Lateral Epicondylitis of the Elbow

The goal of this non-interventional study is to identify patients who respond to platelet-rich plasma (PRP) injections for chronic lateral epicondylalgia (tennis elbow) and to investigate factors associated with treatment response. The study will include approximately 139 adults (18 years and older) with chronic lateral elbow pain who received a PRP injection within the last 48 hours. The main question it aims to answer is: How many patients respond to PRP treatment for chronic lateral epicondylalgia at 90 days after injection? Secondary questions include: Which clinical, demographic, and occupational factors are associated with response to PRP? Can a predictive model be developed to identify patients likely to respond to PRP? How do pain, hand grip strength, and functional outcomes evolve over 90 days in responders versus non-responders? Participants will: Attend three visits at baseline (Day 0), Day 45, and Day 90. Undergo clinical examinations, pain assessments (EVA, DN4), functional tests (hand grip, PRTEE), and questionnaires. Have data on professional activities, medical history, and treatments collected. All procedures are part of routine care, except for the addition of the Clinical Global Impression - Change (CGI-C) scale at Day 45 and Day 90 to assess treatment response. The study will be conducted at the CMRRF de Kerpape and the CHU de Rennes in France. Each participant will be followed for approximately 3 months.