Reif T, Schoch B, Spiguel A, et al. - The intent of this study was to evaluate the ability of proximal humeral allograft-prosthetic composite (APC) to restore usable bone at the time of revision surgery. Researchers reviewed two institutional electronic medical records to assess proximal humeral APC procedures conducted between 1970 and 2018. This study enrolled a sum of 14 individuals (6 male and 8 female individuals) who underwent revision of the APC reconstruction at a mean of 22.8 months. The allograft retention was categorized as type A in 6 shoulders, type B in 3, and type C in 5 at revision. The results found that Type A cases were correlated with nonunion with a well-fixed stem, type B cases were correlated with instability and were converted from a hemiarthroplasty to a reverse total shoulder arthroplasty, and type C cases were correlated with an allograft fracture or nonunion with a loose humeral component. It was demonstrated that a substantial number of revisions of proximal humeral APC reconstructions maintain a portion of the allograft bone (64.3%). For large bone deficits, this study supports the continuous use of the APC reconstruction technique.