Abstract
To the Editor,
We read with interest the article entitled “Measurement of the knee joint line in Turkish population” by Gürbüz et al in Vol. 49, No 1 (2015) of your journal.1 We congratulate them for their inspiring work.
The authors measured femoral width, the distance from the apex of the fibular head to joint line and the distance from the adductor tubercle to the joint line to determine the knee joint line level relative to these landmarks and correlation of relative distance of joint line level to the femoral width. However, the study itself has some methodological drawbacks;
- A total of 117 knees were included in the study, but the number of the patients was 108. That means 9 patients were recorded twice considering right and left knee measurements. This is not appropriate from the statistical point of view since joint line levels relative to specific landmarks for individual persons are not expected to be different in each knee. Therefore, to our knowledge, all the studies in the literature cover only one leg for this type of morphometric studies; otherwise, bilateral measurements should be evaluated in separate groups. 2-5
- To ensure images representative of normal anatomy, patients with preexisting radiologic evidence of arthritis in their knees should be excluded from the study.2-5 However, exclusion criteria of the authors did not cover knee osteoarthritis that definitely might alter joint level measurements due to erosions of subchondral bone as it is seen on Fig 1 in original article (knee with Kellgren-Lawrance grade 3 osteoarthritis and possible valgus deformity). In addition, the patella in the figure showing the knee joint is not centered that was supposed to be one of the criteria of the study.
Statistical analysis results given in the article are very preliminary to understand relationship between variables in details. For instance, just by reporting R2 value for linear regression analysis, we could estimate what percentage of the variability in the dependent variable (adductor tubercle joint line level-AJD) is explained by the independent variable (femoral width-FW).
DOI: 10.3944/AOTT.2015.15.0214
This abstract belongs to the un-edited version of the article and is only for informative purposes. Published version may differ from the current version.