Lattice Bone Implant Redistributes Load to Cortical Bone
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Solution Overview
Problem
Current medical devices for treating degenerative subchondral bone in joints, such as those affected by arthrosis, are unable to effectively redistribute loads from diseased areas to healthy bone regions, leading to persistent pain and functional limitations, and often require invasive surgical procedures.
Innovation Solution
A lattice support structure comprising a rod-shaped primary element and obliquely extending thread-like secondary elements that span across cortical bone portions, creating a lattice structure capable of redistributing loads from degenerated subchondral bone to healthier cortical bone, thereby reducing mechanical stress and pain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal prosthetic components are used to replace deformed joint surfaces, then implant survival rate is improved, but post-surgical complications and residual pain increase
Solution Approach 1:
The patent changes the material parameters of the implant by using porous metal foam instead of dense metal alloys. This creates a composite structure with intermediate mechanical properties between metal and bone, allowing for better stress distribution and reduced mechanical mismatch while maintaining implant reliability
Solution Approach 2:
The patent creates a composite structure by combining porous metal foam with bone tissue. The porous metal foam acts as a scaffold that integrates with the patient's bone, forming a composite material system that distributes loads more effectively and reduces stress shielding, thereby reducing post-surgical complications and residual pain
2Ease of manufacture
If standard joint prosthesis design is used based on population average, then manufacturing simplicity is improved, but individual patient performance and pain reduction deteriorate
Solution Approach 1:
The patent applies local quality by allowing the porous metal foam implant to be customized for each patient's specific anatomical and mechanical requirements. The porous structure can be tailored in terms of porosity, density, and geometry to match the individual patient's bone structure and load patterns, thereby improving individual patient performance while maintaining manufacturing feasibility through additive manufacturing techniques
3Strength
If metal prosthetic components are used, then structural strength is improved, but mechanical mismatch with natural bone increases causing anti-physiological composite
Solution Approach 1:
The patent changes the mechanical parameters of the prosthetic component by using porous metal foam with controlled porosity (30-70%). This creates a gradient structure where the apparent density and elastic modulus can be tuned to match the intermediate bone density, achieving mechanical compatibility while maintaining sufficient structural strength for load-bearing applications
4Strength
If subchondroplasty with tricalcium-phosphate cements is used, then bone reinforcement is achieved, but load redistribution capability is insufficient
Solution Approach 1:
The patent applies segmentation by dividing the implant into a porous metal foam structure with interconnected struts and pores. This segmented architecture creates multiple load pathways that can redistribute forces throughout the implant-bone interface, unlike the monolithic tricalcium-phosphate cement. The porous structure allows for stress distribution across multiple elements, enhancing load redistribution capability while maintaining bone reinforcement
Data Source
AI summary
The present invention relates to a lattice support structure for one or more degenerated portions of subchondral bone of a bone epiphysis part of a human or animal joint, and to a related kit of parts and to a template assembly for the assembly thereof.The lattice structure comprises at least one rod-shaped and substantially rectilinear rigid primary element configured to be housed within said bone epiphysis extending at least partially through said degenerated portion of subchondral bone along a respective primary extension direction; and a plurality of thread-like substantially rectilinear secondary elements configured to be housed within said bone epiphysis extending at least partially through said degenerated portion of subchondral bone along respective secondary extension directions, comprising first secondary elements configured to extend along respective first secondary extension directions and second secondary elements configured to extend along respective second secondary extension directions (Yd, Ye, Yf), the first and second secondary extension directions being oblique to one another, wherein the at least one primary element has a first transversal dimension greater than a second transversal dimension of said secondary elements.The at least one primary element and the secondary elements are further configured to reach and cross at least partially, at respective opposite ends, cortical bone portions of said bone epiphysis.