Knee PRP Injections
Ultrasound-Guided Platelet-Rich Plasma Therapy

PRP stands for platelet-rich plasma. It is made from a small sample of your own blood, spun in a centrifuge to concentrate the platelets, cells rich in the growth factors the body uses to repair tissue. When injected into the knee, PRP aims to reduce pain and inflammation and support the body’s natural healing.

In the knee, PRP is most often used for:

• Mild-to-moderate knee osteoarthritis, to ease pain and improve function.
• Tendon and ligament problems, such as patellar tendinopathy.
• Early cartilage wear, as part of a wider management plan.

PRP here refers strictly to musculoskeletal use in the knee joint and surrounding soft tissue. It is not the same as PRP used in hair or aesthetic treatments. An ultrasound assessment confirms whether your knee is suitable.

PRP may suit you if you have persistent knee pain from mild-to-moderate osteoarthritis, a tendon or ligament problem, or early cartilage wear, and you want to try a treatment that uses your body’s own healing response, particularly if you are looking to delay or avoid knee surgery or prefer not to rely on repeated steroid injections.

PRP is generally less suitable for very advanced (bone-on-bone) arthritis, and is not appropriate during active infection or certain blood conditions. It is not a guaranteed alternative to a joint replacement where one is clearly indicated.

The only reliable way to know if PRP is right for your knee is a consultant assessment with ultrasound. Your consultant will examine the knee, review your goals and give you a clinical view of whether PRP is likely to help.

At the Harley Street Ultrasound Group, your appointment begins with a diagnostic ultrasound assessment, performed by your specialist consultant doctor. Ultrasound shows the soft tissues, tendons and joint lining in real time and helps confirm the source of your knee pain. And, just as importantly, rule out other causes such as a meniscal problem or significant structural damage that PRP would not address.

Assessing the knee accurately first is what makes the treatment precise. Because the same ultrasound is then used to guide the injection, your consultant can place the PRP directly into the target structure, rather than by external approximations.

If the assessment shows a different treatment would serve you better, your consultant will tell you on the day. See “What if I don’t need an injection?” below.

A PRP knee injection works by concentrating the platelets from a small sample of your own blood and injecting them, under ultrasound guidance, into the knee. The platelets release growth factors that calm inflammation and support the body’s natural repair of joint and soft-tissue. The procedure has three simple steps:

• A small blood draw is taken from your arm, just like a routine blood test.
• The sample is spun in a centrifuge to separate and concentrate the platelet-rich plasma.
• The PRP is injected into the knee under real-time ultrasound guidance, so your consultant can see the needle reach the joint or target tissue exactly.

Because placement is imaging-confirmed rather than estimated by feel, nearby nerves and blood vessels can be identified and avoided. For many patients PRP is considered as a way to delay or avoid knee surgery, though it is not a guaranteed alternative where surgery is clearly needed.

Most patients find a PRP knee injection more comfortable than expected. Local anaesthetic is used, so you typically feel a small sting from the blood draw and a brief pressure or ache as the PRP is injected. Mild soreness or swelling in the knee for a day or two afterwards is normal and a sign the healing response has begun.

The appointment usually takes around 30–45 minutes from assessment to completion:

• Your consultant scans the knee to confirm suitability.
• A small blood sample is taken and spun in the centrifuge.
• The skin is cleaned and local anaesthetic applied.
• The PRP is delivered under live ultrasound guidance, then you rest briefly and receive aftercare guidance.

There is no general anaesthetic and no overnight stay. Because PRP uses your own blood, serious side effects are uncommon.

Your injection is performed by a consultant specialist doctor, not a physiotherapist, nurse or GP. This matters, as the majority of MSK injections in the UK are delivered by non-consultant practitioners, often without ultrasound image guidance.

At the Harley Street Ultrasound Group, you receive both the clinical judgement of a senior specialist and the precision of real-time ultrasound examination in a single appointment. Your consultant assesses the knee, confirms the source of pain, performs the procedure and explains your aftercare personally.

