Can orbital fat repositioning during transconjuctival lower blepharoplasty ever result in lumps or bumps?

Yes, it can result in lumps and bumps, that is one of the risks of surgeryFree fat transfer to this area can do the sameIf you remove the fat and do not transpose it, then a hollow can occur

Lumps and bumps are probably the most common problem after lower lid fat repositioning. Many surgeons prefer this technique, but my personal preference is a standard lower lid blepharoplasty with fat excision, and in the patient that really needs more volume along the bony rim, I prefer fat grafting for many reasons, one of which is a lack of lumps or bumps.Andrew Campbell, M.D.
Facial Rejuvenation Specialist
Quintessa Aesthetic Centers

Yes absolutely and this is the most common problem encountered.  Obviously it is technique based, but my approach to any procedure is to increase the benefits and limit the risks.  For that reason, I do not recommend fat redraping and prefer removal of the fat.  Redraping of the fat is used to provide volume over the orbital rim and this can be done if necessary with a number of safe fillers that are low risk.  I find that I rarely need fillers when the fat has been contoured to the anatomy. Hope this helps and best of luck.

As in all surgeries, the surgeon simply does their best to perform the surgeries skillfully in order to minimize all the risks.

The orbital fat is transposed over the orbital rim to add volume to this area. This helps smooth the transition between the lower lid and cheek. The surgeon must make sure this fat is distributed evenly and smoothly or lumps/bumps can occur. Many surgeons will secure the fat with sutures to prevent migration. Your best bet is to consult with a very experienced eyelid surgeon and have a look at his/her results. 

It is absolutely true that lower blepharoplasty with fat transposition over the orbital rim can lead to lumps or bumps in the area.  This is why is is very important to see a surgeon skilled in this specific technique if this is what you desire. There are a number of ways to make sure this does not happen, but with all medical and surgical procedures there is always a small chance of a suboptimal result.  I prefer to carefully and meticulously drape the fat as a curtain over the orbital rim and secure it with sutures externally through the skin. Without suturing the fat it is my opinion that it could migrate back to its original position and cause the bags to return. Some surgeons suture internally with absorbable stitches. Regardless of the technique, experience and familiarity with the procedure is the most important factor.