Reaming debris in osteotomized sheep tibiae

Induction of periosteal bone formation by intraosseous BMP-2 injection in a mouse model of osteogenesis imperfecta

PURPOSE

Surgical interventions are routinely performed on children with osteogenesis imperfecta (OI) to stabilize long bones, often post fracture. We speculated that a combination of intramedullary reaming and intraosseous injection of recombinant bone morphogenetic protein-2 (BMP-2) could enhance periosteal ossification and ultimately cortical thickness and strength. This approach was conceptually tested in a preclinical model of genetic bone fragility.

METHODS

Six experimental groups were tested including no treatment, intramedullary reaming, and reaming with 5 µg BMP-2 injection performed in the tibiae of both wild type (WT) and Col1a2 ^G610C/+ (OI, Amish mutation) mice. Bone formation was examined at a two-week time point in ex vivo specimens by micro-computed tomography (microCT) analysis and histomorphometry with a dynamic bone label.

RESULTS

MicroCT data illustrated increases in tibial cortical thickness with intramedullary reaming alone (Saline) and reaming plus BMP-2 injection (BMP-2) compared to no intervention controls. In the OI mice, the periosteal bone increase was not statistically significant with Saline but there was an increase of +192% (p = 0.053) with BMP-2 injection. Dynamic histomorphometry on calcein label was used to quantify new woven bone formation; while BMP-2 induced greater bone formation than Saline, the anabolic response was blunted overall in the OI groups.

CONCLUSIONS

These data indicate that targeting the intramedullary compartment via reaming and intraosseous BMP-2 delivery can lead to gains in cortical bone parameters. It is suggested that the next step is to validate safety and functional improvements in a clinical OI setting.

Use of intramedullary nailing in poor sanitary conditions: French Military Medical Service experience

INTRODUCTION

Intramedullary (IM) nailing is the gold standard for treating long bone fractures in developed countries because of its minimally-invasive application and good biomechanical properties. In precarious conditions, external fixation or open plate fixation are often performed because surgeons do not have the means to carry out IM nailing. However, these procedures can lead to infection-related complications and mechanical failures. The aim of our study was to describe the outcomes and postoperative complications of IM nailing of closed, long bone fractures in patients operated in a French front-line combat surgical unit (role 2+). Our hypothesis was that IM nailing is a reliable technique with low morbidity for the initial treatment of long bone fractures, even in precarious situations.

MATERIAL AND METHODS

This was a prospective, single-center, descriptive study of patients operated on between April 2016 and November 2017. All the patients with a closed femur or tibia fracture who were treated by IM nailing were eligible, no matter their time to surgery. The minimum follow-up was 6 months. The primary endpoint was the absence of infection-related complications and the secondary endpoint was fracture union.

RESULTS

Fifty-eight patients were reviewed after an average follow-up of 4.7 months (range, 3-15 months). The mean patient age was 35.2 years (15-85 years) and the majority of patients were men (52 of 58). The fracture was in the femur in 74.1% (n=43) of cases and in the tibia in 25.9% (n=15) of cases. The time to surgery averaged 122.3 days (7-720 days) with a median of 60 days. In 74% of cases (n=43), fracture realignment required an open surgical approach. The postoperative course was considered normal in 96.6% of cases (n=51). No infections were reported as of the last follow-up visit. Union occurred in an average of 4 months in 70.7% of cases (n=41). There were three cases of nonunion after 6 months.

DISCUSSION

Even in precarious situations, IM nailing is an effective, reliable method with a low complication risk and high union rate for the treatment of neglected long bone fractures. This surgical treatment is well suited to the poor sanitary conditions on the African continent.

LEVEL OF EVIDENCE

II, low-powered prospective study.

Early local microcirculation is improved after intramedullary nailing in comparison to external fixation in a porcine model with a femur fracture

INTRODUCTION

The local circulatory changes induced by intramedullary reaming are not fully understood. This study aimed to analyse the short-term local microcirculation associated with different surgical strategies in a porcine model with a mid-shaft fracture.

METHODS

German landrace pigs were subjected to a standardised femoral fracture under standard anaesthesia and intensive care monitoring. One group was subjected to intramedullary reaming and nailing (nail group), while a second group was stabilised with external fixation (fix ex group). Microcirculation [e.g. relative blood flow (flow), oxygen saturation and relative haemoglobin concentration] was measured in the vastus lateralis muscle adjacent to the fracture using an O2C (oxygen to see, LEA Medizintechnik GMBH) device at 0 (before fracture, baseline), 6 (90-min posttreatment), 24, 48 and 72 h.

RESULTS

A total of 24 male pigs were used (nail group, n = 12; fix ex group, n = 12). During the observation period, a significant increase of flow was found at 6 (P = 0.048), 48 (P = 0.023) and 72 h (P = 0.042) in comparison with baseline levels. Local oxygen delivery was significantly higher at 48 (P = 0.017) and 72 h (P = 0.021) in animals in the nail group compared to animals in the external fixation group.

CONCLUSION

This study used a standardised porcine femoral fracture model and determined a significant increase in local blood microcirculation (e.g. flow and oxygen delivery) in animals treated with intramedullary reaming compared to external fixation. These changes may be of importance for fracture healing and local and systemic inflammatory responses. Further studies in this area are justified.

