AKA Knee pain, Steroid injection, PRP injection, Hyaluronic acid injection
Knee pain is a very common condition that affects patients of all ages and accounts for a large number of visits to the GP in the UK. Certain types of knee pain can be alleviated with injections.
The underlying cause for knee pain varies according to different age groups.
Osteoarthritis is by far the commonest cause of knee pain in the middle aged and elderly. It is usually a ‘wear and tear’ process that starts as an occasional ache and proceeds to persistent pain that affects all aspects of daily living including sleep. Sometimes, a simple trauma or twist may start the pain especially at early stage of the disease. Treatment very much depends on the amount of arthritis present in the knee. It varies between pain killers, physiotherapy, knee supports, different injections, key hole cleaning (arthroscopy) and finally a knee replacement.
Knee pain in young adults is usually from an injury or accident (most often sports related). It is caused by damage to one or more of the supporting structures of the knee, such as ligaments and meniscus (shock absorber cartilage disc). Treatment depends of the severity of injury and may result in surgery. Knee injections can be used in less severe cases or in patients with persistent pain following surgery. Knee pain can also be as a result of mal-alignment of the patella (knee cap) and trauma.
What are the different types of knee injections?
There are three types of injections that can be used in the knee joint:
This is the most common joint injection and is used to treat conditions such as osteoathritis. Local anaesthetic is used to numb the area and then the drugs, ususally Depomedrone or Tramcinolone, are administered via injection. Cortisone and corticosteroids are strong anti-inflammatory medicines that helps to reduce pain and swelling in the knee joint.
Viscosupplement (Hyaluronic Acid - HA) injection
Hyaluronic acid is a natural chemical that is present in all joints to provide lubrication to the cartilage and allow smooth, painfree movements. Viscosupplement injections are usually used in conditions where the knee joint is painful but still reasonably healthy from inside, such as early stage arthritis and knee pain following injury or surgery. Synvisc and Ostenil are the most common injections used.
There are numerous injections that fall into this category. In general, it involves injecting a biologically active (live) substance into the joint to treat the pain and achieve some tissue healing to repair any damage.
The most common type is the PRP (Platelet Rich Plasma) injection. The patient’s own blood is removed and specially prepared to extract plasma with platelets. This is then injected back into the patient’s knee joint. The platelets produce specific chemicals that are essential for body’s natural healing process. A large concentration of these chemicals can lead to healing of damaged tissue and provide long lasting pain relief. Other injections in this category are Stem cell injections (either from bone marrow or fat cells) and nStride. Sometimes more than one injection may be needed to achieve better pain relief.
Which injection is suitable for my knee?
The type of injection and the result depends on the nature and severity of the underlying condition. Your consultant will discuss the options available to you during your consultation.
Can an injection replace the need for knee surgery?
It depends on how severe the problem is. Injections work best in early stages and can provide pain relief for a few months. They can help in delaying, and in some cases avoiding, surgery for reasonable amount of time. Injections can be used for pain relief while waiting for more definite surgery especially in the current climate when the NHS waiting list is getting longer.
Can I have injections while waiting for knee replacement?
Yes you can, but joint replacement should be avoided for at least three months following a steroid injection. This is because there is increased risk of infection in joint replacement if done too soon after steroid injection. This is not the case with other types of injections.
How long can I expect the benefits of the injection to last?
The benefits from a steroid injection can last for approximately three to six months. HA and PRP injections can last for much longer but it very much depends on the severity of disease.
How many injections can I have in a joint?
There are no limits but steroid injections shouldn’t be done too frequently as they can become less effective with time. HA and PRP injections can be repeated at shorter invervals and are often recommended to achieve better results.
What are the risks of knee injections?
Knee injections are a very safe procedures and are done in a clinic setting. There is a very small risk of infection (one in few thousand cases). Occassionally the knee may become more sore after a steroid injection but this usually settles within 48 hours.
Can you guarantee that the injections will work?
The pain relief achieved with injection depends on how bad the problem is. Injections work best in early stages of disease. As the disease becomes more severe, the duration of pain relief shortens. In small number of cases, the injection won’t make any major difference. Unfortunately, there is no way to find out beforehand who these patients will be. For this reason, it is always better to try these before moving on to next line of treatment which is surgery.
Can I have an injection if I am diabetic?
If you are diabetic, steroid injections may affect your sugar levels for few days and it is advisable to monitor your the levels more carefully. This usually settles on its own. Other injections don’t affect the sugar levels.
Can I drive after an injection?
Yes you can. The use of local anaesthetic with a steroid injection makes the knee pain free for few hours allowing you to drive comfortably on the same day. HA and PRP injections can take few days to start working.
Can I have injections on the same day of consultation?
Yes you can have a ‘one stop appointment’. The consultant will examine you and discuss the various options to you. Then if you wish to proceed, you will fill out the relevant medical consent forms and confirm you have read the terms and conditions. The injection will then be administered in the same appointment.
Are there any additional risks with injections during COVID-19 pandemic?
A steroid is considered to be an ‘immuno-suppressant’ drug meaning that it can reduce your immunity to fight infection and makes you more susceptible to catch any infection (including COVID-19) for a few days after. Steroid injections seem to have smaller effect on immunity than tablet forms. It is advisable to follow appropriate precautions as per government guidelines for couple of weeks after injection. No such risks are associated with HA or PRP injections.
What after care do I need following injection?
There are no specific restrictions required after injections but try and avoid strenuous activities such as running, jogging, heavy gym exercises and sports for two to three weeks. If you experience worsening pain or swelling, use simple pain killers and and an icepack. If you develop a high temperature with redness and swelling of the knee joint, contact us immediately for medical advice. If it is out of hours, then please call the on call nurse. This is so we can rule out an infection.
Are knee injections available on the NHS?
Yes, steroid injections are available on the NHS in certain circumstances but you would need to have a referral from your GP. Unfortunately, HA or PRP injections are not available on the NHS.