Pain:

Whilst pain after major surgery is expected, this usually improves with time. You will also receive plenty of painkillers to manage this. Information on how to access regular strong painkillers will be provided by nurses on the ward during your stay in hospital. On discharge, you will also be provided with an adequate supply of painkillers to take home. You can of course contact the hospital for more help if needed. 

Severe relentless pain is extremely unusual following a knee replacement. In these cases, the surgeon will be alerted to rule out any unusual causes such as nerve damage or excessive bleeding causing a haematoma (blood clots in the soft tissue) etc.

Infection:

Despite performing surgery in an extremely clean theatre, with the use of antibiotics and a strict aseptic technique, approximately 1 in every 100 individuals can develop a deep infection. The wound site may become red, hot, painful and occasionally discharge pus. Additionally, individuals may feel unwell, have a temperature and in some cases become septic. In these instances, it is important to report to the treating team immediately and follow their advice. It may be necessary to undergo further surgery such as a washout or in severe infection, removal of the original prosthesis and re-implantation of a new prosthesis.

joint stiffness:

Stiffness is one of the common reasons for dissatisfaction and poor outcome. Active engagement with a physiotherapist and regular exercise following surgery is vital for a successful result. Physiotherapists will keep a close eye on the progress and keep the surgeon informed of any concerns. To help with stiffness, manipulation of the knee joint under anaesthesia may sometimes be required. In extreme cases, revision surgery may be necessary.

Bleeding:

Bleeding is common during major surgery. It is usually minor and will be attended  by the surgeon during surgery. However, a very small number of individuals may bleed more than usual, requiring iron tablets or blood transfusion after surgery. As mentioned before, increasing pain and significant bruising at the surgical site could indicate the presence of a haematoma (blood clot in the tissue), which may need surgical removal.

Deep vein thrombosis:

(Blood clots in the veins)

The risk of clinical deep vein thrombosis (DVT) is small. Hot, red, hard and painful areas in the leg a few days or weeks after surgery may indicate a DVT. As DVT is a recognised complication after knee replacement surgery, patients are requested to wear a compressive stocking around their leg before and after surgery, unless there are any contraindications. In addition, they will receive either a foot or calf pump; a mechanical device that helps to maintain blood flow inside the veins. They will also receive blood thinning medication 12-14hrs after surgery, and this will be continued for 6 weeks. Despite all these measures,  it should be noted that a small risk of DVT still remains.

Pulmonary Embolus (PE):

PE is caused when a portion of a DVT breaks off, enters the blood stream and gets deposited in the lungs. PE can cause difficulty in breathing, chest tightness and chest pain. Whilst it can be fatal in an extremely small number of cases, it is generally treated successfully with blood thinning medication.

Nerve and blood vessel damage:

The risk of damage to the nerves and blood vessels around the hip are extremely small. 

Nerve injury could result in decreased sensation, numbness or significant loss of function of the affected muscle. Blood vessel injury could result in severe bleeding requiring the input of vascular surgeons.

Fracture:

Fracture of bones (femur/thigh bone or tibia/shin bone) is a rare complication following knee replacement. Additional fixation of the broken bone may therefore be required, potentially extending the  duration of rehabilitation.

Longevity of prosthesis:

It is reasonable to expect a knee replacement to last 10-15 years. The younger the individual, the greater the chance of requiring a revision (re-do) operation in their lifetime.

Death: 

This extremely rare complication can occur from any of the above surgical complications or   from an anaesthetic complication.

For more information on risks involving knee replacement surgery, please visit the useful links section.