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Design Philosophy
The overriding design goal was to reproduce the normal anatomy and biomechanics of the human elbow. We created an implant that closely matches its typical dimensions and architecture. Three different Implant sizes were designed so as to match the patient's anatomy. Reproducing anatomy extends to the medial and lateral collateral ligaments, which are the primary soft tissue stabilizers of the elbow. When implanting an elbow replacement, these ligaments are elevated off of the humerus, which destabilizes the elbow. This implant is stabilized through a reproduction of these same ligaments on both medial and lateral sides and will provide elbow constraint that mimics that what occurs in the native uninjured elbow. The native soft tissues are also reattached but are not essential to the biomechanical stability of this construct.
This elbow replacement is unconstrained in that it does not exhibit a direct mechanical linkage between the humeral and ulnar components, which is in distinction to how most elbows are implanted today. It derives bony stability through the interaction of a convex metallic distal humerus and a concave polyethylene wear surface affixed to the ulna.
The design philosophy continues with radial head, which is an important secondary elbow stabilizer. When implanting the KTE, it is ideal to preserve the native radial head even if it’s appearance shows slight arthritic damage and yet overall dimensional preservation. As such, the radial head influences the position of the humeral and ulnar body components as these are implanted so as to maintain their native anatomical and biomechanical relationship.
An advantage over its cemented brethren is that this design uses intramedullary screws that gain purchase in the threaded intramedullary canal and can pull the implant into the humerus and ulna, thereby creating a very stable intramedullary fixation based construct that distributes forces over a sizeable number of threads. By leveraging the length of the humerus and ulna as well as the high cortical to cancellous bone ratio within the shafts of these bones, the proposed method of fixation will ensure safe and reproducible uncemented implant fixation. The use of cross locking members augments the construct’s initial stability.
No cement is used, which makes intraoperative changes possible if needed. Optimal bone preservation occurs through a sequence of drilling and broaching that removes only bone that is necessary. No additional bone that would be needed for the cement mantle is lost. If separation between the implant and bone is noted, autograft derived from the resected portions of the distal humerus and proximal ulna can be packed between the implant and bone. This design completely avoids thermal osteonecrosis secondary to the cement curing process as well as bone cementation implantation syndrome.
This elbow replacement is unconstrained in that it does not exhibit a direct mechanical linkage between the humeral and ulnar components, which is in distinction to how most elbows are implanted today. It derives bony stability through the interaction of a convex metallic distal humerus and a concave polyethylene wear surface affixed to the ulna.
The design philosophy continues with radial head, which is an important secondary elbow stabilizer. When implanting the KTE, it is ideal to preserve the native radial head even if it’s appearance shows slight arthritic damage and yet overall dimensional preservation. As such, the radial head influences the position of the humeral and ulnar body components as these are implanted so as to maintain their native anatomical and biomechanical relationship.
An advantage over its cemented brethren is that this design uses intramedullary screws that gain purchase in the threaded intramedullary canal and can pull the implant into the humerus and ulna, thereby creating a very stable intramedullary fixation based construct that distributes forces over a sizeable number of threads. By leveraging the length of the humerus and ulna as well as the high cortical to cancellous bone ratio within the shafts of these bones, the proposed method of fixation will ensure safe and reproducible uncemented implant fixation. The use of cross locking members augments the construct’s initial stability.
No cement is used, which makes intraoperative changes possible if needed. Optimal bone preservation occurs through a sequence of drilling and broaching that removes only bone that is necessary. No additional bone that would be needed for the cement mantle is lost. If separation between the implant and bone is noted, autograft derived from the resected portions of the distal humerus and proximal ulna can be packed between the implant and bone. This design completely avoids thermal osteonecrosis secondary to the cement curing process as well as bone cementation implantation syndrome.