What Is Knee Replacement Surgery?
Knee replacement, also called knee arthroplasty, is a surgical procedure in which worn or damaged joint surfaces are removed. They are then replaced with components made from metal alloy and a hard-wearing plastic (polyethylene) bearing. The underlying bone is prepared precisely so the implant sits securely. It then reproduces the natural movement of the knee as closely as possible.
There are two main approaches, and the right one depends entirely on your individual assessment:
- Total knee replacement: all the main weight-bearing surfaces of the knee are resurfaced. This is the most common form of the operation. It is generally recommended when arthritis affects more than one compartment of the joint.
- Partial (unicompartmental) knee replacement: only the damaged section of the knee is replaced, preserving healthy bone, cartilage and ligaments. This may be considered where wear is confined to a single compartment and the ligaments remain intact.
Within total knee replacement, Mr Shanmugasundaram Rajkumar also offers customised knee replacement using the Conformis implant system. Each implant is designed from your own CT scan to match the specific shape and size of your knee, rather than being selected from a limited range of standard sizes. Conformis implants have shown excellent outcomes in National Joint Registry data.
Knee replacement is a surgical rather than a conservative treatment, and it is usually considered later in the care pathway. Most patients will first have tried measures such as weight management where appropriate. These often also include activity modification, physiotherapy, walking aids, pain relief and sometimes injections. Where these no longer control symptoms and quality of life is significantly affected, surgery may be discussed. This is often the next reasonable step.
Who May Benefit From Knee Replacement Surgery?
Knee replacement is not suitable for everyone, and the decision is always individual. It may be considered for people who experience:
- Persistent knee pain that limits walking distance or daily tasks
- Pain at night or at rest that disturbs sleep
- Stiffness, swelling or difficulty straightening or bending the knee
- Difficulty with stairs, getting out of a chair, driving or standing for long periods
- A knee that gives way, catches or feels unstable
- Progressive deformity, such as increasing bow-leg or knock-knee alignment
- Symptoms that continue despite physiotherapy, medication and other non-surgical measures
Age alone does not determine suitability. What matters more is the degree of joint damage on imaging, how much the symptoms affect your life, your general health, and your ability to take part in rehabilitation afterwards. Some patients are better served by other options first, including an arthroscopic procedure, cartilage preservation surgery or a further period of structured non-surgical care. Your consultant will advise based on your examination and scans.
Conditions Commonly Treated
The procedure is most often performed for degenerative and inflammatory joint disease, including:
- Osteoarthritis of the knee: by far the most common reason, caused by gradual loss of the smooth cartilage surface. Guidance on assessment and management is published by NICE.
- Rheumatoid arthritis and other inflammatory arthropathies affecting the knee joint
- Post-traumatic arthritis following a previous fracture, ligament injury or meniscal damage
- Avascular necrosis or bone collapse within the knee
- Failed or worn previous knee implants, which may require revision knee replacement
Potential Benefits
Outcomes vary between individuals, and no operation can promise a particular result. That said, knee replacement is a well-studied procedure, and for suitable patients it may:
- Reduce arthritic knee pain, including pain at night
- Improve walking distance, stair climbing and general mobility
- Support a return to gentle recreational activity such as walking, swimming, cycling and golf
- Improve knee alignment where deformity has developed
- Reduce reliance on painkillers and walking aids over time
- Support independence and overall quality of life
Modern implants are designed for durability, and long-term performance in the UK is tracked through the National Joint Registry and Scottish Arthroplasty Project. Mr Shanmugasundaram Rajkumar uses only 100% ODEP 10A-rated hip and knee implants, meaning the components used have independently reviewed evidence of performance at ten years.
Your Recovery Timeline
- Day 0–1: Standing and walking with support, usually the same day as surgery
- Week 1–2: Home with crutches, daily wound checks and early physiotherapy
- Week 6: Most patients walk comfortably indoors and outdoors, driving typically resumes
- Month 3–12: Continued improvement in strength, confidence and swelling settling
Consultation and Assessment
A thorough assessment comes before any decision about surgery. A typical consultation includes:
Clinical review
A detailed discussion of your symptoms, how long they have been present, what makes them worse, previous treatments, your general health, medications and what you hope to achieve.
Examination
Assessment of your gait, knee alignment, range of movement, ligament stability, swelling and the health of your hip and spine, since pain can sometimes be referred from elsewhere.
Imaging
Weight-bearing X-rays are usually the key investigation. An MRI scan may occasionally be arranged where soft tissue or early cartilage damage needs clarification. Where customised knee replacement is being considered, a CT scan is also arranged so the Conformis implant can be designed specifically for your knee.
Shared decision-making
You will discuss all reasonable options, including non-surgical management, partial versus total replacement, the likely benefits, the recognised risks and what recovery will realistically involve. Nothing is rushed, and you should leave with enough information to decide at your own pace. If you would like to discuss your symptoms first, you are welcome to arrange an orthopaedic consultation or contact the clinic.
How the Procedure Is Performed
Knee replacement is carried out in an operating theatre under either a general anaesthetic or a spinal anaesthetic, sometimes combined with a nerve block for pain relief. The anaesthetist will discuss the safest option for you.
During the operation, the surgeon accesses the joint, removes the damaged bone and cartilage, prepares the bone surfaces accurately and fits the implant components. Soft tissue balance and alignment are checked carefully before the wound is closed. The operation itself commonly takes somewhere between one and two hours, though this varies.
