Anaesthetics patient guides for patients needing knee and hip surgery

Anaesthetics

The vast majority of surgical procedures require some form of anaesthesia. There are several different types of anaesthetic, each of which can be used in different circumstances. Modern anaesthetics of all types are very safe and it is often more of a question of choosing which type of anaesthetic will help the surgeon perform the procedure and the patient to make the quickest recovery.

Anaesthetics fall into three main categories:

Local

Local anaesthetics can be administered by either the surgeon or the anaesthetist and are delivered into the tissues surrounding the site for the operation. Most dental procedures are carried out under local anaesthetic. Although the initial injection of the anaesthetic can be slightly painful, the rest of the procedure should be completely pain free and has the added advantage that the pain relief will persist for some hours afterwards.

LIA (Local injection of Anaesthetic)

Pain control after local anaesthetic is normally quite good. This has led surgeons to try a more widespread use of local anaesthetic around larger operation sites purely for post operative pain relief.

Using a cocktail of drugs which reduce pain mixed with local anaesthetic and adrenaline, very good long lasting pain relief can be achieved, say following major joint replacement. The reduced need for stronger pain killers, reduction in bleeding and earlier mobilisation is now becoming the norm and is a factor contributing to Rapid Rehabilitation.

Regional

Regional anaesthetics also use local anaesthetic but it is injected around the nerves which supply sensation to the operation site.

These give a wide area of numbness at the operative site which again persists several hours after the procedure

Included in this group are epidural anaesthesia and spinal anaesthesia. Both of these categories rely upon injecting local anaesthetic around the spinal cord. The epidural technique uses a small tube which can be left in for one to 2 days after the procedure and can be topped up, reducing the amount of post-operative pain medication. Epidural anaesthesia is often used in such procedures as Caesarean section and childbirth, but have also been used quite commonly orthopaedic procedures.

Spinal anaesthetic uses a much smaller needle to deliver a single dose which will give enough cover for the operation and some hours afterwards but cannot be topped up. It is much easier and less painful to administer and is the anaesthetic of choice for most joint replacements in the lower limb.

General

General anaesthesia refers to the situation when the patient is temporarily put to sleep for the course of the operation and indeed can be combined with some of the regional anaesthetic techniques. Some procedures cannot be performed under local or regional anaesthesia and therefore need a general anaesthetic.

Advantages:

Modern anaesthetics are extremely safe! It has been said that there is a greater risk in driving a car in a modern city than having an anaesthetic, although we all do this quite frequently.

Some patients do not like to be aware during a surgical procedure. Although sedation is given in combination with the regional anaesthetic, some patients simply do not like the idea of being awake and opt for general anaesthesia. There are of course some procedures which cannot be performed under local anaesthetic.

Disadvantages:

Unless some form of regional anaesthesia is given at the same time, post-operative pain has to be controlled by drugs which have side-effects such as nausea and drowsiness. Some patients may also suffer from significant respiratory illness were anaesthetic drugs cause irritation to the lungs and difficulty in breathing.

There are some medical conditions which do increase the risk from anaesthesia and where possible local or regional techniques will be used in this group, however even with quite significant heart or chest disease, anaesthetic problems are extremely low and very rarely are of significant concern to avoid or recommend against surgery

Your anaesthetist will see you prior to your surgery, assess your condition and discuss the options available with you . As there are several possible choices you will be guided as to which may be the best, but ultimately it would be your choice which type of anaesthetic to have.