Decoding Knee Replacement Surgery: Your Complete Guide to Pain Relief and Mobility

  • Home
  • Decoding Knee Replacement Surgery: Your Complete Guide to Pain Relief and Mobility

The subject of knee replacement and what criteria are used to determine the need for surgery is actually quite involved. It would be simple if every painful knee with arthritis could be x-rayed and then the decision would be made based on the condition of the x-ray. This is not the case.

Knee replacement is one of the most successful procedures in all of medicine. In the vast majority of cases, it relieves pain and greatly enhances the quality of life. At the same time, patients must understand the risks and the reasons not to have this procedure. This includes the most important reason of all: pain alone is not an indication for knee replacement.

In an ideal world, an article such as this would be read before a decision is made to have a knee replacement. Due to the gravity and permanent nature of this procedure, it is always best to explore all conservative options before making such a decision. Unfortunately, this is not always the case. Sometimes a patient will have made up their mind to have a knee replacement before they ever see the surgeon. In some cases, this decision is based solely on the surgeon’s advice. Other times, it is the result of information from friends who may have had a completely different condition that led to the same knee surgery. He or she may have tried to research the subject on the internet. If so, they have found that the information that is available can be very confusing. This patient is the one who would benefit the most from an article such as this.

In this article, an attempt is made to demystify a complex and confusing subject: knee replacement surgery. There are many different conditions that can lead to the decision to have a total knee replacement. In many cases, the distinction between one condition and another can be quite subtle. This has led to a great deal of misunderstanding with respect to why a knee needs to be replaced. I have written this article in response to the many questions my patients ask about this procedure.

What is Knee Replacement Surgery and When is it Necessary?

Overall, the success rates for knee replacements are high, with 9 out of 10 people having a significant increase in pain-free activity. And the lifespan of prosthetic knees can be greater than 20 years with newer models, although there are many factors contributing to its longevity like weight, activity level, and their effects on the immune system.

The strategy for improving your knee function will begin with a thorough evaluation. The concept of knee replacement surgery is to restore knee function that may have been lost for any particular reason. There are many ways to restore function, and no one method is right for every person. However, the surgery usually involves placing some kind of prosthesis within the knee. This can mean resurfacing the ends of the bones that form the knee joint with artificial materials, or capping the ends of the bones with metal alloy and plastic. All of these things are done to decrease pain from inflammation in the joint and prevent possible further damage to the articulating surfaces of the bone.

Knee replacement surgery can be painful for many people. After surgery, you should be prepared for a few weeks of hard work, a little discomfort, and the challenge of getting the most from your new knee. In the end, you can enjoy a long-term benefit of increased mobility and decreased pain.

Knee replacement surgery is typically recommended for individuals who have severe knee damage. These damages can be results from having an injury at a younger age, a gradual wearing down of the knee joint cartilage with age, or fractures of the bone near the joint. Osteoarthritis, often referred to as “wear and tear” arthritis, is the most common cause of knee damage. The individuals who feel they are suffering from the breakdown of articular cartilage include pain, swelling, and stiffness, are likely to have this form of arthritis. Osteoarthritis causes the patient to lose the ability to bend and/or straighten the knee because of damage to the articular cartilage. The patient may suffer extra bits of bone and/or cartilage broken off inside the joint. These loose bodies will irritate the joint causing it to “lock up”. Last, but not least, osteoarthritis causes the surrounding joint to lose muscle strength. Exercises to increase muscle strength are attempted, but often are very painful and are discontinued. All of the above leads to the patient being less active, gaining weight, and increasing the stress on the healthy parts of their knee. This excessive stress and the loss of cartilage make it difficult to perform normal daily activities, and may cause the patient to suffer severe knee pain, decreased mobility, and poor quality of life.

