The actual knee replacement surgery process

Steps that the knee surgeon will take when performing a knee replacement on a patient.

First published in 2009, and reviewed August 2023 by Dr Sheila Strover (Clinical Editor)

 

It is good to know what are the steps involved in and around surgery.

A well informed patient in a happy patient who can participate in the treatment journey effectively making a win-win situation. Rehabilitation is that effective if patients know what is expected of them making the recovery relatively easier.

 

Using a tourniquet

I usually do use a tourniquet, but sometimes I don't and I will explain why.

There are two schools of thought. A surgeon may use a tourniquet for clear vision - if blood is not in the field they can perform the surgery properly. Another reason the surgeon might use a tourniquet is when cement is usually applied to the bone - at the stage of cementation of the prosthesis the sticking of the cement to the bone is usually quite good. The surgeons who don't use a tourniquet do so to be kinder to the patient, because a tourniquet usually is inflated at about 350 mm of mercury, and if it was pumped up and left on the thigh for say and hour and a half that can cause a lot of pain. Secondly, if a tourniquet is used and it is released after the wound is closed haematoma (blood collection in the muscles) can occur and that can be a complication in itself. If the surgeon does not use a tourniquet this kind of complication does not arise. I sometimes get asked about DVT (deep vein thrombosis). I don't think there is any concrete evidence to say that a tourniquet either causes or avoids a DVT.

 

Ensuring sterility

Sterility is to keep the joint clean. Infection is a devastating complication of a Joint Replacement for both the Patient and Surgeon.

Prophylaxis (prevention) is better than cure! I take infection very seriously and hence spend a long time to identify and treat any infections before knee replacement. Remember Knee Replacement is an elective procedure and can wait until the health of the patient is optimised.

Measures to avoid infection before surgery:

1. Treat existing infections in the body like chest infection, urine infection, toe nail infection, dental infection.
2. Take good care while paring toe nails to prevent inadvertent cuts.
3. Don`t work in the garden or DIY from at-least 2 weeks prior to surgery. Cuts and grazes can be a reason to defer surgery.
4. Infection is commoner in patients suffering with Diabetes, Psoriasis,Transplant recipients and long term steroid therapy.
5. notes

 

The incision

Placement of incision: Majority of the surgeons would place the incision in the midline or just to the inside of the midline. There are some surgeons who place the incisions on the outside of the midline.

Size of the incision: In my opinion the size/ length of the incision does not make a huge difference to the long term survivorship or function of the replacement. There is evidence to suggest that if the trauma to the tendons (quadriceps) is minimised, the Early rehabilitation is quicker and patients do better. This however does not reflect on any long term advantages as the function is comparable in knees treated by minimally invasive or traditional incisions by 4-6 months time after surgery.

 

Dislocating the kneecap

Dislocating the patella (knee-cap)has been shown to affect the strength of the tendons and hence surgeons these days push the patella laterally rather than evert it.

 

Making the bone cuts

Surgeons use mechanical alignment jigs to cut the tibia and femur. Recently Navigation has been commonly used to align the knees better. This however is cumbersome, time consuming and surgeons need special training to navigate knee replacement.

Other steps include -

1. Checking prosthesis size and left or right
2. Fixing the prosthesis in place
3. Checking that everything is optimal
4. Closing up the wound
5. Dressings and drains

 

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