Orthopaedic Implant Anchor Structures for Secure Bone Fixation
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Solution Overview
Problem
Conventional femoral implant components with backdrafted surfaces face challenges in using conventional pegs or posts for secure fixation due to the risk of damaging pre-cut holes during installation, which hinders secure anchoring and fixation in knee prostheses.
Innovation Solution
The development of orthopaedic implants with a base portion and transverse portions that include anchor structures with tapered outer surfaces and grooves, allowing for secure anchoring within bone openings, and the use of flowable materials that cure to a hardened state for enhanced fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pegs or posts are used with backdrafted femoral implant components, then fixation is secured, but the risk of damaging pre-cut holes increases during installation
Solution Approach 1:
Instead of impacting the peg axially into the bone hole (conventional method), the peg is inserted at an angle during the roll-on installation process. The peg's longitudinal axis is angled relative to the bone hole, allowing the peg to be driven into the hole as the implant is rolled onto the bone, avoiding direct axial impact that would damage the hole.
Solution Approach 2:
The installation method transitions from static axial impact to dynamic angled insertion during rotation. The peg is inserted at an angle that changes during the roll-on process, with the insertion angle being greater than zero degrees, allowing simultaneous rotation and peg insertion without damaging the pre-cut bone hole.
2Reliability
If pegs are inserted axially during roll-on installation, then fixation is achieved, but interference with pre-cut holes occurs
Solution Approach 1:
The conventional axial insertion method is inverted to an angled insertion method. The peg is inserted at an angle relative to the bone hole axis, allowing the implant to be rolled onto the bone while simultaneously driving the peg into the hole, eliminating the need for separate axial impact steps.
Solution Approach 2:
The bone hole is pre-cut with dimensions and orientation that accommodate the angled peg insertion. The hole is prepared in advance with a size and angle that allows the peg to be driven in during the roll-on process, facilitating smooth installation without interference.
3Strength
If femoral implant components have backdrafted surfaces, then locking capability is improved, but conventional peg installation is hindered
Solution Approach 1:
The installation of the backdrafted femoral implant component and the insertion of the fixation peg are merged into a single simultaneous operation. The roll-on installation process accomplishes both the seating of the backdrafted surfaces and the insertion of the angled peg in one motion, simplifying the overall procedure despite the complex geometry.
Solution Approach 2:
The installation procedure transitions from multiple static steps to a single dynamic roll-on motion. The backdrafted surfaces lock the implant to the bone while the angled peg is simultaneously inserted, creating a dynamic installation process that accommodates the complex geometry without requiring separate adjustment steps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables secure anchoring and fixation of orthopaedic implants on resected bone ends without damaging the bone tissue, providing a tighter fit and improved stability compared to traditional methods.
Implementation Method 1
The anchor structure also includes one or more grooves extending into the tapered outer surface, and the implant further comprises a flowable material positioned about at least a portion of the tapered outer surface of the anchor structure and positioned within the grooves, with the flowable material configured to cure to a hardened state.
Data Source
Figure 1~2
Figure 3~5
Figure 6A~6H
AI summary
An orthopaedic implant (10, 40, 50, 60, 100) including a base portion (12, 1 12) and first and second transverse portions (14, 16, 114, 116) extending transversely from the base portion (12, 112) to thereby define an inner region (18, 1 18) of the implant sized for receipt of an end portion of a bone (B) therein. The implant further includes at least one anchor structure (30, 130) projecting from the base portion (12, 112) and sized and configured for receipt within an opening (O, O') formed in the end portion of the bone (B). The anchor structure (30, 130) extends along a longitudinal axis (L) and includes a proximal end (30a, 130a) attached to the base portion (12, 112) and an opposite distal end (30b, 130b), and further includes a tapered outer surface (36, 136) that inwardly tapers in a proximal-to-distal direction along the longitudinal axis (L). In one embodiment, an anchor structure (130) is provided which includes one or more grooves (140) extending into the tapered outer surface (136), with a flowable material (150) positioned about at least a portion of the tapered outer surface (136) and positioned within the grooves (140), and with the flowable material (150) configured to cure to a hardened state.