Bone graft harvest using a new intramedullary system

Hemorrhagic-Induced Cardiovascular Complications During Reamer-Irrigator-Aspirator-Assisted Femoral Nonunion Treatment

The reamer-irrigator-aspirator (RIA) is a device that has recently been developed to retrieve bone graft from the medullary canal of the femur and the tibia. As for most new surgical procedures, complications arise as part of the learning curve and/or imperfections in the design or technique. To increase awareness of potential complications and to prevent unnecessary harm to the patient, new complications need to be reported. We present case reports of 2 patients who developed severe intraoperative cardiac events presumably caused by excessive and rapid blood loss during RIA bone graft harvesting. This complication has not been described before. Increased awareness of excessive blood loss and subsequent cardiac events during an RIA procedure is warranted.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Radiographic and histological evaluation of ectopic application of deproteinized bovine bone matrix

OBJECTIVE

To evaluate, through radiographic and histological analysis, the tissue reaction induced by a biomaterial based on deproteinized bovine bone matrix (DBBM) in the muscle of sheep.

MATERIALS AND METHODS

Sixteen sheep were used. The animals underwent surgery to insert polyethylene tubes containing the biomaterial in the muscle of the lower back (ectopic site) and were euthanized after 3 and 6 months. Each sheep received three tubes: Group 1 - sham group (negative control - tube without biomaterial), Group 2 - particulate autogenous bone (positive control), and Group 3 - DBBM biomaterial (GenOx Inorg). The material removed was evaluated by radiographic, macroscopic, and microscopic analysis, descriptively.

RESULTS

Macroscopic analysis showed that Group 3 had a greater tissue volume maintenance. Microscopic analysis indicated that Group 1 had a higher concentration of dense, thin collagen fibers (3 and 6 months); in Group 2, there was a decrease in the inflammatory process and the deposition of dense, thin collagen fibers (3 and 6 months); in Group 3, the presence of a dense connective tissue was noted, in which the DBBM particles (3 months) were found. On the periphery of these particles, a deposition of basophilic material was found, indicating the formation of mineral particles and the formation of tissues with osteoid characteristics (6 months).

CONCLUSION

Based on the results obtained, it can be concluded that the biomaterial based on DBBM led to the formation of tissue with similar characteristics to an osteoid matrix in a postoperative period of 6 months. However, none of the groups evaluated showed ectopic bone neoformation.

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.

Nonunion of the Femur and Tibia: An Update

Delayed union and nonunion of tibial and femoral shaft fractures are common orthopedic problems. Numerous publications address lower extremity long bone nonunions. This review presents current trends and recent literature on the evaluation and treatment of nonunions of the tibia and femur. New studies focused on tibial nonunion and femoral nonunion are reviewed. A section summarizing recent treatment of atypical femoral fractures associated with bisphosphonate therapy is also included.

Tibiotalocalcaneal Fusion for Severe Deformity and Bone Loss

Tibiotalocalcaneal fusion is an effective salvage procedure for combined end-stage ankle and subtalar arthrosis and for the management of severe planar deformities of the ankle and hindfoot. Although the procedure results in a rigid ankle and hindfoot, it is often the only means of providing patients with a stable and painless foot and ankle for ambulation. Some patients who require the procedure have substantial bone loss that can be managed with a variety of autograft and allograft options. Options for tibiotalocalcaneal fixation include both internal and external devices, the selection of which depends on the underlying pathology, amount of bone loss, and type of bone graft selected. Relatively high complication rates associated with tibiotalocalcaneal fusion have been reported, with complications ranging from superficial infection to ultimate amputation; however, proper patient selection and careful graft and fixation planning can minimize the postoperative complications of the procedure.

Bone Grafting: Sourcing, Timing, Strategies, and Alternatives

Acute fractures, nonunions, and nonunions with bone defects or osteomyelitis often need bone graft to facilitate union. There are several factors to consider when it is determined that a bone graft is needed. These factors include the source of the bone graft (autograft vs. allograft), proper timing for placement of the bone graft, strategies to avoid further complications (particularly in the setting of osteomyelitis), and with the development of a variety of bone graft substitutes, whether alternatives to autograft are available and appropriate for the task at hand. Autograft bone has commonly been referred to as the "gold standard" of bone grafts, against which the efficacy of other grafts has been measured. The best timing for when to place a bone graft or substitute is also somewhat controversial, particularly after an open fracture or a potentially contaminated bed. The treatment of infected nonunions, particularly those that require a graft to facilitate healing, can be quite challenging. Typically, the infection is completely eradicated before placement of a bone graft, but achieving a sterile bed and the timing of a bone graft require strategic thinking and planning. This review outlines the benefits of autografts, the most suitable sites for harvesting bone grafts, the timing of bone graft procedures, the potential risks and benefits of grafting in the face of infection, and the currently available bone graft extenders.

