Qualitative and Quantitative Differences Between Bone Graft Obtained from the Medullary Canal (with a Reamer/Irrigator/Aspirator) and the Iliac Crest of the Same Patient
ABSTRACT Donor site morbidity and limited volume remain primary drawbacks of using bone graft from the iliac crest and an impetus for finding other sources of autologous bone-graft material. The Synthes Reamer/Irrigator/Aspirator (RIA) has been found to have value as an autologous bone-graft harvesting device. The purpose of this study was to compare the cellular and biochemical characteristics of bone grafts obtained with use of the RIA and from the iliac crest of the same patient.
A prospective study was performed on a consecutive series of ten skeletally mature patients presenting for repair of nonunited tibial or femoral fractures. Graft material was harvested from both the iliac crest (in the standard fashion) and the medullary canal of the femur or tibia (with use of the RIA) of each patient. Portions of each autologous graft sample were assessed histologically and by genomewide transcriptional profiling for biochemical markers known to be expressed during fracture-healing.
Principal-component analysis comparing the messenger RNA expression profiles in the RIA and iliac crest samples showed that the expression profile at each harvest site was unique and independent of patient, age, sex, or any identified comorbidity. Transcriptional analysis showed that the RIA samples had greater levels of expression of genes associated with vascular, skeletal, and hematopoietic tissues. Additionally, stem cell markers and growth factors that act early in the osteogenic cascade were more abundant in the RIA samples compared with the iliac crest samples.
This is the first study to directly compare the histological and molecular profiles of bone grafts from reaming debris and the iliac crest of the same patient. The debris generated during intramedullary reaming, harvested with use of the RIA technique, and the bone graft harvested from the iliac crest possessed a similar transcriptional profile for genes known to act in the early stages of bone repair and formation. This suggests that reaming debris may be a viable alternative to iliac crest bone graft when autologous cancellous graft is needed.
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ABSTRACT: Autologous bone grafting represents the standard of care for treating bone defects but this biomaterial is unreliable in older patients. The efficacy of an autograft can be traced back to multipotent stem cells residing within the bone graft. Aging attenuates the viability and function of these stem cells, leading to inconsistent rates of bony union. We show that age-related changes in autograft efficacy are caused by a loss in endogenous Wnt signaling. Blocking this endogenous Wnt signal using Dkk1 abrogates autograft efficacy whereas providing a Wnt signal in the form of liposome-reconstituted WNT3A protein (L-WNT3A) restores bone forming potential to autografts from aged animals. The bioengineered autograft exhibits significantly better survival in the hosting site. Mesenchymal and skeletal stem cell populations in the autograft are activated by L-WNT3A and mitotic activity and osteogenic differentiation are significantly enhanced. In a spinal fusion model, aged autografts treated with L-WNT3A demonstrate superior bone forming capacity compared to the standard of care. Thus, a brief incubation in L-WNT3A reliably improves autologous bone grafting efficacy, which has the potential to significantly improve patient care in the elderly.Biomaterials 04/2015; 47:29-40. DOI:10.1016/j.biomaterials.2014.12.014 · 8.31 Impact Factor
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ABSTRACT: Introduction Donor-site morbidity, complications and availability remain concerns in autologous bone grafting today. The Reamer/Irrigator/Aspirator system (RIA) provides an alternative method to overcome these problems. According to literature, RIA graft possesses a higher osteogenic potency. This study compares iliac crest and RIA graft performance by determining their in vitro osteogenic capacity in a porcine model. Methods Osteogenic capacity and cell content was determined in RIA and iliac crest bone grafts harvested from six female domestic white pigs. Cells initially washed off, and cells harvested with collagenase were analyzed separately and in combination. Alkaline phosphatase expression (ALP) and cell numbers were evaluated after 7 and 14 days of culture. Matrix mineralization was quantified after 14 days. Results Cell cultures showed a significant increase of matrix mineralization by RIA-derived cells compared to iliac crest bone graft (p = 0.0313). The yield of collagenase derived cells was increased in the RIA group and a synergy between washed off and collagenase derived cells was observed. Cell proliferation was similar in both groups. Discussion The osteogenic differentiation capacity of cell populations isolated from the RIA derived bone graft surpasses that of iliac crest derived cells. It is proposed that the observed effect can be attributed to the origin of the cells and to the specific action of the RIA system. This study provides further evidence indicating that RIA bone graft provides superior osteogenic properties compared to iliac crest bone graft.Injury 10/2014; 45(12). DOI:10.1016/j.injury.2014.10.009 · 2.46 Impact Factor
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ABSTRACT: Upon activation, platelets secrete an array of growth factors that contribute to bone regeneration. Combining platelet rich plasma (PRP) with bone graft substitutes has the potential to reduce or replace the reliance on autograft. Lack of standardisation and improper use may contribute to the conflicting outcomes reported within both pre-clinical and clinical investigations using PRP. This study investigates the effect of PRP dose for bone augmentation. Eighty critical size defects were created in the cancellous bone of the medial proximal tibia and distal femur of 20 five year old female sheep. The defects were treated with three doses of an autologous thrombin activated PRP combined with a biphasic calcium phosphate (BCP) or autograft and empty defects. Radiography, micro-computed tomography, histology, histomorphometry fluorochrome bone labels were examined at 4 weeks. The empty defects did not spontaneously heal. The highest dose of PRP treatment had a significantly greater micro-CT BV/TV compared to the BCP alone (PRP: 30.6±1.8%; BCP: 24.5±0.1%). All doses of PRP treatment were significantly greater than the BCP alone for histomorphometric new bone area (PRP: 14.5±1.3%; BCP: 9.7±1.5%) and bone ingrowth depth (PRP: 2288±210µm; BCP:1151±268µm). From week two onwards, PRP had a significant effect on the weekly bone ingrowth over BCP, however, autograft had the highest amount of weekly fluorescent bone labelling. PRP induces new bone formation with a dose dependant response at four weeks when used with a biphasic calcium phosphate in sheep.Tissue Engineering Part A 03/2014; DOI:10.1089/ten.TEA.2013.0737 · 4.64 Impact Factor