Knee Replacement Surgery: What You Need to Know

A group of medical professionals discusses a knee joint model while examining documents on a table.

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Knee replacement surgery, also known as total knee arthroplasty, is a procedure that replaces damaged knee joint surfaces with artificial components made of metal and plastic. It is commonly performed to relieve pain and improve mobility in individuals with severe knee damage caused by arthritis, injury, or degenerative conditions. The goal is to restore movement by replicating the knee’s natural rolling and gliding motion, allowing patients to regain function and return to daily activities with greater ease.

If you are considering knee replacement surgery, knowing when it may be suitable, how it is performed, and what to expect during recovery can help you prepare for the process.

When Is Knee Replacement Surgery Considered?

Several factors are assessed to determine whether knee replacement surgery is an appropriate treatment option.

Persistent Pain: Knee pain is ongoing and severe, affecting daily activities and rest. Despite non-surgical treatments such as medication, physiotherapy, or injections, the discomfort does not improve.

Limited Mobility: Walking, climbing stairs, and performing basic movements become increasingly difficult due to stiffness and reduced range of motion. Physiotherapy and other conservative treatments no longer provide relief.

Joint Deformity: The knee appears visibly misaligned, bowing inward or outward. This affects balance, posture, and normal movement, potentially leading to additional strain on other joints.

Ineffective Conservative Treatment: Non-surgical treatments, including lifestyle changes, weight management, medications, and physical therapy, have been attempted but have not provided long-term relief.Severe Joint Damage: Imaging tests such as X-rays reveal significant cartilage loss, bone erosion, or deformity that cannot be addressed through non-surgical methods or less invasive procedures.

Benefits of Knee Replacement Surgery

Patients who undergo knee replacement surgery often experience significant improvements in their daily lives. The potential benefits include:

Pain Reduction: Surgery can significantly decrease knee pain, making everyday movements more manageable.

Improved Mobility: The artificial joint enhances movement, allowing for smoother and more natural motion. Activities such as walking and climbing stairs become easier.

Better Joint Stability: The knee regains strength and balance, reducing the risk of falls and improving confidence in movement.

Corrected Deformity: The knee is realigned, restoring a more natural leg position and preventing further strain on surrounding joints.

Long-Lasting Results: With proper post-surgical care and activity management, modern knee implants typically last between 15 and 20 years, allowing patients to maintain mobility and independence.

Types of Knee Replacement Surgery

The type of knee replacement procedure performed depends on the patient’s condition and specific needs.

Total Knee Replacement

This is the most common procedure, which involves replacing all joint surfaces with prosthetics. The surgeon makes an incision of approximately 15–20 cm at the front of the knee, repositions the kneecap, and resurfaces the femur, tibia, and sometimes the patella. This approach is suitable for most patients with severe joint damage.

Minimally Invasive Knee Replacement

This technique uses a smaller incision, typically 8–10 cm, and specialised instruments to insert the same prosthetic components. It reduces tissue disruption and may lead to a quicker initial recovery. However, it is only suitable for select patients based on weight, knee flexibility, and overall health.

Partial Knee Replacement

Also called unicompartmental knee replacement, this procedure replaces only the affected portion of the knee while preserving healthy bone and cartilage. Recovery is often faster than total knee replacement, but this option is only viable for patients with damage limited to one section of the knee.

Preparing for Surgery

Proper preparation before knee replacement surgery helps ensure a smoother procedure and recovery. This includes medical assessments, adjustments to medications, and imaging tests to guide surgical planning.

Medical Evaluation: Blood tests, chest X-rays, and an ECG assess overall health and detect any conditions that may affect surgery. A thorough review of current medications and medical history ensures a safe procedure.

Medication Adjustments: Blood thinners and certain other medications may need to be modified or temporarily stopped before surgery. Doctors provide specific guidance on which medications to discontinue and when they can be resumed. Some medications require gradual adjustments over several weeks.

Pre-Surgical Imaging: X-rays, CT scans, or MRI scans help plan the procedure by determining implant size and ensuring proper alignment. These images allow surgeons to select the most appropriate implant components.

