What is it?
A hydrodilatation is, as the name implies, a treatment where a large volume of fluid (hydro) is injected into a joint to expand (dilate) it. Often, the aim is not just to dilate it but also to release areas that might have become stuck down and in doing so improve the movement. The injection is usually a mixture of saline, local anaesthetic and steroid.
What does it involve?
A hydrodilatation usually involves the insertion of a needle into a joint under ultrasound guidance. Initially anaesthetic will be injected to help with pain symptoms before the saline and steroid follow. Often it will require a clinician to guide the needle into position and an assistant to inject the fluid and maintain the pressure in the joint. As the volume increases, there will be stretching of the joint and this can be uncomfortable until the anaesthetic has taken its effect.
What can be treated?
Hydro-dilatations can be used to treat any joint that has become tight and stiff (frozen), however, for the most part it is used in the treatment of frozen shoulders.
What are the benefits, risks, and side effects?
Benefits include reduction of pain and an improvement in function.
Risks include those common to all injections which are infection, pain and bleeding at the injection site.
Common side effects include a temporary flare of the pain (typically 48-72 hours), thinning and whitening of the overlying skin, there can be a temporary increase in blood glucose, gastric irritation and for women there may be a change in the menstrual cycle or spotting afterwards. There can also be tightness and stiffness in the joint.
Others are possible but these need to be discussed on an individual basis.
What do I need to do afterwards?
It is important to offload the injection site and rest from activities for a period of time. Some patients find that a sling can be helpful after a shoulder hydrodilatation.
The time frame for recovery may vary on an individual basis, but most people, there is some benefit within 4-6 weeks.
What are the common misconceptions?
Steroids, included in the injection, are often given bad press due to the association with body-wide side effects and their close cousin anabolic steroids. While they may share some commonalities, if they are used carefully, with due consideration and careful discussion with your clinician, these injections can be an important step in your treatment with minimal risks to the individual.