Leg length and offset measures with a pinless femoral reference array during THA

Clin Orthop Relat Res. 2010 Jul;468(7):1862-8. doi: 10.1007/s11999-009-1086-1. Epub 2009 Sep 19.

Abstract

The bony fixation of reference marker arrays used for computer-assisted navigation during total hip arthroplasty (THA) theoretically involves the risk of fracture, infection, and/or pin loosening. We asked whether intraoperative assessment of leg length (LL) and offset (OS) changes would be accurate using a novel pinless femoral reference system in conjunction with an imageless measurement algorithm based on specific realignment of the relationship between a dynamic femoral and pelvis reference array. LL/OS measurements were recorded during THA in 17 cadaver specimen hips. Preoperatively and postoperatively, specimens were scanned using CT. Linear radiographic LL/OS changes were determined by two investigators using visible fiducial landmarks and image processing software. We found a high correlation of repeated measurements within and between (both 0.95 or greater) the two examiners who did the CT assessments. Pinless LL/OS values showed mean differences less than 1 mm and correlations when compared with CT measurements.

Publication types

  • Comparative Study

MeSH terms

  • Algorithms
  • Arthroplasty, Replacement, Hip / methods*
  • Arthroplasty, Replacement, Hip / standards
  • Cadaver
  • Female
  • Femur / anatomy & histology*
  • Femur / diagnostic imaging
  • Humans
  • Leg / anatomy & histology*
  • Leg / diagnostic imaging
  • Male
  • Observer Variation
  • Reference Standards
  • Reproducibility of Results
  • Surgery, Computer-Assisted / methods*
  • Tomography, X-Ray Computed