Basic Science and Clinical Application of Reamed Sources for Autogenous Bone Graft Harvest

Autologous bone graft remains the only clinically available source of graft material with osteogenic, osteoinductive, and osteoconductive properties. Although iliac crest autologous bone graft has long served as the benchmark, reamed autogenous bone graft offers several advantages. Reamed autograft has a biochemical and cellular profile that is at least equivalent, and perhaps superior, to that of iliac crest autograft. In addition, larger volumes of reamed autograft can be obtained via less-invasive techniques, giving surgeons an accessible source of mesenchymal stem cells that can be reliably and repeatedly harvested. Early clinical experience involving reamed autogenous bone graft in the management of nonunion, bone defects, and arthrodesis has been encouraging and has demonstrated the necessary properties to warrant regular consideration of reamed graft for these applications.

Principles of Nonunion Management: State of the Art

A substantial proportion of fractures can present with nonunion, and the management of nonunion continues to present a challenge for orthopaedic surgeons. A variety of biological, mechanical, patient, and injury factors can contribute to the occurrence of nonunion, and often the cause of nonunion may be multifactorial. Successful management often requires assessment and treatment of more than one of these factors. This article reviews common factors that may contribute to nonunion including infection, impaired biology, and metabolic disorders. In addition, new and evolving strategies for diagnosing the cause and effectively treating nonunion including the diagnosis of infection, metabolic workup, bone grafting, cell-based therapies, and biological adjuvants are reviewed and discussed.

Scientific Understanding of the Induced Membrane Technique: Current Status and Future Directions

OBJECTIVES

To review the most recent basic science advances made in relation to the induced membrane technique and how those relate to clinical practice, applications, and future research directions.

DESIGN

Review of the literature.

SETTING

Any trauma center which might encounter large segmental bone defects.

ARTICLES REVIEWED

Basic science articles that looked at characteristics of the induced membrane published in the past 30 years.

INTERVENTION

None.

Bone intramedullary reaming grafts the fracture site with CD146+ skeletal progenitors and downmodulates the inflammatory environment

INTRODUCTION

Femoral shaft fractures generally occur in young adults following a high-energy trauma and are prone to delayed union/non-union. Novel therapies to stimulate bone regeneration will have to mimic some of the aspects of the biology of fracture healing; however, which are these aspects is unclear. Locked intramedullary nailing is the current treatment of choice for the stabilisation of femur shaft fractures, and it is associated with accelerated healing and increased union rates. These benefits were partially attributed to the reaming procedure, which, regardless of significantly destroying the haematoma, stimulates the healing response. To better understand how reaming influences healing, we evaluated the viability of the nucleated cell fraction and the frequency of CD146⁺ skeletal progenitors, which contain multipotent cells, in the post-reaming haematoma. We also screened the concentrations of inflammatory mediators and growth factors in the fracture site after reaming compared with those in the original haematoma.

METHODS

Pre- and post-reaming haematomas were percutaneously aspirated from the fracture site of 15 patients with closed femoral shaft fractures. Cellular viability and the percentage of CD146+ progenitors were analysed by flow cytometry. The concentrations of cytokines and growth factors were determined by ELISA.

RESULTS

AnnexinV/Pi analysis showed that the viability of the total nucleated cell fraction was decreased in the post-reaming haematoma. However, the procedure increased the percentage of CD146+ skeletal progenitors in the fracture site. Analysis of cytokines and growth factors in supernatants showed a decreased concentration of the inflammatory mediators IL-6, CCL-4, and MCP-1, along with an increase of anti-inflammatory IL-10, and the growth factors bFGF and PDGF-AB.

CONCLUSION

These findings support the view that the positive effects of reaming on fracture healing might result from mechanically grafting the fracture site with a population of skeletal progenitors that contain multipotent cells; transitioning the signalling environment to a less inflammatory state, and enhancing the availability of specific osteogenic and angiogenic factors. A better understanding of the requisite stimuli for optimal bone repair, considering the disturbances made by orthopaedic treatments, will be determinant for the development of innovative treatments for bone repair.

Diagnostic use of intramedullary reaming biopsy in metastatic long bone disease

INTRODUCTION Bone is the third most common site of metastasis. A histological diagnosis is important in guiding therapy and prognosis. In up to 15% of cases of metastatic disease, the primary tumour remains unknown. This emphasises the importance of adequate, reliable and accurate sampling when performing any type of biopsy. Reaming biopsy is commonly performed during intramedullary nailing of metastatic long-bone disease but there is little published evidence on the diagnostic use and reliability of this technique. AIMS AND METHODS We reviewed 49 cases of confirmed metastatic bone disease to determine adequacy for analysis, diagnostic accuracy and factors affecting reliability. RESULTS Adequate tissue for histopathological analysis was obtained in 96% of cases but metastasis was confirmed in only 51% of cases. The presence of a pathological fracture had no effect on accuracy of the results but metastasis was more likely to be missed in the presence of tissue crushing and or necrosis (P = 0.015). DISCUSSION This study determines the use and accuracy of bone reaming biopsy in metastatic disease and, to the best of our knowledge, is the only study determining the effect of additional factors such as the presence of a pathological fracture and tissue necrosis or crushing on the diagnostic accuracy of this technique. CONCLUSIONS In spite of adequate tissue sampling, the diagnostic accuracy and, hence, reliability of intramedullary reaming biopsy in metastatic bone disease is less than optimal. A reaming histopathology report suggesting no evident metastasis should always be taken in clinical context.

Reamed intramedullary exchange nailing in the operative treatment of aseptic tibial shaft nonunion

PURPOSE

The aim of this study was to evaluate a standardized treatment protocol regarding the rate of secondary bone union, complications, and functional outcome.

