A computational/experimental platform for investigating three-dimensional puzzle solving of comminuted articular fractures

Abstract

Reconstructing highly comminuted articular fractures poses a difficult surgical challenge, akin to solving a complicated three-dimensional (3D) puzzle. Pre-operative planning using CT is critically important, given the desirability of less invasive surgical approaches. The goal of this work is to advance 3D puzzle solving methods toward use as a pre-operative tool for reconstructing these complex fractures. Methodology for generating typical fragmentation/dispersal patterns was developed. Five identical replicas of human distal tibia anatomy, were machined from blocks of high-density polyetherurethane foam (bone fragmentation surrogate), and were fractured using an instrumented drop tower. Pre-and post-fracture geometries were obtained using laser scans and CT. A semi-automatic virtual reconstruction computer program aligned fragment native (nonfracture) surfaces to a pre-fracture template. The tibias were precisely reconstructed with alignment accuracies ranging from 0.03-0.4mm. This novel technology has potential to significantly enhance surgical techniques for reconstructing comminuted intra-articular fractures, as illustrated for a representative clinical case.

Relative accuracy of spin-image-based registration of partial capitate bones in 4DCT of the wrist

“…Additionally, the robustness of the algorithm to partial geometry could be useful in 3D puzzle solving for reconstructing comminuted fractures (Thomas et al 2011). In conclusion, the spin-image algorithm has been shown to tolerate substantial, continuous regions of omitted/missing geometry and should be considered a valuable tool for image analysts and biomechanists for registration and image-based motion capture.…”

ASB Clinical Biomechanics Award Paper 2010

“…Identification of the fracture surfaces was accomplished with a region-growing algorithm that propagated discrete surface patches up to boundaries of high curvature (Thomas et al, 2010). Fracture surfaces tended to have significant surface variations, causing the algorithm to segment them into many smaller surface patches.…”

“…Novel methods for 3D “puzzle solving” reconstruction of intra-articular fractures have recently been developed, with benchtop application to a surrogate model (Thomas et al, 2010). Matching native fragment bone surfaces to an intact template proved to be an effective and computationally tractable methodology.…”

A Simulation Trainer for Complex Articular Fracture Surgery

“…An innovative rapid machining technology 5 was used to recreate the distal tibia geometry, working off models generated from CT segmentations of intact anatomy. A 7.5-kg mass was dropped from a height of 0.5 m in a drop tower to fracture the tibia replica using a talus surrogate impactor (cast from polymethylmethacrylate [PMMA]) to deliver the impact 6 . A silicone rubber mold (TinSil 70 Series RTV; U.S. Composites, West Palm Beach, Florida) of the fracture fragments was negative-cast and was then used to positive-cast identical replica fragments.…”