Knee and Hip Replacement

What are knee and hip replacements?

The knee is a joint complex held together with muscles, tendons, and ligaments. Each bone end is normally covered with protective cartilage. Major bones in the knee include the tibia or lower leg shin bone, the femur (thigh bone), and the patella (kneecap). Medical specialists called orthopaedic surgeons aim to relieve damage to cartilage and bone that restricts movement and causes pain.

Knee replacement surgery¹, also known as arthroplasty, is a very common procedure to treat knees affected by arthritis. It can help patients who experience degeneration of cartilage in the knee. The replacement may be partial or total, or only applied to the kneecap.

Similarly, during hip replacement surgery performed by an orthopaedic surgeon, diseased or damaged parts of the hip joint are removed and replaced with new artificial parts. The main objective is to relieve pain and improve walking and movement. Exercise after surgery can improve muscle strength and range of motion.

When should I see a specialist for a knee or hip replacement?

Patients who have suffered arthritis or severe injuries may consider knee replacement surgery. The procedure can also be a revision knee replacement for patients who have had previous knee replacement surgeries. People with knock knees, bowed legs, knee injuries, or a loss of blood flow to the bones may opt for this procedure.

Hip replacement is an option for patients who suffer from severe arthritis which dramatically limits their quality of life on a daily basis. Persistent pain that does not respond to medication or other therapy is also a reason to consider a hip replacement.

Did you know?

The Risk Assessment and Predictor Tool (RAPT) is a pre-operative tool designed to predict postoperative discharge destination and length of stay for patients undergoing total knee replacement (TKR).

What are the risks of a knee and hip replacement?

As with any surgical intervention, there are some potential risks involved in both knee and hip replacements.

Some of the potential risks associated with knee replacement are:

● Blood clots in leg veins or lungs post-surgery³⁴.
● Nerve and tissue damage.
● Pain.
● Infection of the surgical site.
● Bleeding and wound haematoma.
● Failure of the new joint, requiring replacement.

Some of the potential risks associated with hip replacement are:

● Blood clots in leg veins post-surgery.
● Infection at the surgical site, which can become serious if it is near the new joint.
● Fracture of other, healthy parts of the hip joint during surgery.
● Dislocation of your new joint may occur from time to time.
● Change in leg length may occur with the replacement of the joint.
● Loosening of the new joint, causing pain and discomfort.
● Failure of the new joint, requiring replacement.

How should I prepare for my appointment?

Our orthopaedic surgeons at Mount Elizabeth Medical Centre will choose the knee design that best suits your weight, height, and daily routine, as no two people are alike. Some implants are even specially made to fit women, and come in various materials and shapes.

Talk to our specialists about the benefits of knee replacement procedures, and find out if they are an appropriate treatment option for you or your loved ones.

If you are considering a hip replacement for you or a member of your family, you can feel reassured that our team of orthopaedic surgeons will accompany you before, during and after your surgery. They will explain the procedure in detail, and provide clear indications for a successful recovery and the best possible outcome.

Be sure to raise any questions or concerns you may have in order to feel informed and reassured in the lead-up to your surgery.

What can I expect during a knee replacement or a hip replacement?

During knee replacement surgery², your orthopaedic surgeon may remove a damaged knee part and replace it with an artificial metal or plastic joint. The ends of your bones that make up the knee joint may be capped with metal or plastic parts customised for you.

Your experience of hip replacement surgery, will depend on whether your surgery is traditional or performed using a minimally invasive technique. During the standard procedure, you will receive a general anaesthetic while the surgeon cuts along the hip and the muscles to remove the ball part of the joint. This is then replaced with a prosthesis, using cement or other special material before being attached to the hip bone and inserted into the hip socket. In the newer technique, the same procedure is performed but using a minimally-invasive approach, with smaller incisions.

What happens after my knee or hip replacement?

After knee replacement surgery, a patient will normally stay in hospital for 3 to 5 days. Most patients will start walking independently, without walking aids, around 6 to 8 weeks post-surgery.

Your orthopaedic surgeons will suggest an exercise routine to help you regain the use of your knee. By the six-month mark, full recovery can be achieved depending on the situation, as scar tissue heals and muscles strengthen.

A new technique in hip replacement surgery offers a faster recovery, with patients more likely to be discharged earlier from hospital and back on their feet in a shorter time⁵. An added benefit is a return to a normal lifestyle approximately one month after their surgery. In conventional hip replacement, the recovery time is slower, with patients staying in hospital longer and generally able to return to a normal lifestyle 2-3 months post-surgery.

During recovery, it might be useful to make some adjustments in your home, such as:

● Handrails in bathrooms and bedrooms.
● Installing a shower bench.
● Using a reaching stick to grip items at home.
● Removing loose wires and rugs on the ground.
● Installing indoor clothes-drying racks.

Because you should not drive for a period of time during recovery, arrange for transportation options beforehand. A walker or cane may be advisable after surgery as well.

Having a friend or family member living with you to help out for a week after your operation may help you better focus on your recovery. Take note of your medication schedule, take pain relievers when needed, and follow your doctor’s bathing instructions to keep the wound area clean and dry.

With recovery and exercise under the advice of a physiotherapist, your new joint can last you 10 to 20 years. Patients can often cycle, play golf, or even swim as they regain use and range of motion of their knee or hip. It is very possible for you to regain your original quality of life, and maximise the time that you enjoy with your loved ones.

A/Prof Saminathan Suresh Nathan
Orthopaedic Consultant
Limb Salvage and Revision Arthroplasty Surgery Pte Ltd
Mount Elizabeth Medical Centre

Selected Specialist Publications
[1] Singh G, Han F, Kaki RR, Shen L, Nathan SS. Does Limited Tourniquet Usage in Primary Total Knee Arthroplasty Result in Better Functional Outcomes? Ann Acad Med Singapore. 2015 Aug;44(8):302-6.
[2] Singh G, Tan JH, Sng BY, Awiszus F, Lohmann CH, Nathan SS. Restoring the anatomical tibial slope and limb axis may maximise post-operative flexion in posterior-stabilised total knee replacements. Bone Joint J. 2013 Oct;95-B(10):1354-8. doi: 10.1302/0301-620X.95B10.31477.
[3] Nathan SS, Simmons KA, Lin PP, Hann LE, Morris CD, Athanasian EA, Boland PJ, Healey JH. Proximal deep vein thrombosis after hip replacement for oncologic indications. J Bone Joint Surg Am. 2006 May;88(5):1066-70.
[4] Nathan SS, Aleem MA, Thiagarajan P, Das De S. The incidence of proximal deep vein thrombosis following total kneearthroplasty in an Asian population: a Doppler ultrasound study. Journal of Orthopaedic Surgery, 11, no. 2 (2003): 184-9. (Hong Kong).
[5] Singh G, Lim CT, Jonathan TJ, Nathan SS. Evaluation of the role and cost-effectiveness of end-of-life orthopaedic interventions in cancer patients with skeletal metastases to the hip. J Palliat Care. 2013 Summer;29(2):83-90.