The impact of knee osteoarthritis on daily activities

Knee osteoarthritis impacts people in many different ways and tends to restrict mobility in many instances. This is because of damage caused to the knee joint and subsequent inflammation that occurs. Symptoms that many people experience include pain. This may occur in specific situations such as walking on an incline, prolonged standing, getting up from a chair, or at night. As the condition progresses, pain may become more persistent. Inflammation, the knee may become warm, tender, and swollen, making movement more difficult and painful. Muscle weakness or tightness, the muscles around the knee may become weaker or shrink (atrophy), and conversely, the hamstring muscles at the back of the thigh may become tight. This imbalance in muscle strength can cause further knee problems and affect mobility. Finally, knee stiffness often occurs after periods of inactivity, and this can make the knee difficult to bend and straighten, giving rise to further mobility difficulties. Osteoarthritis is a condition that often progresses over time, and knee pain and mobility can deteriorate. This can significantly impact daily activities and seriously affect the quality of life for sufferers.


Types of Knee Replacement Surgery

Total knee replacement surgery

Total knee replacement surgery is the most common type of knee replacement surgery. It is considered to be the treatment in order to improve patients’ quality of life. It is most commonly suggested for patients who suffer from osteoarthritis. Patients usually undergo this surgery when the pain caused in the knee is so severe that it restricts daily activities and is not relieved by other treatments or medications. A total knee replacement consists of replacing the damaged knee joint and worn surfaces on the tibia and fibula joint with an artificial joint that is designed to move like a healthy human joint. The new artificial joint is usually made from metal and plastic, or a type of cement can be used for the femoral component. A total knee replacement is composed of four main steps. Step one is the preparation of the bone. The cartilage on the end of the bone is removed and the bone is shaped to fit the new artificial joint. Step two is the positioning of the metal implants. The end of the femur and the tibia bone are replaced with metal components to allow movement of the joint. Step three is the resurfacing of the patella. At this stage the patella is prepared to receive a plastic component. Step four is the implantation of the plastic spacers. These spacers will create a smooth gliding surface for movement of the new joint.

Partial knee replacement surgery

Partial knee replacements are diverse and have different considerations for recovery, but we have split the recovery section into the different types of partial knee replacement as recovery can be different for each type. Unicompartmental knee replacements (UKR) have a shorter recovery than total knee replacements and patellofemoral knee replacements. Patience, persistence, and rehabilitation are essentially required for these operations to achieve the best results. Advanced age and motion are known to adversely affect recovery in patients undergoing UKR, while patients in their 50s or 60s who are active and have a flexion contracture less than 15 degrees obtain the best results. Due to the technical complexity and precision involved in a UKR, thus in order to get the best results from this operation, it requires the use of a highly experienced surgeon in the procedure. Patellofemoral knee replacements aim to resurface the damaged patella and femoral trochlea and are best suited for patients that are not overweight, have a strong, healthy quadriceps mechanism, and have isolated patellofemoral arthritis. High-grade activity that involves heavy loading of the extensor mechanism is a relative contraindication for this operation. Randomized controlled trials and cohort studies have demonstrated that physiotherapy and home exercises lead to similar functional results and pain relief at the short and mid terms in comparison to traditional rehabilitation, which is conducted primarily in an outpatient setting. Although these two methods of rehab produced similar results, there is no definitive evidence to show which exercise program is most effective or whether one of them is any more beneficial than general activity.

An Overview of the Pre-Surgery Process for Knee Replacement Patients

The surgical process begins when you are taken to the operating room and given anesthesia. General anesthesia will make you unconscious for the entire surgery while regional anesthesia will numb you from the waist down. The anesthesia specialist and your surgeon will help you decide which type of anesthesia is best for you. The skin around your knee will be scrubbed clean and then sterilized. The surgeon makes an incision about 8-12 inches long in the front of your knee. The damaged part of the joint is removed and the surfaces are prepared for the new artificial joint. This is called the femoral component for the end of the thigh bone, the tibial component usually made of metal and a plastic spacer to create a smooth gliding surface. The patellar component may also be used, depending on the condition of your kneecap. This process usually takes around 1-2 hours.

To prepare for knee surgery, you may be asked for a physical examination by the surgeon. This is the time to speak up and ask any questions you may have regarding the surgery. Tell your surgeon about any medications you are currently taking. You may need to stop taking certain medications in the week before the surgery. Additionally, you may need to take antibiotics before dental work or a urinary tract infection to reduce the risk of infection in your new joint. If you are overweight, losing weight before surgery will help reduce the stress on your new joint. Finally, you may need to donate your own blood before the surgery that can be used for a transfusion during the surgery.