We will never give you an injection you do not need. If, after your ultrasound assessment, your consultant decides an injection is not the right treatment for you, the procedure simply won’t go ahead. You will be charged at our standard diagnostic ultrasound rate, not the full treatment price.

This is a deliberate commitment to clinical integrity. Some providers treat every appointment as a guaranteed procedure; we don’t. You can book knowing that you will receive a genuine specialist assessment first, and that treatment only proceeds when a senior clinician believes it is genuinely warranted.

If an injection isn’t appropriate, your consultant will explain why and set out the alternatives. This may include physiotherapy, a different injection, such as PRP, or onward referral, meaning you still leave with a clear plan.

PRP works gradually rather than instantly. Unlike a steroid injection, which can give fast but temporary relief, PRP supports a slower healing response, many patients notice improvement over several weeks, with benefit often building for up to two to three months.

How long results last varies with the condition and its severity. For knee osteoarthritis, relief can last several months to around a year in responders, after which a top-up may be considered. Many treatment plans involve a course of one to three injections a few weeks apart, depending on your assessment.

PRP does not help everyone, and it is not a cure for arthritis. Your consultant will give you a realistic picture of the likely benefit, the number of sessions and the timeline based on your own knee.

There is no significant downtime. You can usually return to everyday activities the same day, though it is sensible to avoid heavy exercise, running or strenuous knee use for a few days while the knee settles. Some mild soreness or swelling for 24–72 hours is normal and expected.

An important point: avoid anti-inflammatory painkillers (such as ibuprofen and other NSAIDs) for a short period before and after PRP, usually around a week either side, as they can blunt the healing response PRP is designed to trigger. Paracetamol is generally fine; your consultant will give you exact guidance.

You will receive clear written aftercare advice, and a short course of physiotherapy is often recommended to get the best result. Our team remains available if you have any questions as you recover.

They do different jobs. A steroid (cortisone) injection is a strong anti-inflammatory that often gives fast pain relief, but the effect is usually temporary and repeated steroid use is generally limited. PRP works more slowly by supporting the knee’s own healing response, and in suitable patients the benefit can be longer-lasting.

As a general guide, steroid injections can be a good choice for a painful flare where quick relief is the priority, while PRP is often considered for mild-to-moderate osteoarthritis or tendon problems where the aim is more durable improvement, or when someone wants to reduce reliance on repeated steroid injections.

There is no single right answer for everyone. Your consultant will recommend the option best suited to your knee. You can also read about our ultrasound-guided steroid knee injections on its dedicated page.

An ultrasound-guided PRP injection for the knee at The Harley Street Ultrasound Group is £545, all fees inclusive. There are no extra charges for the consultant assessment, the diagnostic ultrasound, the blood draw and PRP preparation, the procedure itself, or your written report.

What’s included in the price:

• Consultant specialist assessment and diagnostic ultrasound
• Blood draw and platelet-rich plasma preparation
• Ultrasound-guided PRP injection into the knee
• Local anaesthetic and all consumables
• Written report and tailored aftercare guidance

There are no referral required and no waiting lists. Importantly, if your consultant assesses you and decides an injection is not clinically appropriate, you will only be charged at our standard diagnostic ultrasound rate, not the procedure price. We accept self-pay and most major UK private health insurers; please confirm cover with your insurer before booking.

Coming to us privately does not affect your NHS care. Our goal is to get you answers and treatment quickly, without the long waits often involved in accessing injection therapy on the NHS, where PRP is not routinely offered for the knee.

You are seen by a consultant specialist who can assess, diagnose and, where appropriate, treat your knee in a single visit. Your report and images can be shared securely with your NHS GP or any specialist, and if your situation needs onward NHS care your consultant will write to your GP accordingly.

We don’t want you waiting months in pain when effective treatment is available now.