Singapore Medical Specialists Centre 290 Orchard Road #09-23 to 27, 30/31 Paragon (Tower 2 Lift Lobby C) Singapore 238859
whatsapp +65 8838 7111 +65 6881 8000


If your knee pain is severe and due to Osteoarthritis, Rheumatoid or Post-Traumatic Arthritis then you may be suitable for a Total Knee Replacement (TKR). Younger patients or those with pain localized to part of the knee joint may be suitable for a Unicompartmental Knee Replacement (UKR).

Joint replacement can be an excellent solution for knee pain and lead to great improvement in peforming activities of daily living.

Causes of Knee Pain

Osteoarthritis – degenerative age-related wear and tear, leading to loss of cartilage, knee stiffness and deformity. This usually occurs in patients over 50 years of age, but may occur in younger patients. Younger patients may be more suitable for a Unicompartmental Knee Replacement Surgery.

Rheumatoid Arthritis – an autoimmune disease causing inflammation of the lining of the knee joint (synovitis) leading to joint destruction. This may affect many joints and body organs, and may occur in younger patients. It is part of a spectrum of conditions called ‘inflammatory arthropathies’ and is treated with the help of a Rheumatologist (medical joint specialist).

Post-Traumatic Arthritis – This can follow an injury to the cartilage or fracture of the bone. Over time more cartilage may be lost and degenerative change can occur.


    If your knee pain is severe and you have difficulty in walking, stair climbing, and have pain at night, you may be a suitable candidate for Total Knee Replacement or Unicompartmental Knee Replacement. You may also have a stiff and deformed knee. If you have tried taking pain killers, physiotherapy exercises and even knee joint injections (such as steroid or hyaluronic acid injections) without success then joint replacement may be the next step for you.

    At the consultation, a careful history and examination is taken to assess the severity of your joint disease, and to exclude pain referred from the hip and spine. You will have weightbearing X-rays of the knees to accurately assess the degree of joint damage. Some patients also undergo a CT scan if undergoing robotic surgery or even other surgery services. A careful discussion will be made with you regarding the risks and benefits of the procedure and what to expect in the long term. You should feel free to ask questions, and express any fears and concerns that you have regarding the orthopaedic surgery. Please bring a friend or close family member also, as my aim is to ensure that you and your family are well informed and prepared, and have realistic expectations regarding the procedure.


    The knee joint can be divided into three compartments – the inside of the knee (medial compartment), the outside of the knee (lateral compartment) and the space between the kneecap and the thigh bone (patellofemoral joint).

    Patients suitable for Total Knee Replacement Surgery may have loss of cartilage in all three compartments, have severe deformity, ligamentous injury or inflammatory joint disease.

    Patients suitable for Unicompartmental Knee Replacement may have localised joint disease in one compartment only.

    Both procedures can be performed with an excellent degree of accuracy using a robotic system such as Makoplasty, Navio or Robodoc.

    Some of the possible advantages of unicompartmental knee replacement over total knee replacement surgery include a smaller incision, less tissue damage and postoperative pain, less blood loss, faster recovery and return to work / sport, greater range of postoperative movement.


    Once you have decided to have surgery, you will be screened for any medical conditions that may need treating, and undergo a series of tests such as a chest X-ray, Electrocardiogram and blood tests. Prior to surgery the anaesthetist may offer you either a General Anaesthetic (where you are asleep during the procedure) or a Spinal Anaesthetic (injection to the spine which numbs the legs). On the day of surgery it is important not to eat or drink anything 8 hours before the procedure.


    Whenever possible, I perform my joint replacements through a small incision (around 10cm or less). Complex and revision cases may not be suitable for minimally invasive surgery. The body tissues are handled very gently during surgery.

    During the procedure I remove the worn joint surfaces from the thigh bone (femur) and shin bone (tibia). I take care to balance the soft tissues so that the knee is stable throughout the range of movement. I replace the joint surface with metal implants (usually cobalt chrome alloy) which are cemented onto the bone. Finally a plastic liner (highly crosslinked polyethylene) is placed between the two metal surfaces to allow a smooth gliding motion and reduce friction.

    During the surgery I use a technique called local infiltration anaesthesia which involves injecting a local anaesthetic into cut tissues. This combined with a range of painkillers (multimodal analgesia) reduces postoperative pain and improves chances for a swift recovery.


    Usually the surgery takes less than an hour. Following the operation you will be transferred to the Recovery area where you will be monitored for several hours until fit for discharge back to the General Ward.

    Whenever possible I aim to get my patients standing and walking immediately following the surgery. I work closely with my physiotherapy colleagues to follow an ‘Enhanced Recovery’ Protocol so that patients start exercising on Day 1 of surgery. The eventual aim is for discharge from the ward on or before Day 3 of surgery.

    It is normal to have temporary pain, swelling, bruising and stiffness following surgery. The wound may take 2 weeks to heal and it is important to keep it clean and dry during this time. Patients may need to use crutches or walking aids for several weeks following surgery. It is very important to perform the knee exercises and attend physiotherapy to get the best out of your surgery.

    Most patients can drive six weeks following surgery. Patients undergoing unicompartmental knee replacement can sometimes return to work at six weeks or earlier depending upon their occupation. Patients undergoing total knee replacement often need longer to recover – on average between six to twelve weeks in my experience, although there are exceptions.

    In the days and weeks following surgery, you will be followed up closely in clinic, to monitor your progress, general wellbeing and to monitor for any complications that might occur. You should be attending physiotherapy sessions also during this period.

    My aim is to relieve your pain and restore function to your limbs through joint replacement. Although it can take some time and effort to recover, most patients can achieve an excellent result.

Alan Cheung Orthopaedics
Singapore Medical Specialists Centre 290 Orchard Road #09-23 to 27, 30/31 Paragon (Tower 2 Lift Lobby C) Singapore 238859
6836 5705