PRP Injection for Knee Arthritis Explained by Dr. Mayur Rabhadiya

What Is a PRP Injection for Knee Arthritis?

Platelet-rich plasma, commonly called PRP, is a blood-derived injection that may be considered for selected patients with symptomatic knee osteoarthritis.

A small quantity of the patient’s blood is collected and processed to separate a plasma fraction containing a higher concentration of platelets than the original blood sample. This preparation is then injected into the knee joint.

Platelets contain proteins and signalling molecules involved in inflammation, tissue response and healing processes.

PRP may reduce pain or improve function in some patients. However, it is not a proven cartilage-regeneration treatment and does not reliably reverse established knee arthritis.

Dr. Mayur Rabhadiya considers PRP only after confirming the diagnosis, assessing the arthritis stage and discussing the uncertainty of benefit.

Patients comparing all injection options should first read about knee injections for arthritis.

How Is PRP Prepared?

PRP preparation generally involves:

Collecting blood from a vein in the patient’s arm.
Placing the blood into a specialised preparation system.
Centrifuging the blood to separate its components.
Selecting the platelet-containing plasma fraction.
Preparing the final injection using sterile technique.
Injecting the preparation into the knee joint.

The entire appointment may take longer than a standard medicine injection because the blood must be collected and processed before the joint injection.

PRP is described as autologous because it is prepared from the patient’s own blood.

However, the exact composition of the final product depends on the equipment, processing method and patient’s blood characteristics.

PRP Is Not One Standardised Product

One of the main challenges in interpreting PRP research is that different studies and clinics may use substantially different preparations.

PRP may vary according to:

Platelet concentration
White blood-cell concentration
Red blood-cell contamination
Centrifugation method
Processing time
Total injection volume
Activation method
Number of injections
Interval between injections
Storage and handling

PRP containing a greater concentration of white blood cells is often called leukocyte-rich PRP.

A preparation with fewer white blood cells may be called leukocyte-poor PRP.

Evidence from one PRP system should not automatically be applied to every other preparation marketed under the same name.

This lack of standardisation is one reason guidelines remain cautious.

How Is PRP Intended to Help Knee Arthritis?

PRP is intended to influence the biological environment inside the knee.

The platelet-derived substances may affect:

Inflammatory signalling
Pain-related pathways
Joint-lining activity
Cellular communication
Tissue response after injection

These proposed biological effects do not establish that PRP rebuilds the joint.

PRP does not reliably:

Regrow normal articular cartilage
Restore severely lost joint space
Correct bow-leg or knock-knee deformity
Repair advanced meniscal degeneration
Reverse bone-on-bone arthritis
Restore severely restricted movement
Guarantee avoidance of knee replacement

Symptom improvement, when it occurs, should not be described as proof of cartilage regeneration.

What Does the Evidence Show?

Some clinical studies and systematic reviews report improvement in pain and function after PRP, particularly in selected patients with mild or moderate knee osteoarthritis.

Other high-quality studies have not shown a meaningful advantage over placebo injections.

Research results are difficult to combine because studies differ in:

PRP preparation
Patient age
Arthritis severity
Number of injections
Comparison treatment
Rehabilitation programme
Outcome measures
Follow-up period

The responsible conclusion is that PRP may help some patients, but the probability, magnitude and duration of improvement cannot be predicted reliably.

It should be presented as a selective symptom-management option with uncertain benefit, not as an established disease-modifying treatment.

Who May Be Considered for PRP?

PRP may be discussed in a patient who has:

Clinically confirmed knee osteoarthritis
Persistent pain despite core non-surgical treatment
Mild or moderate arthritis
Reasonably preserved knee movement
Limited fixed deformity
Realistic expectations
No active infection
No immediate need for knee replacement
A preference to avoid or limit certain medicines
An understanding that improvement is not guaranteed

The patient should already have, or be willing to follow, an appropriate programme of exercise and activity modification.

PRP should not replace the core measures explained in non-surgical knee arthritis treatment in Mumbai.

Who May Be Less Likely to Benefit?

