FAQs Knee Replacement

1. What are the complications of surgery?

As with all operations, it is very important that you fully understand the ‘pros’ and ‘cons’ before electing to proceed with surgery. Whilst the benefits are clear, time must be given to discuss ‘what can go wrong’.

The main risks of knee replacement include:

  • The main complication post-operatively is that of infection. It occur less that 1%.  In such cases the patient will develop a temperature, possibly with rigors and inflammation and redness of the wound in the early stages
  • Deep Vein Thrombosis(DVT) Or  blood clot, leading to pulmonary embolism (blood clot to lung) This risk is very small, less than half of one percent (0.2-0.4%)
  • Nerve or blood vessel damage during surgery
  • sensitive scar with permanent numbness on the lateral aspect of the scar.
  • Chronically painful knee replacement (of unknown cause)
  • urinary or chest infection

These may prolong your stay in hospital by a few days. They will occur in 2-4% of cases.

Whilst all of these complications are extremely rare, they can occur.

2. How long will I be in hospital for?

Patients usually stay in hospital for two days but this could be extended up to one week. During this time you will have daily physiotherapy.

Patients are ready to leave hospital when they can:

* Bend the knee to a right angle
* Manage stairs independently
* Walk independently with a stick

3. After knee replacement

  • In hospital, postoperatively, early knee movement, within the first 24 hours, is encouraged with:
    • Good analgesia. Often patient controlled methods. Epidural methods also commonly used.
    • Physiotherapy. Continuous passive motion machine may be used. Exercises taught. Most patients walk on the 2nd postoperative day.
  • Early discharge is encouraged after 2 days only if:
    • Wound healing is satisfactory
    • Mobility is satisfactory
    • Knee flexion of 90 degrees is achieved
    • No complications have been identified.
  • Orthopaedic follow up is usually at about 6 weeks in outpatients

4. After you go home you should continue exercising to strengthen and improve the range of motion of your new knee.

Although you should be able to get back to light work (such as a desk job) in about 6 weeks, it may take longer (3 months) to start doing more active work.

Don’t engage in strenuous activities like jogging, running, or active sports until your surgeon says so.

If you have any of the following after returning home call your surgeon or the hospital who will contact your surgeon:

  • Fever or high temperature.
  • sudden shortness of breath or chest pain.
  • increase in knee pain.
  • excessive warmth, redness, or discharge from the incision site.
  • swelling or pain of the calf or leg.

5. When and who will take my stitches out?

Sutures/clips in the skin will be removed at two weeks by your GP or at the hospital if preferred.

6. Will I require physiotherapy following my op?

You will need to see a physiotherapist regularly within the first few weeks post-op.

7. When do I see My surgeon again after hospital discharge?

All patients will be reviewed after six weeks to check on their progress.
The main concern is to ensure that the wound is healing well and that the swelling is beginning to reduce. However, you should expect the knee to be swollen sometimes for several months.

8. When do I recover fully from surgery?

Recovering from a total knee replacement operation takes time; sometimes it takes as long as a year for the knee to feel comfortable again.

Interrupted sleep, unfortunately, is normal in the first three months after such major surgery and you should be prepared for this.

9. When can I return to other activities after knee replacement?

  • Return to work. This depends on type of work, but may take up to 6 weeks.
  • Driving: if left knee replaced and automatic, then driving can be resumed as soon as 2 week after surgery. If right knee replaced 6 weeks off driving is to be expected.
  • Travelling.  Measures to prevent thromboembolic complications are recommended. We recommend avoid flying for 6 weeks.
  • Sleeping positions. Sleeping on back, side and stomach is safe any time.
  • swimming is recommended, usually from the time sutures are removed (about 2 weeks).
  • Dancing, golf , cycling (level ground)   6 weeks
  • Activities which stress the joint should be avoided  for 12 weeks ( for example: tennis, squash, jumping, skiing, jogging).

10. How long will my new knee last?

15 years, 90% of replaced knees will still be functioning correctly.

11. What is computer-assisted knee replacement?

A computer with specialized software is used in the operating room to assist the surgeon to achieve proper placement and alignment of the knee prosthesis. The system provides instant information on the boney alignment of the knee joint, the function and tensions of the ligaments required for knee stability, and the special cuts that must be made in the femoral and tibial bones to achieve a precise placement of the prosthesis.

12. Why was computer-assisted surgery developed?

The long-term results of knee replacement operations before computer-assisted techniques were developed have been very good. In fact, total knee replacement is one of the most successful operations performed in the human body. In many published studies, over 90% of the knee replacements were reported to be intact and functioning 15 years after surgery. However, not all knee replacement procedures are successful because the exact alignment desired at surgery is not obtained. There are many reasons that cause this problem and even the most experienced joint replacement surgeons may encounter this complication.
Total knee replacements require exact alignment and balancing so that weight bearing forces are spread evenly across the knee joint. An analogy would be correctly aligning or balancing a tire on a car so that that there is even wear over an extended period of time, and not excessive wear on just one side. The same is true of a knee replacement. The plastic insert is sensitive to abnormal pressures which could result in premature wear and possible failure of the replacement.

13. What are the downsides of computer-assisted surgery?

There is additional time, usually 15 minutes, that is added to the operative procedure. This is necessary to input the information and recheck that the computer is collecting the correct information it requires. It is possible that the surgeon will determine that the computer is not providing the appropriate data and convert to visual alignment methods. In this case, other instruments are used in the procedure to obtain correct alignment of the replacement.

14. What is minimally invasive surgery of the knee joint?

This term is applied when the surgeon selects a method in which the tissues about the knee joint are disturbed or cut in the least amount possible to perform the surgery.

In years past, the use of arthroscopic-guided surgery in the knee joint was considered minimally invasive as it allowed the surgeon to perform a great deal of the surgery through small incisions. Visualization through the arthroscope decreased the need for large incisions or any incision at all. A majority of ligament reconstructions and other knee repairs are now performed by surgeons trained in these arthroscopic techniques.

Knee replacements are now being performed using minimally invasive types of techniques. The instruments used during the procedure are smaller and the incisions are also smaller resulting in fewer disturbances of the soft tissues. The computer-assisted surgical technique allows in some cases the ability to use smaller incisions as the computer provides virtual visualization or navigation during the procedure.

Whenever the surgeon can minimize the incision or disturbance of soft tissues, generally there will be less pain after surgery and a more speedy recovery. Less pain medication is necessary and the patient is out of bed sooner and more frequently. The rehabilitation process is easier and the muscles regain their function faster. This has been proven in all aspects of knee surgery when these lesser invasive techniques have been applied.