The therapeutic options in arthritis can be divided into medical and surgical. For convenience, the medical options may be thought of as therapies requiring non-surgical modalities like drugs and injections. To make sense of this one must consider arthritis as being caused by active inflammation (the rheumatic group of conditions) or mechanical overload.
In this group of patients there has been some injury to the joint in the past and this results in progressive wear and tear to the joint which in turn results in arthritis. The most common of these is the primary group where (presumably) due to the shape of the body, weight is unevenly distributed through the joint. Over many years this results in wear and tear. Similarly, following trauma, the there may be uneven weight distribution in the knee due to fractures or the cartilage itself may have been lost. The same effect occurs after severe infections, or tumors or congenitally if a person is born with abnormal joints. These are all much rarer. Following the rheumatic conditions the after effects cause the same problems even if the rheumatic condition is no longer active.
The pharmaceutical agents (drugs) for this disease are the painkillers and over the counter supplements. Weight loss can be a very useful adjunct to this and the patient should aim to lose about 5 kg over 6 months. Surgical procedures known as barometric procedures are designed to help patients lose weight by eating less.
In order of increasing effectiveness and unfortunately side effects, the painkillers are:
1. Acetaminophen: Commonly known as tylenol, panadol or paracetamol, this is a great starter drug. It is weak but can be given in divided doses up to 4 grams a day. It is often available in combined preparations where side effects are of the added drug. The major side effects with the drug are liver damage which only happens in overdose situations.
2. The opiates: This includes various drugs that work like morphine. Variants include codeine (combined with acetaminophen as panadeine), tramadol, morphine, fentanyl, pethidine. all of these drugs are effective painkillers but cause nausea, dizziness and constipation.
3. The non-steroidal anti-inflammatory drugs (NSAIDS): There are many in this group of highly effective painkillers (eg. aspirin, brufen, ponstan, indocid, voltaren, synflex). Unfortunately they also have the worst of the side effects of gastric ulceration, renal damage, heart damage and stroke. To reduce gastric ulceration, acid reducing drugs are sometimes prescribed. This can reduce gastric ulceration but not duodenal ulceration and can have their own side effects and be expensive in the long run. The Cox-2 inhibitors are a special group of such drugs which may have less ulcerative side effects but worse vascular and renal side-effects. In general, if a patient has been taking these drugs for up to a year, the side effects of drugs would be worse than surgery.
4. Over the counter agents: Glucosamine is a simple compound merging glucose and amine. It is absorbed whole and therefore would be effective as is. It is a building block of cartilage. The original studies quoting Viartril-S showed impressive results in regenerate cartilage as seen on MRI. This resulted in an explosion of preparations in this lucrative market. Many companies have been shown to have suboptimal preparation with either ineffective preparations or reduced concentration of effective drug per tablet. Being marketed as a health supplement, there are no well designed studies to support its use and, most of concern, its side effect profile. The best index of success is therefore an experienced physician who has used a particular drug. More recently, most studies do not show that this is an effective agent. The cost is high. 3 years of continuous use is the cost of a knee replacement prosthesis. While present guidelines do not support its use it seems reasonable to try it for 6 months given the safety profile. Following that period, the drug probably behaves as a placebo. Transdermal preparations are not supported in the literature. Chondroitin sulphate is often sold in preparations with glucosamine. It is however a large molecule and broken down in the gastrointestinal tract to small sugars. It therefore does not work as a 'building block of cartilage'. It is not recommended in the literature. There is a group of analgesics derived from the herbal preparations of ginger and chilli (capsacin). These seem safe in the long term and have reasonable benefit. As in all such categories of agents there is no good evidence to support its use and no accounting of side effects. Doctors, being to held to the standards of evidence based medicine, may be reluctant to prescribe these agents long term and refer such cases for specialist review because of the lack of evidence involved in their long term use.
These injectable agents that may be relevant to arthritis include steroids, viscosupplementation, platelet rich plasma therapy and stem cells. With the present available literature, strong support for use can is only available with steroids and viscosupplementation. The remaining 2 are largely experimental and cannot be recommended for routine use. With any injection there is the risk of infection and this can compromise further surgery on the knee.
Active inflammatory arthritis
In these conditions the knee is warm and swollen. More than one joint may be involved. There may be a rash and sometimes even organs may be involved. These are the rarer forms of arthritis and affect mainly women in childbearing age. They may go by the name of Rheumatoid arthritis, Systemic Lupus Erythematosus, mixed connective tissue disease, autoimmune disease. It usually results when for some reason the persons immune system turns on itself.
Infections (septic arthritis) are a special form of inflammatory disease that are treated by antibiotics and drainage and can cause damage that leads to the "overload" syndromes described above. They are otherwise not considered under this heading. Gout is a special form of inflammatory arthritis where the presence of uric acid crystals cause damage to the joint. It is controlled with drugs which reduce the bodies reaction to these crystals. After that the treatment is similar to the state of mechanical overload.
In autoimmune arthritis, typically antibodies to the body's own cells result in damage to the joints. This means that therapy has 2 components namely therapy to combat the antibodies (ie. immune suppression) and therapy to control the pain.
Immune suppression takes a few forms. The most classic of this is the use of steroids. Similarly non-steroidal anti-inflammatory drugs (NSAIDS) may be used that have the dual function of pain killing and immune suppression.The newer generations of therapies include the disease modifying anti-rheumatics drugs (DMARDS) and even chemotherapeutics. Side-effects are significant and can be severe but they have been very effective in reducing the overall and often potentially devastating manifestation of these disease. Sometimes injections into the joint are done to reduce the systemic side effects of these agents. In general these conditions are managed by rheumatologists and because the drug interactions are often significant rheumatologists are the best doctors to decide when surgery on this group of patient is timely.