Preparing for knee replacement surgery

The day before surgery, pack a bag with your immediate needs for the hospital and confirm your transportation to the hospital. Leave any valuables at home. On the day of surgery, shower with an antiseptic soap and dress in freshly washed clothes. Follow your physician’s orders regarding when to arrive at the hospital. It is likely to be early. Remember, being well-prepared for your surgery will contribute to a smoother, more comfortable recovery.

In the days before surgery, eat a well-balanced diet, prescribed by your physician. If you develop a cold, sore throat, fever or any other illness, your surgery may have to be postponed. Visit your dentist to have any tooth, gum, bladder or bowel problems treated to reduce the risk of infection. An infection in another part of your body can delay your surgery. Follow your physician’s instructions about when to stop taking aspirin, ibuprofen, or other blood-thinning medication and when to stop eating and drinking before surgery. Failure to follow your physician’s instructions can result in the postponement of your surgery. Make your home safer for your return from the hospital. Remove all loose rugs, electrical cords, and any obstacles that may be in your way. Consider the following safety measures: a shower chair, a stable chair with a firm seat cushion and two armrests, a raised toilet seat, a stable hand-held showerhead and a long-handled sponge and dressing stick. A physical or occupational therapist can help you decide what would be helpful to have.

Before having knee replacement surgery, there are several things you can do to prepare for the procedure. The decision can affect you in the years ahead. Knowing what to expect and being an active participant in the planning of your surgery will lead to a better outcome. Use the list below to help you prepare for your surgery.

The surgical process

Knee replacement is most often done under general anaesthetic. This means you will be asleep during the operation. Alternatively, you may be offered an injection in the back which numbs the lower part of your body. This is called an epidural. Some people find the idea of being awake during the operation unsettling. With an epidural, you will be drowsy and might not be aware of what is happening. You may be able to choose to have this combined with a light general anaesthetic. It is also possible to do the operation using a spinal anaesthetic. This is similar to an epidural. General or spinal/epidural anaesthetic is usually agreed upon by talking it over with the anaesthetist to decide what is best for you. A less likely option is to do the operation using a local anaesthetic. This is usually for people who are unable to have a general or spinal/epidural anaesthetic for health reasons. With local anaesthetic, the limb being operated on is numbed using an injection. You will be awake during the operation but you may be given a medicine to make you feel very drowsy.

In the surgical ward, you will be prepared for your operation. You will be taken on a trolley to the anaesthetic room. The anaesthetist will see you on the trolley before taking you into the room. A needle will be put into a vein in your arm (usually on the back of your hand). This is connected to a tube which takes the anaesthetic into your body. There are a number of ways to carry out anaesthesia.

Post-surgery care and recovery

At the early stages of postoperative care, and usually around 2-5 days after the surgery, cold therapy is widely used to reduce the postoperative pain and swelling experienced after knee surgeries. Ankle pumps and straight leg raises are isometric exercises which help in the prevention of blood clots and the improvement of muscle function. These exercises should be performed on an hourly basis for as many repetitions as comfort allows. Range of motion of the knee will be worked on in the initial stages through the act of the patient/family member performing knee slides for 6-8 minutes at a time, 3 times a day. A plastic bag can be placed under the heel to help with the sliding and it should not be forced if it is causing pain.

The final step in the journey to recover at a full level of activity without pain or discomfort is the rehabilitation that is undertaken after the surgery is completed. Due to the fact that an individual may encounter different rates of progression during the discharge and rehabilitation phase, it is difficult to give a precise timeframe and description regarding the various treatments and exercises that may be encountered. When the original bandage is to be removed is decided by the individual surgeon and is usually done so within 10-14 days of the surgery. At this point, the individual can begin taking baths instead of showers, however, they must ensure that the wound is fully dried and a waterproof dressing is applied before submersion of the knee in water. This is usually 3-4 weeks after the surgery but can be up to 7-10 days for some individuals. This treatment is now commonly employed and is considered a standard of care for patients who have undergone knee replacement or ACL reconstruction surgery.

