Reliability of quantitative point shear-wave ultrasound elastography on vastus medialis muscle and quadriceps and patellar tendons

Aim: The aim of this work was to evaluate the reliability of pSWE in assessing the stiffness of the vastus medialis muscle and of the quadriceps and patellar tendons. Material and methods: For this purpose, 18 subjects (9 males and 9 females of 57±22 years) in good clinical conditions were included in this study. pSWE examination was conducted by a unique expert operator with more than ten years of experience in musculoskeletal ultrasound. Two sets of five measurements for each muscle and tendon district were bilaterally performed at the same manner, at least fifteen minutes apart. The mean value of the measurements of each set was statistically compared with that of the other set. Results: No significant differences were found comparing the mean value of the measurements of the two sets of evaluation performed in muscle and tendon areas (vastus medialis muscle: p=0.285; quadriceps tendon: p=0.979; patellar tendon: p=0.187). The intraclass correlation coefficient was excellent for all areas (vastus medialis muscle: 0.969; quadriceps and patellar tendons: 0.995 and 0.989, respectively). Conclusion: The pSWE technique demonstrated that it was a reliable method for measuring stiffness in vastus medialis muscle and quadriceps and patellar tendon in subjects who had undergone orthopedic surgery. This opens the possibility of many applications in monitoring stiffness before and after surgery and during rehabilitation.