Understanding the Risks of Knee Replacement Surgery
Knee replacement can provide substantial improvement in pain, walking and daily function when it is performed for the correct clinical indication. However, it remains a major operation. Possible complications should be discussed before surgery so that the patient can make an informed decision and recognise warning signs during recovery.
Risks may relate to anaesthesia, the surgical wound, infection, blood circulation, the heart or lungs, knee movement, ligament balance, implant fixation and individual medical conditions. For the complete surgical overview, visit Knee Replacement Surgery in Mumbai.
Individual Risk Varies Between Patients
Age, frailty, diabetes, heart or lung disease, kidney disease and anaemia
Smoking, body weight, previous blood clots, previous knee surgery and infection history
Surgical complexity, rehabilitation capacity, simultaneous bilateral surgery and revision surgery
How Safe Is Knee Replacement?
Most appropriately selected patients undergo knee replacement without a serious complication. Risk should nevertheless be evaluated individually. A medically fit patient undergoing a straightforward primary knee replacement may have a different risk profile from a patient undergoing simultaneous replacement of both knees, revision knee replacement, surgery after fracture, surgery with severe deformity or surgery with uncontrolled medical conditions. The key question is whether the expected improvement in pain and function reasonably outweighs the individual risk.
Infection After Knee Replacement
Infection may involve the skin and superficial wound, deeper tissues, or the artificial joint and implant. It may occur during early wound healing, several weeks or months after surgery, or years after a previously successful replacement. Possible symptoms include increasing pain, swelling, redness, wound drainage, progressive stiffness, persistent warmth, fatigue, feeling unwell and fever. Absence of fever does not exclude implant infection. Deep infection may require blood tests, joint-fluid aspiration, antibiotics, surgical cleaning, exchange of the plastic bearing, or removal and revision of the implant in selected cases.
How Infection Risk May Be Reduced
Antibiotics around surgery, strict sterile technique, skin preparation and appropriate wound care
Screening or treatment of active infections, diabetes optimisation, smoking cessation and nutrition assessment
Delaying surgery when there is active skin infection, open wound, uncontrolled diabetes, untreated infection elsewhere or another medical concern affecting healing
Blood Clots and Pulmonary Embolism
A blood clot may form in a deep vein of the calf, thigh or pelvis. Possible warning signs include new calf pain, calf tenderness, increasing calf, ankle or foot swelling, redness and unequal swelling between the legs. A clot may occasionally travel to the lungs and cause pulmonary embolism. Sudden breathlessness, chest pain, fainting, coughing blood or rapid unexplained deterioration requires emergency care.
Blood-Clot Prevention
Early walking, ankle exercises, compression devices and adequate hydration
Prescribed blood-thinning medication taken exactly as directed
Individual assessment of previous clotting risk and avoidance of prolonged immobility
Bleeding, Anaemia and Wound-Healing Problems
Some blood loss occurs during and after knee replacement. Anaemia may cause fatigue, dizziness, weakness, breathlessness on activity and reduced rehabilitation tolerance. Wound complications may include persistent drainage, skin separation, delayed healing, increasing redness, blistering, skin-edge damage and superficial infection. Risk may be increased by diabetes, smoking, obesity, poor circulation, malnutrition, previous scars, steroid or immunosuppressive medication and excessive swelling. Persistent drainage should be reviewed promptly because it may increase the risk of deeper infection.
Pain and Stiffness After Knee Replacement
Pain is expected during early recovery, but a small proportion of patients continue to have significant pain after healing. Possible causes include infection, stiffness, instability, implant loosening, patellar problems, nerve-related pain, tendon irritation, referred pain from the hip or spine or complex pain mechanisms. Read Pain After Knee Replacement Surgery. Scar tissue, swelling and muscle guarding may restrict movement. Treatment may include physiotherapy, pain and swelling control, manipulation under anaesthesia in selected patients, investigation for infection or mechanical problems and revision surgery when a correctable implant problem exists. Read Stiffness After Knee Replacement Surgery.
Instability, Wear and Loosening
A replaced knee may feel unstable because of quadriceps weakness, ligament imbalance, implant wear, component position, inappropriate bearing thickness, trauma or progressive soft-tissue damage. Implants are designed to function for many years but are not permanent biological tissue. The plastic bearing may wear, bone loss may develop and components may loosen. Increasing walking pain, recurrent swelling, reduced walking distance, instability or progressive X-ray changes require assessment. Read How Long Does a Knee Replacement Last?.
Fracture, Nerve and Blood-Vessel Injury
A fracture around the implant may occur after a fall, significant trauma, osteoporosis or progressive bone loss. Treatment depends on fracture location, implant stability, bone quality, displacement and patient health. Nerve or blood-vessel injury is uncommon but may cause numbness, weakness, foot drop, severe nerve pain, reduced circulation or a cold and pale foot. A small numb patch beside the scar is common, but new foot weakness, widespread numbness, loss of pulse or a cold discoloured foot requires urgent assessment.
Kneecap, Anaesthetic and Medical Complications
Kneecap-related complications may include pain around the kneecap, abnormal tracking, clicking, instability, patellar fracture or wear or loosening of a resurfaced patellar component. Medical complications may include nausea, low blood pressure, urinary retention, confusion in vulnerable patients, lung complications, heart rhythm problems, heart attack, stroke, kidney problems and medication reactions. Preoperative medical and anaesthetic assessment is therefore an important part of planning.
Falls During Recovery
Weakness, medication, poor balance and unfamiliar walking aids can increase fall risk. A fall may cause wound damage, soft-tissue injury, fracture, implant-related injury or loss of confidence. Fall-risk reduction includes using the prescribed walking aid, removing loose rugs, improving lighting, using handrails, avoiding wet floors, wearing suitable footwear and asking for assistance when necessary.