The probability of meaningful improvement may be lower when there is:

Complete joint-space loss
Severe bone-on-bone arthritis
Major bow-leg or knock-knee deformity
Marked stiffness
Significant instability
Persistent pain at rest
Severe walking restriction
Pain arising primarily from the hip or spine
Several previous injections with minimal benefit
An incorrect or uncertain diagnosis

PRP may still occasionally be considered when surgery is not currently possible or desired, but the limitations must be explained clearly.

Advanced structural damage cannot be corrected by changing the concentration or brand of PRP.

Assessment Before a PRP Injection

Before recommending PRP, the assessment may include:

Pain location and pattern
Duration of symptoms
Walking and stair limitation
Night pain
Knee swelling
Knee movement
Limb alignment
Ligament stability
Muscle strength
Previous medicines and injections
Weight-bearing X-rays
General medical history

MRI is not routinely required when clinical examination and weight-bearing X-rays already confirm knee osteoarthritis.

A hot, red or rapidly swollen knee may require investigation for infection, gout or inflammatory arthritis rather than a PRP injection.

How Is the PRP Injection Performed?

After the blood has been processed:

The knee is positioned appropriately.
The injection site is identified.
The skin is cleaned using an antiseptic solution.
A sterile needle is inserted into the joint.
Excess joint fluid may be removed when clinically appropriate.
The PRP preparation is injected.
A small dressing is applied.

Temporary pressure or discomfort may occur.

Many knee injections can be performed using anatomical landmarks. Ultrasound guidance may be considered when the anatomy is difficult, a significant fluid collection is present or additional confirmation of needle placement is required.

Ultrasound improves visualisation of placement but cannot guarantee that the biological treatment will work.

How Many PRP Injections Are Required?

PRP treatment protocols vary.

A programme may involve:

One injection
Two injections
Three injections
Another system-specific schedule

The interval between injections may also vary.

There is no universally accepted number that is best for every patient.

Some studies have reported more favourable results with a series of injections, while others have shown limited or no advantage. Different studies also used different PRP compositions, making direct comparison difficult.

A patient should ask:

Which preparation is being used?
How many injections are proposed?
Why has that schedule been selected?
What is the total cost?
What evidence supports the protocol?
What happens if the first injection does not help?

More injections do not automatically mean a better result.

How Quickly Does PRP Begin to Work?

PRP does not usually produce immediate pain relief.

Temporary discomfort may occur during the first few days. When improvement occurs, it may develop gradually over several weeks.

A local anaesthetic may provide early temporary numbness, but this is different from the effect of PRP itself.

The response should be assessed according to meaningful changes in:

Walking
Stair use
Chair-rise
Sleep
Exercise participation
Pain-medicine requirement
Daily independence

Improvement during the first few hours does not establish long-term treatment success.

How Long Can PRP Relief Last?

Some patients report improvement lasting several months. Other patients experience brief improvement or no meaningful benefit.

Duration may depend on:

Arthritis stage
PRP preparation
Number of injections
Knee alignment
Muscle strength
Body weight
Activity level
Rehabilitation
Associated inflammation
Individual biological response

It is not possible to promise six months, one year or any other fixed period of relief.

If symptoms improve, that period should be used to continue exercise, strengthening and weight management where relevant.

What Should Be Done After PRP?

Patients may be advised to:

Avoid strenuous activity for a short period
Continue gentle knee movement
Avoid running, jumping and heavy leg exercise immediately
Monitor the injection site
Resume exercise gradually
Follow the individual rehabilitation plan
Contact the clinic if symptoms worsen significantly

The patient should not immediately perform a prolonged walk or demanding workout to test the injection.

Aftercare protocols vary. Patients should follow the instructions given for the specific procedure rather than applying another clinic’s protocol.

Medicines Before and After PRP

Patients should provide a complete list of medicines and supplements before treatment.

