Date of Award
Bachelor of Science
calcaneal osteotomy, capstone, biomedical engineering, finite element analysis, step plate, pediatric flat feet
A calcaneal osteotomy is a surgical procedure used to correct flat feet. In adults it is a simple procedure where the calcaneus or heel is cut, shifted medially toward the inside of the foot, and then two screws are inserted from the bottom of the heel into the rest of the heel and forefoot. In pediatric cases this technique cannot be used because the two screws would violate the growth plate in the heel. For this reason, a step plate is used. The current step plates used in pediatric calcaneal osteotomies are difficult for surgeons to install due to their size and screw location relative to the incision. The plates are also bulky and known to cause discomfort in patients. The goal of our capstone project was to create an improved calcaneal step plate that was easier to install and more comfortable for patients.
Our final prototype was a titanium step plate that only used two screws and both screws were easier to view through a smaller incision. The overall size of our final prototype was much smaller than the current plate. When subject to finite element analysis (FEA) of a force 11.1 times the body weight of a 13 year old boy, the titanium plate experienced a max force of 1431 MPa which is below the failing point of titanium which is 44000 MPa. The shear force on each screw was tested to determine if using only two screws would cause a fracture in the cancellous bone. Using FEA and a force of 10000 N to simulate body weight forces, the screw was subject to a max shear force of 149 MPa, which is below the shear modulus of cancellous bone which is 288 ± 117 MPa.
Mulvey, Connor; Schiffer, Michael; Moyer, John; and Bismillah, Kayenat, "A Preliminary Report on an Improved Plate Design to Correct Pediatric Flat Feet" (2019). Honors Theses. 2332.
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