A number of different injections can be used when treating knee and hip problems. Some help to precisely diagnose your hip or knee pain and others are used to actually treat your pain.

So what types of injection are available?

Local anaesthetic injections (for diagnosis of difficult cases)

Sometimes pain felt in the hip or knee region can actually be coming from somewhere else completely and not from the hip or knee at all. A common site that mimics pain coming from the hip or knee is the spine. It is also common for knee pain to be mimicked by hip joint problems, a condition called referred pain. When there is a possibility of the pain being mimicked, it is vital to find the real site of pain so that the right area is treated.

In these cases Mr Sood performs an injection of long acting local anaesthetic into the joint that is painful, usually with ultrasound guidance. If the pain disappears, then the injected joint is definitely the site of pain. If not, the true source of pain being felt needs to be found.

Steroid injections

These are used to treat inflammatory joint pain and swelling, caused by the lining of the joint becoming inflamed.  This is called synovitis.

Although many doctors recommend and give these for wear and tear arthritis, we do not use steroid injections to treat hip or knee arthritis pain as, at best, these have a temporary suppressive effect and, at worst, no effect at all. We believe that other much better injections exist. Also, if a patient has severe arthritis and might need a joint replacement in the near future, such steroid injections can increase the risk of infection in the replaced joint which is a dreaded complication.

Hyaluronic acid (gel) viscosupplementation injections

Arthritic joints lack hyaluronic acid (HA), which is normally found in joints. HA is thought to be one cause of the pain that occurs in arthritis. In most patients, an injection of HA can ease the pain of knee arthritis for anything between a few weeks and a few months. Indeed some of our patients have one injection a year and have been maintained on this for a few years. This has been a wonderful option for their arthritis and is independent of the severity of arthritis. Mr Sood has used such injections for over 10 years and has a huge experience as a result.

Mr Sood also uses HA injections for hip arthritis and has had good success with most patients getting significant relief of pain. In hip arthritis the injections make pain more manageable and so can delay the need for surgery for some time. However, with severe arthritis, a hip replacement will usually be needed in due course.We have a few patients who cannot have a hip replacement because of severe medical problems and they are grateful for the pain relief provided by HA injections.

It is important to be aware that not all patients benefit from gel injections and that it is not possible to predict who will and who won't be helped.

Platelet-rich plasma (PRP) injections

These injections harness the healing effect of platelets that are found in blood.  The process is quick and easy.  A sample of blood is taken from the patient, the blood is spun down in a centrifuge and the platelet-rich fraction is injected into the knee or hip.

Mr Sood uses these injections in selected patients with knee arthritis. We have had good results in most patients and there is increasing evidence for the usefulness of this type of injection in easing pain and reducing the progression of arthritis.

These injections are also used to treat tendon pain where simpler non-invasive treatments haven't worked.

Stem-cell injections

These are an exciting possibility in hip and knee arthritis, but the evidence for this type of injection has not yet reached the threshold for us to offer it to our patients routinely. We are continuing to monitor the latest research. Watch this space

Thus a variety of different injections can be used to treat hip and knee pain. Further research will identify more pain-relieving injections. One day we might even have injections available that do more than just relieve pain. They might even help to prevent or reverse the joint damage or wear in the joint.  This is an incredibly exciting possibility but we are not there yet.

Some people with knee arthritis worry more about having a knee replacement than those with hip arthritis do about having a hip replacement. Why is this? Well the worry usually arises when people talk to others who have had a knee replacement or know someone who has had a knee replacement that hasn't gone so well. But that's not the whole story. As with most things in life, there can be some truth behind the concerns, but it is also true that modern knee replacements done by experienced specialist knee surgeons give reliable results in a vast majority of patients.

So what concerns do people have?

It doesn't always work

If patients have a knee replacement done for the right reasons, at the right time by the right (specialist) knee surgeon and have the right rehabilitation afterwards, then a predictably good result is the norm.  What is true is that whilst a well done hip replacement tends to work well in most people and requires relatively little rehabilitation,  knee replacements are more difficult to get right.

A specialist knee surgeon should take the time to talk to you in detail about your pain and its effect on your life, examine you and look at appropriate xrays. This will allow an accurate diagnosis of your condition and what treatment is required. Knee replacement may sometimes be delayed because pain is not yet bad enough and it is important that your surgeon replaces your knee when it needs replacing and not before. Otherwise there will be a danger that, at best,  the relief of pain won't be as expected, and at worst, should you suffer a complication, you will regret having the procedure done.  Where replacement surgery isn't required because things aren't bad enough yet, other treatments should be offered to help with ant pain that exists.

When the time comes to have a knee replacement, patients can rest assured that it is a reliable and successful operation provided it is performed by a surgeon who is specially trained and skilled in knee replacement surgery. Knee replacement is technically more difficult to get right than hip replacement and this is one important reason why some patients have poorer results than others. A surgeon who does a good number of knee replacements will tend to have better results, but this is not the whole story. Planning the surgery carefully in advance, meticulous attention to detail during the procedure, using specific techniques to make the replaced joint perform perfectly and supervising rehabilitation afterwards are all absolutely essential. The surgeon should also be meticulous about measures to prevent complications including infection. The result will then be predictably good in a vast majority of patients.

