Validity and reliability of ultrasonographic assessment of femoral and tibial torsion in children and adolescents: a systematic review.

Torsional disorders of the lower limb are common in childhood, and they are one of the primary reasons parents seek consultation with healthcare providers. While clinical manoeuvres can assess femoral and tibial torsion, their reliability is medium to low. Various imaging-based techniques, including computed tomography, magnetic resonance imaging, fluoroscopy, biplanar radiology and ultrasonography, have been used to evaluate torsional alterations of the lower extremity. Among these, ultrasound assessment offers certain advantages: it is a low-cost, non-irradiating technique, which allows the follow-up of children's torsional development. However, to the best of the authors' knowledge, its validity and reliability have not been summarised in a systematic review. This study aims to analyse the validity and reliability of ultrasonography in determining femoral and tibial torsion in children and adolescents. A search from Medline (via PubMed), Web of Science, Scopus and CINAHL databases were performed from inception to 16 March 2023. No restrictions were placed on the publication year or language. The methodological quality of all eligible studies was independently reviewed by two authors using QUADAS and STARD checklists. Overall, 1546 articles were identified through the searches; 30 were considered eligible for full-text screening; and 8 studies were finally included in this review. The included studies were conducted in Germany, Norway and the UK. Among them, 7 studies analysed the validity of ultrasonography compared with other imaging techniques such as computed tomography, magnetic resonance imaging and biplanar X-ray, and 4 studies assessed intra- and inter-observer reliability. All the studies assessed femoral torsion, but only one of them also included tibial torsion.     Conclusion: Ultrasound is a good alternative for routine evaluation and follow-up of femoral torsional alterations in children and adolescents due to its safety, accessibility and immediate results in the clinical examination room. Although ultrasound has good accuracy and reliability for routine evaluations, there is controversy about whether it is sufficient for surgical planning. In cases where greater accuracy is required, magnetic resonance imaging and biplanar radiography are the preferred imaging techniques. What is Known: • Several imaging-based techniques have been described for the assessment of torsional alterations of the lower extremity. • Computed tomography, magnetic resonance imaging, biplanar radiology and ultrasonography are the most used and studied methods. What is New: • Ultrasonography represents a good alternative for the assessment of femoral and tibial torsional alterations in children and adolescents, given its safety, accessibility and immediacy of results in the consultation room. • Its accuracy and reliability are good but not sufficient for surgical planning, in which case MRI and biplanar X-ray will be the preferred choices.