Limb Positioning Apparatus with Load Feedback Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current positioning devices for orthopaedic surgery, particularly during hip replacement operations with an anterior approach, require additional personnel for operation, leading to increased costs and potential muscle or ligament damage due to uncontrolled traction and rotational stresses, and lack intuitive control for small adjustments by the surgeon.
Innovation Solution
A patient limb positioning apparatus with a coupling bracket and a movement assembly driven by actuators, including a load transducer and electronic control unit that allows direct control by the surgeon to manage load and position, reducing the need for additional operators and minimizing tissue stress through precise load and position control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated operator is used to control the positioning device, then the limb positioning precision is improved, but the operational complexity and cost increase due to additional personnel
Solution Approach 1:
The surgical system enables the surgeon to directly control limb positioning through integrated actuators and control interfaces, eliminating the need for a dedicated positioning operator. The surgeon maintains direct control over the positioning device while performing the surgical procedure, thereby reducing personnel requirements and operational complexity while preserving positioning precision.
2Stability of the object's composition
If traction is applied during extension movement, then the limb positioning stability is improved, but the risk of muscle or ligament damage increases due to uncontrolled traction forces
Solution Approach 1:
The system incorporates sensors and control mechanisms that continuously monitor traction forces applied to the limb during extension movements. The control system adjusts traction forces in real-time based on feedback signals, ensuring forces remain within safe limits while maintaining limb positioning stability. This prevents muscle or ligament damage by avoiding excessive or uncontrolled traction forces.
Solution Approach 2:
The positioning device employs dynamic control of traction forces during extension movements, allowing the system to adaptively adjust force magnitudes based on the surgical stage and tissue conditions. The actuators provide controlled, variable traction rather than fixed forces, enabling stable positioning while minimizing the risk of tissue damage through force optimization.
3Object-affected harmful factors
If the traction carriage is automatically released during extension, then the risk of tissue overdistension is reduced, but the limb positioning stability deteriorates due to sudden movements
Solution Approach 1:
The control system uses real-time feedback from position sensors and force sensors to determine when automatic release of the traction carriage is appropriate. By monitoring extension position and traction force simultaneously, the system can release the carriage at optimal moments that minimize both tissue overdistension and positioning instability, rather than using fixed release criteria.
Solution Approach 2:
The system employs dynamic control strategies for carriage release during extension, where the decision to release is based on real-time assessment of surgical stage, limb position, and tissue response. This dynamic approach allows the system to maintain stability by coordinating release timing with the surgical workflow while still preventing tissue overdistension through controlled force reduction.
4Ease of operation
If multiple manipulations are performed on the limb, then the surgical access optimality is improved, but the time required for the operation increases
Solution Approach 1:
The positioning device enables preliminary positioning and stabilization of the limb in optimal configurations before the surgical procedure begins. The system can pre-set traction forces, extension angles, and rotation positions based on the planned surgical approach, allowing the surgeon to start the procedure with the limb already in optimal position rather than requiring multiple adjustments during surgery, thereby reducing operational time.
Data Source
AI summary
A patient limb positioning apparatus comprises a movement assembly operating on a coupling bracket which can be engaged with the patient's limb, to move the limb according to a plurality of axes of movement. The movement assembly comprises, for at least one of said axes of movement, a drive unit which can be activated to move the coupling bracket according to a predetermined direction of movement. A load transducer detects a load transmitted between the coupling bracket and the drive unit in the respective direction of movement, to emit a signal representative of a detected load value. An electronic control unit is selectively switchable to a load control command mode and is suitable to cyclically compare the measured load value with a pre-set load value, to control activation of the drive when the detected load value differs from the pre-set load value.