There are various treatments for plantar fasciitis, including physical therapy, orthopedic inserts or steroid infiltrations. However, it is estimated that about 20% of patients do not respond to first-line treatment [Rompe, Sports Med Arthrosc Rev, 2009]. It is therefore necessary to be able to integrate new treatments into the management of this condition. The objective of the study is to assess the effect on pain and the safety of the percutaneous ultrasound-guided tenotomy associated with a platelet rich plasma injection to treat refractory plantar fasciitis.

• Pre-inclusion visit (consultation for scheduling the procedure) After verification of the inclusion criteria, the investigating rheumatologist will inform the patient of the study and give him/her the information note. The patient will be offered a period of reflection before signing the consent form. As the procedure requires prior precautions, this will allow the patient to become aware of them. The patient will be given a prescription for a walking boot and a pair of walking sticks.
• Inclusion visit (D0)

After verification of all the inclusion and non-inclusion criteria, the following examinations will be performed during the inclusion visit before the procedure:

• Signature of the consent by the patient and the investigator

• Interrogatory including collection of concomitant treatments, evaluation of the walking perimeter, evaluation of sports activities

• Clinical examination of the foot (Heel tenderness index)

• Standard X-ray of the foot (if not performed at screening)

• Plantar ultrasound = echogenicity of the plantar aponeurosis, measurement of thickness in mm, search for hypervascularization by Doppler

• VAS pain during activity

• FAAM self-questionnaire

• Procedure in 3 steps:

  1. Local anesthesia by tibial block 60 minutes before the tenotomy
  2. Venous sampling of 10 ml and centrifugation for 5 minutes
  3. Needle tenotomy and injection of 1 ml of PRP at the end of the procedure

• Prescription of enoxaparin at a preventive dose for 7 days

The tolerance of the procedure will be evaluated immediately after the procedure, using a VAS for pain. This will be collected by a nurse. We will also collect the acceptability of the procedure as well as the immediate complications (vagal discomfort, bleeding at the injection site).

The patient will then be monitored for two hours (4 times) in order to verify the lifting of the sensory block and the pain during it.

At the end of the consultation, the patient will receive a patient logbook to be completed at home in the 7 days following the procedure and at 14 days (collection of pain at the injection site and possible side effects) and a second logbook to be completed 6 weeks after the procedure.

-First protocol follow-up at home: D7 The patient will have filled out a daily pain VAS and notified any side effects related to the procedure and the analgesic intake during the first week.

A telephone contact will be made at this date by an investigating physician, or a mandated person, in order to ensure that the logbook has been filled out correctly and that there are no complications. The call will also remind the patient to return the questionnaire by mail (stamped and addressed envelope provided).

- Second protocol follow-up at home: S6 +/- 3 days

Six weeks after the procedure, the patient will complete the patient booklet given at D0 at home:

• FAAM self-questionnaire
• VAS pain during activity
• Occurrence of complications
• Gait perimeter
• Third protocol follow-up: consultation at M3 +/- 7 days A follow-up consultation is performed 3 months after the procedure. This corresponds to the usual follow-up of the patient.

During the consultation, the following examinations will be performed

• Clinical examination (HTI)
• Ultrasound of the foot
• VAS pain during activity
• Complications
• FAAM self-questionnaire
• Gait perimeter
• Questions about returning to sport
• Fourth protocol follow-up: consultation at M6 +/- 7 days (main objective) During the consultation, the following examinations will be performed
• Clinical examination (HTI)
• Ultrasound of the foot
• VAS pain during activity
• Complications
• FAAM self-questionnaire
• Gait perimeter
• Questions about returning to sport

Inclusion Criteria :

Patient with chronic inferior heel pain diagnosed as plantar fasciitis plantar fasciitis evolving for more than 3 months with a pain VAS at activity ≥ 4/10

• Failure of the initial management including physical therapy, adaptation of footwear and local steroid infiltration
• Patient 18 years of age or older
• Patient affiliated to a social security plan
• Patient able to understand the protocol and having signed an informed informed consent

Exclusion Criteria :

• Patients on NSAIDs and refusing to discontinue them 1 week and 1 week after the procedure
• Corticosteroid infusion at the same lesion site in the last 3 months
• History of PRP injection at the same lesion site
• Treatment with antiplatelet agents [Acetylsalicylic acid (Aspegic, Kardegic, Duoplavin, Resitune, Asasantine), Clopidogrel (Plavix, Duoplavin), Dipyridamole (Persantine, Cleridium, Asasantine)]
• Coagulation disorders: thrombocytopenia < 150,000 platelets/mm3 - Patients on curative anticoagulants
• Any medical condition that may interfere with pain assessment
• Current hematological disease or in remission for less than 5 years (hematological malignancies, myelodysplasia, autoimmune thrombocytopenia), chemotherapy
• Infection at the time of inclusion (bacterial infection and/or presence of fever and/or antibiotic treatment)
• Pregnant or breastfeeding women or those refusing effective contraception
• Patient deprived of liberty or under legal protection (guardianship or curatorship)
• Patients under court protection
• Patients participating in another clinical research protocol involving a drug or medical device
• Patients unable to follow the protocol, as determined by the investigator
• Patient refusing to participate in the study