Abstract
We do appreciate the interest of Stefania Fatone and her colleagues in our study. Below we provide our comments and responses to her questions.
The usual prosthesis in our participants was composed of a total surface weight-bearing socket and a sleeve as suspension mechanism. A total of 10 participants used a SACH foot, while the other 6 used a carbon fiber foot.The comparator socket was an exact duplicate of the usual socket. No other components were modified. We decided to do an exact duplicate socket because a hole for tubing is needed to fit the Ottobock Harmony® P2 and HD, so participants could keep their own socket.
In relation to the subjects who suffered skin injury, blisters appeared after adapting the vacuum-assisted system, so the testing was completed once the distal valve was installed and blisters resolved. In our sample, as discussed in the paper, 1 we believe blisters appeared in patients with low activity levels because they spent more time sitting, and the pull produced by the prosthesis while seated allowed the entrance of air into the socket resulting in lack of total contact between the socket and limb, something reported previously in literature. 2 That is the reason why we suggested an additional distal valve in the socket of low-activity amputees when installing an Ottobock Harmony P2 and HD vacuum assisted suction system (VASS).
Regarding statistical analysis, when several statistical tests are performed on a single data set, the probability of identifying at least one significant result due to chance increases. The more hypotheses tested, the higher chance for a false positive result (type I error). When decreasing the probability of a type I error, the probability of a type 2 error (false negative result) increases. We understand that the results obtained must be interpreted according to the probability of a type I error (p-value), the magnitude of the observed effect and the clinical plausibility of the results.
We hope our comments are helpful for the potential clinical application and research on VASS in transtibial amputees.
Footnotes
Author contribution
All authors contributed equally in the preparation of this manuscript.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.