Robotic Surgery and Bilateral Knee Replacement Risks
Robotic assistance may support planning, bone preparation, implant positioning, alignment and ligament-balance assessment, but it cannot eliminate infection, blood clots, medical complications, scar formation, falls, individual pain responses, implant wear or rehabilitation-related problems. Read Robotic vs Conventional Knee Replacement. Simultaneous bilateral knee replacement places greater immediate demands on blood count, heart and lungs, pain management, mobility, rehabilitation and home support. Read Bilateral Knee Replacement Surgery in Mumbai.
Risk Factors That May Require Optimisation
Poorly controlled diabetes, smoking, significant obesity, anaemia, heart disease, lung disease or kidney disease
Malnutrition, active infection, previous blood clots, poor skin condition, immunosuppressive medication, frailty or severe muscle weakness
These factors do not automatically prohibit surgery, but they may require treatment, specialist review, risk counselling, procedure modification, delay or additional monitoring
Questions to Ask Before Surgery
What are my individual risks and which medical conditions need optimisation?
How will blood clots and infection risk be reduced?
Is partial, total, robotic or simultaneous bilateral replacement appropriate in my case?
What outcome cannot be guaranteed, what warning signs should I watch for and whom should I contact after discharge?
Warning Signs After Surgery
Increasing wound redness, wound drainage, persistent or increasing pain, increasing swelling or progressive stiffness
Fever, feeling unwell, new calf pain, new instability, new weakness or numbness, or a fall followed by severe pain
Sudden breathlessness, chest pain, fainting, coughing blood, a cold pale or blue foot or sudden severe deterioration requires emergency care
Why Patients Consult Dr. Mayur Rabhadiya
Dr. Mayur Rabhadiya follows an evidence-based and patient-specific approach to knee-replacement risk assessment. His evaluation emphasises confirming that surgery is clinically justified, balancing expected benefit against individual risk, identifying medical conditions requiring optimisation, selecting partial or total replacement appropriately, assessing whether bilateral surgery is suitable, discussing robotic and conventional options realistically, planning infection and blood-clot prevention, recognising complications early and avoiding guarantees of risk-free surgery. Read more about Dr. Mayur Rabhadiya’s qualifications and joint-replacement practice.
Knee-Replacement Risk Assessment in Ghatkopar, Mumbai
Diabplus Clinic, Ghatkopar East: 601, 6th Floor, Skyline Status, Mahatma Gandhi Road, opposite Pooja Hotel, Pant Nagar, Ghatkopar East, Mumbai, Maharashtra 400077. Visit Dr. Mayur Rabhadiya in Ghatkopar East.
Savla Clinic, Ghatkopar West: 2/3, Dharmodaya Building, next to Raj Medical, near NULife Hospital, Jivdaya Lane, Ghatkopar West, Mumbai, Maharashtra 400086. Visit Dr. Mayur Rabhadiya in Ghatkopar West.
Frequently Asked Questions
Is knee replacement a high-risk operation?
Most appropriately selected patients do not develop a serious complication, but risk varies according to medical health and procedure complexity.
What are the warning signs of a blood clot?
New calf pain, tenderness, redness and increasing calf, ankle or foot swelling require assessment.
Does robotic surgery remove surgical risk?
No. Robotic assistance does not eliminate infection, clots, medical complications or implant-related problems.
Should I seek a second opinion?
A second opinion is appropriate when individual risks, alternatives or the need for surgery have not been clearly explained.
About the Author
Dr. Mayur Rabhadiya is an Orthopedic & Joint Replacement Surgeon with clinical focus in knee-replacement risk assessment, total and partial knee replacement, robotic-assisted knee replacement, bilateral knee replacement, painful and stiff knee-replacement assessment, knee-replacement infection evaluation, revision knee replacement and complex joint reconstruction. Qualifications: MBBS, D’Ortho, DNB Orthopedics, MNAMS Orthopedics, Fellowship in Robotic & Computer-Navigated Joint Replacement. Written and medically reviewed by Dr. Mayur Rabhadiya. Last medically reviewed: June 2026.
Clinical References
American Academy of Orthopaedic Surgeons: Total Knee Replacement
American Academy of Orthopaedic Surgeons: Infection After Joint Replacement
American Academy of Orthopaedic Surgeons: Deep-Vein Thrombosis
American Academy of Orthopaedic Surgeons: Revision Total Knee Replacement
Book a Knee-Replacement Risk Assessment
Consultation may be useful if knee replacement has been advised, you have diabetes, cardiac disease, kidney disease or a history of blood clots, both knees have been advised replacement, previous surgery makes the knee complex, you want to understand robotic and conventional risks, you require medical optimisation before surgery or you are uncertain whether the expected benefit outweighs the risks. Book an orthopedic consultation with Dr. Mayur Rabhadiya in Ghatkopar, Mumbai. Call or WhatsApp: +91 84249 03913 / +91 96113 30063
Medical Disclaimer
This page provides general patient education and does not replace individual orthopedic, medical or anaesthetic assessment. The likelihood and importance of each complication depend on the patient’s health, operation, implant, medical optimisation and rehabilitation. Seek prompt medical advice for wound drainage, increasing redness, worsening pain, progressive swelling, fever, calf pain or inability to bear weight. Sudden chest pain, breathlessness, fainting, coughing blood or a cold and pale foot requires emergency care.
Explore the complete Knee Replacement Guides hub for preparation, surgery, recovery and long-term outcome articles.