* 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
