The recovery of knee mobility plays a crucial role in the postoperative phase after an anterior cruciate ligament injury, necessitating the use of articulated knee braces to strike a delicate balance between immobilization and progressive angular movements. While immobilization is vital to prevent muscle contractions, controlled movement is essential for therapy. To address these challenges, an innovative knee brace prototype with an integrated electrostimulation system was designed and developed. The prototype was meticulously crafted using CAD software, and materials were carefully selected based on the Von Mises study to ensure adequate resistance. The integrated electrostimulation system generates electrical pulses with specific characteristics, promoting muscle relaxation, increased blood flow, and endorphin secretion in the stimulated muscle, particularly the quadriceps. ABS and 3003 aluminum alloy materials were used for the modeling of the knee brace, because they demonstrate a behavior of elasticity close to the desired, indicating that the prototype would only have a minimal deformation in the initial section of the lower part of the knee brace if a load of 150 kgf is applied, as athletes can weigh around 90-120 kg. Further improvements to the power stage and implementation of a Darlington pair to maintain the mirror current are planned, aiming at optimizing the electrostimulation system's performance, the output current should be between 1 to 1.5 amperes which is enough to produce the muscle contraction and relax. This knee brace prototype presents significant potential as an auxiliary tool for postoperative ACL rehabilitation, contributing to patients' successful recovery and improved quality of life.