Retractable Insert Acetabular Reamer for Bone Preservation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional orthopedic reamers cause excessive bone removal and abrasion in the acetabulum during hip arthroplasty, leading to reduced bone strength and increased risk of infection and trauma due to the need for multiple reamers of varying sizes.
Innovation Solution
A bone cutter with a retractable, rotatable insert within a partially hemispherical reamer shell allows for separate reaming of the acetabular roof and floor without removing the device, minimizing bone loss and trauma by enabling independent axial and rotational movement of the insert.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If multiple prior art reamers of increasing diameter are used to form a hemispherical cavity, then the desired cavity shape is achieved, but excessive bone is removed from the acetabular floor and fossa
Solution Approach 1:
The reamer shell is designed with a movable insert that can transition between retracted and extended positions. When retracted, the shell reams the acetabular roof and labrum. When extended, the insert contacts and reams the acetabular floor and fossa. This dynamic configuration allows the same device to perform multiple reaming functions while preserving bone structure.
Solution Approach 2:
The reamer is divided into functional segments: a fixed reamer shell for reaming the acetabular roof and labrum, and a movable insert for reaming the acetabular floor and fossa. This segmentation allows independent control of each reaming action, enabling precise bone preservation while achieving the desired hemispherical cavity shape.
2Manufacturing precision
If multiple prior art reamers are inserted and removed during the procedure, then the acetabulum can be reamed to the desired diameter, but the risk of infection and trauma increases
Solution Approach 1:
A single reamer shell is designed to perform multiple functions by combining a fixed reaming surface for the acetabular roof and labrum with a movable insert for the acetabular floor and fossa. This multi-functional design eliminates the need to insert and remove multiple separate reamers, reducing infection risk and surgical trauma while maintaining reaming precision.
Solution Approach 2:
The reaming procedure is made continuous by keeping the reamer shell in place and simply extending or retracting the insert as needed. This eliminates the repeated insertion and removal cycles of multiple reamers, maintaining a continuous useful action that reduces infection risk and procedural trauma.
3Shape
If a rigid hemispherical reamer shell is used, then the cavity is formed from the acetabular fossa outwards to the roof, but the acetabular floor and fossa suffer excessive abrasion
Solution Approach 1:
The reamer shell transitions from a static rigid structure to a dynamic configuration with a movable insert. The insert can be retracted to prevent contact with the acetabular floor during initial reaming of the roof and labrum, then extended to contact and ream the floor and fossa. This dynamic control eliminates excessive abrasion while maintaining effective cavity formation.
Solution Approach 2:
The acetabular roof and labrum are reamed first with the insert retracted, preparing the cavity before the insert is extended to ream the acetabular floor and fossa. This preliminary action sequence prevents premature contact and abrasion of the floor and fossa bone structure.
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 design preserves more bone structure, reduces the risk of infection and trauma, and allows for a more precise and minimally invasive procedure by eliminating the need for multiple reamers.
Implementation Method 1
the reamer apex contacts and abrades the acetabular floor and fossa
Data Source
AI summary
An orthopedic bone cutter for cutting bone and tissue is described. The orthopedic bone cutter comprises a cutting shell and a cutting insert that resides within an opening that extends through the apex region of the shell. A pin and slot mechanism positioned within the shell interior provides for independent axial and rotational movement of the insert within the shell. The shell comprises a partially hemispherical structure having a plurality outwardly extending and spaced apart shell cutting teeth. The insert comprises an annular sidewall that meets an end wall having a plurality of outwardly extending and spaced apart insert teeth. With the insert at a retracted position within the shell, the bone cutter is rotated in a first direction to cause the shell cutting teeth to cut, for example, an acetabular roof and labrum. Then, rotation of the shell in a second opposite direction causes the shell to stop cutting, but provides for the insert to extend outwardly to cut the acetabular floor and fossa.