Shear-Wave Elastography in Musculoskeletal Pain: Current Evidence and Clinical Applications for Tissue Stiffness Assessment

Background and Objectives: Shear-wave elastography (SWE) is a quantitative ultrasound technique that estimates tissue stiffness based on the propagation velocity of shear waves. In musculoskeletal pain, it can provide biomechanical information that complements clinical examination and conventional ultrasound, although its relationship with pain has not been fully established. Materials and Methods: A narrative review was conducted of the literature indexed in PubMed, Embase, Web of Science, Cochrane Library, CINAHL, and PEDro on SWE and musculoskeletal pain. Priority was given to studies with the strongest evidence and the greatest clinical relevance. Results: SWE allows for the assessment of muscles, tendons, fascia and peripheral nerves, but its results depend on technical and biological factors, such as position, tension, muscle contraction, probe orientation and the equipment used. The evidence is more consistent in conditions with known tissue alterations, such as plantar fasciitis, Achilles or patellar tendinopathy and carpal tunnel syndrome, where it can support diagnosis and may contribute to clinical assessment and treatment monitoring. In other conditions, such as spinal pain and myofascial pain, where the structure causing the clinical symptoms is not so well defined, SWE findings are more heterogeneous. Currently, there are no fully accepted ultrasound parameters of clinical relevance, and comparisons between studies remain limited by methodological variability. Conclusions: SWE is a useful complementary tool in musculoskeletal pain, but not yet a standalone diagnostic modality or an objective measure of pain. Its clinical role will depend on standardized protocols, validated reference values, and higher-quality studies assessing its diagnostic, prognostic, and treatment-monitoring value.