Osteoarthritis of the Hip
Other popular names
- OA of the Hip
- Osteoarthrosis of the Hip
- Arthrosis of the Hip
Osteoarthritis – What is it?
Osteoarthritis is the loss of cartilage. Cartilage is the lubricant lining of a joint. Once the cartilage wears away, areas of bone within the joint can rub against other areas of bone and this can be painful.\
This presents with pain usually felt in the groin and the thigh and the resultant stiffness in the joint leads to a limitation of motion. This usually presents with an inability to take shoes and socks on and off comfortably, cut toe nails or climb in and out of the bath. Pain in the groin usually restricts walking distance.
The X-ray shows a normal hip joint on the left with a smooth round ball in a smooth socket with a space between the bones. This joint space represents the amount of cartilage within the joint. The right hip is arthritic with a very deformed head and loss of joint space. The areas of lost cartilage cause areas of bare bone to rub against one another which causes pain.
Who does it affect?
Generally a condition associated with age, however it could be due to heredity factors, childhood conditions or injury. Often people engaged in active sport may suffer with osteoarthritis as they get older.
10% of the population are affected by osteoarthritis.
Why does it happen?
Like other joints that carry your weight, your hips may be at risk for "wear and tear" arthritis (osteoarthritis), the most common form of the disease. The smooth and glistening covering (articular cartilage) on the ends of your bones that helps your hip joint glide may wear thin.
Osteoarthritis is a disease which affects joints in the body and the hip is one such joint. The surface of the joint is damaged and the surrounding bone grows thicker. ‘Osteo’ means bone and ‘arthritis’ means joint damage and swelling (inflammation). Other words used to describe osteoarthritis are ‘osteoarthrosis’, ‘arthrosis’ and ‘degenerative joint disease’.
When a joint develops osteoarthritis, the cartilage gradually roughens and becomes thin, and the bone underneath thickens. The bone at the edge of the joint grows outwards (this forms osteophytes or bony spurs). The synovium swells slightly and may produce extra fluid, which then makes the joint swell slightly. The capsule and ligaments slowly thicken and contract, as if they were trying to stabilise the joint as it gradually changes shape. Muscles that move the joint may weaken and become thin or wasted.
When we look at osteoarthritic joints under a microscope, we see the joint is trying to repair itself. All the tissues of the joint are more active than normal. For example, new tissue is produced to try to repair the damage, such as the osteophytes. In many cases, especially in small finger joints, the repair is successful. This explains why many people have osteoarthritis but experience few or no problems. However, sometimes the repair cannot compensate for the damage. Osteoarthritis may then seriously affect the joint, making it painful and difficult to move. This occurs particularly in large joints such as the knees and hips.
Osteoarthritis is a slow process that develops over many years. In most cases there are only small changes that affect only part of the joint. Sometimes, though, osteoarthritis can be more severe and extensive.
In severe osteoarthritis, the cartilage can become so thin that it no longer covers the thickened bone ends. The bone ends touch and start to wear away. The loss of cartilage, the wearing of bone, and the bony overgrowth at the edges can change the shape of the joint. This forces the bones out of their normal position and causes deformity.
Your first sign may be a bit of discomfort and stiffness in your groin, buttock, or thigh when you wake up in the morning. The pain flares when you are active and gets better when you rest. Sleep disturbance and stiffness of the hip is common.
If you do not get treatment for osteoarthritis of the hip, the condition keeps getting worse until resting no longer relieves your pain. The hip joint gets stiff and inflamed. Bone spurs might build up at the edges of the joint.
When the cartilage wears away completely, bones rub directly against each other. This makes it very painful for you to move. You may lose the ability to rotate, flex or extend your hip. If you become less active to avoid the pain the muscles controlling your joint get weak, and you may start to limp.
During a physical examination, your consultant will determine how much the disease has progressed and in doing so you will be required to move and rotate your leg and hip into various positions to check for pain.
An x-ray will be used to determine the extent of the osteoarthritis and also to detect if you have developed bone spurs or other abnormalities.
Osteoarthritis is not a life threatening condition, it is a quality of life threatening condition. Therefore, all treatments should be judged on an ability to relieve pain and improve quality of life. If pain can be relieved with simple measures such as painkillers, the use of a walking stick and avoiding activities that aggravate the pain, no further surgical treatment is needed. Physiotherapy may have a role in improving muscle function around the hip but unfortunately no treatment can actually replace cartilage.
If you have early stages of osteoarthritis of the hip, known as gonarthrosis, treatment may include:
- Exercise – Low impact exercise such as walking, swimming and cycling keeps muscle strength and tone. Hip joint stretches to keep the hip supple are beneficial. A consultation with a physiotherapist for education and a home exercise program can be useful.
