Conditioned Pain Modulation in Patients With Hemophilia
Introduction: Hemophilic arthropathy is characterized by functional alterations, disabling physical sequelae, and chronic pain. Conditioned pain modulation describes the net effect of endogenous pathways that enhance or diminish the effects of afferent noxious stimuli.

Objectives: To describe conditioned pain modulation in patients with hemophilia and identify the best predictive model of conditioned pain modulation in these patients Methods: Cross-sectional cohort study. 51 patients with hemophilic arthropathy will be recruited in 3 regions of Spain. The main study variable will be the conditional pain modulation (Conditioned Pain Modulation Index, using an ischemic technique of the arm using the pain pressure threshold as a test stimulus), with age being the dependent variable. The secondary variables, estimated as modifying or confounding variables, will be kinesiophobia (Tampa Scale for Kinesiophobia), catastrophizing (Pain Catstrophizing Scale), trait and state anxiety (State-Trait Anxiety Inventory) and the main clinical, anthropometric, and sociodemographic.

Expected results: Identify the degree of modulation conditioned by pain in patients with hemophilic arthropathy. Identify the best predictive model for conditioned pain modulation in these patients based on the study variables
- EligibilityCriteria: Inclusion Criteria:  Patients diagnosed with hemophilia A or B. Patients over 18 years of age. Persons with a medical diagnosis of bilateral hemophilic ankle arthropathy. Patients with clinical assessment by Hemophilia Joint Health Score (>4 points). Persons with hemophilia on prophylactic treatment with FVIII / FIX coagulation concentrates or monoclonal antibodies. Have signed the informed consent document.  Exclusion Criteria:  Patients with neurological or cognitive alterations that prevent the comprehension of the questionnaires and physical tests. Patients who have had an ankle hemarthrosis in the 6 months prior to the start of the study. Patients who have taken analgesic or anti-inflammatory drugs in the 30 days prior to the study. Patients who are undergoing an intervention (physiotherapeutic or orthopedic) at the time of the study. - HealthyVolunteers: No - Gender: Male - MinimumAge: 20 Years - MaximumAge: 65 Years - StdAgeList: Adult, Older Adult - StudyPopulation: A sample size of 51 patients with hemophilic ankle arthropathy has been estimated.  The assessment will take place at the premises of the hemophilia Associations included in the study. All evaluations will be performed by the same physical therapist, following the same evaluation protocol.  Given the characteristics of the study, the risks of bleeding in these patients during the evaluations should be minimized by designing a well-structured and justified protocol. Likewise, it should be emphasized that the study does not imply any change in the routines and medical management guidelines of the patient with respect to the usual clinical follow-up conditions, following the premises of the physician who usually attends the patient at his or her referral hospital. - SamplingMethod: Non-Probability Sample