Pronator quadratus muscle changes are commonly seen lesions on wrist MRI examinations, although many times they are not valorized despite other associated wrist injuries. Different conditions can affect the pronator quadratus muscle, such as trauma, inflammatory and infectious pathologies(1). Traumatic muscular changes can appear as edema, hematoma, or even strain, depending on the degree and mechanism of the trauma(2). Classically wrist radiographs played an important role in the evaluation of traumatic lesions, including the pronator quadratus fat pad sign in the lateral view radiograph, but...

We retrospectively reviewed wrist MRI examinations performed at our hospital from January 2011 until November 2012. There were a total of 370 patients, 149 females and 221 males with average of 40.46 years. All the studies were evaluated for the presence of pronator quadratus muscle changes (edema, lesion, atrophy), bone changes (edema, fracture), ligament lesion (partial or complete), triangular fibrocartilage complex lesion and synovitis/effusion. The main used statistical methodologies were Pearson’s chi-squared test and kappa concordance coefficient and determination of 95% confidence intervals.

From the total of 370 exams, 63 patients (21.6%) had pronator quadratus muscle changes. From these 63 cases with pronator quadratus muscle changes, 82.5% presented edema, 19.0% had lesions and 15.9% presented atrophy. There were associations with statistical significance between pronator quadratus muscle changes with traumatic bone changes (p<0.001), ligament lesion (p=0.014) and effusion/synovitis (p<0.001). There was not statistical significant association between pronator quadratus muscle changes and triangular fibrocartilage complex lesion (p=0.296). The kappa concordance coefficient was very low between pronator quadratus muscle changes and...

There was evidence that traumatic bone changes, ligament lesions, and effusion/synovitis occur with much more frequency in patients with pronator quadratus muscle changes. Although there was not statistical significant association between pronator quadratus muscle changes and triangular fibrocartilage complex lesion, probably due the high incidence of associated degenerative changes in our population. As shown with the kappa concordance coefficients, the absence of pronator quadratus muscle changes cannot predict the absence of other wrist lesions. Radiologists must be aware of the importance of the evaluation of...

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