The authors examined the liver function and liver volume of 91 right liver lobe donors.
Within a year of donating, 96% had regained full liver function but only 85% had full pre-donation liver volume.
Unfortunately, these results say nothing about the long term risk of scarring (cirrhosis) or otherwise.
Duclos J, Bhangui P, Salloum C, Andreani P, Saliba F, Ichai P, Elmaleh A, Castaing D, & Azoulay D (2016). Ad Integrum Functional and Volumetric Recovery in Right Lobe Living Donors: Is It Really Complete 1 Year After Donor Hepatectomy? American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons, 16 (1), 143-56 PMID: 26280997