Evaluation of Elastic Stiffness in Healing Achilles Tendon After Surgical Repair of a Tendon Rupture Using In Vivo Ultrasound Shear Wave Elastography

Abstract

BackgroundThere has been no published report assessing the mechanical properties of a repaired Achilles tendon after surgery using shear wave elastography (SWE). The aim of this study was to investigate the changes in mechanical properties of the healing Achilles tendon after surgical repair of a tendon rupture using ultrasound SWE and how these changes correlate with tendon function.Material/MethodsTwenty-six patients who underwent surgical repair for Achilles tendon rupture were examined with ultrasound SWE coupled with a linear array transducer (4–15 MHz). The elasticity values of the repaired Achilles tendon in a longitudinal view were measured at 12, 24, and 48 weeks postoperatively. Functional outcomes were assessed with the American Orthopedic Foot and Ankle Society (AOFAS) rating system at 12, 24, and 48 weeks postoperatively. General linear regression analysis and correlation coefficients were used to analyze the relationship between elasticity and the AOFAS score.ResultsThere were significant differences with respect to the mean elasticity values and functional scores of the repaired Achilles tendon at 12, 24, and 48 weeks postoperatively (all P<0.05). Tendon function was positively correlated with the elasticity of the repaired Achilles tendon (P=0.0003).ConclusionsOur findings suggest that SWE can provide biomechanical information for evaluating the mechanical properties of healing Achilles tendon and predict Achilles tendon function.

Real-time sonoelastography: principles and clinical applications in tendon disorders.

“…Peak of thickness occurred at 6 months, with a tendency to reduce at 1 year, but never achieving a normal value; while functional score gradually improved with return to previous sport activity 38 . Similar results were reported also after open repairs 39 .…”

Lower extremity work along with triceps surae structure and activation is altered with jumping after Achilles tendon repair

“…Lengthening of the Achilles tendon, which typically occurs within the first 12 weeks following injury, has been found to relate to poor performance on isolated calf strength testing, altered biomechanics, and poor patient outcomes . Also at the tendon level, tendon mechanical properties have been found be altered following rupture and to relate to performance on strength testing and walking gait …”

Side-to-side differences in Achilles tendon geometry and mechanical properties following achilles tendon rupture

“…Similarly, shear modulus was found to be lower in individuals with tendon pain compared to the asymptomatic side 27 . When looking over time using shear wave elastography, shear modulus has been reported to increase following Achilles tendon repair, however, side-to-side comparisons have not been reported 7 . The lack of side-to-side comparison may be due to concerns regarding saturation of stiff tissue using commercially available shear wave elastography.…”

“…For example, at three months post-rupture, only 50% of individuals are able to complete a single, unilateral heel-rise 6 . Assessing tendon structure -including both geometrical and mechanical properties -following rupture has been suggested to fill this void [7][8][9] . Animal studies have identified differences in tendon structure throughout the healing course 10,11 .…”

“…To overcome these obstacles, non-invasive ultrasound techniques have been proposed to measure tendon mechanical properties in vivo. Shear wave elastography has been applied to the Achilles tendon rupture population in one study 7 , and has been found to relate to elastic modulus with tensile testing 15 . Continuous shear wave elastography (cSWE) has been developed 16 and utilized in assessment of Achilles tendons in a healthy population 17 , and has been applied to Achilles tendon rupture in a case study 18 .…”