Considerations and Costs

From 1997-2006, the demand for primary knee replacement increased by 65 percent. With increased demand comes increased cost. Over the last decade, Medicare spending for knee and hip replacements has doubled to an estimated $14 billion a year. During a time period when the new Obama administration is attempting to cut healthcare costs, the cost of orthopedic surgery has drawn attention from Medicare and commercial payers who have implemented several “cost-saving” measures such as non-coverage policies and bundled payment for orthopedic procedures. This creates a difficult road for under or uninsured patients to receive quality treatment. However, the true effect of these measures on knee replacement is yet to be determined.

Knee replacement surgery is a complex yet increasingly common procedure, most often performed on older adults to alleviate arthritis symptoms and increase mobility. Whether partial or total surgery, patients face the prospect of weeks or months of pre and postoperative care. Most of the complications surrounding knee replacement surgery occur after the operation in the clinical setting. The high demand from an ever-increasing elderly population, combined with a longer life expectancy and the greater overall health of the elderly, more patients are opting for knee replacement as a solution to their pain and mobility problems. A continuous increase in the number of knee replacement surgeries performed has caused the procedure to be scrutinized by the public and governmental agencies.

Factors affecting the cost of knee replacement surgery

Most of us would have experienced purchasing an electronic or household appliance. We would have observed that the price of the item would vary across different locations or among different retailers. The price of the same item may even differ from time to time. This price variation is due to many factors including the variable cost of production and transportation as well as the mark-up cost by the seller. In the context of medical and surgical services, the factors influencing price can be seen as more complex due to the intangible nature of healthcare services and the involvement of third party payers. The price of a knee replacement surgery in Singapore can vary quite substantially from as low as $6000 to a high of $30000 for a local patient and from $12000-$45000 for a foreign patient. This creates confusion and uncertainty amongst patients seeking this procedure. The following is a list of factors outlined by the Ministry of Health, with a detailed definition and analysis of how it may influence the price of knee replacement surgery in Singapore.

Costs of knee replacement surgery in Singapore

The total cost for knee replacement surgery would vary in public hospitals and private hospitals. The cost package in public hospitals ranges from $3000 to $9000. Depending on the type of ward, the cost would differ. If the knee replacement surgery were to be done on a B2 ward, the cost would be $3000. This cost is the same as the recommendation given by the Ministry of Health to conduct the surgery in a private hospital. On the other hand, knee replacement surgery done in a private hospital would range from $10,000 to $25,000. The higher cost is mainly attributed to the type of prosthesis used and the skill of the surgeon. Usually, with a higher cost, there is also a higher level of privacy and better personalized medical service. To add, the prosthesis used is paid by the patient and is charged separately in private hospitals.

Singapore ranks among the most advanced countries in the field of medical science, specifically orthopaedic surgery. It has a sophisticated healthcare infrastructure that is well-regulated by the Ministry of Health. Moreover, the first world status has attracted many overseas patients coming to seek medical treatment in Singapore, particularly regional patients from neighbouring countries like Indonesia, Malaysia, Brunei, and Hong Kong. Over the years, many public and private hospitals have created “centres of excellence” to support medical tourism. Unlike the medical services in public hospitals, treatment in private hospitals is generally more expensive.

Integrated shield plans and coverage for knee replacement surgery

Patients who are considering knee replacement surgery must bear in mind the accumulation of medical costs. Conservative management of knee arthritis involves prolonged use of medications, physiotherapy, rehabilitative aids, or regular joint aspirations and injections. In comparison, the costs of surgery will result in significant savings on long-term spending on conservative management. However, the large upfront costs of surgery may be off-putting for some. Understanding the cost structure from diagnosis to post-operative care is important and will give you an idea of which are the more cost-effective treatment options. Being informed of both the direct bill and the amount claimable from Medisave or insurance is important. Patients should check on the amount claimable from their Medisave account under the Medisave withdrawal limits for surgical procedures before they will be able to claim from Medisave. Do take note that claims to insurance can only be made after Medisave funds have been exhausted.


What are the different types of knee replacement surgeries available?

Knee replacement surgery encompasses two main types: partial knee replacement, focusing on replacing the damaged section of the knee, and total knee replacement, which involves replacing the entire knee joint with an artificial material.

What should I expect from my doctor in terms of pre-surgery preparation? 

