Periprosthetic joint infection (PJI) is one of the most serious complications that can occur after a hip or knee replacement. Thankfully, it is uncommon, but when it does happen, diagnosing it quickly is essential. The earlier an infection is identified, the sooner treatment can begin, and the better the outcome.

Diagnosing a periprosthetic joint infection isn’t always straightforward. Symptoms can vary, and some infections develop gradually with few obvious signs at first. For this reason, orthopaedic specialists use a combination of clinical assessment, blood tests, joint fluid analysis, and imaging to build a complete picture.

Looking for early signs of infection

The first step is a thorough clinical examination. While some patients develop redness, swelling, warmth around the joint, or wound drainage, others may simply notice increasing pain or stiffness after what had previously been a successful recovery. These subtler signs are just as important to investigate.

Blood tests are used to measure inflammatory markers, usually C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR). Raised levels don’t automatically confirm an infection, but they indicate that further investigation is needed.

Joint aspiration and synovial fluid analysis

If blood tests and clinical findings raise concern, the next step is to examine the fluid inside the joint. A joint aspiration uses a fine needle to remove a small fluid sample from around the artificial joint, typically under sterile conditions and often guided by ultrasound.

The fluid is then sent to the laboratory. Specialists look at white blood cell count, neutrophil percentage, and whether bacteria can be identified. Newer laboratory markers – proteins produced specifically during infection – have also improved diagnostic accuracy, particularly in complex or borderline cases.

Modern diagnostic criteria

The 2018 International Consensus Meeting (ICM) introduced a structured scoring system that combines blood tests, joint fluid results, and clinical findings rather than relying on any single investigation. This reflects the reality that no one test is definitive – a patient may have normal blood tests but abnormal joint fluid, or vice versa.

A 2025 update to the ICM guidelines incorporated newer diagnostic technologies, and a separate 2025 study developed a machine-learning probability model to further support clinical decision-making in uncertain cases. Together, these advances mean that diagnosis is more accurate than ever, even when infections present atypically.

What happens if an infection is confirmed?

A confirmed periprosthetic joint infection will almost always require surgical treatment. Depending on the nature of the infection, how long it has been present, and the patient’s overall health, this may involve a one-stage or two-stage revision procedure – removing and replacing the implant while eradicating the infection.

Mr Alazzawi specialises in revision hip and knee surgery for infection-related complications and leads a highly experienced team that manages some of the most complex cases referred from across the region. If you have had a joint replacement and are experiencing increasing pain, swelling, warmth, or other concerns, early specialist review is important.

Find out more about revision hip and knee surgery with Mr Alazzawi here and book in for a consultation to discuss your suitability.

If you have been told that your hip replacement is no longer working as it should, the prospect of further surgery can feel daunting. Revision hip replacement is a more involved procedure than the original operation, but it is also a well-established one. With the right specialist, many patients go on to achieve excellent outcomes.

In this article, Mr Alazzawi explains what revision hip replacement surgery actually involves, and why it requires a different level of expertise to primary hip replacement.

What is revision hip replacement surgery?

Revision hip replacement involves removing some or all of the components from an existing hip replacement and replacing them with new implants. In some cases, only one part of the prosthesis needs to be addressed – such as the socket or the stem. In others, the entire implant must be removed and rebuilt from scratch.

The procedure is always more complex than the original hip replacement. This is because the surgeon must work around existing implants and scar tissue, as well as areas of bone loss caused by years of wear, loosening, or infection. Getting the new implant to fit securely and function well in this environment requires careful planning, advanced surgical technique, and significant experience.

Why is bone loss such an important factor?

One of the most significant challenges in revision hip surgery is managing bone loss. When an implant loosens over time, it can cause the surrounding bone to break down (osteolysis). This can leave the surgeon with less healthy bone to work with when securing the new implant.

