A preliminary clinical test found that a pelvis-fixed smartwatch can track orientation for augmented-reality navigation during hip replacement surgery, reporting mean absolute errors of 2.8 degrees for inclination and 3.6 degrees for anteversion. While small, the study suggests a lower-cost sensing approach for OR guidance systems. The key implication for the medtech ecosystem is feasibility: integrating consumer-style inertial sensing into surgical navigation workflows could reduce hardware friction and speed adoption if accuracy holds up across broader patient anatomies. Future validation will likely need larger cohorts, better characterization of failure modes, and integration with existing navigation platforms to confirm reliability under real intraoperative conditions.