Both platelet rich plasma (PRP) and dextrose treat chronic lateral epicondylalgia (CLE), mechanically by enhancing tendon cell proliferation, differentiation, and maturation. In fact, hypertonic glucose injection is much cost-effective as compared to PRP. Hence, it is of clinical value to compare the recovery of extensor carpi radialis breveis (ECRB) muscular structure and muscular function between PRP and hypertonic glucose injection.~The investigators will measure functional outcome and force gradation after PRP and glucose injection in CLE patients using multi-electromyography, functional score (Disabilities of the Arm, Shoulder and Hand (DASH) and Patient-Rated Tennis Elbow Evaluation (PRTEE)) and force (gripping power and maximal voluntary contraction (MVC) during wrist extension) before and 12 weeks after injection. The hypotheses of this study are 1) lower MVC and greater force fluctuations of a force task in the affected muscle in individuals with CLE; 2) lower discharge rate and higher discharge variability of motor units of a force task in the affected muscle in individuals with CLE than those in the contralateral sound side; 3) the PRP group shows a greater improvement in a visual analog scale (VAS), DASH, PRTEE score, MVC, and the size of force fluctuations than the glucose group after treatment. 4) the PRP group shows a greater discharge rate and lower discharge variability for a force task than the glucose group after treatment.
The purpose of this study is to find out functional and electromyographical changes after platelet rich plasma and dextrose injection in chronic lateral epicondylitis.