MRI appearances of the femur following bone graft harvesting using the Reamer-Irrigator-Aspirator

The reamer-irrigator-aspirator is increasingly being used to harvest autologous bone graft from the femur. The purpose of this study was to investigate the extent of neo-vascularisation and new bone formation that occurs within the medulla following the procedure, and determine if new bone formation would potentially allow a repeat bone harvest in those individuals subsequently requiring further bone graft. Eleven patients who had undergone femoral bone harvest were examined with MRI. The nature of the tissue within the medulla and the extent of neo-vascularisation were assessed. MRI was performed between 3 months and 28 months following bone graft harvest, mean 14 months. Intense vascularisation of the endostial cortical surface and neo-vascularisation of the haematoma within the canal occurred as soon as 3 months following bone harvest. From as early as 14 months the tissue was replaced by normal intramedullary bone. The formation of new bone within the medullary canal gives the potential for a repeat reaming, should further bone graft be required at a later date.

Reamer Irrigator Aspirator bone graft harvesting: complications and outcomes in an Asian population

INTRODUCTION

Autologous bone grafting has been accepted as the gold standard in the treatment of non-unions and in definitive filling of segmental bone defects. However, there have been well-recognised complications associated with their harvest. The Reamer Irrigator Aspirator (RIA) system is an alternative technique of autologous bone graft harvesting. Studies have been published in the Western population showing the efficacy and outcome of this technique. No prior studies were done in the Asian population, who has smaller average canals, different femoral geometry as compared to Caucasians and weaker bone density in both genders. We aim to present the findings and discuss its suitability in the Asian population when dealing with segmental bone loss and non-unions requiring reconstruction.

METHODS

We conducted a retrospective analysis of all trauma patients with segmental bone loss and non-unions treated with RIA bone grafting over a 4.5 year period. A total of 57 cases of RIA bone grafting were conducted on 53 patients. The amount of bone graft harvested, blood loss and post-operative pain were measured. Patients were followed up for union rate as well as complications of the procedure.

RESULTS

Union was achieved in 86.8% of patients. The mean time to union was 17.64 weeks. Seven patients did not achieve union after the first RIA surgery, in which six of seven were open fractures initially and six were smokers. One major intra-operative complication was recorded, that being a fractured femoral shaft due to thinning of the cortex by the RIA harvester. There were two patients who developed donor site superficial soft tissue infection that resolved after a course of antibiotics. There were no long-term complications seen in all patients.

CONCLUSIONS

The safety and efficacy of RIA bone graft harvesting for the management of non-union in the Asian population is promising, with adequate graft quantities, high success and low complication rates that are comparable to the Caucasian population. The diameter of the medullary canal in our population is suitable for this procedure. We believe that RIA bone graft harvesting provides a reliable and safe alternative source of autologous bone grafts for bone grafting of non-union sites.

Retrograde Versus Antegrade Femoral Bone Graft Harvesting Using the Reamer-Irrigator-Aspirator

OBJECTIVES

To compare retrograde versus antegrade femoral bone graft harvesting using the reamer-irrigator-aspirator system to determine whether there was any difference in intraoperative, postoperative, or patient outcome variables.

DESIGN

Retrospective cohort study.

SETTING

Urban Level I Trauma Center.

PATIENTS/PARTICIPANTS

Ninety-four (62 antegrade and 32 retrograde procedures) consecutive adult patients who underwent femoral autologous bone graft harvesting using the Synthes reamer-irrigator-aspirator system between April 2008 and March 2013.

MAIN OUTCOME MEASUREMENTS

Amount of bone graft, perioperative fractures or other complications, and postoperative hip and/or knee pain.

RESULTS

There was no significant difference between demographic or medical comorbidities between the groups. There was no significant difference in the side of the graft harvest, graft volume, hospital length of stay, or the ability to ambulate on postoperative day 1. There was a significantly increased incidence of iatrogenic fracture or prophylactic nailing with antegrade reaming (4 vs. 0, P = 0.01). Average length of follow-up was 500 (range, 20-1477) days for the antegrade group and 378 (range, 19-706) days for the retrograde group. The antegrade group had a nonsignificant increased incidence of hip pain (8.1% vs. 3.1%, P = 0.66), and the retrograde group had a significantly higher incidence of knee pain (15.6% vs. 1.6%, P = 0.02) at 6-month follow-up. Neither hip nor knee complaints were present at final follow-up. No cases of delayed femur fracture, infection, or abductor and/or antalgic gait involving the donor extremity were seen at final follow-up.

CONCLUSIONS

This study provides support to the safety of femoral bone graft harvesting using both antegrade and retrograde techniques. Both techniques provide reliable, high-volume, nonstructural autologous bone graft with minimal associated morbidity.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Advanced concepts in knee arthrodesis

The aim is to describe advanced strategies that can be used to diagnose and treat complications after knee arthrodesis and to describe temporary knee arthrodesis to treat infected knee arthroplasty. Potential difficult complications include nonunited knee arthrodesis, limb length discrepancy after knee arthrodesis, and united but infected knee arthrodesis. If a nonunited knee arthrodesis shows evidence of implant loosening or failure, then bone grafting the nonunion site as well as exchange intramedullary nailing and/or supplemental plate fixation are recommended. If symptomatic limb length discrepancy cannot be satisfactorily treated with a shoe lift, then the patient should undergo tibial lengthening over nail with a monolateral fixator or exchange nailing with a femoral internal lengthening device. If a united knee arthrodesis is infected, the nail must be removed. Then the surgeon has the option of replacing it with a long, antibiotic cement-coated nail. The authors also describe temporary knee arthrodesis for infected knee arthroplasty in patients who have the potential to undergo insertion of a new implant. The procedure has two goals: eradication of infection and stabilization of the knee. A temporary knee fusion can be accomplished by inserting both an antibiotic cement-coated knee fusion nail and a static antibiotic cement-coated spacer. These advanced techniques can be helpful when treating difficult complications after knee arthrodesis and treating cases of infected knee arthroplasty.

