Radiofrequency Energy Effects on the Mechanical Properties of Tendon and Capsule

Purpose: To compare the mechanical properties of tendon and capsule after radiofrequency (RF) energy treatment. Type of Study: An in vitro study. Methods: RF energy was applied to ovine extensor tendon and human cadaveric glenohumeral capsule varying in the treatment wattage and time (5, 10, or 20 W for 10 or 30 seconds). The associated tissue length changes and dynamic and failure properties of the tissues were investigated using a materials testing machine. Results: Length changes in the 2 tissues were comparable across the range of treatment settings used with both increases in the treatment wattage and time increasing the amount of tissue shrinkage observed. However, tendon showed greater changes in its mechanical properties after RF treatment, with significant decreases in the failure properties of the tissue as well as the dynamic and static stiffness. Conclusions: RF treatment shrinks collagenous tissues in a progressive manner correlated to the treatment wattage. However, it has different effects on the mechanical properties of tendon and capsule with the properties of tendinous tissues dramatically reduced. Clinical Relevance: RF treatment has been shown to effect the mechanical properties of different collagenous tissues differently; therefore, it must be used specifically and with caution around areas of mixed tissue origin.