What is involved in a Platelet-Rich Plasma (PRP) shoulder injection?

Platelet-Rich Plasma (PRP) Shoulder Injection Procedure

PRP shoulder injections have limited evidence supporting their use for rotator cuff tendinopathy or partial tears, and should not be routinely recommended as first-line treatment for shoulder conditions. 1

What is PRP?

Platelet-Rich Plasma (PRP) is an autologous blood product that contains a concentrated amount of platelets above baseline levels found in whole blood. The theoretical benefit comes from platelets' ability to release growth factors that may promote tissue healing.

PRP Preparation Process

1. Blood Collection:

   • Autologous blood is drawn from the patient (typically 10-60 ml depending on the protocol)
   • Blood is collected in tubes with or without anticoagulants
   • EDTA anticoagulant should be avoided for PRP preparation 1

2. Centrifugation:

   • Blood undergoes centrifugation to separate components
   • Protocols vary, but typically involves low-g centrifugation (e.g., 170 x g for 10 min) 1
   • This separates blood into layers: platelet-poor plasma, buffy coat (containing platelets and leukocytes), and red blood cells

3. Extraction:

   • The platelet-rich portion is extracted
   • Final PRP should contain approximately 1 to 1.5 million platelets per μL 1

Injection Procedure

1. Pre-procedure:

   • Patient positioning: seated or lying with shoulder exposed
   • Skin preparation with antiseptic solution
   • Local anesthetic may be used at the injection site
   • Ultrasound guidance is often used for accurate needle placement

2. Injection Technique:

   • Typically uses a 22-30 gauge needle
   • Common approach is posterior or lateral to the shoulder joint
   • For rotator cuff pathology, injection is directed into the subacromial space
   • Approximately 2-5 mL of PRP is typically injected 2
   • Some protocols may include activation of PRP before injection, though collagen-rich tissues may activate PRP naturally 1

3. Post-injection:

   • Brief period of rest (10-15 minutes)
   • Patient is advised on post-procedure care

Post-Procedure Care

1. Immediate Post-Injection (0-72 hours):

   • Avoid heat application (hot showers, heating pads, saunas) for 48-72 hours 3
   • Cold therapy may be used for pain management 3
   • Avoid NSAIDs as they may interfere with platelet function
   • Relative rest of the shoulder for 24-48 hours

2. Rehabilitation Phase:

   • Gradual return to normal activities after 48-72 hours
   • Gentle stretching exercises may begin after 3-7 days
   • Progressive strengthening as tolerated

Treatment Protocol

• Typically involves 1-3 injections at 1-4 week intervals 2, 4
• Follow-up evaluation at 6 weeks, 3 months, and 6 months 2

Clinical Evidence and Limitations

• Limited evidence does not support routine use of PRP for rotator cuff tendinopathy or partial tears 1
• Strong evidence does not support biological augmentation of rotator cuff repair with platelet-derived products for improving patient-reported outcomes 1
• Limited evidence supports the use of liquid PRP for potentially decreasing retear rates after surgical repair 1
• Some studies show PRP may provide longer pain relief compared to corticosteroid injections in shoulder conditions 4, 5

Important Considerations and Caveats

• PRP preparations are poorly standardized across clinical settings 1
• The content, purity, and biological properties of PRP vary widely and impact clinical efficacy 1
• Patient selection is crucial - older age is associated with poorer outcomes in rotator cuff pathology 1
• Patients should be informed about the limited evidence supporting PRP use for shoulder conditions
• Cost considerations: PRP is often not covered by insurance
• PRP should be considered only after conventional treatments have failed

Alternative Treatments

• Physical therapy (strongly recommended as first-line treatment) 1
• Corticosteroid injections (moderate evidence supports single injection for short-term improvement) 1
• Hyaluronic acid injections (limited evidence supports use) 1

PRP shoulder injections remain a treatment with uncertain benefits for most shoulder conditions, particularly for rotator cuff pathology, and should be considered only after conventional treatments have failed.