Clinical Utility of the Pronator Quadratus Sign: A Systematic Review and Meta-Analysis

The pronator quadratus (PQ) fat pad (PQFP) sign, visualised as a radiolucent stripe on lateral wrist radiographs, has long been proposed as an indirect marker of distal radius or wrist fractures. However, its diagnostic reliability has been variably reported. The objective of this review is to systematically evaluate the diagnostic accuracy and prognostic value of the PQFP sign in detecting wrist and distal radius fractures. A systematic review and meta-analysis were performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Electronic databases (PubMed, Embase, Cochrane Library, Web of Science, and Scopus) were searched up to September 2025. Studies assessing the PQFP sign on plain radiographs or ultrasound, using advanced imaging or clinical follow-up as reference standards, were included. Pooled sensitivity, specificity, and risk ratios (RRs) were calculated using random-effects models. Ten studies met the inclusion criteria. Six datasets contributed to the diagnostic accuracy analysis, yielding a pooled sensitivity of 0.65 and specificity of 0.85, indicating moderate diagnostic performance with substantial inter-study heterogeneity. Five studies assessed the prognostic value of a positive PQFP sign, demonstrating a 2.44-fold increased risk of underlying fracture (RR = 2.44, 95% confidence interval (CI) 1.31-4.56, p = 0.005). Sensitivity analysis excluding ultrasound-based data maintained statistical significance (RR = 1.83, 95% CI 1.36-2.47; I² = 0%). The PQFP sign shows moderate specificity but variable sensitivity for distal radius fractures. A positive PQFP sign substantially increases the likelihood of fracture and should prompt further imaging, especially when radiographs appear equivocal. However, due to heterogeneity and modest sensitivity, the sign should not be used in isolation for fracture exclusion.