Femoral marrow cavity bone harvesting used for arthroscopic refilling of misplaced or enlarged bone tunnels in revision ACL surgery: an arthroscopically supported technique with antegrade intramedullary bone harvesting by a reamer-irrigator-aspirator (RIA) system

PURPOSE

In anterior cruciate ligament (ACL) revision surgery, refilling of misplaced or enlarged tunnels frequently requires bone harvesting from the iliac crest. Unfortunately, donor-site pain displays a relevant complication. In order to optimize patients' comfort, we developed a procedure combining minimally invasive intramedullary bone harvesting from the femur with arthroscopic tunnel refilling.

METHODS

Patients with ACL reconstruction failure that were not eligible for one-step revision surgery but required tunnel refilling prior to the next ACL reconstruction were enrolled prospectively. Cancellous bone was harvested intramedullarily from the ipsilateral femur using the reamer-irrigator-aspirator system in a minimally invasive manner. Afterwards, the femoral and tibial tunnels were arthroscopically refilled using cones and push rods. Computer tomography (CT) analyses were carried out before and after the filling procedure. Pain levels were assessed during the entire follow-up. Patients undergoing iliac crest bone harvesting for other reasons served as a control group. Finally, the quality of the newly formed bone stock was evaluated in the subsequent ACL reconstruction procedure.

RESULTS

Five patients were included during a 6-month period. Prior to refilling, tunnel analysis revealed a mean tunnel volume of 7.9 cm(3) at the femur [SD ± 5.3 cm(3)] and of 6.7 cm(3) [SD ± 5.1 cm(3)] at the tibia. The CT analyses further revealed that graft failure was predominantly caused by tunnel misplacement. Post-operatively, pain levels due to intramedullary bone harvesting were significantly lower compared to iliac crest bone harvesting at every analysed time point. Three to five months after tunnel filling, CT analyses showed sufficiently incorporated bone stocks with filling rates of 75 % femoral and 94 % tibial. ACL revision surgery was performed 4-5 months after tunnel filling without any complication.

CONCLUSION

Intramedullary bone harvesting from the ipsilateral femur combined with arthroscopic refilling of the bone tunnels ensures a high-quality bone stock for further ACL reconstruction. The clinical relevance is shown by the feasibility of this technique and the significantly reduced pain levels during post-operative recovery.

Increased osteogenic capacity of Reamer/Irrigator/Aspirator derived mesenchymal stem cells

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 analysed separately and in combination. Alkaline phosphatase expression (ALP) and cell numbers were evaluated after 7 and 14 days of culture. Matrix mineralisation was quantified after 14 days.

RESULTS

Cell cultures showed a significant increase of matrix mineralisation 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.

Incidence of donor site morbidity following harvesting from iliac crest or RIA graft

INTRODUCTION

Clinical management of non-union of long bone fractures and segmental bone defect is a challenge for orthopaedic surgeons. The use of autologous bone graft (ABG) is always considered the gold standard treatment. Traditional techniques for harvesting ABG from iliac crest usually involve several complications, particularly at the donor site. The Reamer-Irrigator-Aspirator (RIA) is an intramedullary reaming system that generates a large volume of cancellous bone material in a single-step reaming process; this bone material can be collected and potentially used as an ABG source. Our interest is to compare the complications associated with the standard technique of harvesting from iliac crest with those of the innovative RIA harvesting device.

MATERIALS AND METHODS

A database of 70 patients with long bone non-unions was studied. The patients were divided into two groups according to the surgical harvesting technique used: RIA system ABG (35 patients) and iliac crest ABG (35 patients).

RESULTS

At the 12-month follow-up, pain at the donor site was reported in no patients in the RIA system ABG group and five of 35 patients (14.28%) in the iliac crest ABG group. Local infections at the donor site were found in no patients in the RIA system ABG group compared with five patients (14.28%) in the iliac crest ABG group. There were no fractures in the RIA system ABG group and one case (2.85%) of anterior superior iliac spine (ASIS) dislocation in the iliac crest ABG group. No systemic infections were detected in either group.

DISCUSSION

We analysed the scientific literature on the use of RIA technique to collect ABG for use in patients with anthropic-oligotrophic non-unions, with a focus on the complications associated with this technique.

CONCLUSION

RIA bone graft for the treatment of non-unions and segmental bone defect of long bones seems to be a safe and efficient procedure with low donor site morbidity.

