Osteocutaneous radial forearm free flap: long-term radiographic evaluation of donor site morbidity after prophylactic plating of radius.

The osteocutaneous radial forearm free flap (ORFFF) is an ideal source of vascularized bone and soft tissue for repair of defects in reconstructions of the head and neck. However, studies have revealed significant donor site morbidity, decreasing the popularity of this procedure. We have previously reported our technique of prophylactic internal fixation of the radius at the time of graft harvest, developed to decrease donor radius fractures. This is a retrospective radiographic review of our long-term radius donor site morbidity. Forearm radiographs more than 3 years after ORFFF with prophylactic plating were evaluated and compared with prior postoperative films. No donor radius fractures were identified. All radiographs exhibited remodeling and/or reconstitution of donor radii. There was no evidence of implant failure, loosening, or surrounding osteopenia. This study lends further credibility to the ORFFF, when prophylactically plated, as a safe and reliable source of vascularized bone and soft tissue for reconstructive procedures.

Immunohistochemical localization of bone morphogenetic proteins (BMPs) 2, 4, 6, and 7 during induced heterotopic bone formation.

The distribution and staining intensity of bone morphogenetic proteins (BMPs) 2, 4, 6, and 7 were assessed by immunohistochemistry in ectopic bone induced in Nu/Nu mice by Saos-2 cell derived implants. Devitalized Saos-2 cells or their extracts can induce endochondral bone formation when implanted subcutaneously into Nu/Nu mice. BMP staining was mostly cytoplasmic. The most intense BMP staining was seen in hypertrophic and apoptotic chondrocytes, osteoprogenitor cells such as periosteal and perivascular cells, and osteoblasts. BMP staining in osteocytes and osteoclasts was variable, ranging from undetectable to intensely stained, and from minimal to moderately stained in megakaryocytes of the induced bone marrow. BMP-2, 4, 6, and 7 staining in Saos-2 implant-induced bone indicates the following: (1) Saos-2 cell products promote expression of BMPs by host osteoprogenitor cells, which in turn, leads to bone and marrow formation at ectopic sites; (2) strong BMP staining is seen in maturing chondrocytes, and thus may play a role in chondrocyte differentiation and/or apoptosis; (3) BMP expression in perivascular and periosteal cells indicates that osteoprogenitor cells also express BMP; (4) BMP release by osteoclasts may promote osteoblastic differentiation at sites of bone remodeling. These new data can be useful in understanding the role of BMPs in promoting clinical bone repair and in various pathologic conditions.