Knee Replacement Complications & Risks: Is It Dangerous?

Quick answer

Knee replacement complications are uncommon but include blood clots, infection, stiffness, persistent pain, instability, loosening and fractures around the implant. Knee replacement is not considered dangerous for most patients when health is optimised before surgery and the operation is done by an experienced team.

✅ Last medically reviewed by Prof. Dr. Ibrahim Shaarawi, Professor of Orthopaedic Surgery, on 12 October 2026

About your surgeon: Prof. Dr. Ibrahim Shaarawi

Professor of Orthopaedic Surgery, Faculty of Medicine, Ain Shams University.
Visiting Professor of Orthopaedic Surgery, Ohio, USA.
Certificate in complex fractures and trauma, University of Maryland, USA.
He has performed more than 750 knee replacements (total, partial, both knees in one operation and revision surgery) and more than 3,000 knee arthroscopies.
His joint replacement experience also includes 650 total hips, 1,400 hip hemiarthroplasties and 55 reverse shoulder replacements.
Rated 4.9 and 5.0 on Google by about 300 patients.

He sees patients at his clinics in Nasr City, Mohandeseen and New Cairo (5th Settlement).

Every operation carries risks, and knowing them helps you prevent many of them. Here are the possible complications of knee replacement and how we reduce them, as part of our guide to total knee replacement surgery.

Is knee replacement dangerous?

For most patients it is a safe, routine operation. Risk rises with heart and lung disease, uncontrolled diabetes, obesity and smoking, which is why we optimise these first. Replacing both knees in one operation carries more complications than one knee, so we reserve it for fit patients.

Side-view X-ray of a total knee replacement after surgery — The knee implant seen from the side — Image: Mikael Häggström, M.D. / Wikimedia Commons, CC0

Possible complications

X-ray of a knee replacement with slight overhang of the tibial component — Implant position is checked on X-ray; malposition can cause pain — Image: Manjunath Ramanna et al. / Wikimedia Commons, CC BY 2.0

Complication	How it shows	How we reduce it
Blood clots (DVT)	Calf pain and swelling; breathlessness if a clot travels	Early walking, clot-prevention medication, stockings
Infection	Warmth, redness, discharge, fever	Antibiotics at surgery, treating infections beforehand, sterile technique
Stiffness	Difficulty bending	Early exercise and physiotherapy
Persistent pain	Pain beyond the expected recovery	Careful selection, accurate alignment, rehabilitation
Instability	Giving way	Ligament balancing and the right implant
Loosening or fracture	Pain on walking, often years later	Good fixation and follow-up X-rays

Table: knee replacement complications and how we reduce them

Video: A successful total knee replacement and walking straight after surgery

Prof. Dr. Ibrahim Shaarawi, Professor of Orthopaedic Surgery, explains (in Arabic).

Why does pain happen after knee replacement?

Pain and swelling are expected in the first weeks. Pain that persists can come from stiffness, nerve sensitivity, pain referred from the hip or spine, infection or loosening — see pain after knee replacement.

Key numbers to know

At a specialist revision centre, the reasons for revision were infection (36.1%), aseptic loosening (21.9%) and periprosthetic fracture (13.7%) (Postler et al., 2018).
In the best-quality studies, about 20% of patients reported troublesome long-term pain after knee replacement (10%–34% across studies) (Beswick et al., BMJ Open 2012).
Replacing both knees in one operation gave function similar to one knee, but complications were about 42% higher and the hospital stay about 0.8 days longer, with no difference in mortality (Shinwari et al., 2026).

Treatment	When we use it	What to expect
Conservative care: exercise, weight loss, topical pain relief	Grade 1–3 arthritis	Better pain and movement; many patients delay surgery
Joint injections (steroid, hyaluronic acid or PRP)	Persistent pain despite conservative care	Temporary relief that varies between patients
High tibial osteotomy (HTO)	Active patients under 60 with bow legs and arthritis on the inner side only	Realigns the leg and keeps the natural knee
Partial knee replacement	Arthritis limited to one compartment with healthy ligaments	Faster recovery and a more natural-feeling knee
Total knee replacement	Severe (grade 4) arthritis with pain limiting daily life	Pain usually resolves; walking on day 1–2
Revision knee replacement	Loosening, infection or instability of a previous knee replacement	Bigger surgery with special components to restore stability

Table: knee arthritis treatment options from conservative care to replacement

At Prof. Dr. Ibrahim Shaarawi’s clinics in Nasr City, Mohandeseen and New Cairo (5th Settlement) we examine the knee and review standing X-rays at the same visit, then decide on conservative care, osteotomy, or a partial or total knee replacement according to the arthritis grade, your age and activity.

How to lower your risk

Control diabetes, blood pressure and weight before surgery.
Stop smoking at least several weeks before.
Treat dental and urinary infections first.
Walk early and take clot-prevention medication as prescribed.
Keep up the exercises in exercises after knee replacement.

When to call your surgeon urgently

Fever, increasing redness, or discharge from the wound.
Calf pain and swelling, or sudden breathlessness or chest pain (emergency).
A sudden inability to bear weight after a fall.
Severe pain that keeps getting worse.

For long-term results see knee replacement success rate, and for failure and revision failed knee replacement and revision surgery.

Looking for an experienced knee surgeon? Read our guides to the best knee specialist in Egypt and the best orthopaedic surgeon in Egypt to see how to choose.

Frequently asked questions about knee replacement complications

Is knee replacement a dangerous operation?

For most patients it is safe; risk depends mainly on general health, which we optimise before surgery.

What is the most serious complication?

Infection and blood clots are the most important; both are uncommon and largely preventable with the right measures.

How common is long-term pain?

In the best studies about 20% report troublesome long-term pain, often milder than before surgery.

Is it riskier to replace both knees together?

Yes, complications are about 42% higher than for one knee, although function is similar, so we choose fit patients.

Can complications be treated?

Yes. Most are treated successfully; infection or loosening may need revision surgery.

To have your knee assessed and your X-rays reviewed, book a consultation, call +20 155 240 4488 or message us on WhatsApp at +20 155 554 7181.

Medically reviewed by Prof. Dr. Ibrahim Shaarawi, Professor of Orthopaedic Surgery. This article is general medical education and does not replace an examination or the treatment plan your surgeon sets for you. See our medical disclaimer.

Related knee replacement guides

Guides on risks and recovery:

Knee Replacement Complications: Risks, Prevention and Is It Dangerous?