Patient-Specific Augment for Bone Defect Fit
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Solution Overview
Problem
Existing knee joint implants require significant bone resection to accommodate standard, non-custom augments, leading to unnecessary bone removal and a less-than-optimal fit, which can compromise the stability and longevity of the implant.
Innovation Solution
Patient-specific augments are designed using three-dimensional images of the patient's knee anatomy, allowing for a precise match to the bone defect's surface without resection, enabling a seamless interface with standard implant components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard non-custom augments are used, then ease of manufacture is improved, but manufacturing precision and fit to bone defect deteriorate
Solution Approach 1:
The augment is divided into two distinct surfaces: a first surface with a three-dimensional patient-specific shape that conforms to the bone defect, and a second surface with a standard shape that interfaces with the implant. This segmentation allows each surface to be optimized independently - the first surface for precision fit and the second for ease of manufacture and assembly.
Solution Approach 2:
Different surfaces of the augment have different geometric properties tailored to their specific functions. The first surface has a patient-specific three-dimensional geometry for precise bone engagement, while the second surface has a standard geometry for easy implant integration. This local differentiation resolves the contradiction between precision and ease of manufacture.
2Ease of operation
If significant bone resection is performed to accommodate standard augments, then ease of implant installation is improved, but loss of substance (bone) increases
Solution Approach 1:
By segmenting the augment into patient-specific and standard surfaces, the design allows the implant to be installed using standard resection protocols while the patient-specific surface compensates for bone defects without requiring additional bone removal. The first surface conforms to the actual bone geometry, eliminating the need for excessive resection.
Solution Approach 2:
The augment's geometry parameters are changed from fixed standard dimensions to patient-specific dimensions for the first surface. This parameter customization allows the augment to adapt to varying bone defect sizes and shapes, enabling accurate fit without requiring standardized bone resection that would remove healthy bone.
3Device complexity
If standard augments are used, then device complexity is reduced, but reliability and stability of implant deteriorate
Solution Approach 1:
The augment is segmented into functional surfaces with different requirements. The first surface provides reliable bone engagement through patient-specific geometry, while the second surface maintains simplicity for implant integration. This segmentation allows the complex patient-specific geometry to be isolated to only where needed, without complicating the overall implant design.
Solution Approach 2:
Complex three-dimensional patient-specific geometry is applied locally only to the first surface that contacts the bone defect, while the second surface maintains simple standard geometry for implant interface. This localized complexity ensures high reliability at the critical bone-augment interface without unnecessarily complicating the entire device.
Data Source
AI summary
A patient-specific augment can be attached to an implant component for a bone of a joint of a patient. The patient-specific augment has first and second surfaces. The first surface is a three-dimensional patient-specific surface that closely matches and can mate to a substantially unaltered and unresected surface of a bone defect of the specific patient only in one position. The second surface is designed to engage a non-custom surface of the implant.