- Walking stick – Using a walking stick in the opposite hand reduces load in the hip and usually increases your walking distance. A strong stick of correct length with a non-slip rubber end is best.
- Paracetamol – A simple but safe analgesic when used correctly. Often needs to be used 3 or 4 times a day (1000mg / 2 tablets on each occasion). This can be safely used by most people at 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 affect 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 may react with other medicines or be dangerous.
- Glucosamine and Chondroitin Sulphate – The most common arthritis remedies at the present time. There is some early evidence that over time they may help to maintain articular cartilage and slow progression of Osteoarthritis. Nothing can ‘put cartilage back’ after Osteoarthritis is established. Some people also report a reduction in arthritis symptoms when taking these substances. Their main side effect is diarrhoea. They should not be taken if you are pregnant or allergic to shellfish.
- Fish oils – Have been associated with some improvement in cartilage quality and may be beneficial.
- Anti-inflammatories (NSAID’s) – Several types of Non steroidal anti-inflammatories are available. They can be very effective in reducing pain and swelling associated with osteoarthritis. All these medications have potential side effects and are not always tolerated. The most common effects are: exacerbating asthma, stomach upset (ulcers etc), increased blood pressure and ankle swelling.
- Weight loss – There is no doubt that if you are above ideal weight, weight loss can have a significant impact in reducing pain from osteoarthritis. Weight loss can also reduce the risk of anaesthetic complications and wound healing. Many people after loosing weight no longer need surgery for their Osteoarthritis. You may be given an ideal weight to attain prior to consideration for surgery. Consulting a dietician may be beneficial.
- Injections – A hip injection is often used by your specialist to differentiate between back pain and hip joint pain. An injection is given to ‘numb’ the hip and you then keep a record of the pain experienced. Sometimes steroids are used to provide longer relief of pain. The procedure is done under X-ray guidance with a small risk of infection.
If you have later stages of osteoarthritis, your hip joint hurts when you rest at night, and/or your hip is severely deformed, your doctor may recommend total hip replacement surgery, known as an arthroplasty.
Hip replacement surgery is hugely successful at relieving pain. The technique has been used now for over fifty years. Over ninety percent of patients who have their hips replaced are delighted with the outcome. The damaged joint is removed and replaced with an inanimate bearing and pain relief is very predictable. Range of motion is less predictable and depends on how the soft tissues around your hip heal up after surgery and it is mainly dictated by how stiff your hip was before the surgery. Effectively if you had a stiff painful hip before the operation you should a stiff painless hip afterwards.
Metal on Metal hip replacement
Metal on Metal hip replacements were developed in Birmingham in the 1980’s and became very popular in the 1990’s. Various companies developed new designs of resurfacing type hip replacements; see X-ray.
More recently a lot of metal on metal hip replacements were inserted in the York area and unfortunately these were of the DePuy ASR variety. This implant has since been withdrawn due to complications of high metal ion levels within the patients’ blood and loosening of the implant and loss of muscle bulk and bone due to an adverse reaction to the metal ions.
Due to the high number that were put in in York I have developed a very large experience now of revising these implants.
This X-ray shows a resurfacing on a stem on the left and a full resurfacing on the right.
When I revise these hips I aim to give a stable hip joint with a metal against plastic bearing and with this I have been successful in removing pain and discomfort and correcting metal ion levels in these affected patients.
Rehabilitation is important to restore the flexibility in the hip and work your muscles back into shape.
Hip replacement surgery, whilst being one of the most successful operations in the whole of surgery, is still a major operation with complications.
There are risks of:
- Leg length discrepancy
- Infection causing early loosening of the components and wear of the components.
- There is also a small risk of blood clots in the legs (DVT).
Nonetheless, the vast majority of patients are delighted with the outcome because their pain goes and they can expect at least ten to twenty pain free years before further surgery is necessary.
Failure of Hip Replacement
Hip replacements can fail in the early stage because of infection and this can occur within the first two years and requires further surgery to remove the infection and then implant a new hip.
A previously well-functioning hip replacement that then becomes painful in later years fails either because the bearing surface wears out or the implant becomes loose from the bone.
As can be seen in this X-ray here – the plastic bearing is actually very thin at the top.
This presents with a hip replacement that was pain free for many years and then pain develops in the groin and the thigh. This X-ray shows the left hip socket has actually flipped out of the bone altogether. In this example, the stem is loose from the cement and has sunk within the bone, the cement has fractured and the femur is weak (lytic):
With aseptic loosening and wear of the component the only treatment option is surgery and this is very commonly done and very successfully done and I spent a very enjoyable year in Toronto, Canada working for a world expert in revision joint surgery.
This X-ray shows how the loose joint can be replaced and the area of thin bone can be bypassed with modern contemporary devices: