Intramedullary Nail Self-Centering Locking Hole
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Solution Overview
Problem
Intramedullary nails tend to bend during insertion into the medullary canal of bones, causing distal locking holes to become misaligned with the aiming holes, making it difficult to accurately insert locking screws.
Innovation Solution
The design of an intramedullary nail with a distal locking hole that extends laterally through the nail, featuring an elongated first opening and a second opening with a coupling element, allowing bone fixation elements to be inserted at an angle, even when the nail is bent, ensuring proper alignment and secure fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an intramedullary nail is inserted into the medullary canal to stabilize the bone, then the bone fixation is improved, but the distal locking holes become misaligned with the aiming holes due to nail bending
Solution Approach 1:
The locking hole is designed with an elongated first opening that can accommodate angular misalignment dynamically. When the nail bends during insertion, the elongated opening allows the bone fixation element to still pass through by accepting a range of insertion angles, thus maintaining alignment functionality despite the nail's deformation to match the medullary canal curvature
Solution Approach 2:
The geometry of the locking hole is changed from a standard circular opening to an elongated asymmetric opening. This parameter change in the opening shape allows it to tolerate angular deviations caused by nail bending, enabling bone fixation elements to be inserted even when the nail conforms to the natural curvature of the medullary canal
2Adaptability or versatility
If the intramedullary nail conforms to the natural curvature of the medullary canal, then the comfort and stability in the bone is improved, but the distal locking holes move out of alignment with the aiming holes
Solution Approach 1:
The elongated first opening of the locking hole creates a dynamic tolerance zone that adapts to the angular changes occurring when the nail bends to match the medullary canal. This dynamic design allows the locking mechanism to remain functional across a range of angles, accommodating the nail's adaptation to the curved canal while preventing complete misalignment
Solution Approach 2:
The locking hole design adds an angular dimension of tolerance through the elongated opening. Instead of requiring precise alignment in a single plane, the elongated geometry provides an additional degree of freedom that accommodates the angular deviations caused by the nail conforming to the curved medullary canal
Data Source
AI summary
An intramedullary nail includes a body sized and shaped for insertion into a medullary canal of a bone and extending along a longitudinal axis from a proximal end to a distal end and a channel extending through the body along the longitudinal axis in combination with a locking hole extending laterally through the body along a central axis and in communication with the channel, the locking hole defined by a first opening extending through a first portion of a wall of the nail and a second opening extending through a second portion of the wall substantially opposing the first portion, the first opening being elongated in a lateral direction relative to the longitudinal axis of the nail and the second opening including a coupling element configured to lock a portion of a bone fixation element therein.