of the indicators used by doctors to analyze the severity of knee degeneration. Pathologically, osteophytes can compress or tighten the knee capsule or ligaments, limiting the range of knee motion, and even leading to knee deformity. If the patient's knee degeneration is severe and requires joint replacement surgery, the surgeon must remove all osteophytes during the procedure in order to restore the balance of soft tissue and ligament tension, as well as improve the patient's knee joint mobility.
This article was written by Dr. Cheung Man Hong, a consultant in Orthopaedics at the Hong Kong Adventist Hospital - Stubbs Road
Published in the Hong Kong Economic Journal
Overview of Treatment Methods
The treatment for knee osteoarthritis can be divided into several aspects: non-surgical treatment (including drug therapy and non-drug therapy) and surgical treatment.
Non-drug treatment
For patients with relatively mild symptoms, X-rays showing the knee has not reached severe degeneration, and without significant knee deformity and knee stiffness, doctors generally will first consider non-surgical treatment options. The principles and goals of non-surgical treatment are as follows:
- Reduce further joint wear
- Slow down the developement of complication of osteoarthritis
- Alleviate the symptoms of osteoarthritis, such as pain
- Maintain and improve the joint mobility
- Strengthen the leg muscles
According to the clinical guidelines of the American Academy of Orthopedic Surgeons, the effective non-drug treatment methods proven by clinical studies include weight management and effective physical therapy and training.
Weight management
Many people think weight control is a cliche, but in fact, there is a large amount of medical literature that proves that for patients with a body mass index (BMI) above 25, weight control can effectively relieve pain, and is even more effective than medication. Because weight control is one of the important factors that can reduce the burden on the knee, it is an effective way to reduce further joint wear. To maintain a normal weight index, you must learn to start from diet, exercise, and emotional support in order to achieve an ideal and healthy weight management.
Exercise and physical therapy
Many patients think that since they already have knee degeneration and overuse, continuing to exercise will accelerate the overuse and degeneration. So should they do more exercise or reduce activity to protect the joint? The answer is that they should continue to exercise, and even strengthen their training. In fact, lack of exercise in the knee and lower limbs will cause muscle loss. If there is muscle atrophy, they cannot support the knee, making the knee unstable, and increasing the pressure on the cartilage and related soft tissues, and thus further aggravating the degeneration. In simple terms, the less you move, the more it hurts.
This article was written by Dr. Cheung Man Hong, a consultant in Orthopaedics at the Hong Kong Adventist Hospital - Stubbs Road
