Abstract
We read with great interest the article titled "Variability between full-length lateral radiographs and standard short knee radiographs when evaluating posterior tibial slope in revision ACL patients." 1 The detailed and well-written study provided valuable insights, and we appreciate the hard work and dedication of the authors. After discussing the article in our recent journal club meeting, we had some queries, and we appreciate assistance in better understanding certain aspects of the study.
We are curious whether the value of the posterior tibial slope (PTS) is comparable on full-length lateral (FLL) and short standard knee (SSK) radiographs, given that both use different reference points for measurement.
2. Is the anatomical axis for the proximal tibia (used in SSK for PTS measurement) similar to the mechanical axis of the tibia (used in FLL for PTS measurement)? If there is an inherent difference between these axes, wouldn't this inherently cause a difference in PTS measurements between SSK and FLL radiographs?
3. Faschingbauer et al
2
described the PTS as the "angle between the tibial plateau line and a line drawn (described as the mechanical axis of the tibia on the FLL radiograph) between the midpoint of the tibial plateau and the midpoint of the tibiotalar joint on the FLL radiograph." However, Figure 2B in your study does not seem to explain the mechanical axis, as the center of the tibial plateau is not taken as a reference point. Could you please clarify this?
4. In the results and discussion sections, it is mentioned that there is a ≥2° difference between FLL and SSK radiographs for PTS measurements. Is this difference due to the anatomical characteristics of the tibia, or is it because of the 2 different methods used for the PTS measurement?
We hope these queries help further illuminate the intricacies of the study, and we would appreciate your response to enhance our understanding.
Thank you for your attention to these matters.
Footnotes
The authors have declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.