Reasons for poor growth after a hair transplant : There are many variables that could contribute to poor growth following a hair transplant. One major reason is when the wrong hair is used. This is commonly as a result of using hair that is already miniaturized or that is destined to be lost. The individual may have undergone a traditional hair transplant surgery where follicles were taken from the back of the head. However this are is vast with some areas already thinning or destined to go thin. If these types of hairs are used, poor growth may result.

Dr U has described a new method for determining which areas of the back and sides of the head are safe for harvesting and which are not. he calls this method the FUE Shave Test

Other Reasons For Poor Growth After a Hair Transplant

In this video, Dr U breaks down various reasons for poor growth after a hair transplant:

https://youtu.be/bDMyXFV3v2Q?list=PLHNSPUQnYInJPvwLHW9hJ9nDp5F3Q5D0I

Another possibility is that the surgeon selected follicles which had already been in a state of decline.
Also, storage and handling processes can affect the ability of grafts to survive in the recipient area. It is important to avoid pulling the follicles too hard or inadvertently severing them with instruments. Air drying, warm storage temperatures and being outside the body for too long can also undermine the health of the follicles.
After the hair transplant, and inflammatory condition involving the grafted sites could result in poor growth. Inflammation could have resulted from use of irritants, intervening diseases like dandruff, trauma of any kind etc

poor growth after a hair transplant can be avoided by using an experience doctor and clinic — This patient experienced unusually looking placement of hair grafts due to the inexperience of the surgeon. However in most cases, abnormal looking growth is often just a temporary phase.*

https://www.youtube.com/watch?v=bDMyXFV3v2Q&index=11&list=PLHNSPUQnYInJPvwLHW9hJ9nDp5F3Q5D0I