Risks of Knee Replacement Surgery & Expectation Management Post Surgery

Risks of Knee Replacement Surgery & What to Expect Post Surgery


For most patients, knee replacement provides good pain relief and enables them to get back to a good level of function and enjoyment of life. However, all surgery is weighing up risks and benefits. Knee Replacement Surgery is offered when you anticipated benefit is high and your risks are considered low.


Expectations Post Knee Replacement

  • Knee replacement is not the same as your original knee when you were 20 or 30 years old. It is a good operation when your pain levels are moderate to severe, your ‘world is shrinking’ – i.e. it is getting harder to do the activities that you normally like to do, or it is interfering with sleep.
  • Most patients can be very active post knee replacement – Walking, hiking, swimming, cycling, travel, gentle tennis, gentle snow skiing etc.
  • High level activities such as soccer, AFL, intensive running, martial arts are usually not possible (Some patients will do these activities but most will not feel confident to do this).
  • Most patients do not like to kneel after knee replacement (You can try, it will not damage the prosthesis, but often the scar remains a little painful when attempting to kneel.
  • Numbness around the front of the knee is normal after surgery, this does not usually bother patients.
  • Most knee replacements make small amount of noise, this is just the sound of the metal on plastic and is not harmful.
  • Mild stiffness is common after knee replacement. Major stiffness or instability (wobbly) is uncommon.


Recovery after Knee Replacement

  • Seeing a Physio prior to surgery is important as it results in a faster recovery.
  • Immediate full weight bearing, and range of motion exercise is started in hospital.
  • Ice is useful – 15 minutes of icing every 2 hours is beneficial. Some patients like to rent the GAMEREADY ice and compression machine. Contact our rooms prior to surgery if you would like to rent GAMEREADY.
  • Most patients spend 3 – 4 nights in hospital.
  • Crutches are used for 2 – 6 weeks post-surgery.
  • Most patients are reasonable (60 – 70% recovered) by week 6. By 3 months most patients are good, best results can take up to 12 months post-surgery.
  • Recovery is often bumpy, you will have good days and setbacks, particularly in the early period. This is normal.


Risks of Knee Replacement Surgery

  • Infection – This is rare, around 1% risk. Deep infection requires an extended stay in hospital, intravenous antibiotics and revision (redo) knee replacement.
  • Bleeding – Significant blood loss is now very rare after knee replacement surgery. Blood transfusion is best avoided and is rarely used.
  • Injury to major blood vessels, nerves or ligaments – Injury to these structures is very rare but can occur despite our best efforts.
  • Stiffness – Mild stiffness is common. Significant stiffness requires a manipulation to free the knee up. Long term, major stiffness is uncommon but can be a difficult problem to treat. It is recommended you take 6 weeks of Vitamin C 500mg daily, and Vitamin D (Ostelin 1000) as these can help reduce stiffness.
  • Instability – Mild instability (feeling wobbly) can be treated by strengthening your muscles. Major instability is rare and requires revision surgery.
  • Revision surgery – In general, 80% of knee replacements will last at least 20 years. This is slightly higher in young patients, and much lower in older patients. The most common reason for revision is loosening of the prosthesis
  • Dissatisfaction post surgery – Around 5 – 10 % of patients have a degree of being unhappy with their knee replacement. Usually, they are still better than before surgery but they may not be as good as they hoped. Major dissatisfaction to the point of the patient regretting undergoing knee replacement is much less common.
  • Numbness – Is almost universal around the front of the knee and rarely troublesome.
  • Blood Clots – In the leg (DVT) or lungs (PE) can occur. Most are small and rarely troublesome. You will be on a blood thinner (Clexane) in hospital and will be sent home on Aspirin 100mg daily for 6 weeks. This can reduce the risk
  • Fracture – After prosthetic implantation is rare.
  • Medical risks – Heart attack, stroke, pneumonia etc. These are rare.
  • Catastrophic risks – Loss of leg, death etc. These are very rare.



Optimising your Health Before Surgery


Optimising your health prior to surgery will help give your best knee after surgery and will minimise the chance of complications.

  • See a Physiotherapist to start a Prehab program before surgery
  • Optimise your weight is needed – The CSIRO Low Carb Diet book is a good starting point, as is the Healthy Weight for Life program. Speak to Daniel’s secretary if your would like to access these programs.
  • Quit smoking
  • Optimise Diabetes / sugar control



If you have questions about the above, book an in person or phone consult with Daniel before surgery