Insight on Platelet-rich Plasma and Applications for Heel Pain

Platelet-rich plasma (PRP) is becoming increasingly popular, with current applications for tendonitis, joint pain, maxillofacial surgery, cardiovascular surgery, treatment of soft tissue ulcers, plantar fasciitis, and injuries.
 
PRP is a form of regenerative therapy. It is a component of whole blood taken via venipuncture from a patient, centrifuged into a concentrate, and then injected into the affected area. The centrifuge separates the blood into three layers: platelet poor plasma, PRP and erythrocytes.¹ The provider then injects PRP into the affected area.  PRP has a high concentration of growth factors including platelet derived growth factor, transforming growth factor, vascular endothelial growth factor, and epithelial growth factor.² These proteins have regenerative effects.  Injected PRP, in theory, increases the release of growth factors to enhance the healing process.³

Using PRP for Plantar Fasciitis

A 51-year-old active female presented with 4 months of plantar heel pain. Her weekly exercise consisted of mountain biking and walking.  She was able to bike but not walk for exercise due to her pain. She had tried a night splint, changing to supportive shoes, supportive inserts, stretching, and regular massage to the area without relief. X-rays showed a plantar calcaneal spur, no arthritis at the subtalar joint and were otherwise normal. Her biomechanical exam revealed mild rearfoot eversion, full range of motion at the ankle and subtalar joint, a flexible pes planus foot type, no equinus present, pain at the origin of the medial and central bands of the plantar fascia, and positive Tinel’s sign along Baxter’s nerve with a negative Tinel’s sign along the tibial nerve. She was diagnosed with Baxter’s neuritis and plantar fasciitis. She went to physical therapy for 2 months and continued to have constant pain. An injection of dexamethasone 4mg/mL with marcaine was performed for Baxter’s neuritis at the 4-month mark. This resolved her nerve pain and symptoms but the plantar fasciitis pain persisted. She elected to have PRP injection after 6 months of plantar fasciitis that did not improve with traditional treatment. The PRP injection was performed in the office after a local anesthetic block of 1 cc 2% lidocaine. The area of thickened plantar fascia tissue was identified using ultrasound and ultrasound guidance was used to inject 3 cc of PRP. She had one injection of PRP. Four weeks after injection, she noted resolved plantar fasciitis pain and she was able to return to walking for exercise pain free.
 
For plantar fasciitis that does not improve with traditional treatments such as arch supports or custom orthotics, stretching, and shoe changes, PRP may be a treatment to consider. When considering PRP compared with corticosteroid injection, both show pain relief at 3 months but PRP showed improvement in the visual analog scale pain scales (VAS) at 6 and 12 months.⁴ Compared with saline placebo, corticosteroid injection reduces pain at both 6 and 12 weeks and decreases plantar fascia thickness.⁵ The American College of Foot and Ankle Surgeons lists corticosteroid injection as first line treatment for plantar fasciitis.⁶ Complications of corticosteroid injection are post injection pain and risk of fat pad atrophy which is rare.⁷ PRP has been shown to be as effective at reducing pain scores as corticosteroid injection at 3 weeks and 6 months.⁸ PRP can improve pain, decrease plantar fascia thickness, and improve functional ability.⁹ Complications of PRP include post procedure pain. In a study comparing PRP injections to saline injections, the PRP group had a higher percentage change in the plantar fascia thickness and a higher change in the VAS pain score.¹⁰ PRP is a good alternative to corticosteroid injection.
 
When considering PRP injections for heel pain, one should take into consideration the patient’s health and inflammation status. The quality of the PRP harvested for use is directly related to the health of the patient. A generally healthy patient is going to have better quality PRP than an unhealthy patient. PRP is contraindicated in active autoimmune disease, severe liver disease, active anticoagulant therapy, infection, cancer, pregnancy or breastfeeding, recent illness, smoking, steroid injections to the area within a month of PRP, and low platelet count. It is wise to screen patients for these conditions prior to injecting PRP to get the best results.