This includes:

Anti-inflammatory medicines
Aspirin
Clopidogrel
Warfarin
Apixaban
Rivaroxaban
Other anticoagulants
Herbal products
Steroids
Supplements that may affect bleeding

Some PRP protocols modify the use of anti-inflammatory medicines around the injection, but recommendations are not identical across preparations and clinicians.

Do not stop prescribed medicines independently.

The possible effect on platelet function must be balanced against the medical reason the medicine was prescribed.

Risks and Side Effects

Possible risks include:

Pain during injection
Temporary post-injection soreness
Knee swelling
Bruising
Bleeding
Vasovagal symptoms during the blood draw
Local inflammatory reaction
Failure to improve
Infection
Injury to surrounding structures

Because PRP is prepared from the patient’s own blood, the risk of a conventional drug allergy may be lower than with some manufactured products. However, reactions to additives, preparation materials or local anaesthetic remain possible.

Seek prompt assessment for:

Rapidly increasing pain
Severe swelling
Spreading redness
Increasing warmth
Fever
Chills
Inability to bear weight

PRP and Medical Conditions

PRP may require modification, postponement or further assessment in patients with:

Active infection
Significant anaemia
A low platelet count
A platelet-function disorder
Uncontrolled systemic illness
Significant bleeding risk
Poorly controlled medical conditions

Unlike a corticosteroid injection, PRP does not usually produce the same predictable temporary rise in blood glucose.

However, diabetes still affects infection risk, general health and treatment planning.

A blood-derived injection should not be assumed to be suitable merely because it is described as natural.

PRP Compared With Cortisone

A cortisone injection has a direct anti-inflammatory effect and may provide relatively rapid but short-term relief.

PRP:

Is prepared from the patient’s blood
May take longer to produce improvement
Has variable preparation methods
Has uncertain and inconsistent evidence
Does not cause the same predictable steroid-related glucose rise

Neither treatment regrows established cartilage or cures advanced knee osteoarthritis.

Read more about cortisone injection for knee arthritis.

PRP Compared With Hyaluronic Acid

Hyaluronic acid is a manufactured injectable product intended to supplement the joint-fluid environment.

PRP is a patient-derived preparation containing platelets and plasma.

Some comparative studies favour PRP for longer-term symptom improvement, while other studies do not establish a reliable clinically important difference.

Neither treatment is uniformly recommended for every patient.

Read the detailed guide to hyaluronic acid injection for knee arthritis.

PRP Compared With GFC Therapy

PRP and GFC are both prepared from the patient’s blood, but the preparation process and final composition may differ.

The terms should not be used interchangeably.

Differences may include:

Platelet concentration
White blood-cell content
Method of growth-factor release
Processing equipment
Final injection composition
Number of injections
Supporting evidence

No current evidence establishes either preparation as universally superior for every patient with knee arthritis.

Read the dedicated comparison of GFC therapy versus PRP.

Can PRP Regrow Knee Cartilage?

PRP should not be described as a proven cartilage-regeneration treatment.

Some laboratory studies demonstrate biological effects, but laboratory activity is not the same as clinically restoring normal human joint cartilage.

High-quality clinical evidence has not established that PRP reliably:

Increases useful cartilage thickness
Restores lost joint space
Reverses advanced osteoarthritis
Prevents structural progression
Rebuilds a bone-on-bone knee

Patients should distinguish between possible symptom improvement and proven structural regeneration.

Can PRP Delay Knee Replacement?

PRP may reduce symptoms enough for a selected patient to continue non-surgical care without immediate surgery.

It cannot guarantee avoidance or delay of knee replacement for a specific period.

Delay is useful only when the patient maintains acceptable:

Walking ability
Sleep
Function
Independence
Quality of life

Repeated injections should not be used merely to postpone reassessment while pain, deformity and disability continue to progress.

When Should PRP Treatment Be Reassessed?

The complete treatment plan should be reviewed when:

PRP provides no meaningful improvement
Relief lasts only briefly
Each injection produces less benefit
Walking continues to decline
Night pain becomes persistent
Deformity progresses
Knee movement is being lost
Strong pain medicines remain necessary
Repeated injections are being proposed
Knee replacement may now be appropriate

Changing only the PRP kit or concentration may not solve the problem when advanced structural arthritis is the principal cause of disability.

