Osteochondral lesions pose a significant clinical challenge due to their high prevalence, multifactorial etiology, and potential to progress toward long-term joint degeneration. This chapter presents a comprehensive overview of the diagnostic workup for chondral and osteochondral injuries, highlighting the critical importance of early detection and individualized evaluation. Epidemiological evidence underscores the widespread burden of cartilage defects across multiple joints and age groups. Key anatomical and biomechanical factors are discussed, with particular attention to associated conditions such as malalignment, ligamentous injuries, and patellar instability, which may influence both lesion progression and treatment outcomes. Accurate diagnosis relies on a structured clinical assessment that integrates detailed patient history, targeted physical examination, and advanced imaging. Radiographic analysis of joint alignment is fundamental in identifying biomechanical contributors to cartilage damage and planning corrective strategies. Complementary diagnostic tools—including MRI, arthroscopy, and molecular biomarkers—provide further insights into lesion severity, joint health, and metabolic status. Ultimately, the integration of patient-specific and lesion-specific parameters is essential to guide tailored treatment approaches. A multidisciplinary and systematic diagnostic framework is critical to optimize therapeutic decisions and promote long-term joint preservation.