title: Improving the accuracy of wide resection of bone tumors and enhancing implant fit: A cadaveric study.
abstract: OBJECTIVE
  Customized three-dimensional (3-D) jigs have been shown to increase the accuracy of skeletal tumor resection in comparison to freehand techniques. However, the utility of these jigs in subsequently enhancing the fit of endoprosthetic implants has yet to be determined. We hypothesized that custom jigs would improve implant fit compared to freehand resection.
  
  
  METHODS
  Nine matched pairs of cadaveric femurs were scanned by CT. The images then had 'virtual' tumors positioned on the distal medial femoral condyle and preoperative resection plans were generated. Custom implants were designed to fit into the resected spaces and 3-D printed. Similarly, customized 3-D jigs were designed and printed for half of the femurs. Resections were then performed using the jigs or freehand. The implants were positioned in the resected femurs and the accuracy-of-fit was quantitatively assessed by re-scanning the resected femurs and calculating the deviation from the implant (in degrees) for each of the 3 cutting planes. The results were then compared between jig and freehand resections.
  
  
  RESULTS
  For the first plane, the jig resulted in less deviation than the freehand cut, but it did not achieve statistical significance. However, for the 2nd and 3rd planes, the jigs deviated 1.78° and 2.20° from the implants compared to 4.41° and 7.96° for the freehand cuts, both of which were statistically significant improvements (p = 0.038 and p = 0.003).
  
  
  CONCLUSIONS
  In summary, customized 3-D jigs were shown to improve the accuracy-of-fit between implants and host bone, moving this technology closer to clinical implementation.
authors.affiliation: Department of Mechanical Engineering, Stony Brook University, Stony Brook, NY 11794-2300, United States.
authors.forename: Carlos G
authors.initials: CG
authors.lastname: Helguero
authors.affiliation: Department of Mechanical Engineering, Stony Brook University, Stony Brook, NY 11794-2300, United States.
authors.forename: Imin
authors.initials: I
authors.lastname: Kao
authors.affiliation: Department of Orthopaedics, Stony Brook University Hospital, Stony Brook, NY 11794-8181, United States.
authors.forename: David E
authors.initials: DE
authors.lastname: Komatsu
authors.affiliation: Department of Orthopaedics, Stony Brook University Hospital, Stony Brook, NY 11794-8181, United States.
authors.forename: Shazad
authors.initials: S
authors.lastname: Shaikh
authors.affiliation: Department of Orthopaedics, Stony Brook University Hospital, Stony Brook, NY 11794-8181, United States.
authors.forename: Derek
authors.initials: D
authors.lastname: Hansen
authors.affiliation: Stony Brook University School of Medicine, Stony Brook, NY 11794-8434, United States.
authors.forename: Jacob
authors.initials: J
authors.lastname: Franco
authors.affiliation: Department of Orthopaedics, Stony Brook University Hospital, Stony Brook, NY 11794-8181, United States.
authors.forename: Fazel
authors.initials: F
authors.lastname: Khan
keywords: 3-D printing; Cadaver; Cutting guide; Tumor