Sequential harvesting of bone graft from the intramedullary canal of the femur

The effectiveness of using the Reamer/Irrigator/Aspirator (RIA) System (Synthes, Inc, West Chester, Pennsylvania) to obtain bone graft from the intramedullary canal of long bones for the treatment of bone defects and nonunions has been previously documented. However, there is nothing in the literature discussing the potential for reaming the same canal at subsequent surgeries. The authors detail their experience of 8 instances of sequential reaming in 7 patients. Six patients were harvested twice, and 1 patient was harvested 3 times. In each patient, the bone graft was obtained from the same canal. The main outcome measurements were time interval between reamings, reamer head size, indication for reaming, volume of harvested bone graft, and complications. Average volume of graft obtained in the first reaming procedure was 34 mL (range, 25-50 mL). After an average of 9 months (range, 3-16 months), the subsequent reaming was performed. Average volume of graft obtained in the second procedure was 45 mL (range, 28-65 mL). In the authors' series, no reaming-related complications were observed. The graft volume was the same or increased during the subsequent intramedullary reaming in all but 1 case, suggesting that the intramedullary canal is a potentially renewable source for bone graft. There were no complications related to the sequential reaming procedure. Overall, the authors' data suggest that sequential reaming with the RIA has the potential to safely and effectively provide a large quantity of bone graft on multiple occasions.

A radiographic and clinical comparison of reamer-irrigator-aspirator versus iliac crest bone graft in ankle arthrodesis

PURPOSE

We evaluated radiographic fusion at follow-up and complication rates in patients who had either iliac crest (ICBG) or femoral reamer-irrigator-aspirator (RIA) bone graft for tibiotalar fusion.

METHODS

We retrospectively reviewed charts and radiographs of all patients who had a tibiotalar fusion from August 2007 to February 2011. Records were analysed for patient demographics, complications, and clinical symptoms. Radiographs were reviewed in sequential order by two fellowship-trained foot and ankle surgeons and one orthopaedic surgeon who specialises in foot and ankle surgery to determine radiographic fusion at routine follow-up. Patients were contacted to determine current visual analog scores (VAS) at their graft site.

RESULTS

Mean patient age was 49.4 ± 12.1 years in the RIA group and 49.3 ± 15.4 years in the ICBG group (p = .97). Pre-operative characteristics showed no significant differences between groups. The ICBG group had significantly more nonunions than the RIA group (six vs. one, p = 0.04). Two patients in the ICBG had chronic pain at their graft site based on their VAS score; there were none in the RIA group. Radiographic fusion at follow-up was similar between groups, with no significant difference (12.48 ± 3.85 weeks vs.12.21 ± 3.19 weeks, p = .80).

CONCLUSIONS

There was a significantly higher nonunion rate in the ICBG group, but both groups had a solid radiographic bony fusion at similar follow-up time points. Our results suggest RIA bone graft is a viable alternative to ICBG for tibiotalar fusion.

More adverse events than expected in the outcome after use of the reamer-irrigator-aspirator

PURPOSE

The reamer-irrigator-aspirator (RIA) system is described as having high success rates and only few complications. The RIA was originally designed to ream the intramedullary canal in a single step prior to the placement of an intramedullary nail for femur fixation. Its purpose was to collect and evacuate marrow contents during reaming to prevent embolism into the systemic circulation. Marrow evacuation is also used to stimulate healing in nonunion fractures, segmental bone defects, and osteomyelitis. Despite the described success rates, we experienced severe adverse events. Our aim was to describe these events and point out possible complications.

METHODS

A retrospective study of all consecutive patients treated for nonunion fractures, bone defects, or osteomyelitis from October 2007 to March 2010. All patients were treated with the RIA system. We analyzed demographic characteristics, consolidation on X-rays, time from injury to healing, complications, and postoperative pain caused by the reaming procedure.

RESULTS

We included 32 patients (21 males) with an average follow-up of 277 days. Successful healing was achieved in 66 % of all patients, and 18 % suffered from postoperative pain. A complication due to the use of the RIA system was registered in 31 % of the patients. Recorded complications were bone defects, signs of lung embolism, a myocardial infarction, and fissure fractures.

CONCLUSIONS

The RIA system has benefits in the treatment of nonunion and osteomyelitis defect, but is not without risk. Meticulous surgical technique is mandatory and peroperative constant monitoring of patients and the assembled device is mandatory.

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.

Bone Regeneration Based on Tissue Engineering Conceptions - A 21st Century Perspective

The role of Bone Tissue Engineering in the field of Regenerative Medicine has been the topic of substantial research over the past two decades. Technological advances have improved orthopaedic implants and surgical techniques for bone reconstruction. However, improvements in surgical techniques to reconstruct bone have been limited by the paucity of autologous materials available and donor site morbidity. Recent advances in the development of biomaterials have provided attractive alternatives to bone grafting expanding the surgical options for restoring the form and function of injured bone. Specifically, novel bioactive (second generation) biomaterials have been developed that are characterised by controlled action and reaction to the host tissue environment, whilst exhibiting controlled chemical breakdown and resorption with an ultimate replacement by regenerating tissue. Future generations of biomaterials (third generation) are designed to be not only osteoconductive but also osteoinductive, i.e. to stimulate regeneration of host tissues by combining tissue engineering and in situ tissue regeneration methods with a focus on novel applications. These techniques will lead to novel possibilities for tissue regeneration and repair. At present, tissue engineered constructs that may find future use as bone grafts for complex skeletal defects, whether from post-traumatic, degenerative, neoplastic or congenital/developmental "origin" require osseous reconstruction to ensure structural and functional integrity. Engineering functional bone using combinations of cells, scaffolds and bioactive factors is a promising strategy and a particular feature for future development in the area of hybrid materials which are able to exhibit suitable biomimetic and mechanical properties. This review will discuss the state of the art in this field and what we can expect from future generations of bone regeneration concepts.

