Advertisement for orthosearch.org.uk
Results 1 - 2 of 2
Results per page:
Applied filters
Content I can access

Include Proceedings
Dates
Year From

Year To
Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_3 | Pages 76 - 76
1 Apr 2018
Cristofolini L Morellato K Soffiatti R Rotini R Guerra E
Full Access

Introduction

The standard treatment of proximal humerus fractures includes pre-contoured metal plates and up to nine cortical and trabecular screws. Frequent failures are reported, especially in case of poor bone quality. The scope of this study was to assess the strength of an innovative reconstruction technique (Cement-and-screws) based on a commercial plate, with a reduced number of screws compared to the standard, and with the injection of a beta-TCP additivated acrylic bone cement (Cal-Cemex, Tecres, Italy). The focus was on a four-fragment fracture of the proximal humerus, in combination with a bone defect. For comparison, also a standard technique, based on a commercial system of plate and screws was tested (Screws-only).

Materials and Methods

Six pairs of cadaveric humeri were obtained through an ethically-approved donation program. The humeri were osteotomized to simulate a reproducible four-fragment fracture with the aid of a dedicated jig. Preparation included the simulation of a bone defect in the humeral head. One humerus of each pair was randomly assigned to one of two reconstruction techniques: (i) cement-and-screws humeri were repaired with a commercial fixation plate, 2 cortical and 3 trabecular screws (Philos, DePuy Synthes), and with injection of an acrylic cement additivated with beta-TCP (Cal-Cemex, Tecres); (ii) for comparison, screws-only humeri were prepared with the same commercial plate, 2 cortical and 6 trabecular screws. The reconstructed humeri underwent a biomechanical test. An axial force was cyclically applied, where the load magnitude started at 140 N and increased by 1% at each cycle. Failure was defined as fragment motion exceeding 8 mm.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_2 | Pages 80 - 80
1 Jan 2017
Cavallo M Maglio M Parrilli A Martini L Guerra E Pagani S Fini M Rotini R
Full Access

Autologous bone grafting is a standard procedure for the clinical repair of skeletal defects, and good results have been obtained. Autologous vascularized bone grafting is currently the procedure of choice because of high osteogenic potential and resistance against reabsorption. Disadvantages of this procedure include limited availability of donor sites, clinical difficulty in handling, and a failure rate exceeding 10%. Allografts are often used for massive bone loss, but since only the marginal portion is newly vascularized after the implantation non healing fractures are often reported, along with a graft reabsorption. To overcome these problems, some studies in literature tried to conjugate bone graft and vascular supply, with encouraging results. On the other side, several studies in literature reported the ability of bone marrow derived cells to promote neo-vascularization. In fact, bone marrow contains not only hematopoietic stem cells (HSCs) and MSCs as a source for regenerating tissues but also accessory cells that support angiogenesis and vasculogenesis by producing several growth factors. In this scenario a new procedure was developed, consisting in an allogenic bone graft transplantation in a critical size defect in rabbit radius, plus a deviation at its inside of the median artery and vein with a supplement of autologous bone marrow concentrate on a collagen scaffold.

Twenty-four New Zealand male white rabbits (2500–3000 g) were divided into 2 groups, each consisting of 12 animals. Surgeries were performed as follow:

Group 1 (#12): allogenic bone graft (left radius) / allogenic bone graft + vascular pedicle + autologous bone marrow concentrate (right radius)

Group 2 (#12): sham operated (left radius)/ allogenic bone graft + vascular pedicle (right radius)

For each group, 3 experimental time: 8, 4 and 2 weeks (4 animals for each time).

The bone used as graft was previously collected from an uncorrelated study. An in vitro evaluation of bone marrow concentrate was performed in all cases, and at the time of sacrifice histological and histomorphometrical assessment were performed with immunohistochemical assays for VEGF, CD31 e CD146 to highlight the presence of vessels and endothelial cells. Micro-CT Analysis with quantitative bone evaluation was performed in all cases.

The bone marrow concentrate showed a marked capability to differentiate into osteogenic, chondrogenic and agipogenic lineages. No complications such as infection or intolerance to the procedure were reported. The bone grafts showed only a partial integration, mainly at the extremities in the group with vascular and bone marrow concentrate supplement, with a good and healthy residual bone. immunohistochemistry showed an interesting higher VEGF expression in the same group. Micro CT analysis showed a higher remodeling activities in the groups treated with vascular supplement, with an area of integration at the extremities increasing with the extension of the sacrifice time.

The present study suggests that the vascular and marrow cells supplement may positively influence the neoangiogenesis and the neovascularization of the homologous bone graft. A longer time of follow up and improvement of the surgical technique are required to validate the procedure.