TRAUMAPhyseal Fractures, Part II: Fate of Interposed Periosteum in a Physeal FractureGruber, Helen E. Ph.D.*; Phieffer, Laura S. M.D.*; Wattenbarger, J. Michael M.D.*†Author Information Study conducted at Carolinas Medical Center, Charlotte, North Carolina, U.S.A. From the *Department of Orthopaedic Surgery, Carolinas Medical Center, and the †Miller Orthopaedic Clinic, Charlotte, North Carolina, U.S.A. Address correspondence and reprint requests to J. Michael Wattenbarger, M.D., Miller Orthopaedic Clinic, Medical Center Plaza, 1001 Blythe Blvd., Suite 200, Charlotte, NC 28203, U.S.A. (e-mail: Michael.Wattenbarger@millerclinic.com). Supported in part by the Charlotte-Mecklenburg Health Services Foundation. Presented in part at the 2001 Annual Meeting of the Pediatric Orthopaedic Society of North America. Journal of Pediatric Orthopaedics: November-December 2002 - Volume 22 - Issue 6 - p 710-716 Buy Abstract This study describes the histologic features of periosteum interposed into a physeal fracture of the rat proximal tibia. Periosteum was introduced into a physeal fracture in two groups of animals: those with an intact physis after fracture, and those with the medial half of the physis surgically ablated. Specimens of the proximal tibia underwent histologic analysis at 2, 4, 6, 10, and 21 days after fracture to determine the histologic features of interposed periosteum in a physeal fracture. In animals with an intact physis, interposed periosteum underwent one of two fates: it was degraded by giant cells in the fracture plane, which allowed cellular infiltration, or if the periosteum was closely surrounded by physeal cartilage, the physis grew around it and appeared to force it toward the metaphysis. In animals whose physis received surgical ablation, physeal bar formation was always present, with poor organization of the remaining lateral growth plate. Histologic evidence from this study also underscores the fact that physeal bar formation occurs from the migration of osteoblasts and osteoclasts along vertical septa. © 2002 Lippincott Williams & Wilkins, Inc.