Introduction: Ultrasound elastography has been gaining attention as a relatively new imaging
modality for assessing the elasticity of soft tissue. In this paper, we present
our findings on quadriceps elasticity measurements taken before and after ACL
reconstruction surgery.
Material and Method: The study population consisted of 5 patients who had ACL reconstruction
surgery. Each patient had leg circumference measurements, muscle thickness
measurements, and ultrasound elastography assessments which were performed
pre-operatively as well as post-operatively on days 1, 4, 7 and 14. All
measurements were taken 10cm above the knee cap.
Result: The elasticity of the quadriceps muscle was lowest on the first post-operative day and gradually recovered to pre-operative levels. Although the elasticity of the operated side and unoperated side was equal pre-operatively, the unoperated side was less elastic than the operated side after the operation. Muscle thickness was reduced on both sides post-operatively but it was more marked on the operated side. Similar changes were observed for leg circumference.
Discussion: There have been several studies involving the use of ultrasound elastography. Many have studied the Achilles tendon but there are few studies on the quadriceps muscle. Our study revealed that the elasticity of the quadriceps muscle was lowest on the first post-operative day and that it gradually recovered to pre-operative levels. The unoperated side had a reduction in elasticity post-operatively and this remained lower than that of the operated side. It can be hypothesized that the acute changes in elasticity were due to effects from the surgery (i.e. presence of intra-articular hematomas, use of tourniquets, etc.) The reduction of elasticity in the unoperated leg was likely due to increased weightbearing on that side after the operation. Limitations of the study include small sample size as well as the lack of long term data.
