Lapidus Fixation Plate for Metatarsocuneiform Joint Stability
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Solution Overview
Problem
Current surgical techniques for correcting Hallux Abducto Valgus (HAV) deformities, such as bunions, often require invasive procedures like osteotomy or fusion, which may not provide adequate mechanical stability and reorientation of the first metatarsal, leading to complications like metatarsalgia and stress fractures.
Innovation Solution
A Lapidus plate designed for joint arthrodesis at the first metatarsocuneiform joint, featuring a thin, rigid, elongated structure with a twist along its axis and recesses to accommodate anatomical contours, providing multiplanar stability and reorientation of the first metatarsal, while avoiding invasion of the fusion site with screws, and allowing for distraction if necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If osteotomy or fusion procedures are used to correct HAV deformities, then mechanical stability and reorientation of the first metatarsal are improved, but the surgical invasiveness and risk of complications increase
Solution Approach 1:
The fixation plate is divided into multiple segments including a first portion for the first metatarsal, a second portion for the medial cuneiform, and an intermediate portion connecting them. This segmentation allows the plate to conform to the anatomical contours of the joint while providing stable fixation across the fusion site, addressing the need for mechanical stability without requiring overly invasive procedures
Solution Approach 2:
The plate features locally adapted properties with recesses that accommodate specific anatomical contours of the first metatarsocuneiform joint. The intermediate portion has a specific geometry designed to fit the joint's natural shape, providing localized stability and promoting proper alignment while minimizing disruption to surrounding healthy tissue
2Reliability
If traditional fixation plates are used, then joint fusion can be achieved, but adequate multiplanar stability and reorientation capability are not provided
Solution Approach 1:
The intermediate portion of the plate extends in multiple dimensions relative to the first and second portions, creating a three-dimensional configuration that provides stability in multiple planes. This geometric arrangement allows the plate to resist forces from various directions while accommodating the natural orientation of the first metatarsocuneiform joint, enabling both stable fusion and proper reorientation
3Reliability
If screws are placed to secure the fixation plate, then mechanical stability is improved, but invasion of the fusion site occurs
Solution Approach 1:
The design extracts the screw fixation function from the fusion site itself by placing screw holes in the first and second portions of the plate that are positioned to engage the metatarsal and cuneiform bones separately. This configuration allows screws to secure the plate to the bones without the screw paths intersecting or invading the fusion site between the first metatarsal and medial cuneiform, thereby maintaining mechanical stability while protecting the fusion interface
Data Source
AI summary
The present disclosure generally relates to fixation plates for use in correcting Hallux Valgus deformities under the Lapidus approach. The plate includes holes defined therethrough in such a way to facilitate multiplanar stability across the metatarsocuneiform joint. The plate is further sized and shaped to approximate the natural anatomic contour of the bone segments surrounding the metatarsocuneiform joint. Related methods for using the Lapidus approach to correct Hallux Valgus deformities are also described.