Before the surgery, your doctor will thoroughly explain the process, allowing you to ask questions. After comprehensively reviewing the consent form, you’ll sign it to grant permission for the treatment. A medical evaluation will assess your health and history, including allergies and medications, particularly those impacting bleeding. Your orthopaedic surgeon might suggest consulting a physical therapist and making post-surgery plans, tailoring recommendations based on your health status.

How do doctors decide which type of knee replacement is best for each patient?

Orthopaedic surgeons often decide based on a comprehensive evaluation considering factors like age, activity level, overall health, joint damage, and specific conditions. Using this information, they determine the ideal knee replacement type for each patient. Currently, The Orthopaedic & Pain Practice offers navigated total knee replacement for potential patients.

Is it possible to reduce pain without undergoing a total or partial joint replacement procedure?

In specific cases of severe arthritis-related damage or substantial knee injuries where non-surgical treatments have proven ineffective, knee replacement surgery becomes the sole viable option for relieving persistent pain and restoring mobility.

Are there exercises that can help strengthen knees prior to and after a knee replacement surgery? Do all patients need Physiotherapy following their operation on their knee? 

Physical therapists guide patients in targeted exercises for strength and recovery, focusing on balance, range of motion, and strengthening through activities like leg raises, ankle pumps, and knee straightening; gradually reducing reliance on aids and incorporating low-impact exercises. They play a vital role in both pre-surgery preparation and post-surgery recovery; these specialists enhance overall patient quality of life through hands-on care and personalised exercises. Patients usually need physiotherapy to recover from the surgery and return to their daily activities.

How do artificial joints interact with the human body in order to replace damaged or osteoarthritic knees?

Artificial joints perform their role by replacing the elements of the knee that have been injured or destroyed due to osteoarthritis or injurious sources. This restores the mechanics of the joint, allowing for more mobility while simultaneously reducing pain and other symptoms.

What factors affect the cost associated with having a total or partial joint replaced? 

The type of knee replacement surgery, medical services, implant material, and pre- and post-operative care can all affect the cost. Patient health and insurance coverage might affect cost. Talk to an orthopaedic surgeon to get an accurate cost estimate. They can give details on surgery prices, additional fees, and insurance coverage.

Are there any long-term risks associated with having had a knee replaced?

Knee replacement surgeries relieve pain and increase mobility, but long-term risks like infection, implant loosening, and wear are minimal and vary by individual. With proper check-ups with your orthopaedic surgeon, these risks can be minimised.

What should I do if my knee pain worsens after having had my total or partial joint replaced? 

If your knee pain worsens after a total or partial joint replacement, it’s advisable to promptly contact your orthopaedic surgeon for a thorough evaluation and appropriate guidance.



Dr Yong Ren’s Profile

Dr Yong Ren graduated from the National University of Singapore’s Medical faculty and embarked on his orthopaedic career soon after. Upon completion of his training locally, he served briefly as an orthopaedic trauma surgeon in Khoo Teck Puat hospital before embarking on sub-specialty training in Switzerland at the famed Inselspital in Bern.

He underwent sub-specialty training in pelvic and spinal surgery, and upon his return to Singapore served as head of the orthopaedic trauma team till 2019. He continues to serve as Visiting Consultant to Khoo Teck Puat Hospital.

Well versed in a variety of orthopaedic surgeries, he also served as a member of the country council for the local branch of the Arbeitsgemeinschaft für Osteosynthesefragen (Trauma) in Singapore. He was also involved in the training of many of the young doctors in Singapore and was appointed as an Assistant Professor by the Yong Loo Lin School of Medicine. Prior to his entry into the private sector, he also served as core faculty for orthopaedic resident training by the National Healthcare Group.

Dr Yong Ren brings to the table his years of experience as a teacher and trainer in orthopaedic surgery. With his expertise in minimally invasive fracture surgery, pelvic reconstructive surgery, hip and knee surgery as well as spinal surgery, he is uniquely equipped with the tools and expertise necessary to help you on your road to recovery.

Lorem ipsum dolor sit amet consectetur adipiscing elit ut arcu a dignissim suscipit non ac eget tellus in nisl mauris nec.

Author Image Link

Sarah Taylor

Obstetrics & Gynaecology