Many patients stay in hospital for one to three nights. Selected, well-prepared patients may be suitable for day-case joint replacement, an approach in which Mr Shanmugasundaram Rajkumar is experienced, though this depends on your health, home circumstances and how you progress on the day.
Recovery and Aftercare
Recovery is gradual and requires active participation. A general guide is as follows, though timescales differ from person to person:
- Day of surgery to day two: physiotherapists usually help you stand and walk with support very soon after the operation. Early movement helps reduce stiffness and lowers the risk of blood clots.
- First two weeks: wound care, pain relief, blood-clot prevention (often with medication and stockings) and daily exercises to regain bend and straightening.
- Two to six weeks: most people move from crutches to a stick and gradually increase walking. Driving is often possible around six weeks, once you can perform an emergency stop safely and your insurer agrees.
- Six weeks to three months: continued physiotherapy, improving strength and function, with a return to desk-based work often earlier and to physical work later.
- Three to twelve months: ongoing improvement in comfort, stamina and confidence. Some swelling, warmth or numbness near the scar can persist for many months.
Follow-up appointments are arranged to review your wound, progress and range of movement. Seek prompt medical advice if you develop spreading redness, wound discharge, fever, sudden calf pain or swelling, chest pain or breathlessness.
Risks and Considerations
Knee replacement is a major operation, and all surgery carries risk. Recognised complications, most of which are uncommon, include:
- Infection, superficial or deep
- Blood clots in the leg or lung
- Bleeding, bruising or wound healing problems
- Stiffness or persistent pain
- Nerve or blood vessel injury
- Tendon/ligament injury
- Numbness around the scar
- Implant loosening or wear over time, potentially needing revision surgery
- Anaesthetic and general medical risks
It is also worth understanding the limitations. A replaced knee is not identical to a natural knee. Some patients notice clicking, kneeling can remain uncomfortable, and high-impact activities such as running are generally discouraged. A proportion of people remain dissatisfied even after a technically successful operation, which is why careful selection and realistic expectations matter. Alternatives will always be discussed where clinically appropriate.
Why Choose Mr Shanmugasundaram Rajkumar?
Mr Shanmugasundaram Rajkumar is a Consultant Trauma and Orthopaedic Surgeon specialising in hip and knee surgery, joint replacement and complex trauma care. His practice combines modern surgical technique with evidence-based, patient-centred care.
- more than 16 years of consultant experience
- Fellowship-trained in lower limb arthroplasty, revision surgery and knee surgery
- Expertise in primary and revision hip and knee replacement
- Offers customised knee replacement using the Conformis implant system, with excellent outcomes recorded in the National Joint Registry
- Previous experience at Wrightington Hospital, a recognised centre for joint replacement surgery
- Honorary Senior Clinical Lecturer at the University of Glasgow
- College Tutor/ Regional Surgical Advisor for the Royal College of Physicians and Surgeons of Glasgow
- Outcomes evidenced through National Joint Registry / Scottish Arthroplasty Project data
- Experienced in knee meniscus and cartilage preservation surgery
- Active researcher involved in randomised trials and UK and European multicentre studies
- Published in peer-reviewed orthopaedic journals and a reviewer for international surgical journals
- National lecturer and medical educator in Trauma & Orthopaedics
Location and Areas Served
Consultations for knee replacement surgery are available in Glasgow, with patients travelling from across the west of Scotland, including Renfrewshire and surrounding communities. Appointments are arranged to allow enough time for a full assessment and unhurried discussion.
Frequently Asked Questions
Is knee replacement surgery painful?
You will not feel the operation itself because of the anaesthetic. Discomfort afterwards is expected and is managed with a combination of medication, nerve blocks where appropriate, ice and early movement. Most people find pain improves steadily over the first few weeks.
How long does the operation take?
Typically one to two hours, plus time in the anaesthetic and recovery areas.
How long is recovery?
Many patients walk with support the same day and manage daily tasks within four to six weeks, but full recovery commonly takes several months and can continue for up to a year.
How long does a knee replacement last?
Modern implants are designed for long-term durability, and registry data shows most remain in place many years after surgery. Longevity varies with age, weight, activity and implant type. Your surgeon will discuss what is realistic for you.
What is customised knee replacement?
Customised knee replacement uses the Conformis implant system, in which the implant is designed from a CT scan of your own knee rather than chosen from standard off-the-shelf sizes. This aims to match your natural anatomy more closely, and outcomes recorded in the National Joint Registry have been excellent.
Are there alternatives?
Yes. Physiotherapy, weight management where relevant, pain relief, injections, bracing, arthroscopic procedures or partial knee replacement may all be appropriate depending on your diagnosis.
When should I book a consultation?
If knee pain is limiting your sleep, mobility or independence despite non-surgical treatment, a specialist assessment is a sensible next step.
At a glance
Anaesthetic
Spinal or general
Operation time
60–90 minutes
Hospital stay
1–3 nights, or day-case
Recovery
6–12 weeks to daily activities
Implants
100% ODEP 10A-rated
Fees & insurance
New Consultation
£180
Follow-up
£110
Insurers
Bupa · AXA Health · Aviva · Vitality · WPA
Self-pay
All-inclusive quotation on request
A written quotation is provided before any procedure is booked.
Discuss your knee
Request an appointment at Ross Hall Hospital, Glasgow.