A 2024 clinical review published in the Annals of Joint highlighted that preoperative planning is essential in revision cases, and that the adoption of custom 3D-printed implants shows promising results for patients with large bone defects – allowing surgeons to restore the hip’s anatomy more precisely than standard off-the-shelf components allow.

Mr Alazzawi uses advanced pre-operative imaging and 3D planning software to assess bone stock and determine the most appropriate implant strategy for each patient. This may include custom-made components where standard sizes are not sufficient.

How is infection managed during revision surgery?

Periprosthetic joint infection (PJI) is one of the most serious and complex reasons for revision surgery. When infection is present, the surgical approach must address not only the failing implant but also the bacteria that have settled around it.

Treatment often involves removing the implant entirely, clearing the infection, and reimplanting a new joint. Mr Alazzawi has a particular interest in this area and recently presented at the British Hip Society Meeting on the use of targeted local antibiotic therapy, including CERAMENT®. This approach can reduce the need for prolonged courses of systemic antibiotics while targeting the affected tissue more precisely.

What other techniques are used in revision hip surgery?

Depending on the cause and extent of implant failure, revision surgery may involve:

• Dual mobility bearings to reduce the risk of dislocation, particularly where the surrounding muscles have weakened
• Tantalum (trabecular metal) components for areas of significant bone loss, which allow bone to grow into the porous structure of the implant over time
• Stemmed or longer femoral components to achieve stable fixation beyond the area of bone damage
• Bone grafting in cases where the pelvis or femur requires structural support

What should I expect after revision hip surgery?

Recovery from revision hip replacement takes longer than recovery from a primary procedure. Most patients will use crutches for several weeks and will not bear full weight immediately. Physiotherapy plays an important role in rebuilding strength and confidence in the new joint.

The timeline and rehabilitation plan will depend on the complexity of the procedure and the reason for revision. Mr Alazzawi and his multidisciplinary team will guide you through every stage of recovery, with a personalised plan designed around your individual needs.

If you have concerns about a previous hip replacement, book a consultation with Mr Alazzawi for a comprehensive assessment and a clear plan for moving forward.

For many patients’ considering hip replacement surgery, one of the biggest concerns is whether they’ll be able to return to the sports and activities they enjoy afterwards. The goal of surgery isn’t just to relieve pain, but to restore movement, confidence, and quality of life. Whether it’s golf, cycling, swimming, tennis, hiking, or even running, helping patients to stay active is often a major priority.

Modern hip replacement techniques are designed with this in mind. Advances in surgical methods and improved implant technology, mean that many patients can return to an active lifestyle far sooner than they expect. The key is understanding what recovery involves, which activities are realistic, and how the right surgical approach can support a safe and successful return to sport.

How long does hip replacement recovery take?

Before returning to sport, the priority is allowing the hip to heal properly. In the early weeks after surgery, the focus is on pain control, walking safely, and rebuilding strength. Most patients are encouraged to start moving very soon after surgery, often on the same day or the day after their procedure.

This early mobilisation is a big part of the rapid recovery approach that Mr Alazzawi uses. Modern pain management, minimally invasive techniques, and carefully planned rehabilitation all help reduce hospital stay and improve confidence during those first few weeks.

Many patients are walking with sticks or crutches for a short period, progressing steadily as strength improves. Low-impact activities such as walking and gentle cycling often begin within the first few weeks, while swimming may be possible once the wound has healed fully.

By around six to twelve weeks, many patients feel a significant improvement in both pain and mobility. However, recovery is individual, and returning to sport should always be guided by your surgeon and physiotherapist rather than a fixed timeline.

Which sports can you return to after a hip replacement?

Most patients can return to low-impact sports after hip replacement, and these are generally encouraged as part of a healthy, active lifestyle. Activities such as walking, golf, cycling, swimming, rowing, doubles tennis, and yoga are all commonly resumed once recovery is well underway.

Higher-impact sports such as long-distance running, singles tennis, football, or contact sports require a more careful approach. While some patients do return to these activities, they may place greater stress on the implant over time, which could affect how long it lasts. Decisions should be made on an individual basis depending on age, fitness level, and the type of implant used.