Knee Replacement Procedure

Anaesthesia and Preparation: Patients receive either general anaesthesia, which induces unconsciousness, or spinal anaesthesia, which numbs the lower body. Throughout the procedure, vital signs are closely monitored. The surgical site is cleaned and sterilised to reduce the risk of infection.

Surgical Approach: The surgeon makes an incision at the front of the knee to access the joint. The kneecap is moved aside, and damaged bone and cartilage are exposed for removal.

Bone Reshaping: Damaged joint surfaces are carefully removed using specialised guides to shape the femur and tibia, ensuring a precise fit for the artificial components. Only the necessary amount of bone is removed to accommodate the implants.

Implant Placement: Metal components are secured to the femur and tibia, usually using bone cement. A plastic insert is placed between them to provide smooth movement. If necessary, the patella is resurfaced with a plastic component to improve joint function.

Final Adjustments and Closure: The surgeon checks the knee alignment and stability by moving the joint through a range of motion. The incision is closed with sutures, and sterile dressings are applied. A drain may be placed to prevent fluid buildup.

Recovery After Knee Replacement Surgery

Recovery begins with pain management and physiotherapy, which starts within 24 hours to restore movement. Most patients stay in the hospital for two to three days before discharge. In the first six weeks, physiotherapy improves mobility, with walking aids used initially. Swelling and discomfort gradually ease. By weeks 6–12, strength and balance improve, allowing for greater independence. Full recovery can take up to 12 months, with most resuming light activities by three months and more strenuous tasks by six months. Follow-up appointments ensure progress and implant function.

Potential Risks and Complications

While knee replacement surgery is a well-established procedure, there are potential risks. These include infection, which occurs in approximately 1–2% of cases and may require antibiotics or additional surgery. Blood clots can develop in the leg veins, requiring blood-thinning medication. Some patients experience stiffness or persistent pain despite surgery, and implants may loosen or wear down over time, potentially requiring further intervention. Though rare, nerve or blood vessel injuries can affect leg function.

Conclusion

Knee replacement surgery can provide lasting relief from chronic knee pain, restoring mobility and improving quality of life. Learning about the procedure, its benefits, and the recovery process can help patients prepare and make informed decisions about their care.

If you are experiencing persistent knee pain and considering surgery, schedule a consultation today to explore your options.

Dr. Ambrose Yung

Specialist Orthopaedic Hip & Knee Surgeon

Dr Ambrose Yung Wai Yin is a Senior Orthopaedic Hip & Knee Surgeon with over 20 years of experience in the field of orthopaedics.

Areas of Expertise:

Knee Surgery: Complex procedures like revision knee arthroplasty, partial knee replacement, and primary total knee replacement.
Minimally Invasive Surgery: Shoulder, ankle, and knee surgeries with minimal scarring and quicker recovery times.
Limb Reconstruction: Specialized in both upper and lower limb reconstruction.

Computer-guided Knee Replacement: Dr. Yung trained at the prestigious Oxford University Hospital in the UK, where he specialized in computer-guided partial and total knee replacements.

Dr. Chee Kin Ghee

Specialist Hand & Orthopaedic Surgeon

Dr Chee Kin Ghee is a specialist hand surgeon with over 20 years of experience in hand and orthopaedic surgery.

His clinical expertise includes treatments for complex hand, wrist, and upper limbs injuries, wrist and finger joint replacement, minimally invasive hand and wrist surgery, and nerve compression release surgery

Dr Chee was awarded a 1-year fellowship (HMDP by MOH) & trained at world-renowned Wrightington Hospital Upper Limb Unit, UK.
He was trained in the management of complex upper limb conditions, including complex joint replacement of the shoulder, elbow, wrist, and hand, as well as modern minimally invasive upper limb surgery.

Dr. Low Mun Hon

Dr Low Mun Hon has over 20 years of experience managing trauma and orthopaedic clinical care. Prior to this, he has been in private practise as a practitioner at Singapore Sports & Orthopaedic Clinic (SSOC).