Outcomes and complication rates of different bone grafting modalities in long bone fracture nonunions: a retrospective cohort study in 182 patients

BACKGROUND

Novel bone substitutes have challenged the notion of autologous bone grafting as the 'gold standard' for the surgical treatment of fracture nonunions. The present study was designed to test the hypothesis that autologous bone grafting is equivalent to other bone grafting modalities in the management of fracture nonunions of the long bones.

METHODS

A retrospective review of patients with fracture nonunions included in two prospective databases was performed at two US level 1 trauma centers from January 1, 1998 (center 1) or January 1, 2004 (center 2), respectively, until December 31, 2010 (n = 574). Of these, 182 patients required adjunctive bone grafting and were stratified into the following cohorts: autograft (n = 105), allograft (n = 38), allograft and autograft combined (n = 16), and recombinant human bone morphogenetic protein-2 (rhBMP-2) with or without adjunctive bone grafting (n = 23). The primary outcome parameter was time to union. Secondary outcome parameters consisted of complication rates and the rate of revision procedures and revision bone grafting.

RESULTS

The autograft cohort had a statistically significant shorter time to union (198 ± 172-225 days) compared to allograft (416 ± 290-543 days) and exhibited a trend towards earlier union when compared to allograft/autograft combined (389 ± 159-619 days) or rhBMP-2 (217 ± 158-277 days). Furthermore, the autograft cohort had the lowest rate of surgical revisions (17%) and revision bone grafting (9%), compared to allograft (47% and 32%), allograft/autograft combined (25% and 31%), or rhBMP-2 (27% and 17%). The overall new-onset postoperative infection rate was significantly lower in the autograft group (12.4%), compared to the allograft cohort (26.3%) (P < 0.05).

CONCLUSION

Autologous bone grafting appears to represent the bone grafting modality of choice with regard to safety and efficiency in the surgical management of long bone fracture nonunions.

The viability of cells obtained using the Reamer–Irrigator–Aspirator system and in bone graft from the iliac crest

We hypothesised that cells obtained via a Reamer–Irrigator–Aspirator (RIA) system retain substantial osteogenic potential and are at least equivalent to graft harvested from the iliac crest. Graft was harvested using the RIA in 25 patients (mean age 37.6 years (18 to 68)) and from the iliac crest in 21 patients (mean age 44.6 years (24 to 78)), after which ≥ 1 g of bony particulate graft material was processed from each. Initial cell viability was assessed using Trypan blue exclusion, and initial fluorescence-activated cell sorting (FACS) analysis for cell lineage was performed. After culturing the cells, repeat FACS analysis for cell lineage was performed and enzyme-linked immunosorbent assay (ELISA) for osteocalcin, and Alizarin red staining to determine osteogenic potential. Cells obtained via RIA or from the iliac crest were viable and matured into mesenchymal stem cells, as shown by staining for the specific mesenchymal antigens CD90 and CD105. For samples from both RIA and the iliac crest there was a statistically significant increase in bone production (both p < 0.001), as demonstrated by osteocalcin production after induction.

Medullary autograft cells harvested using RIA are viable and osteogenic. Cell viability and osteogenic potential were similar between bone grafts obtained from both the RIA system and the iliac crest.

Cite this article: Bone Joint J 2013;95-B:1269–74.

Cell-based therapies for regenerating bone

Cellular therapies to replenish bone lost due to acquired conditions such as trauma, infection, tumor, periprosthetic osteolysis and other etiologies have become widespread. Traditional, open, surgical bone grafting techniques have given way to newer cellular therapies that are potentially less invasive and have a lower complication rate and faster recovery time. These new technologies include bone marrow harvesting with concentration of osteoprogenitor cells with/without cell culture, scaffolds which are both osteoconductive and osteoinductive, attempts to facilitate mesenchymal stem cell and osteoprogenitor cell homing both locally and systemically, genetic engineering of specialized stem cells, and the use of potentially immune-privileged fetal and other types of stem cells. Some of these techniques have already been introduced into the orthopaedic clinic, whereas others are still in the pre-clinical testing phase. Given the limited supply of autologous graft, these new techniques will have a dramatic impact on bone regeneration in the future.

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.

The reconstruction of large bone defects in the upper limb

Large bone defects in the upper limb pose many challenges in reconstructive surgery. Conventional and innovative methods have been described, employing the use of microsurgical and non-microsurgical techniques to overcome both bony and soft tissue defects. This article reviews the success and pitfalls of different techniques of reconstruction of large bone defects in the upper limb, including microsurgical transfer of the free vascularised fibula graft as a diaphyseal bone replacement and as a hemivascularised joint transplant, and non-microsurgical options using conventional bone grafting, the induced membrane technique and the role of callotatic distraction-lengthening procedures.

