Hip Implant Positioning via Posture-Dependent Reference Features

The method performs preliminary identification of reference features and determination of adjustment parameters while the patient is in a standing posture (first posture). This preliminary action establishes the biunique relationship between reference features and adjustment parameters before the surgery. When the patient is later positioned in the lying posture (second posture) for surgery, the system uses the pre-determined relationship to accurately derive the corresponding adjustment parameters, thereby maintaining high positioning accuracy without requiring complex real-time measurements during the actual surgical procedure.

The method introduces reference features (anatomical landmarks) as intermediaries to bridge the gap between the standing posture (first posture) and the lying posture (second posture). By identifying these reference features in both postures and establishing a biunique relationship between them, the system can accurately transform adjustment parameters from the standing posture to the lying posture. This intermediary approach allows the surgical team to benefit from the ease of lying position surgery while maintaining positioning accuracy through the reference feature-based transformation.

The method replaces the mechanical approach of using the operating table plane for pelvic tilt correction with a navigational approach using reference features and image-based measurement. Instead of relying on mechanical reference surfaces that are affected by soft tissue laxity and position changes, the system uses anatomical landmarks (reference features) that can be identified through imaging and palpation, and mathematically transforms their positions to derive accurate adjustment parameters. This substitution eliminates the harmful effects of soft tissue deformation and position variability while maintaining ease of operation.