Systemic Biochemical Signature and Functional Quality Index of Calcaneal Bone Marrow Aspirate in Adults Undergoing Foot or Ankle Surgery

Inclusion Criteria * Age 40 to 80 years. * Scheduled for clinically indicated foot or ankle surgery at the participating university hospital. * Ability to understand the study procedures and provide written informed consent. * Willingness to provide preoperative blood samples and intraoperative calcaneal bone marrow aspirate according to the study protocol. * Participants may have comorbidities, including type 2 diabetes mellitus and, when present, active Wagner grade 2-4 diabetic foot ulcers. These clinical characteristics will be recorded for observational analyses and do not define separate study groups. Exclusion Criteria * Critical limb ischemia without revascularization options or hemodynamic instability. * Active systemic infection or sepsis at the time of enrollment. * End-stage renal disease requiring dialysis. * Current use of high-dose systemic corticosteroids or other immunosuppressive drugs. * Current or recent malignancy within the last 5 years, except adequately treated non-melanoma skin cancer. * Significant cognitive impairment or psychiatric condition that, in the opinion of the investigator, precludes informed consent or adherence to study procedures. * Pregnancy or breastfeeding.