According to Assoc. Prof. Areesak, knee osteoarthritis is caused by the wear and tear of cartilage—tissues that cover the end of the bones, which act as a cushion that distributes the pressure and weight over the surfaces of knee joints.
The breakdown of cartilage results in changes in the structure of joints including deformity, buildup of excess fluid in joints, formation of bone spurs, laxity of muscles and ligaments around the joints. Osteoarthritis commonly occurs in the weight bearing joints of the hips and knees.
The conditions cause joint pain, swelling and difficulties in daily activities. Lack of exercise due to limited mobility may cause the recurrence of other diseases such as hypertension and diabetes.
Although it is not known exactly what causes cartilage to wear away, there are several contributing risk factors. Overweight increases pressure on all joints. A lot of activity or postures such as kneeling or sitting on the floor by tucking the legs one side can stress the joints.
For some individuals, it may be hereditary, especially in families with history of weak joints or cartilage. The chance of developing the disease also increases with age.
Symptoms and signs of knee osteoarthritis include pain and swelling in the knee that increases with movement, creaking or crackly sound that is heard when the knee moves, formation of bone spurs, degeneration or weakening of muscles around the joint, and less stability in the joint.
Together with the patient's description, a medical history and physical exam is important for accurate diagnosis. X-rays that show abnormalities could be helpful in confirming the diagnosis. In some cases blood tests may be necessary to rule out other diseases.
The goal of treating knee osteoarthritis is to relieve the pain and return mobility. The treatment typically starts with physical therapy that includes exercises that would strengthen the muscles around the knee, bracing, and placing a hot compress to the swollen part of the knee.
In addition to exercise, pain relievers and anti-inflammatory drugs may help decrease pain and swelling. However, taking the medications for extended periods increases the chance of side effects on the liver, stomach and intestines. The drugs may cause gastric ulcer which in some cases could lead to perforation and bleeding in the stomach.
Though providing a short-term relief, steroid injections increase risk of crystals buildup and deterioration of the knee joint. Injections of hyaluronic acid substitutes to lubricate the joint is another option.
When other treatments don't work, surgery is the last resort. Laparoscopic or open knee surgery removes damaged parts from the joint, cut and realign bones and replace the knee totally or partially.
Technological developments from intraoperative gonimeters—devices that measure angles for knee alignment during an operation—to computer navigation have continuously enhanced the efficiency of knee replacement surgery, which traditionally relied the surgeon's experience and skills.
The robotic surgical system is the latest breakthrough technology which has received worldwide enthusiasm for its application in procedures to treat a range of conditions including knee osteoarthritis.
According to Assoc. Prof. Keerati, the robot-assisted surgical system comprises three components: robotic arms, 3D endoscope and the computer station that processes data and controls the first two.
In an operation, the computer station processes information from CT images for preoperative planning to determine the size, position and angle of the knee joint and send commands to the robotic arms.
Looking at 3D images, the surgeon removes damaged cartilage and bones form the joint by maneuvering the robotic arms, which can make tiny incisions as narrow as 0.2 mm. and achieve the accuracy of bone cuts with a deviation of up to 1 mm. or 1 degree of knee angle. The surgeon then replaces the damaged parts with man-made parts made from cobalt chromium or titanium alloys
With greater precision than conventional surgery, robotic surgery avoids damaging ligaments and tissues around the joint, enabling the patient to bend the knee more than 120-130 degrees, which is close to normal knee flexion.
In addition to less blood loss and very small incisions, a recovery time for partial knee replacement is much shorter; the patient can get up and walk the day after surgery.
Candidates for partial knee replacement are patients with degradation occurring in some parts of the knee joint, e.g. thigh bone or shinbone. They must also have good hip joints to make the alignment of the leg perfectly straight from the center of the hip to through the center of the knee.