Dr. Low graduated from Monash University Medical School (Melbourne). Thereafter, he pursued his internship at The Alfred Hospital in Melbourne.

He subsequently continued his practice of medicine at Singapore General Hospital (SGH). During this period, he was awarded the membership of the Royal College of Physicians and Surgeons at Glasgow in 2008 & Master of Medicine in Orthopaedic Surgery (National University of Singapore) in the same year.
Dr Low had previously worked as an orthopaedic trainee at various local teaching hospitals i.e. Ng Teng Fong General Hospital (NTFGH), Tan Tock Seng Hospital (TTSH), KK Women’s and Children’s Hospital (KK Hospital) and Singapore General Hospital (SGH).

Justin Lim Xuan Li

Physiotherapist

Justin is a skilled and experienced physiotherapist who specializes in the treatment of neuro-musculoskeletal conditions (nerve, muscle and joint).

Over the years, he honed his clinical skills across all sectors of healthcare, allowing him to attain mastery of the sophisticated human body and address complex problems effectively, allowing him to successfully address complex neuro-musculoskeletal conditions at an accelerated pace.

Justin graduated from Trinity College Dublin and started his career in National Healthcare Group Polyclinics. His skills quickly gained recognition and was appointed as a clinical educator for physiotherapy students and even tasked to develop Clinical Practice Guidelines.
Subsequently, he continued his practice in community care settings such as Thye Hwa Kwan Rehabilitation Centres and Saint Andrew Community Hospital, where he focused on developing his skills for geriatric rehabilitation and improving quality of care in rehabilitation centres. He then moved on to private practice in Parkway East Hospital, specializing in post operative and outpatient rehabilitation.

Chan Jing Cheng (JC)

Physiotherapist

JC has over 12 years of experience in treating Chronic pain, Orthopaedic and Geriatric conditions.

He had worked at various Private Hospitals, Singapore General Hospital, NTUC Health Elder Care and Lions Home for the Elders.
He is passionate about solving complex musculoskeletal disorders and helping clients relief pain from trauma and illness.
He has a special interest in the Shoulder, Spine, Hip and Knee joint conditions.
He has helped thousands of clients go through rehabilitation smoothly and achieved higher satisfaction after orthopaedic surgery.

Zita Sham

Physiotherapist

Zita graduated with a Diploma in Physiotherapy from Nanyang Polytechnic (Singapore) in 2014 and started working in Ng Teng Fong General Hospital to serve her sponsorship bond.

Later in 2015, she pursued a Bachelor’s Degree in Physiotherapy from Trinity College Dublin, which was provided in Singapore Institute of Technology.

After completion of her studies, Zita worked in the Day Rehabilitation Centre in Jurong Community Hospital for 6 years, where she focused on community rehabilitation for a variety of patients. Patients that were mainly seen consisted of post-operative, geriatric and neurological conditions.
Zita also has a passion in musculoskeletal and sports physiotherapy and is looking to pursue that. She is also keen to provide home-based physiotherapy to reach out to those in need of her expertise.

Joanna Lim

Hand Occupational Therapy

Joanna’s primary specialization and passion is in hand therapy and upper limb rehabilitation, having more than 10 years of experience in this field.

Joanna obtained her Diploma in Occupational Therapy (Merit) from Nanyang Polytechnic in 2006. Under the MOH Health Science Scholarship, she graduated from La Trobe University, Australia, with a Bachelor’s degree in Occupational Therapy (1st class Honors) the following year. Upon graduation, she worked in Changi General Hospital and Sengkang General Hospital.

She has worked with hand and orthopedic surgeons in both inpatient and outpatient settings, providing quality therapy services for clients with a variety of hand and upper limb conditions, including fractures, sprains/strains, tendon injuries, nerve injuries, repetitive strain disorders and complex trauma injuries.
During her tenures at CGH and SKGH, Joanna was a Senior Occupational Therapist and held the role of Hand Therapy and Upper Limb Rehabilitation Unit Leader. She was in charge of clinical supervision and management of staff, manpower planning, and daily operations of the unit.