METHODS

This study was started as a prospective study in a single Level I Trauma Centre between 2003 and 2012. The study group consisted of 188 patients with the diagnosis of an aseptic tibial shaft nonunion. Exchange nailing was performed following a standardized surgical protocol. Long-term follow-up was analyzed for rate of bone healing and functional outcome.

RESULTS

Osseous healing was achieved in 182 out of 188 patients (97 %). In 165 out of 188 patients (88 %), bone healing was observed timely and uneventfully after a single exchange nailing procedure. An open approach was necessary in 32 patients (17 %). Twenty-three patients (12 %) required additional therapy such as extracorporeal shock wave therapy. Post-operative complications were observed in seven patients (4 %). Almost all patients demonstrated osseous healing within 12 months, with the majority of osseous healing occurring within six months. A relevant shortening of the fractured tibia was observed in 20 out of 188 patients (11 %). After a median follow-up of 23 months (range 12-45 months), outcome was evaluated using the assessment system of Friedman/Wyman. In summary, 154 out of 188 patients (82 %) had a good functional long-term result.

DISCUSSION

Reamed intramedullary exchange nailing including correction of axis alignment is a safe and effective treatment of aseptic tibial shaft nonunion with a high rate of bone healing and a good radiological and functional long-term outcome.

Interlocking intramedullary nail fixation with additional bone grafting from trochanter via a femoral hollow trephine in the treatment of femoral shaft fractures: design and clinical application

PURPOSE

The purpose of this study was to describe and evaluate the clinical application of the technique of interlocking intramedullary (IM) nailing via an entry point at the tip of greater trochanter using a specially designed femoral hollow trephine to stabilize diaphyseal fractures of the femur.

METHODS

From February 2010 to April 2014, 35 consecutive patients with femoral shaft fractures were treated by the therapy of bone grafting from trochanter region with interlocking IM nail. The average age of these 23 male and 12 female patients was 37.5 years (range, 22-67 years). Fractures were classified according to AO classification system (15 type A, 17 type B, 3 type C). Femoral canal reaming and the collection of cancellous bone were simultaneously performed in a single step with the specially designed femoral hollow trephine, followed by regular IM nailing procedure.

RESULTS

Of the 35 cases, the mean volume of spongy bone obtained was 5.63 cm³ (range, 3.0-7.0 cm³). Thirty-five patients with femoral shaft fractures had a mean follow-up period of 16.2 months (range, 12-22 months). All patients achieved bony union, at a mean of 5.4 months (range, 4-6 months). No patient developed a delayed union or a nonunion. There were no complications such as infections, injury of vascular and nerve, or heterotopic ossification in hip.

CONCLUSIONS

These results indicate that the technique of use of IM nailing with the femoral hollow trephine significantly decreases the occurrence of nonunion in femoral shaft fractures.

Donor site morbidity with reamer-irrigator-aspirator (RIA) use for autogenous bone graft harvesting in a single centre 204 case series

Donor site morbidity and complication rate using the reamer-irrigator-aspirator (RIA) system for intramedullary, non-structural autogenous bone graft harvesting were investigated in a retrospective chart and radiographic review at a University affiliated Level-1 Trauma Centre. 204 RIA procedures in 184 patients were performed between 1/1/2007 and 12/31/2010. RIA-indication was bone graft harvesting in 201 (98.5%), and intramedullary irrigation and debridement in 3 (1.5%) cases. Donor sites were: femur - antegrade 175, retrograde 4, tibia - antegrade 7, retrograde 18. Sixteen patients had undergone two RIA procedures, two had undergone three procedures, all using different donor sites. In 4 cases, same bone harvesting was done twice. Mean volume of bone graft harvested was 47 ± 22ml (20-85 ml). The complication rate was 1.96% (N=4). Operative revisions included 2 retrograde femoral nails for supracondylar femur fractures 6 and 41 days postoperatively (antegrade femoral RIA), 1 trochanteric entry femoral nail (subtrochanteric fracture) 17 days postoperatively (retrograde femoral RIA) and 1 prophylactic stabilization with a trochanteric entry femoral nail for intraoperative posterior femoral cortex penetration without fracture. In our centre, the RIA technique has a low donor site morbidity and has been successfully implemented for harvesting large volumes of nonstructural autogenous bone graft.

[Effect of intramedullary reaming and nailing on the production of growth factors in the femur fracture callus in rats]

INTRODUCTION

Many studies have been conducted to determine the different effects that reaming or intramedullary nailing have on fracture healing, but there is no evidence in the literature of the effect of intramedullary reaming on osteogenesis. We performed a prospective study to analyse the effect of intramedullary reaming and nailing on the production of growth factors during the process of fracture healing in the femur of rats.

MATERIAL AND METHODS

A transverse mid-shaft non-comminuted femur fracture was produced in 64 rats; 34 rats did not receive any treatment, and a standardized surgical procedure was performed on 30 rats, by exposing the left knee, reaming the medullary canal from distal to proximal, and then fixing the fracture with a steel pin. The rats were sacrificed at the 24th hour, 4th, 7th and 15th days after the fracture. The amount of growth factors that appeared in the callus fracture was measured using histopathology studies. The primary categorical variables analysed were PDGFA, TGF2 and TGFβ-R2. These variables were analysed in each group at the different sacrifice times.

RESULTS

The results of the primary variables of the study, stratified by the time until sacrifice, showed no statistically significant differences.

