Tibial plateau coverage in UKA: a comparison of patient specific and off-the-shelf implants

J Arthroplasty. 2014 Sep;29(9):1694-8. doi: 10.1016/j.arth.2014.03.026. Epub 2014 Mar 28.


Poor tibial component fit can lead to issues including pain, loosening and subsidence. Morphometric data, from 30 patients undergoing UKA were utilized; comparing size, match and fit between patient-specific and off-the-shelf implants. CT images were prospectively obtained and implants modeled in CAD, utilizing sizing templates with off-the-shelf and CAD designs with patient-specific implants. Virtual surgery was performed, maximizing tibial plateau coverage while minimizing implant overhang. Each implant evaluated to examine tibial fit. Patient-specific implants provided significantly greater cortical rim surface area coverage versus off-the-shelf implants: 77% v. 43% medially and 60% v. 37% laterally. Significantly less cortical rim overhang and undercoverage were observed with patient-specific implants. Patient-specific implants provide superior cortical bone coverage and fit while minimizing overhang and undercoverage seen in off-the-shelf implants.

Keywords: CT-based imaging; ConforMIS; overhang; patient specific implants; tibial component; unicompartmental knee arthroplasty.

Publication types

  • Comparative Study

MeSH terms

  • Arthroplasty, Replacement, Knee / instrumentation*
  • Arthroplasty, Replacement, Knee / methods*
  • Computer Simulation*
  • Humans
  • Knee Joint / diagnostic imaging
  • Knee Joint / surgery*
  • Knee Prosthesis*
  • Prosthesis Design
  • Prosthesis Fitting
  • Tibia / diagnostic imaging
  • Tibia / surgery*
  • Tomography, X-Ray Computed