Not being an orthopedist, I cannot comment on their validity.
But I think I can explain why the papers have not created much interest.
Are you familiar with the term "impact factor"? If not, here is a link explaining what it is:
A journal's impact factor is an indication of how widely cited its articles are. One can also assume that it is a good indication of how popular the journal is and by inference, how many people read its papers. The impact factor has been criticized, but it is one of the few measures of a journal's influence.
The two papers in question were published in Orthopaedics & Traumatology: Surgery & Research. A list of the top 40 orthopedic journals ranked by impact factor in 2013 showed that it ranked 37th with an impact factor of 1.061. That means the average number of citations for any paper published in OTSR was about 1, and 36 orthopedic journals were more widely cited than OTSR.
A paper in Physics World claims that that 90% of published papers are never cited and 50% are never read by anyone but the authors and the journals' peer reviewers. I believe this is true of papers in medical journals too. [Update: This paragraph is untrue. See my post of 3/23/17.]
I was unable to obtain any figures regarding the number of subscribers to OTSR, but I suspect it is not large. This may also account for the lack of responses to the papers. My own experience is similar. It was very rare to receive any feedback about any of the over 90 peer-reviewed papers, editorials, or reviews that I had written.
Consider this. A blog post of mine "Appendicitis: Diagnosis, CT Scans and Reality" which I wrote 4 years ago has received over 77,000 [Updated on 3/23/17] page views and more than 100 comments. I am certain that post has been read far more than all of my published research papers combined. In fact, my 550 blog posts have recorded over 1 million page views.
What does it all mean?
Journals may have to adapt and become more like blogs. In the future, medical information may be disseminated by blogs and comments rather than journal articles and letters to the editor.
Will scientists' CVs be valued more for the number of page views their papers receive than the number of peer-reviewed papers they publish?