DISCUSSION

Even if the presence of an intramedullary wire facilitates the fracture repair and the stabilising the bridge of bone between both edges of the fracture site, no evidence was found that reaming changes the expression of the growth factors studied (PDGFA, TGFβ-R2 and TGFβ2) during the callus formation in rats.

The use of Reamer Irrigator Aspirator (RIA) autograft harvest in the treatment of critical-sized iliac wing defects in sheep: investigation of dexamethasone and beta-tricalcium phosphate augmentation

Bone grafts are commonly used for the treatment of segmental bone defects and fracture non-unions. Recently, osseous particles obtained during intermedullary canal reaming (using a Reamer-Irrigator-Aspirator (RIA) device) have been evaluated as graft material during in vitro and clinical studies. The aim of this study was to evaluate and quantify new bone formation after implantation of bone graft material obtained after reaming of the tibia in a bilateral critical-sized iliac wing defect in sheep and to investigate the effect of the augmentation of this graft. A reamer bone graft alone, or after short term incubation in a dexamethasone enriched solution, and a reamer graft collected using beta-tricalcium phosphate (β-TCP) granules in the filter of the RIA collection device were compared to autologous iliac wing graft. In addition, reamer graft was combined with the cellular fraction collected from the irrigation fluid with and without short-term incubation in a dexamethasone enriched solution. It was hypothesized that the amount of physical bone in the reamer bone graft groups would be higher than the amount in the autologous iliac wing graft group and that augmentation of a reamer bone graft would increase bone formation. Three months after implantation, the amount of new bone formation (as percentage of the total defect volume) in the defects was evaluated ex-vivo by means of micro-CT and histomorphometry. The mean amount of bone in the autologous iliac wing graft group was 17.7% and 16.8% for micro-CT and histomorphometry, respectively. The mean amount of bone in all reamer graft groups ranged between 20.4-29.2% (micro-CT) and 17.0-25.4% (histomorphometry). Reamer graft collected using β-TCP granules (29.2±1.7%) in the filter produced a significantly higher amount of bone in comparison to an autologous iliac wing graft evaluated by micro-CT. RIA bone grafts added a small increase in bone volume to the 3month graft volume in this preclinical sheep model. The current model does not support the use of short-term high concentration dexamethasone for augmentation of a graft volume. If avoidance of an iliac wing graft is desirable, or a reaming procedure is required, then a RIA graft or RIA graft plus β-TCP granules are as good as the current gold standard for this model.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Reamed versus minimally reamed nailing: a prospectively randomised study of 100 patients with closed fractures of the tibia

It is generally accepted that in tibial fractures the results of reamed intramedullary nailing are better than those of unreamed. However, it is not known whether the clinical effects of reaming are cumulative or if minimal reaming would induce the same beneficial effects as more extensive reaming. This international multicentre study has investigated the effects of different degrees of reaming. 100 patients with closed diaphyseal tibial fractures were prospectively randomised in two centres. Method of treatment was reamed nailing up to 12 mm inserting an 11 mm tibial nail (n: 50), and minimally reamed nailing up to 10 mm inserting a 9 mm tibial nail (n: 50). All patients included in the study had follow-up studies at 4,8,12,16,26 and 52 weeks after trauma. Sixty-six male and thirty-four female patients with an average age of 37.5 years were included in the study. Gender, age, and injury side were identical in both groups. There was no significant difference of complications in the two methods. The rate of deep wound infections was higher in the reamed group (n: 3) versus the minimally reamed group (n: 1). Union occurred earlier in the reamed group (17 wks) compared to patients with minimally reamed nailing (19 wks), and there were more patients with reamed nails in whom the fracture had healed by 16 weeks (57%) versus the minimally reamed group (43%), however, this was not statistically significant. Pain scales were similar for both groups from week 4 to week 52. A considerable number of outcome parameters including knee and ankle function, as well as the comparison of time intervals to restart certain activities, and return to work showed no significant statistical difference between the two groups. However, patients of the extensive reamed group returned earlier to running, training, and normal sports activities. This study found no significant evidence that more extensive reaming gave better results, however there seemed to be a tendency of more aggressive reaming to induce earlier fracture healing with a tendency of faster recovery times.

Growth factor release in extra- and intramedullary osteosynthesis following tibial fracture

INTRODUCTION

Recent studies indicate alterations of local and systemic growth factor level during fracture healing. As a result, osteogenic and angiogenic growth factors allow us to monitor fracture healing on a molecular level. We hypothesised that closed intramedullary (IM) reaming and nail fixation, in contrast to open reduction and internal plate fixation (ORIF), could exert an effect on the cellular elements present in the intramedullary canal, leading to increased release of mediators. The purpose of the study was to investigate whether different osteosynthesis techniques influence the released quantity of cytokines.

PATIENTS AND METHODS

A total of 34 patients with tibia fractures treated with IM fixation and 19 patients treated with ORIF were included in the study. In addition to clinical and radiological examination, serum concentrations of transforming growth factor beta 1(TGF-β1), macrophage-colony stimulating factor (M-CSF) and vascular endothelial growth factor (VEGF), were analysed at 1, 2, 4, 6, 8, 12, and 24 weeks after surgery.

RESULTS

Expression of TGF-β1 and M-CSF was increased during the first 2 weeks of fracture healing in patients treated with the IM fixation technique compared with those treated by ORIF. After 24 weeks, M-CSF levels in patients with IM fixation were clearly higher. Conversely, VEGF levels were higher during the first 2 weeks of fracture healing in patients treated by ORIF compared with IM fixation. However, these results were not significant.

