Accuracy, Inter- and Intra-Observer Reliability of a CT Alignment Measurement Protocol for Robotic-Arm Assisted Total Knee Arthroplasty

5 pages•Published: October 26, 2019

Jingwei Zhang, Scott Persohn, Manoshi Bhowmik-Stoker, Jason Otto, Meenakshisundaram Paramasivam, Ahmad Wahdan, Robert H. Choplin and Paul Territo

Abstract

Component position and overall limb alignment following Total Knee Arthroplasty (TKA) have been shown to influence device survivorships and clinical outcomes. However, these parameters are often assessed through 2D radiographs after surgery, which can be prone to inaccuracy. The purpose of this paper is to develop a new method for 3D CT based overall limb alignment and component position measurements. The technique utilizes a new mathematical model to calculate prosthesis alignment from the coordinates of anatomical landmarks used in RATKA. The hypothesis is that the proposed technique demonstrated good accuracy, as well as low intra and inter-observer variability.
Two groups of patients (n=120 per group) underwent RATKA and conventional TKA at 4 imaging locations between October 2016 and August 2018, where they were recruited and consented for this prospective, non-randomized, multicenter study. CTs were collected 6 weeks post-operatively and analyzed using RATKA landmarks and the proposed technique. Measurements of 30 randomly selected cases were compared to the surgeons’ operative plan and component target positions for accuracy analysis. Two surgeons performed the same measurements separately for inter-observer variability analysis. One of the two surgeons repeated the measurements 30 days later to assess intra-observer variability.
Average measurement error of overall limb alignment, femoral and tibial component positions were less than 1 degree. Bland Altman plots analysis showed great reproducibility between observers. Correlation analysis showed low variability within observer, with slopes between 0.8 to 1.0 and R-squared > 0.8.
The proposed method demonstrated great accuracy to plan and low intra and inter-observer variability. This can be a great tool for RATKA studies where component accuracy is assessed using post-operative CTs.

Keyphrases: component position, ct analytics, limb alignment, robotic arm assisted, total knee arthroplasty

In: Patrick Meere and Ferdinando Rodriguez Y Baena (editors). CAOS 2019. The 19th Annual Meeting of the International Society for Computer Assisted Orthopaedic Surgery, vol 3, pages 448-452.

Links:	https://easychair.org/publications/paper/3ZQF
	https://doi.org/10.29007/j8rv

BibTeX entry

@inproceedings{CAOS2019:Accuracy_Inter_Intra_Observer,
  author    = {Jingwei Zhang and Scott Persohn and Manoshi Bhowmik-Stoker and Jason Otto and Meenakshisundaram Paramasivam and Ahmad Wahdan and Robert H. Choplin and Paul Territo},
  title     = {Accuracy, Inter- and Intra-Observer Reliability of a CT Alignment Measurement Protocol for Robotic-Arm Assisted Total Knee Arthroplasty},
  booktitle = {CAOS 2019. The 19th Annual Meeting of the International Society for Computer Assisted Orthopaedic Surgery},
  editor    = {Patrick Meere and Ferdinando Rodriguez Y Baena},
  series    = {EPiC Series in Health Sciences},
  volume    = {3},
  publisher = {EasyChair},
  bibsource = {EasyChair, https://easychair.org},
  issn      = {2398-5305},
  url       = {/publications/paper/3ZQF},
  doi       = {10.29007/j8rv},
  pages     = {448-452},
  year      = {2019}}

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