Strategies for controlled delivery of growth factors and cells for bone regeneration

The controlled delivery of growth factors and cells within biomaterial carriers can enhance and accelerate functional bone formation. The carrier system can be designed with pre-programmed release kinetics to deliver bioactive molecules in a localized, spatiotemporal manner most similar to the natural wound healing process. The carrier can also act as an extracellular matrix-mimicking substrate for promoting osteoprogenitor cellular infiltration and proliferation for integrative tissue repair. This review discusses the role of various regenerative factors involved in bone healing and their appropriate combinations with different delivery systems for augmenting bone regeneration. The general requirements of protein, cell and gene therapy are described, with elaboration on how the selection of materials, configurations and processing affects growth factor and cell delivery and regenerative efficacy in both in vitro and in vivo applications for bone tissue engineering.

Approaches to proximal tibial bone harvest techniques

OBJECTIVES

The iliac crest is the standard site for harvesting bone; however, this procedure may require another specialist and a general anaesthetic. The proximal tibial bone harvest has gained popularity for harvesting autogenous bone. An analysis of the clinical literature regarding the various regions for harvesting bone demonstrates that the use of the proximal tibia led to shorter hospital stays, lower morbidity rates, and a shorter learning curve for the surgeon. The purpose of this study was to analyze the clinical anatomy of a proximal tibial bone harvest graft to provide the anatomical architecture supporting a safe procedure.

MATERIALS AND METHODS

Dissection of 58 lower limbs from embalmed cadavers was conducted to determine the anatomy of a proximal tibial bone harvest (PTBH).

RESULTS

Dissection revealed that the medial approach has fewer clinically relevant neurovascular structures in harms way, and a larger surface area, providing the clinician a confident surgical window to perform the procedure.

CONCLUSIONS

The anatomical basis of this study suggests that the medial proximal tibial bone harvest approach would have fewer serious structures in harm's way compared to the lateral; however, the lateral approach may be preferred for a subgroup of patients.

Harvest of cortico-cancellous intramedullary femoral bone graft using the Reamer-Irrigator-Aspirator (RIA)

The "Reamer-Irrigator-Aspirator" (RIA) is a device that provides continuous irrigation and aspiration during intramedullary reaming of long bones. The RIA system is first used to collect the reaming material from medullary cavities, a thick paste of finely morselized osseous particles containing significantly elevated levels of stem cells and growth factors as reported by quantitative analyses. The volume of bone graft material available from an adult femur corresponds to the amount of cancellous bone graft obtained from both the anterior and posterior iliac crests. The assembly and technicalities of the RIA system require a training period to prevent any femoral fracture, which appears to be the major RIA-related complication. The elective indications for RIA bone grafting are filling of bone defects in the epiphyseal and metaphyseal regions. Diaphyseal defects may also be managed using the RIA system provided the graft is placed in a constrained system (induced membrane) to prevent dispersion of the graft into the surrounding soft tissues and is aerated with a porous material to promote its revascularization. Other RIA indications include debriding intramedullary infections and reaming for intramedullary nailing of long bone fractures to reduce the risk of fat embolization.

[Spinal arthrodesis. basic science]

Spinal arthrodesis consists of a combination of a system of mechanical stabilisation of one or more vertebral segments with a biological substance that promotes osteoneogenesis, with aim of achieving the permanent fusion between areas more or less the same size of these segments. In spinal arthrodesis, the biological support par excellence is the autograft. However, obtaining this involves a high incidence of morbidity and, in cases of arthrodesis of more than one intervertebral space, the quantity available is usually insufficient. The extraction and implantation time prolongs the surgery, increasing the exposure to and risk of bleeding and infection. For these reasons, there is a search for substances that possess the properties of the autograft, avoiding the morbidity and added surgical time required to extract the autograft. The biomechanical-biological interaction in vertebral arthrodesis has been studied in this article.

Use of the reamer–irrigator–aspirator technique to obtain autograft for ankle and hindfoot arthrodesis

The use of autograft bone is the best option when undertaking a procedure that requires bone graft because it is osteogenic, osteoconductive and osseo-inductive. Pain, morbidity and complications associated with harvesting iliac or non-iliac sites occur in between 6% and 30% of cases. An alternative source of graft with possibly a lower morbidity is the intramedullary canal. In this study, 28 patients undergoing 30 arthrodesis procedures on the hindfoot had a mean of 48 cm3 (43 to 50) of bone harvested locally from the hindfoot or the tibial shaft by antegrade or retrograde reaming. No patient sustained a fracture of the calcaneum, talus or tibia. There was no morbidity except for one complication when the reamer breached the medial tibial cortex. This healed uneventfully.

This method of using the reamer–irrigator–aspirator system is an extension of the standard technique of intramedullary reaming of the lower limb: it produces good-quality bone graft with viable growth factors consistent with that of the iliac crest, and donor site morbidity is low. This is an efficient method of obtaining autologous bone for use in arthrodesis of the ankle or hindfoot.

