Bunionectomy Capital Fragment Positioner and Guide Wire Targeting
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Solution Overview
Problem
Current minimally invasive bunionectomy techniques face challenges in accurately positioning the capital fragment of the first metatarsal bone due to acute angles and instability in the sagittal, coronal, and transverse planes, leading to potential malpositioning and postoperative complications.
Innovation Solution
A system comprising a capital fragment positioner with an L-shaped handle and a guide wire targeting assembly, including a lower block secured to the foot with K-wires and an upper block rotatably mounted on the lower block, allows for precise alignment and fixation of guide wires and cannulated screws to stabilize the capital fragment across the osteotomy, enabling accurate positioning and stabilization in three cardinal planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If percutaneous guide wires are introduced at acute angles for minimally invasive bunionectomy, then soft tissue dissection is reduced and postoperative swelling is decreased, but accurate placement of guide wires and stabilization of the capital fragment becomes difficult
Solution Approach 1:
The patent introduces a guide wire targeting assembly as an intermediary device that facilitates accurate guide wire placement at acute angles. The assembly includes a lower block secured to the foot and an upper block with guide wire tubes that can be rotated to achieve the required 15-25 degree angle relative to the metatarsal shaft, eliminating the need for multiple attempts and reducing soft tissue trauma while ensuring precise wire placement
Solution Approach 2:
The upper block of the targeting assembly is rotatably mounted on the lower block, allowing dynamic adjustment of the guide wire introduction angle. This rotational capability enables the surgeon to accommodate individual anatomic variations and achieve the optimal acute angle for minimally invasive access while maintaining accurate placement
2Manufacturing precision
If the capital fragment is mobilized to reduce angular deformity in minimally invasive bunionectomy, then angular correction is achieved, but instability in the sagittal, coronal, and transverse planes increases
Solution Approach 1:
The patent employs preliminary action by introducing and securing guide wires across the osteotomy site before completing the angular correction. The guide wires are placed through the rotatable targeting assembly to provisionally stabilize the capital fragment in the desired position, preventing instability in all three planes while allowing the angular deformity to be corrected
Solution Approach 2:
The guide wire targeting assembly acts as an intermediary stabilization device that maintains capital fragment stability during the angular correction process. The assembly provides temporary fixation that prevents malpositioning while allowing the necessary mobilization and angular reduction to occur
3Adaptability or versatility
If conventional tubular drill guides are used for guide wire introduction, then angulation adjustability is infinite, but positional stability is completely unconstrained leading to inaccurate placement
Solution Approach 1:
The patent applies local quality by providing constrained stability at the specific location where guide wire placement is required. The lower block is secured to the foot with K-wires to establish a stable reference point, while the upper block provides localized angulation adjustment. This combination ensures both adaptability for individual anatomy and reliability for accurate placement at the critical osteotomy site
Data Source
AI summary
The system for surgical correction of a bunion includes a capital fragment positioner and a guide wire targeting assembly. The positioner has an L-shaped handle having a transverse post extending across the end of the long arm of the handle and two tubes at opposite ends of the post extending orthogonally to the plane of the handle. The handle extends obliquely from the post to enable fluoroscopic visualization of the capital fragment. The guide wire targeting assembly includes a lower block that may be secured to the foot by K-wires and an upper block rotatably mounted on the lower block. The upper block supports guide wire tubes and is rotated to position the guide wires across the osteotomy cut in the metatarsal bone. Cannulated fixation screws are inserted over the guide wires in proper position to fix bones on opposite sides of the osteotomy.