It is a very painful procedure

Modern knee replacement involves paying careful attention to keeping patients comfortable at all stages. Some pain will undoubtedly be experienced but this should always be manageable. It is controlled by appropriate medication and by regular icing.

Patients have little pain relatively speaking,  after a hip replacement, but after a knee replacement things differ because the knee is a very different joint. The knee can swell and feel tight and stiff. The arthritic pain disappears straightaway but is replaced by a tight stiff pain for a period of time. Patients also have to work to gain a good knee bend. There is no doubt that things differ from patient to patient, but another important factor is how well the surgery is performed including how carefully the tissues are handled, how the replacement is positioned and even how carefully the wound is closed. Some surgical techniques can help the knee feel more natural after the surgery and allow patients to progress very quickly with minimal pain.

All patients can expect to be walking on the day of surgery or certainly the morning after. Most of Mr Sood's patients go home on the second day after surgery and are mobile, have a knee that bends well and have good pain control.

A lot of physiotherapy is needed afterwards

Physiotherapy is certainly needed afterwards, usually 6-8 sessions, but well performed surgery makes the physiotherapists job much easier as movement is regained quickly and strengthening of muscles occurs more quickly.

It is important that your surgeon also partners with you in your rehabilitation and recovery. This should involve reviewing your progress and identifying what is amiss if things are going more slowly than usual to help you get back on track. Liaison with your physiotherapist as necessary is also important.

When movement is not regained as quickly as necessary it is sometimes necessary to manipulate the knee under a brief anaesthetic. This should not be needed very often. As a guide, Mr Sood manipulates on average one of his knee replacements a year (less than 1%).  High rates of manipulation are more common with knee replacements that are performed by non-specialised Orthopaedic surgeons.

The knee won't bend like before

In general, a well performed knee replacement should bend as much as the knee did before the replacememt. In cases where the knee bend is poor before surgery, special techniques during surgery should allow the amount of bend to be improved, sometimes very significantly, but again your surgeon needs to be skilled in dealing with such problems.

I won't be able to kneel

This is an interesting one. In fact there is no reason why patients can't kneel after a knee replacement. This is the case whether or not the knee cap is resurfaced. Kneeling does not damage the replacement in any way. Some people are able to kneel without any issues whereas others don't. Studies show that 60-80 % of people can in fact kneel after total knee replacement when encouraged to do so and reassured but that only 40-50% of people kneel without such encouragment.  There are a number of  possible reasons for patients not kneeling. Some patients are given conflicting or unclear advice about kneeling by others and so are fearful of kneeling. Others avoid it because it doesn't feel right. This may be because the knee doesn't bend enough to allow proper kneeling or can relate to the sensation over the skin on the front of the knee being slightly altered, a common and unavoidable consequence of having a surgical cut over the front of the knee.

Once more the influence of having surgery performed well so that a good bend is achieved is underlined.

Mr Sood encourages patients who want or need to kneel, to try to kneel regularly and often gets his patients to try this in clinic when they attend for follow-up so that they feel safe and reassured.

Conclusion

You can be reassured that a predictably good result after knee replacement surgery can be expected if the circumstances are right. Assessment should be detailed and knee replacement surgery offered appropriately and at the right time by a specialist knee surgeon who understands how to do the operation well. Such a surgeon will be able to achieve good results even in more complex cases by planning the procedure and employing specialist techniques where necessary. Choose your surgeon carefully. If the same surgeons name comes up repeatedly from people who have had good results, this can be an important way to help make the choice. It is also important to see a surgeon who can offer the whole range of treatment options and doesn't recommend knee replacement surgery before it is necessary.  Good luck.

I am often asked whether running will cause premature development of knee arthritis. Many of my patients are very keen runners and, whilst they want to continue is to run, they also want to save their knees. Some also already have early joint wear.   I have always given my patients the same advice. So long as their muscles are in good shape and their knees don't react by swelling or becoming painful after running, the health benefits of running will almost certainly outweigh the risks.

I am aware that many doctors advise such people (without good  evidence) to stop running, and I have always disagreed with such blanket advice for all. At best it is wrong and at worst it deprives keen runners of something that they enjoy and that brings them physical and mental benefits. Humans are designed to be active, and the positive effects of being active are in the news more now then ever.

Now, the specific question about whether running can cause knee arthritis in healthy individuals has been looked at in a good study. The researchers measured the levels of harmful inflammatory chemicals in the knees of healthy runners aged between 18 and 35 before, and after they had run for 30 minutes. They found that the levels of these chemicals went down after running, but not after 30 minutes of other non-running physical activity. It therefore seems that running is actually chondroprotective ie. it prevents cartilage damage and wear.

Is this also true in older runners?  Another study comes to the rescue. Researchers compared middle aged to older-aged long distance runners with a mean age of 58 years, to a group of healthy non-runners of the same mean age.  The study looked at progression of arthritis on xrays taken at regular intervals.  They found that there was no difference in the amount of arthritis in both goups, so running did not increase the likelihood of getting arthritis in older people. So even older people can enjoy the health benefits of running without worrying about their knees.

So I feel happy to continue to advise my active patients to keep running!