Wankier, Zakary; Sinclair, Sarina PhD; Drew, Alex PhD; Taylor, Carolyn MS; Kubiak, Eric MD; Agarwal, Jayant MD (University of Utah)
Faculty Advisor: Sinclair, Sarina (School of Medicine, Orthopaedics)
Introduction:
Osseointegration (�OI�) technology is the direct skeletal attachment of a prosthetic limb to bone using an intramedullary stem. For OI to be effective and secure, bone in-growth and remodeling around the implant must be achieved. Physicians need an effective way to measure bone remodeling in order to make informed decisions on treatments. This work describes methodology that was developed that utilizes computed tomography (CT) imaging as a tool for analyzing bone remodeling around an OI implant.
Method:
Subjects implanted with a new Percutaneous Osseointegrated Prosthesis (POP) had CTs taken of their residual femur at 6 and 52-weeks post-op. The CT images were used to segment and create three-dimensional models of the femur.
Following segmentation, models were aligned to a common world coordinate system. STLs of the aligned medullary cavity and femur volume were entered into custom Matlab code to calculate cortical and medullary morphology measurements. Morphology data from 6 and 52-week scans were compared in order to determine if bone remodeling around the POP implant could be detected.
Results:
Comparing data from post-operative visits suggests that important indicators of bone remodeling around the device could be detected. One year after implantation of the POP device the medullary parameters had minimal % differences (-1.5 and 2.2) compared to 6-weeks, validating that consistent alignment was achieved between scans from different time points. Cortical area, perimeter, and thickness around the POP implant showed positive percent changes at 12-months of 19.44%, 4.04% and 14.36% respectively. Increases in cortex morphology values indicate bone remodeling around the implant, with largest increases observed at the distal end for each parameter.
Discussion:
This pilot study utilized CT imaging as a tool for quickly and accurately analyzing bone remodeling around a new osseointegrated device. Additional work will further validate and optimize these methods for clinical use.
This study described an investigational device, limited by federal law to investigational use. No long-term data exists about its performance.