Osteoarthritis of the Knee

OA of the knee is common affecting 10% of the population. It is arthritis from wear and tear. It can occur with no obvious cause (Idiopathic) or be related to previous trauma, often decades earlier and sometimes not memorable. Your inherited anatomy, especially if very “bow legged or knock kneed” can lead to OA. Some specific forms of arthritis run in the family, the commonest is called Primary Generalised Osteoarthritis, and cause swelling of the fingers (Heberdens nodes), pain at the base of the thumb and hip and knee arthritis.

Treatment

OA of the knee is never life threatening. The main aim of treatment is therefore symptomatic, for pain. Sometimes surgery is recommended when pain is not so bad, especially if there is severe or progressive deformity, or in old age, there is difficulty mobilizing with danger of falling.

The treatment is usually a progression, from the simple to major surgical intervention. The inflammation and pain associated with arthritis commonly runs a fluctuating course, and pain can settle despite a period of increased symptoms.

Simple Measures

Exercise – Non impact exercises to keep strength and tone in the thigh muscles. This will help to improve your feeling of stability and security, especially for stairs and hills. It does not fundamentally change the arthritis in your knee.

Water based exercises are ideal if possible.

Footwear - Shock absorbing footwear and walking/exercising on soft surfaces such as grass rather than concrete can make a big difference. Air or Gel joggers and SORBOTHANE shoe inserts provide the ultimate cushioning and reduce jarring. These can be sourced at Athletes foot, Footlocker etc..

Paracetamol – a simple but effective analgesic. Often needs to be used 3 or 4 times a day (two tablets / 1000mg on each occasion) This can be safely used by most people for prolonged periods at these doses.

Natural Remedies – Often not proven but some people gain relief from various naturopathic potions, magnets, acupuncture and the like. This effect may be placebo, but some plant substances have proven anti-inflammatory effects. You should check the use of these with your local doctor as some react with other medicines and may be dangerous with medical conditions.

Glucosamine and Chondroitin Sulfate – (Osteoeze, Arthroeze and most joint supplement formulas) are the most common “arthritis remedies” at the current time. There is some early evidence that over time they may help to maintain articular cartilage and slow the progression to OA. Nothing can “put cartilage back” after OA is established. Some people also report a reduction in arthritis symptoms when taking these substances. Their main side effect is mild diarrhea, but they do contain seafood elements and should not be taken if you have a seafood allergy.

Fish oil - This has been associated with some improvement in cartilage quality and may be beneficial

Anti-inflammatories (NSAIDs) – Non steroidal anti-inflammatory drugs are available only on prescription. There are many different agents, all related. They can be very effective in reducing the swelling and pain associated with arthritis. All of these medications have potential side effects and are not always tolerated. The commonest effects are

• Exacerbating asthma
• Causing gastrointestinal upset (ulcers)
• Increasing blood pressure
• Leading to retention of fluid – ankle swelling

Celebrex and Mobic are the newest of these tablets and are supposed to have less side effects.

Minimally Invasive Techniques

Injections – Cortisone injected into the knee can be helpful for a couple of months, but provides no longterm relief. It has some negative effects and cannot be used repetitively. It may be very helpful in specific circumstances, such as to reduce fluid in the joint.

Synvisc – (by Bayer – information on the internet). This is a hyaluronic acid substitute from an animal source. It is supposed to replenish the lubricant fluid of the knee. It is in fact removed from the knee (metabolised) within a couple of weeks. It costs about $500 for a course of three injections and may give some benefit for three to nine months, but in my practice has rarely lived up to its promise.

Arthroscopy – In early arthritis pain may be coming from a torn cartilage (Meniscus) within the knee. This can be trimmed or debrided. Depending on the progression of the arthritis, the results can be unpredictable, but often beneficial.

In advanced arthritis, arthroscopy is of variable benefit, and effects are often short lived. In specific circumstances, especially with catching, locking or a loose body, it may provide a much greater benefit. It cannot reverse the arthritis in your knee.

Major Surgery

This should be reserved for failure of the lesser measures described above. These are all major operations and involve some time in hospital. Whilst usually successful they can occasionally lead to life or limb threatening complications.

Osteotomy - This involves cutting the thigh bone (femur) or leg bone (tibia) and changing the alignment of your leg. It is most commonly done for bow legged deformity and mostly for people with arthritis at a younger age (less than 60 years). It has the advantage that there is no replacement in the knee joint to wear out or come loose, and does not lead to restrictions in activity. It relies on putting the load through the side of the knee which is not worn out, and is therefore limited to people with arthritis in one half of the knee only. An osteotomy is aimed to provide functional relief for 5-10 years, at which time a knee replacement can be performed.

Unicompartmental Replacement or Half Knee Replacement - This is an artificial knee replacing only the worn, usually inner, half of the knee. Like the osteotomy the other half of the knee must be in good condition. It is a smaller operation and maintains better bend than a full or total knee replacement but has all the other potential negatives associated with a full knee replacement. Statistically ½ knees are likely to fail significantly earlier than full knee replacements.

Total Knee Replacement - This involves resurfacing the knee with a metal and plastic artificial joint (prosthesis). It is excellent for relieving pain and stability within the knee. They rarely bend fully, usually reaching about 120degrees. The knees I usually use are the “Duracon”, and “Triathlon”, manufactured by Stryker, a worldwide Orthopaedic implant company based in the USA. 2% of these knee replacements fail within the first 10 years, some quite early, with infection or other complications. The other 98% last between 10 and 20 years.

The wear and loosening rate increases with high levels of physical activity. When they fail a revision procedure can be performed to put in another knee, but in general terms these are not as successful as first time or primary replacements.

This is why people are told they are too young for a knee replacement. There is no absolute age cut off, but a knee replacement done at an early age will almost guarantee further surgical procedures in that persons’ lifetime, and may present difficulties in maintaining mobility into old age. Sometimes, despite a young age, there is no other option and we perform knee replacements with this in mind. Artificial joints are not suitable for impact or twisting sports such as tennis or running, but golf walking and swimming are encouraged.

To Summarise

Start with a regular exercise/walking program and good shoewear, use simple painkillers and by all means try ‘natural remedies’ if you wish. At some point you may reach the point where ‘something needs to be done’ we will try to guide you through this.