Testicular Elastography in Male Infertility: A Systematic Review and Meta-Analysis of Semen Parameters and Azoospermia

Background/Objectives: Quantitative testicular elastography has been proposed as a non-invasive marker of spermatogenic impairment, but published results differ across semen phenotypes, azoospermia categories, and ultrasound platforms. Methods: We performed a PRISMA-conformant systematic review and meta-analysis of observational studies in which quantitative testicular elastography contributed extractable data to at least one meta-analysis. Correlation coefficients were pooled after Fisher-z transformation and back-transformed to r; group contrasts were synthesized as standardized or raw mean differences using random-effects models. SWE/SWV formed the main evidence base, with strain-ratio studies analyzed separately as an ancillary synthesis. Risk of bias was assessed uniformly with the revised JBI tool for analytical cross-sectional studies. Results: Eleven studies contributed to the final quantitative synthesis. Mean stiffness was inversely associated with sperm concentration (r = −0.37, 95% CI −0.41 to −0.32, p < 0.001; I2 = 0%) and motility (r = −0.43, 95% CI −0.58 to −0.24, p < 0.001; I2 = 8%), whereas morphology was not significantly associated (r = −0.12, 95% CI −0.31 to 0.08, p = 0.25). Azoospermic men had greater standardized stiffness than normozoospermic men (SMD 1.695, 95% CI 1.491–1.899; I2 = 0%). No evidence of a stiffness difference between NOA and OA was found (SMD 0.47, 95% CI −0.43 to 1.38; I2 = 97%). The ancillary strain-ratio retrieval estimate was highly imprecise (SMD 4.10, 95% CI −2.44 to 10.64; I2 = 99%). Neither comparison establishes equivalence or excludes a clinically important difference. The stiffness–volume correlation was also highly heterogeneous (I2 = 95%). Conclusions: Available evidence suggests inverse associations of testicular stiffness with sperm concentration and motility and higher stiffness in azoospermia. Few studies per outcome, a dominant cohort, and technical and statistical heterogeneity limit confidence in the pooled estimates. The NOA–OA, retrieval, and stiffness–volume syntheses are exploratory and cannot support clinical recommendations. Diagnostic thresholds and the value of elastography for individual clinical decisions remain unestablished.