Electromagnetic stimulation in bone tissue engineering: A comprehensive systematic review and meta-analysis

Electromagnetic fields (EMFs) are a non-invasive means of promoting osteogenic differentiation, but the wide variation in waveform, intensity, frequency, and exposure duration makes suitable settings difficult to identify. This systematic review and meta-analysis summarized the in vitro and in vivo evidence on the effect of externally applied, time-varying EMFs on osteogenesis. Following the PRISMA 2020 guideline, PubMed, Scopus, Web of Science, and Google Scholar were searched up to October 10, 2025. Of 1282 records, 71 articles were included, providing 58 in vitro and 21 in vivo studies. In vitro outcomes were synthesized narratively, and in vivo bone mineral density (BMD) and bone volume fraction (BV/TV) were pooled using a random-effects model. In most in vitro studies, EMF exposure maintained or increased cell viability and proliferation and was associated with higher expression of osteogenic markers and greater mineralization, although null and negative findings were also reported. In four animal studies, EMF increased BMD (mean difference 0.12 g/cm³, 95% CI 0.07-0.17) and BV/TV (0.20, 95% CI 0.09-0.31) at 12 weeks. These effects were stable in leave-one-out analyses, but heterogeneity was very high (I² > 90%), and meta-regression showed no time-dependent change in the effect. A few parameter-comparison studies suggested that intensities of about 1-2 mT and daily exposure of about 2-4 h may be favorable, but this finding should be regarded as hypothesis-generating. Standardized exposure protocols, complete reporting of field parameters, and adequately powered in vivo and clinical studies are needed. This review was registered in PROSPERO (CRD420250530893).