CONCLUSION

Our results show that 1 week after surgery neither reamed IM fixation nor ORIF of the tibia could increase the expression of VEGF, M-CSF and TGF-β1 in its favour.

Reaming debris as a novel source of autologous bone to enhance healing of bone defects

Reaming debris is formed when bone defects are stabilized with an intramedullary nail, and contains viable osteoblast-like cells and growth factors, and might thus act as a natural osteoinductive scaffold. The advantage of using reaming debris over stem cells or autologous bone for healing bone defects is that no extra surgery is needed to obtain the material. To assess the clinical feasibility of using reaming debris to enhance bone healing, we investigated whether reaming debris enhances the healing rate of a bone defect in sheep tibia, compared to an empty gap. As golden standard the defect was filled with iliac crest bone. Bones treated with iliac crest bone and reaming debris showed larger callus volume, increased bone volume, and decreased cartilage volume in the fracture gap, and increased torsional toughness compared to the empty gap group at 3 weeks postoperative. In addition, bones treated with reaming debris showed increased torsional stiffness at 6 weeks postoperatively compared to the empty defect group, while bending stiffness was marginally increased. These results indicate that reaming debris could serve as an excellent alternative to iliac crest bone for speeding up the healing process in bone defects that are treated with an intramedullary nail.

Reamer-irrigator-aspirator indications and clinical results: a systematic review

BACKGROUND

The 'reamer-irrigator-aspirator' (RIA) is an innovation developed to reduce fat embolism (FE) and thermal necrosis (TN) that can occur during reaming/nailing of long-bone fractures. Since its inception its indications have expanded to include the treatment of long-bone osteomyelitis and as a harvester of bone graft/mesenchymal stem cells (MSCs).

METHODS

This study involved a systematic review, via Pubmed® and Google Scholar®, of English language sources (nine non-clinical studies, seven clinical studies and seven case reports) using the keywords: 'reamer', 'irrigator', 'aspirator' (1st May 2010). Sources were reviewed with reference to the RIAs efficacy in (1) preventing FE/TN, (2) treating long-bone osteomyelitis, (3) harvesting bone graft/MSCs, and (4) operating safely. Experimental data supports the use of the RIA in preventing FE and TN, however, there is a paucity of clinical data.

CONCLUSIONS

The RIA is a reliable method in achieving high volumes of bone graft/MSCs, and high union rates are reported when using RIA bone-fragments to treat non-unions. Evidence suggests possible effectiveness in treating long-bone osteomyelitis. The RIA appears relatively safe, with a low rate of morbidity provided a meticulous technique is used. When complications occur they respond well to conventional techniques. The RIA demands further investigation especially with respect to the optimal application of MSCs for bone repair strategies.

The biology of intramedullary reaming

In this review we focus on the local biologic and physiologic effects of intramedullary reaming of long bones. Among the topics discussed are the consequences for vascularity, as well as the pathophysiology of intramedullary pressure generation and temperature increase. Reaming techniques and their suggested effects on bone formation are outlined. Moreover, techniques for avoiding local and systemic complications are summarized.

RIA use in a community orthopedic trauma practice: applying technology, respecting biology

The RIA (Reamer Irrigator Aspirator) device is an incredibly powerful tool. It can be used to obtain biologically active tissue for healing at local or distant sites. Additionally, it can be used to lower the negative bioburden of disease and even to assist in diagnosis. As with any powerful tool, it should be used with detailed pre-planning and great respect. Once properly understood and implemented, the device can be used in many ways:

Biological rationale for the intramedullary canal as a source of autograft material

Bone harvested by intramedullary reaming offers a minimally invasive alternative to harvesting bone from the iliac crest, which has long been considered the gold standard for autogenous bone grafting. The biologic potential of intramedullary reaming material has been studied both in vitro and in vivo. The material provides osteogenic, osteoinductive, and osteoconductive properties that are comparable to the material harvested from the iliac crest. In addition to the ability to obtain a large volume of bone, the graft harvested by the Reamer-Irrigator-Aspirator has been shown to be rich in growth factors, including BMP-2, TGF-beta1, IGF-I, FGFa, and PDGFbb.

The Early Effects of Intramedullary Reaming of the Femur on Bone Mineral Density; an Experimental Study in Pigs

Background and Aims:

Both fracture and fracture treatment affect bone mineral density (BMD). BMD after standard intramedullary reaming of the femoral cavity and after reaming with a reamer-irrigator-aspirator (RIA) system were studied with the hypothesis that the RIA technique would lead to lower BMD levels.

Material and Methods:

Dual-energy X-ray absorptiometry (DXA) was performed on the third day after operation with standard intramedullary nailing technique (n = 6)or RIA technique (n = 7) in intact femora of young Norwegian landrace pigs.

Results and conclusion:

Significantly lower BMD were found in the mid-shaft and total femur after reaming with the RIA technique compared to the non-operated femur. Traditional reaming technique resulted in significantly higher BMD in the distal femur.

Interpretation:

The results of this study indicate that standard reaming increased BMD in the distal femur, suggesting compressive effects on trabecular bone. The RIA technique decreased BMD in the femoral diaphysis and total femur, suggesting removal of trabecular bone. A possible clinical impact of the findings remains to be investigated.