PRP Treatment in a Recreational Runner

A 46-year-old female runner with 6 months of consistent heel pain came to the office for evaluation. She had tried physical therapy for 3 months, switching to a spin bike and stopping running for 6 weeks, shock wave treatments, and a walking boot for 4 weeks. She was running 35 miles per week prior to her symptoms. She was training for a marathon to take place in 8 months. After reviewing her previous treatments and performing a comprehensive evaluation, her biomechanical exam showed a flexible pes planus foot with no equinus and full range of motion at the ankle and subtalar joint, she had a neutral calcaneus position. Her exam showed pain at the medial band of the origin of the plantar fascia and a negative tinel’s sign along the tibial nerve and Baxter’s nerve. Her x-rays were negative for fracture, mass, arthritis, and calcaneal spur. At this point, MRI was ordered. Her MRI showed central cord plantar fasciitis with a talar dome lesion which was not symptomatic. She had one steroid injection at 6 months from symptom onset with minimal pain relief. She returned to physical therapy and continued to use the spin bike and avoid running and walking for exercise. She elected to have PRP injection after 8 months of plantar fasciitis symptoms. The PRP injection was performed in the office under local anesthesia. A local block was performed at the injection site of 1 cc 2% lidocaine plain. Using ultrasound, the thickened plantar fascia was identified at the calcaneal origin. Using ultrasound guidance, 4 cc PRP was injected into the plantar fascia. She noted pain relief after 3 weeks and has returned to a walk/run program with the help of her physical therapist. She has postponed her marathon training but hopes to race in a marathon in the spring.
 
When considering PRP in a runner or long distance hiker, I find it helpful to take into account their goals and training program. If a race or long distance hike is coming up, PRP might not be the best option because in my experience, it can take longer to recover compared with corticosteroid injection.

Clinical Pearls to Consider

When considering adding PRP to your practice, I feel one should take into consideration the cost of the PRP kits, the centrifuge and having staff trained in phlebotomy on hand to draw the blood. A simple way to start adding PRP to your practice is to use this at the surgery center. This can decrease your investment by having nursing staff do the blood draw and provide the necessary equipment. If you start to have good results and outcomes, consider adding this as a regenerative offering at your practice.
 
To prepare the patient for PRP injection before they come in, have the patient stop all non-steroidal anti-inflammatory drugs (NSAIDS) 10 days prior to the injection. NSAIDs can affect platelet secretome release and may decrease growth factor release.¹¹ I also have them hydrate 24 hours prior to the venipuncture and I recommend eating something prior to the procedure. Bringing a water bottle and having headphones or phone for distraction if they are concerned about the venipuncture or the injection itself can be helpful.
 
An important step to preparing the PRP is adding an anticoagulant to the whole blood prior to using the centrifuge. Sodium citrate 4% is frequently used in my observation and does not come with PRP kits. This is available through medical supply companies and compounding pharmacies.
 
After the injection, acetaminophen or a narcotic may be elected as appropriate for pain control, but NSAIDs are contraindicated. NSAIDs inhibit inflammation cascade and with PRP the desired response is to restart the inflammation cascade to restart the healing process. An arch support and supportive shoe is recommended for 2 weeks and then slow return to their preferred shoes. I have the patient use mild heat but avoid ice to the area. The goal is increased inflammation to start the inflammatory cascade of healing and ice can slow this down.  Light stretching to the area every hour or so the first 3 days is my instruction but I have the patient avoid any forceful manipulation.
 
For return to exercise after PRP injection, I recommend rest the first week. At weeks 2–3, light, I allow low impact exercises. At weeks 3–4, the patient may return to exercise as tolerated. I find it important to remind runners and competitive athletes to go slow as they add on mileage or activity. Having them work with their coach or physical therapist is helpful for this progression.

Final Thoughts

As PRP is becoming more popular, it is likely that more patients will ask about it. This article hopefully shared some relevant cases and related considerations to allow the reader to expand their knowledge on this regenerative option.

Dr. Westfall is the co-founder of Central Oregon Foot and Ankle.

References

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