Adjustable Glenoid Rasp for Bone-Sparing Implant Preparation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing glenoid implants for shoulder arthroplasty with eccentric erosion require significant bone removal due to mismatched designs, leading to undesirable bone stock loss.
Innovation Solution
A biconvex glenoid implant device with an adjustable rasp and base that oscillates relative to a pivot axis, allowing precise preparation of the glenoid cavity by minimizing bone removal through oscillating motion and adjustable plunge depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a standard glenoid implant design is used, then the implant can be universally applied, but significant bone stock must be removed to accommodate the implant
Solution Approach 1:
The rasp is made adjustable relative to the base along the proximal-distal axis, allowing the distance the rasp extends distally beyond the base to be varied. This dynamic adjustment enables the surgeon to adapt the bone removal depth to the specific degree of erosion present, removing only the necessary amount of bone stock while accommodating the implant.
Solution Approach 2:
The implant design incorporates a biconvex bone-facing surface with a first convex portion and a second convex portion angled relative to the first. This parameter change in the implant geometry allows it to mate with both the paleoglenoid and neoglenoid surfaces at different angles, accommodating varying degrees of erosion without requiring excessive bone removal.
2Ease of manufacture
If more bone is removed to accommodate standard implants, then implant installation is easier, but bone stock is unnecessarily depleted
Solution Approach 1:
The rasp is configured to oscillate about a pivot axis and can be adjusted to the appropriate plunge depth before the base is fixed to the paleoglenoid. This preliminary adjustment ensures that the bone surface is properly prepared to the exact depth needed, making implant installation straightforward while preventing unnecessary bone removal.
Solution Approach 2:
The device replaces continuous rotational drilling with an oscillating rasp motion. The rasp oscillates back and forth to prepare the bone surface, which provides more controlled and precise bone removal compared to traditional continuous drilling, thereby reducing unnecessary bone stock loss while maintaining ease of installation.
3Device complexity
If a fixed rasp position is used, then the device structure is simpler, but it cannot adapt to varying degrees of erosion
Solution Approach 1:
The rasp is adjustable relative to the base along the proximal-distal axis, allowing the distance the rasp extends distally beyond the base to be varied. This dynamic feature enables adaptation to different erosion stages while maintaining relatively simple device structure through straightforward mechanical adjustment mechanisms.
Solution Approach 2:
The single device with an adjustable rasp can accommodate multiple stages of erosion by varying the rasp's plunge depth, eliminating the need for multiple fixed-position devices. This multi-functionality achieves adaptability across different erosion scenarios without proportionally increasing device complexity.
4Productivity
If the rasp extends further distally, then more neoglenoid can be prepared, but the risk of damaging paleoglenoid increases
Solution Approach 1:
The rasp is adjusted to the appropriate plunge depth before the base is fixed to the paleoglenoid. This preliminary positioning ensures that the rasp will only remove bone to the necessary depth to prepare the neoglenoid, preventing accidental damage to the paleoglenoid while still allowing extensive neoglenoid preparation when needed.
Solution Approach 2:
The surgeon can adjust the rasp position, perform preliminary bone preparation, then readjust the rasp plunge depth based on the exposed bone surface conditions. This iterative feedback process allows the surgeon to monitor bone removal in real-time, preparing as much neoglenoid as needed while immediately stopping before damaging the paleoglenoid.
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
The device effectively prepares the glenoid cavity for biconvex implants by reducing bone stock loss, adapting to varying degrees of eccentric erosion, and ensuring a smooth surface for implant reception.
Implementation Method 1
rotation of the shaft causes the hammer to strike the prongs in alternation, which may in turn cause the anvil to pivot back and forth in an oscillating pattern relative to the pivot axis
Implementation Method 2
Because the rasp may be connected to the anvil, the oscillation of the anvil may cause the rasp to oscillate along with the anvil. The oscillation of the rasp may smooth the neoglenoid in preparation for a glenoid implant.
Data Source
AI summary
A reaming device for preparing a glenoid of a patient may include a base configured for mounting to bone and an oscillatory rasp configured to be translatable in a proximal-distal direction relative to the base while the base is coupled to the glenoid of the patient.