Intramedullary application of bone morphogenetic protein in the management of a major bone defect after an Ilizarov procedure

We describe a patient with insufficient bone regeneration of the tibia after bone transport over an intramedullary nail, in whom union was ultimately achieved after exchange nailing and intramedullary application of rh-bone morphogenetic protein-7 at the site of distraction.

Growth factor release following femoral nailing

The aim of this study was to investigate whether growth factors essential for fracture healing are substantially increased in the immediate aftermath following reaming of the intramedullary cavity for stabilisation of femoral shaft fractures. Consecutive adult patients whose femoral shaft fractures stabilised with either reamed (10 patients) or unreamed (10 patients) intramedullary nailing were studied. Peripheral blood samples and samples from the femoral canal before and after reaming and nail insertion were collected. Serum was extracted and using Elisa colorimetric assays the concentration of Platelet Derived Growth Factor-BetaBeta (PDGF), Vascular Endothelial Growth Factor (VEGF), Insulin-like Growth Factor-I (IGF-I), Transforming Growth Factor beta 1 (TGF-beta1) and Bone Morphogenetic Protein-2 (BMP-2) was measured. The mean age of the twenty patients who participated in the study was 38 years (range 20-63). Reaming substantially increased all studied growth factors (p<0.05) locally in the femoral canal. VEGF and PDGF were increased after reaming by 111.2% and 115.6% respectively. IGF-I was increased by 31.5% and TGF-beta1 was increased by 54.2%. In the unreamed group the levels of PDGF-BB, VEGF, TGF-beta1 remained unchanged while the levels of IGF-I decreased by 10%. The levels of these mediators in the peripheral circulation were not altered irrespectively of the nail insertion technique used. BMP-2 levels during all time points were below the detection limit of the immunoassay. This study indicates that reaming of the intramedullary cavity is associated with increased liberation of growth factors. The osteogenic effect of reaming could be secondary not only to grafting debris but also to the increased liberation of these molecules.

Effect of re-implanted particles from intramedullary reaming on mechanical properties and callus formation

This study investigated the quality and quantity of healing of a bone defect following intramedullary reaming undertaken by two fundamentally different systems; conventional, using non-irrigated, multiple passes; or suction/irrigation, using one pass. The result of a measured re-implantation of the product of reaming was examined in one additional group. We used 24 Swiss mountain sheep with a mean tibial medullary canal diameter between 8 mm and 9 mm. An 8 mm ‘napkin ring’ defect was created at the mid-diaphysis. The wound was either surgically closed or occluded. The medullary cavity was then reamed to 11 mm. The Reamer/Irrigator/Aspirator (RIA) System was used for the reaming procedure in groups A (RIA and autofilling) and B (RIA, collected reamings filled up), whereas reaming in group C (Synream and autofilling) was performed with the Synream System. The defect was allowed to auto-fill with reamings in groups A and C, but in group B, the defect was surgically filled with collected reamings. The tibia was then stabilised with a solid locking Unreamed Humerus Nail (UHN), 9.5 mm in diameter. The animals were killed after six weeks. After the implants were removed, measurements were taken to assess the stiffness, strength and callus formation at the site of the defect.

There was no significant difference between healing after conventional reaming or suction/irrigation reaming. A significant improvement in the quality of the callus was demonstrated by surgically placing captured reamings into the defect using a graft harvesting system attached to the aspirator device. This was confirmed by biomechanical testing of stiffness and strength. This study suggests it could be beneficial to fill cortical defects with reaming particles in clinical practice, if feasible.

The biological and physiological effects of intramedullary reaming

This paper summarises the current knowledge on the effects of medullary reaming of long-bone fractures. Following a review of intramedullary vascular physiology, the consequences for vascularity, the autograft effects, the generation of heat, and fat embolism are outlined. Also, alternative reaming techniques are described.

Quantitative assessment of growth factors in reaming aspirate, iliac crest, and platelet preparation

Large bony defects and non-unions are still a complication in trauma and orthopedic surgery. Treatment strategies include the use of autogenous materials (iliac crest), allogenic bone, bone substitutes, and currently stimulation with growth factors such as BMP-2, BMP-7 or the growth factors containing platelet-rich plasma (PRP). Another source of bone graft material might be the cuttings produced during intramedullary reaming. The aim of this study was to compare the quantity of various growth factors found within iliac crest, bony reaming debris, reaming irrigation fluid, and platelet-rich plasma. Iliac crest and reaming debris and irrigation samples were harvested during surgery. PRP was prepared from blood. The growth factors in the bony materials (iliac crest or reaming debris) and of the liquid materials (platelet-poor plasma (PPP), platelet-rich plasma (PRP) or reaming irrigation) were compared. Elevated levels of FGFa, PDGF, IGF-I, TGF-beta1 and BMP-2 were measured in the reaming debris as compared to iliac crest curettings. However, VEGF and FGFb were significantly lower in the reaming debris than from iliac crest samples. In comparing PRP and PPP all detectable growth factors, except IGF-I, were enhanced in the platelet-rich plasma. In the reaming irrigation FGFa (no measurable value in the PRP) and FGFb were higher, but VEGF, PDGF, IGF-I, TGF-beta1 and BMP-2 were lower compared to PRP. BMP-4 was not measurable in any sample. The bony reaming debris is a rich source of growth factors with a content comparable to that from iliac crest. The irrigation fluid from the reaming also contains growth factors.

