How to manage pain after joint replacement surgery

Knee replacement surgery is a reconstructive procedure that is performed when the joint has worn out, with the goal of allowing pain-free movement in the knee. After the operation, the patient will start their rehabilitation program and as they learn to carry out their daily activities and begin to exercise, their medical team will want to ensure that they are as comfortable as possible.

Leading orthopaedic surgeon Mr Fahad Gulam Attar explains how post-operative knee pain is managed with the help of an anaesthetist to ensure that the patient has a successful recovery.
 

How do you measure how much pain a patient feels?

We sometimes use a pain rating scale where 0 equates to no pain and 10 is the worst. We ask the patient to rate their pain on this scale, as it helps us to measure the success of the medication in reducing their pain to an acceptable level.
 

What are the different options for pain control?

The anaesthetist will discuss the following options:

1. Oral pain medication (multi-modal analgesia)
There are several different types of oral pain medication. The patient is given these pain pills on a regular basis, which is known as multi-modal analgesia. Each tablet works differently on the body and reduces the need for stronger medication, such as morphine.

2. Nerve blocks
A nerve block is an injection of local anaesthetic (or “freezing”) medication near the nerves, which then gives sensation to the surgical site. This makes the area feel numb and pain-free for several hours and can be used along with a spinal or general anaesthetic. A small tubing is left in place in some cases to provide a continuous flow of freezing medications for pain control, which lasts longer than 24 hours.

Nerve blocks reduce the amount of other pain medication needed and avoid side effects such as nausea, vomiting and drowsiness. The patient may be able to eat and drinker sooner after their operation, especially if the general anaesthetic is avoided. It provides long-lasting pain relief with minimal side effects.

3. Patient-controlled analgesia (PCA)
PCA is a pump containing pain controlling medicine, which connects to the patient’s intravenous (IV) line and provides fair rapid pain relief. It delivers liquid substances directly into a vein, safely and effectively, as the patient pushes a button when they experience pain. The pump beeps every time it delivers a small dose of medication. It is programmed to allow pain medication every five minutes, with a maximum dosage allowed per hour. The dosage of medication can be adjusted if the patient lets the nurse know how well their pain is controlled.
 

Are there any risks of nerve blocks?

Motor block is the most common risk, where the limb feels numb and heavy but means that the block is working. It less common to have bleeding or bruising after the injection and to have failure of the block working at all. It is rare to have nerve injury, where weakness in the nerve could last up to six weeks and very rare to have permanent nerve injury.

It is extremely rare to have local anaesthetic toxicity, which is where the injection into the blood stream causes ringing in the ears and a metallic taste in the mouth. These symptoms are not harmful and will go away but it is recommended to let the anaesthetist know.
 

What advice can you give to a patient about pain management?

Good pain control is important to allow you to exercise and recover successfully.