Autogenous bone graft: donor sites and techniques

Autogenous cancellous bone graft provides an osteoconductive, osteoinductive, and osteogenic substrate for filling bone voids and augmenting fracture-healing.The iliac crest remains the most frequently used site for bone-graft harvest, but the proximal part of the tibia, distal end of the radius, distal aspect of the tibia, and greater trochanter are alternative donor sites that are particularly useful for bone-grafting in the ipsilateral extremity.The most common complication associated with the harvest of autogenous bone graft is pain at the donor site, with less frequent complications including nerve injury, hematoma, infection, and fracture at the donor site.Induced membranes is a method that uses a temporary polymethylmethacrylate cement spacer to create a bone-graft-friendly environment to facilitate graft incorporation, even in large segmental defects.

Complications following autologous bone graft harvesting from the iliac crest and using the RIA: a systematic review

Bone grafting is a commonly performed surgical procedure to augment bone regeneration in a variety of cases in orthopaedic and maxillofacial surgery. Autologous bone graft remains to be the 'gold standard' and the iliac crest to be the most common harvesting site. The intramedullary canal of long bones represents another potential site for large volume of autologous bone graft harvesting and is recently being used as an alternative donor site. However, harvesting of autologous bone graft is associated with morbidity and a number of complications. The aim of this systematic review was to collect and summarise the existing data on reported complications after harvesting autologous bone from the iliac crest (anterior and posterior) and the long bone intramedullary canal using the RIA device. We searched the PubMed Medline and Ovid Medline databases, from January 1990 to October 2010, to retrieve all relevant articles. A total of 92 articles (6682 patients) were included in the analysis. Overall, the complication rate following RIA was 6% (14 complications in 233 patients) and 19.37% after iliac crest bone graft harvesting (1249 complications in 6449 patients). The rate of each of the reported complications was assessed and, when the donor site was properly documented, comparison within the anterior and posterior iliac crest donor sites was performed. Although the difference of the overall morbidity rates between the two harvesting sites was not statistically significant (p=0.71); the rates of certain complications were found to significantly differ when anterior or posterior iliac crest was used. The rates of infection (p=0.016), haematoma formation (p=0.002), fracture (p=0.017), and hyperthrophic scar (p=0.017) were significantly higher when the donor site was the anterior iliac crest compared to the posterior iliac crest; whereas the rates of chronic donor site pain (p=0.004) and sensory disturbances (p=0.003) were significantly lower. The incidence of bone graft harvesting related complications can be reduced further if certain principles are followed depending on the performed harvesting methods; but overall the use of RIA device as harvesting method seems a promising alternative with a low complication rate.

Reaming Irrigator Aspirator system: early experience of its multipurpose use

The evolution of contemporary intramedullary reaming systems has recently generated the Reamer Irrigator Aspirator system (RIA-Synthes®), which has progressively gained in popularity as well as in indications. The preliminary results of its use over the initial period of 18 months ata single tertiary referral centre were prospectively collected and are presented. The wide spectrum of RIA's indications have been exploited, including 7 patients with polytrauma that underwent acute femoral nailing, 8 with femoral intramedullary osteomyelitis, 9 with pathological lesions of the femoral shaft, as well as 18 patients where the RIA system has been used to harvest morselised autologous bone graft in the presence of recalcitrant atrophie non-unions and bone defects. Overall its use was proven safe and efficient, achieving aggressive medullary canal debridement, collection of adequate samples for further analysis in the infected and oncology cases, as well as impressive volumes of the osteoinductive and osteogenic reaming debris for grafting purposes. No pulmonary complications or evidence of the second hit sequelae were recorded in the polytrauma patient subgroup despite the presence of a high ISS Further controlled clinical studies should follow focused in all different applications of this reliable, user-friendly and impressively versatile system, to validate these preliminary results.

Management of aseptic tibial nonunion

Tibial nonunion remains a significant clinical challenge despite advances in surgical management. New techniques to help manage tibial nonunion include extracorporeal shock wave therapy and percutaneous application of bone marrow aspirate. Management strategies vary based on the type of nonunion: aseptic or infected, and atrophic or hypertrophic. Extracorporeal shock wave therapy has been shown to be as effective as surgical management in patients with stable hypertrophic nonunion. New fixation options include locked plates and intramedullary compression nails. Novel methods of external fixation have been developed for bone graft harvest from the intramedullary canal. Several biologic adjuncts also are available, including bone marrow aspirates, stem cells, and bone morphogenetic protein.

What bone graft substitutes should we use in post-traumatic spinal fusion?