Frequently Asked Questions About PRP for Knee Arthritis

What does PRP stand for?

PRP stands for platelet-rich plasma.

Is PRP made from my own blood?

Yes. Blood is collected from the patient and processed before the selected plasma fraction is injected.

Is every PRP injection the same?

No. Platelet concentration, white blood cells, preparation systems, volume and injection schedules can differ.

Does PRP cure knee arthritis?

No. It may improve symptoms in selected patients but does not cure structural osteoarthritis.

Can PRP regrow cartilage?

Current clinical evidence does not establish reliable regeneration of established lost cartilage.

Does PRP work better in early arthritis?

Some evidence suggests that patients with mild or moderate arthritis may be more likely to benefit than patients with advanced deformity, but improvement cannot be guaranteed.

Can PRP help bone-on-bone arthritis?

Temporary relief is possible, but substantial or durable improvement may be less likely in advanced disease.

How many PRP injections are required?

Protocols vary from one to several injections. There is no universally accepted number for every patient.

How quickly does PRP work?

When improvement occurs, it usually develops gradually over several weeks rather than immediately.

How long does PRP last?

Some patients improve for several months, while others receive brief or no meaningful relief.

Is PRP painful?

Temporary discomfort may occur during blood collection, injection and the early post-injection period.

Can the knee hurt more after PRP?

Yes. Temporary soreness or swelling can occur. Severe or progressively worsening symptoms require assessment.

Is ultrasound guidance necessary?

Not for every knee injection. It may be useful when anatomical access is difficult or direct confirmation is required.

Can PRP be performed while taking blood thinners?

Possibly, but the medicine and bleeding risk must be reviewed. Do not stop blood thinners independently.

Is PRP suitable for patients with diabetes?

It may be considered after individual assessment. PRP does not usually cause the steroid-related rise in glucose, but diabetes remains relevant to infection risk and general health.

Is PRP better than cortisone?

Neither is universally better. Cortisone generally provides shorter-term anti-inflammatory relief, while PRP has a slower and less predictable response.

Is PRP better than GFC?

Current evidence does not establish either preparation as universally superior. They differ in processing and final composition.

Can PRP prevent knee replacement?

No. It may improve symptoms temporarily but cannot guarantee avoidance of future surgery.

About Dr. Mayur Rabhadiya

Dr. Mayur Rabhadiya is an Orthopedic & Joint Replacement Surgeon in Mumbai.

His qualifications include MBBS, D’Ortho, DNB Orthopedics, MNAMS Orthopedics and a Fellowship in Robotic & Computer-Navigated Joint Replacement.

His approach to platelet-derived injections is evidence-based and patient-specific. PRP is considered only after reviewing the diagnosis, arthritis severity, medical history, previous treatment, available evidence and realistic alternatives.

His practice includes knee arthritis assessment, selected GFC therapy, total knee replacement, partial knee replacement, robotic knee replacement, bilateral knee replacement and revision knee replacement.

Last medically reviewed: June 2026.

Book a Knee Arthritis Injection Consultation in Mumbai

Patients considering PRP, GFC or another knee injection can consult Dr. Mayur Rabhadiya for individual assessment at Ghatkopar East or Ghatkopar West, Mumbai.

Call +91 84249 03913 or +91 96113 30063.

Appointments can also be requested through the orthopedic doctor consultation page.

Medical References

This patient-education page is informed by the American Academy of Orthopaedic Surgeons clinical practice guideline and high-quality clinical research evaluating platelet-rich plasma for knee osteoarthritis.

Medical Disclaimer

This information is intended for general patient education and does not replace clinical examination or personalised injection advice.

PRP preparation methods and treatment protocols vary. Suitability depends on the diagnosis, arthritis severity, blood count, medical conditions, medicines, previous treatment and patient expectations. No PRP preparation can guarantee pain relief, cartilage regeneration or prevention of knee replacement.