The influence of a one-step reamer-irrigator-aspirator technique on the intramedullary pressure in the pig femur

BACKGROUND

Increased intramedullary pressure in the femoral cavity causes intravasation of bone marrow content to the circulation which may lead to occlusion of pulmonary vessels and cardiorespiratory dysfunction. A one-step reamer-irrigator-aspirator (RIA) technique has been developed to reduce the intramedullary pressure (IMP) during the reaming procedure. This study was design to compare IMP with a standard reaming technique with IMP during reaming with the RIA system with a hypothesis that the RIA system would involve lower pressures.

MATERIAL AND METHOD

In a randomised study in 19 Norwegian landrace pigs reamed intramedullary nailing was performed with two different reamer devices. Nine animals were operated with a traditional reamer and 10 animals with RIA. One animal in the RIA group was excluded due to a perioperative femoral fracture, and three animals in the traditional group were excluded due to a perforation of the distal medial femoral cortex. The intramedullary pressure was registrated with a transducer-tipped pressure monitoring catheter during reaming.

RESULTS

There was a significantly higher intramedullary pressure (P<0.05) during reaming in the traditional reamer group (mean 188+/-38 mmHg) than in the RIA group (mean 33+/-8 mmHg). Intramedullary pressures recorded before surgery, at the opening of the femoral cavity with an awl, by insertion of a guide wire, at insertion of the intramedullary nail, and 10 min after nail insertion showed no significant differences between the groups.

CONCLUSION

The use of a one-step reamer-irrigator-aspirator technique in the pig femur induced less intramedullary pressure increase than the use of a traditional reamer.

Experimental background--review of animal studies

Most of the research on the physiological effects of intramedullary nailing is technically difficult or ethically impossible to perform in humans. A substantial range of factors apply in clinical cases, which means that the data obtained from this source may lack the control needed to reveal the basic mechanisms of pathophysiology associated with this surgical procedure. Consequently, animal studies have been relied upon to provide answers that would otherwise be unavailable. This review manuscript summarizes the available literature on animal studies dealing with the local and systemic effects of intramedullary nailing. It focuses on whether these studies have contributed to our clinical knowledge of the procedure's impact on perfusion and fracture healing, as well as the medical relevance of coincident systemic effects.

DATA SOURCES

Medline, personal library of the first author and of the Department of Trauma Surgery, University of Pittsburgh Medical Center.

STUDY SELECTION

All animal studies on intramedullary stabilization published in English, German, and French.

CONCLUSIONS

The relevance of animal studies investigating the impact of a surgical procedure and its influence on concomitant injuries depends on the design and the type of the animal model. If this fact is considered, and if a model is selected that simulates a systemic impact comparable with the clinical situation, then animal studies may provide a valuable source of otherwise unobtainable information. Such an example is the study of fat embolization associated with intramedullary nailing. Animal subjects enable assessment of the intervention's additive surgical impact, measurement of side effects that may have adverse results, and influence of cofactors (eg, thoracic trauma, severe shock, polytrauma) that predispose the individual to postoperative complications.

Failure of reamed nailing in humeral non-union: an analysis of 26 patients

The use of an intramedullary nail in the treatment of humeral non-unions remains controversial. This study evaluated the treatment of humeral delayed and non-unions with reamed nailing and compression. In a retrospective analysis of prospectively gathered data from 26 cases all treated with the Telescopic Locking Nail (TLN), the healing rate after the first intervention for non-union was 58%. After one or more re-interventions combined with an external cancellous bone graft at some time during follow-up, 90% of the 21 patients with complete follow-up eventually healed after a mean of 22 months. A total of 49 procedures with a mean of 1.9 per patient were needed. After a mean follow-up of 65 (range 24-88) months, we conducted a study to assess the functional results in the shoulder and elbow. Twelve patients were suitable for inclusion. We used the Neer and Morrey score for shoulder and elbow function, respectively. For the Neer score the median was 91 points and for the Morrey score 94 points. The outcome suggests that simple reamed nailing of humeral non-union is insufficient. Reamed interlocked nailing is feasible, provided that the primary intervention for non-union is combined with an external cancellous bone graft.

Human reaming debris: a source of multipotent stem cells

The biological characteristics of human reaming debris (HRD) generated in the course of surgical treatment of long bone diaphyseal fractures and nonunions are still a matter of dispute. Therefore, the objective of the present investigation has been to characterize the intrinsic properties of human reaming debris in vitro. Samples of reaming debris harvested from 12 patients with closed diaphyseal fractures were examined ultrastucturally and were cultured under standard conditions. After a lag phase of 4-7 days, cells started to grow out from small bone fragments and established a confluent monolayer within 20-22 days. The cells were characterized according to morphology, proliferation capacity, cell surface antigen profile, and differentiation repertoire. The results reveal that human reaming debris is a source of multipotent stem cells which are able to grow and proliferate in vitro. The cells differentiate along the osteogenic pathway after induction and can be directed toward a neuronal phenotype, as has been shown morphologically and by the expression of neuronal markers after DMSO induction. These findings have prompted interest in the use of reaming debris-derived stem cells in cell and bone replacement therapies.