How can surgical technique improve recovery?

The type of hip replacement and the surgical approach used can make a real difference to recovery and return to sport. For example, MAKO robotic-assisted hip replacement allows for highly accurate implant positioning using advanced 3D planning. Better alignment can improve stability, movement, and confidence when returning to activity.

Another important option is the Direct Anterior Approach (DAA) total hip replacement. This technique uses a muscle-sparing approach, meaning the surgeon works between muscles rather than cutting through them. As there is less disruption to the surrounding soft tissues, many patients experience less pain and a quicker early recovery.

Combined with enhanced recovery protocols, the DAA approach often allows for a smoother transition back to everyday life and eventually sport.

Guidance with returning to sport after a hip replacement

Returning to sport after a hip replacement is absolutely possible, but it’s important to approach it with patience and realistic expectations. Your new hip is designed to improve quality of life, reduce pain, and restore movement, not necessarily to perform exactly like a natural joint.

Success often comes from choosing the right activities, following your rehabilitation plan closely, and giving your body time to adapt. Get in touch to book a consultation and Mr Alazzawi can help guide you toward the best surgical approach and recovery plan based on your lifestyle and goals.

If knee pain is starting to affect your day-to-day life, you may have already come across the term total knee replacement. But when arthritis is confined to a single knee compartment, a partial knee replacement can be a very effective alternative.

In this blog, we’ll break down the key differences, who each procedure is suitable for, and what you can expect in terms of recovery and long-term outcomes.

Total knee replacement or partial knee replacement?

A total knee replacement, involves resurfacing all three compartments of the knee. This is usually recommended when arthritis is widespread or when the knee has become unstable.

A partial knee replacement is used when damage is limited to just one part of the knee, most commonly the inner (medial) compartment. In this procedure, only the worn-out section is replaced, while the healthy bone, cartilage, and ligaments are preserved. This means much of your natural knee structure remains intact.

However, it’s only suitable for carefully selected patients, which is why a thorough assessment, including scans and clinical examination, is essential before making a decision.

What are the benefits of partial knee replacement?

For the right patient, partial knee replacement can offer several advantages over a total replacement. The surgery typically involves a smaller incision and less disruption to the surrounding tissues, which can lead to less pain and a quicker recovery in the early stages.

Patients often regain movement faster and report that their knee feels more normal. This can make everyday activities, like walking, climbing stairs, or getting in and out of a chair, feel more intuitive.

A recent TOPKAT trial 10-year follow-up, published in The Lancet Rheumatology, found that patients with arthritis confined to one part of the knee experienced similar pain relief and function at 10 years, whether they had a partial or total knee replacement.

Partial knee replacement can also be appealing for more active patients. A study presented at the American Academy of Orthopaedic Surgeons found that nearly 60% of athletes returned to sport after partial knee replacement, with most returning to the same level of intensity. The median return time was just 10 weeks, showing how quickly some patients can get back to the activities they enjoy.

Technology is improving for knee replacements

Advances in imaging and surgical planning are improving outcomes for both partial and total knee replacements. Techniques such as 3D imaging and robotic-assisted surgery, like MAKO robotic-assisted knee replacement, allow for highly accurate implant positioning. This is especially important in partial knee replacement where precision is key.

These technologies help ensure the implant fits your anatomy as closely as possible, which can lead to better function, less pain, and a smoother recovery.

Which option is right for you?

For patients with arthritis limited to one area, a partial replacement can offer faster recovery and a more natural-feeling joint. For those with more widespread damage, a total replacement remains the most effective and reliable option.

If you’re unsure which path is best, book a consultation. Mr Alazzawi can assess your knee, discuss your goals and talk through your options. He can guide you toward the treatment that fits your needs and lifestyle.

Get in touch to book an assessment with Consultant Orthopaedic Surgeon Mr Alazzawi today.