Bone Plate with Recesses and Grooves for Fracture Fixation
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Solution Overview
Problem
Conventional bone plates for internal fixation of fractures often damage the periosteal blood supply due to extensive contact with the bone, leading to compromised healing and increased risk of infection, while attempts to reduce contact have compromised stability, especially in torsion.
Innovation Solution
A bone plate design featuring recesses around screw holes and transverse grooves on the bone-facing surface to minimize contact, allowing for the use of both locking and conventional screws, with a geometry that maintains mechanical strength and allows for bending without deformation, using screw hole plugs for added strength and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional plates are made to fit the bone as closely as possible and screwed tightly onto the bone, then mechanical stability is improved, but the periosteal blood supply is damaged
Solution Approach 1:
The patent removes the harmful contact between the plate and bone by creating recesses in the plate's bone-facing surface. These recesses extract the problematic contact areas while preserving the necessary mechanical stability through the remaining contact zones and locking screw mechanism.
Solution Approach 2:
The plate features localized recesses at specific contact points with the bone, creating areas of reduced contact where blood supply is critical. This local modification allows the plate to maintain overall stability while protecting specific vulnerable regions from compression damage.
2Object-affected harmful factors
If the contact between the plate and the bone is reduced to very small areas, then damage to the periosteal blood supply is minimized, but locking the screws becomes imperative as conventional screws could produce contact pressures in excess of bone compressive strength
Solution Approach 1:
The patent segments the screw fixation system into two distinct types: locking screws that engage with the plate through threaded holes, and conventional screws for compression. This segmentation allows each screw type to perform its specific function without compromising bone strength, with locking screws eliminating the need for high contact pressures.
Solution Approach 2:
The locking mechanism acts as an intermediary between the screw and bone, transferring loads through the plate structure rather than through direct compression at the screw-bone interface. This intermediary mechanism protects the bone from excessive contact pressures while maintaining fixation stability.
3Object-affected harmful factors
If recesses are created around screw holes to eliminate potential contact between plate and bone, then blood supply is protected, but plate strength may be compromised
Solution Approach 1:
The patent carefully controls the depth and dimensions of the recesses to optimize the balance between protecting blood supply and maintaining plate strength. By adjusting these geometric parameters, the design achieves sufficient clearance from the bone while preserving the structural integrity of the plate.
Data Source
AI summary
A plate for treatment of bone fractures with reduced potential contact to bone through a combination of annular recesses surrounding the screw holes at the lower, bone facing surface of the plate and transverse grooves between the holes, allows for use of locking as well as conventional bone screws. With the transverse grooves cut into the plate from the lower side, as well as from the sides, the strength of the plate at the span between the holes is lower than at the screw holes. The plate can be bent in both planes without undue deformation of the screw holes. Protection of the holes during bending is afforded by hole plugs, which may be provided pre-installed in order to reduce surgery time. Screw hole plugs may then be left in place in the holes not used for bone screws.