Viable osteoblastic potential of cortical reamings from intramedullary nailing

To analyze the effect of intramedullary reaming on fracture healing, we investigated whether or not cortical reamings contain viable bone cells. There are several tissue components contained in medullary reamings including blood, bone marrow and cortical bone. This study is focused on the cortical reamings, which are produced during reaming of the medullary cavity. They may stimulate fracture healing but it is still unclear if they contain vital bone cells. We tested the hypothesis that these cortical reamings are a source of viable bone cells and compared cell cultures with cultivated cells from iliac crest biopsies. Responses of protein content and ALP activity to vitD stimulation in the cells were considered as properties of viability. Ten in tact living sheep femora were fully reamed and the cortical reamings were cultivated in a standard manner and compared with cultivated cells from ipsi-lateral iliac crest biopsies from the same animals. Cells started to grow from the reamings as well as the iliac crest within 2-5 days, and covered the entire culture flask within 9-13 days. Protein content and ALP activity in cells from both reamings and iliac crest were significantly responsive to vitD stimulation. Cortical reamings from intramedullary nailing have osteoblastic potential and contain living bone cells similar to bone cells from the iliac crest. These findings may further explain the superior healing of fractures, treated with reamed nailing.

Bone Debris: Dead Matter or Vital Osteoblasts

BACKGROUND

Mechanical manipulation, pressure, and temperature increase can induce bone necrosis during intramedullary reaming.

METHODS

In this study, the bone debris obtained after reaming 18 sheep tibiae was analyzed to investigate its vitality by measuring alkaline phosphatase activity. Two different reamer designs were used for the project. Bone cells were first cultivated in a specific growth medium, counted 3 weeks after the reaming procedure, and then cultivated for another 5 weeks.

RESULTS

At the end of the project, qualitative evaluation showed positive alkaline phosphatase activity in most of the cases, and quantitative evaluation also showed enzyme activity. The positive alkaline phosphatase results were independent of the reamer sizes and reamer design. No significant results were obtained from a comparison of different reamer sizes and designs. This indicates that osteoblasts survive after correctly performed reaming.

CONCLUSION

The results prove the vitality of the bone debris and confirm clinical observations.

Bone formation following intramedullary femoral reaming is decreased by indomethacin and antibodies to insulin-like growth factors

OBJECTIVE

We aimed to: 1). compare rates of in vitro bone formation following reamed and nonreamed intramedullary fixation in a murine model of femoral fracture healing; and 2). examine whether antibodies to insulin-like growth factor (IGF) I, IGF II, or indomethacin (an inhibitor of the inflammatory process) affect bone formation following intramedullary reaming.

DESIGN

Experimental study.

PARTICIPANTS

Twenty-four C57 black mice were randomized to two groups: reamed ( = 12), and nonreamed intramedullary nail insertion ( = 12).

INTERVENTION

In the reamed group, the femoral canals were successively reamed with 30-, 27-, 25-, and 23-gauge stainless steel pins and stabilized with a 27-gauge pin. In mice randomized to the nonreamed group, a 27-gauge pin was inserted. An external three-point bending force created a midshaft transverse femoral fracture. Seven days postsurgery, each mouse was killed, and the right femur was removed. Following pin removal, the callus was minced, the bone marrow was removed, and both were ultracentrifuged at 1200 rpm for 5 minutes. The supernatent was cocultured with 3-day-old murine calvarial cells in culture media. At day 5 of culture, reamed plasma and calvarial cell cocultures were exposed to either 1.0 micro g/mL of anti-IGF I, 1.0 micro g/mL of anti-IGF II, 2 micro M indomethacin, or served as controls (calvarial cells only). The cells were cultured for a total of 21 days.

MAIN OUTCOME MEASUREMENTS

The number of bone nodules was quantified by light microscopy.

RESULTS

Reamed pin insertion resulted in 4.1-fold and 8.9-fold increases in the mean number of bone nodules compared to pins inserted without reaming and controls, respectively (399 +/- 40.0 vs. 97.0 +/- 21.0, < 0.001). The positive effect of intramedullary reaming on bone nodule formation was reversed with the administration of antibodies to IGF I and IGF II. The addition of anti-IGF I or anti-IGF II to calvarial, or osteoblastlike, cells treated with supernatent from the callus and bone marrow of mice with prior intramedullary reaming resulted in significant declines in the mean number of bone nodules ( < 0.001). Specifically, treatment of osteoblastlike cells with anti-IGF I or anti-IGF II resulted in 7.0-fold and 5.4-fold declines in mean bone nodule formation compared to cells without such treatment.

CONCLUSIONS

Intramedullary reaming prior to pin insertion resulted in a significantly greater number of bone nodules than pin insertion only. Antibodies to IGF I, IGF II, and indomethacin reversed the stimulatory effect of reaming on bone nodule formation, suggesting their role in modulating the course of fracture healing following intramedullary reaming.

Effects of intramedullary femoral fracture fixation: what is the impact of experimental studies in regards to the clinical knowledge?

This review manuscript summarizes the available literature on animal studies dealing with the local and systemic effects of intramedullary (IM) reamed and unreamed nailing. It focuses on the question of whether the large numbers of studies have contributed to our clinical knowledge about its impact on perfusion, fracture healing, and about the clinical relevance of systemic side effects. The effects of IM contents that are squeezed out of the medullary canal into the venous and the systemic circulation due to reaming and nailing has been a major issue. In addition, the impact of the surgical procedure and the timing of such a major operation as femoral fractures surgery has been a major source of debate within the last decade. The compilation of relevant studies investigating the degree of impact of a surgical procedure and the influence of concomitant injuries depends on the design and the type of the animal model. If this fact is considered and if a model is selected that reflects the systemic impact comparable with the clinical situation, animal studies represent a valuable source of information. In this respect, fat embolization represents an additive surgical impact and can cause clinically relevant side effects if cofactors (e.g., thoracic trauma, severe shock, and polytrauma) are present that set the individual up for postoperative complications.