The use of trapeziometacarpal prostheses for the treatment of rhizarthrosis is becoming increasingly common. The longevity of these implants depends on the quality of the surgical procedure, particularly the precise positioning of the trapezial cup. A standardized surgical technique is essential to achieve reproducible outcomes, and the choice of surgical approach plays a major role in this reproducibility. Few publications have emphasized the importance of the surgical approach in optimizing trapeziometacarpal prosthesis placement. During the procedure, extensive release of the first metacarpal is a key step in correcting dorsal subluxation and ensuring optimal exposure of the trapezium. Such exposure enables accurate centering of the trapezial cup, thereby reducing the risk of early loosening or impingement against the prosthetic neck. In this article, we provide a detailed, step-by-step description of trapeziometacarpal prosthesis implantation technique, highlighting the critical points at each stage.