Surgical treatment of spinal fractures consists of postural reduction and segmental arthrodesis, together with an eventual performance of spinal canal decompression. Spinal arthrodesis consists of the combination of a hardware system for mechanical stabilisation together with a biological substance for enhancement of bone formation. To date, autologous graft is the only biological substance demonstrated to possess osteogenic properties. Cancellous bone graft has greater cellular activity than cortical graft, whereas cortical graft is stronger. Consequently, according to biological and biomechanical properties of autograft, spinal posterior arthrodesis is better enhanced by cancellous autograft, whereas anterior interbody tricortical bone is more suitable for anterior fusion. Allograft does not cause harvesting complications as autograft does, and also its amount is theoretically unlimited; nevertheless the rate of bone fusion facilitated by allograft is far from that enhanced by autograft given that allograft has no osteoprogenitor cells. There is little evidence on the efficacy of demineralised bone matrix for spinal fusion. Bone morphogenetic proteins (BMPs) are in use in spinal surgery, but their exact role with respect to type, dose, and carrier, together with their cost-effectiveness, need further clinical delineation. Calcium phosphate compounds appear to be good as carriers; however, they have no osteoinductive or osteogenic properties. Current clinical literature seem to indicate their usefulness for bony fusion in spinal surgery, when combined with bone marrow aspirate or used as an extender for autologous bone graft. Age, length of fusion, location, and concurrent diseases should be definitive for fusion outcome; papers on spinal arthrodesis should neatly stratify these variables. Unfortunately, since that is not the rule, conclusions drawn from current literature are very unreliable. Autograft remains the gold standard, and cancellous bone is advisable in posterolateral approaches, whereas tricortical iliac crest autograft appears appropriate for interbody support. In longer segments, its expansion with BMPs looks safe at least. Basic knowledge has been achieved from animal experiments, and clinical application of the findings to humans should be done very cautiously; in any case, both anterior and posterior arthrodesis must be protected with instrumentation used according to appropriate biomechanical principles. A combination of failure of the correct graft together with proper instrumentation will result in poorer outcome, even if the right graft is used.

Managing bone defects

The management of bone defects caused by trauma and nonunion continues to represent a substantial clinical challenge in the management of orthopaedic trauma patients. A variety of treatment options have been described and reported in the literature. The relative rarity of these injuries means that high level, comparative evidence to guide their management is sparse. As such, treatment decisions must be based on knowledge of the available evidence, contemporary fracture management principles, and consideration of patient and surgeon factors. This article reviews the available evidence for the different treatment options available for the management of bone defects.

The use of the reamer-irrigator-aspirator to harvest mesenchymal stem cells

The scarcity of mesenchymal stem cells (MSCs) in iliac crest bone marrow aspirate (ICBMA), and the expense and time in culturing cells, has led to the search for alternative harvest sites. The reamer-irrigation-aspirator (RIA) provides continuous irrigation and suction during reaming of long bones. The aspirated contents pass via a filter, trapping bony fragments, before moving into a 'waste' bag from which MSCs have been previously isolated. We examined the liquid and solid phases, performed a novel digestion of the solid phase, and made a comparative assessment in terms of number, phenotype and differentiation capacity with matched ICBMA. The solid fraction from the filtrate was digested for 60 minutes at 37° C with collagenase. Enumeration was performed via the colony-forming unit fibroblast (CFU-F) assay. Passage (P2) cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages, and their phenotypes assessed using flow cytometry (CD33, CD34, CD45, CD73, CD90, and CD105). MSCs from the RIA phases were able to differentiate at least as well as those from ICBMA, and all fractions had phenotypes consistent with other established sources. The median number of colonies for the three groups was: ICBMA = 8.5 (2 to 86), RIA-liquid = 19.5 (4 to 90), RIA-solid = 109 (67 to 200) per 200 μl. The mean total yield of cells for the three groups was: ICBMA = 920 (0 to 4275), RIA-liquid = 114,983 (16,500 to 477,750), RIA-solid = 12,785 (7210 to 28 475). The RIA filtrate contains large numbers of MSCs that could potentially be extracted without enzymatic digestion and used for bone repair without prior cell expansion.

Treatment of long bone defects and non-unions: from research to clinical practice

The treatment of long bone defects and non-unions is still a major clinical and socio-economical problem. In addition to the non-operative therapeutic options, such as the application of various forms of electricity, extracorporeal shock wave therapy and ultrasound therapy, which are still in clinical use, several operative treatment methods are available. No consensus guidelines are available and the treatments of such defects differ greatly. Therefore, clinicians and researchers are presently investigating ways to treat large bone defects based on tissue engineering approaches. Tissue engineering strategies for bone regeneration seem to be a promising option in regenerative medicine. Several in vitro and in vivo studies in small and large animal models have been conducted to establish the efficiency of various tissue engineering approaches. Neverthelsss, the literature still lacks controlled studies that compare the different clinical treatment strategies currently in use. However, based on the results obtained so far in diverse animal studies, bone tissue engineering approaches need further validation in more clinically relevant animal models and in clinical pilot studies for the translation of bone tissue engineering approaches into clinical practice.

Bone graft harvesting using the RIA (reaming irrigation aspirator) system - a quantitative assessment

INTRODUCTION

Autologous bone graft is still considered to be the gold standard for treating non-unions in trauma and orthopedic surgery. Intramedullary bone graft harvest appears to be an alternative to other bone graft options such as iliac crest bone graft and synthetic bone substitutes. A one-step reamer-irrigator-aspirator (RIA) system has been developed to reduce the intramedullary pressure and, as a consequence, minimize the risk of fat embolization. The purpose of this study was to determine whether the quantity of harvested intramedullary bone graft is comparable to the quantity of graft that was harvested from the iliac crest in other studies. The aim of the present study was to quantify harvested bone marrow and to compare our results to already published data.

METHODS

Eight human cadavers (7 males, 1 female, and 16 limbs) with an average age of 68 years (range, 49-79 years) were obtained for this study. Intramedullary reaming was performed in the tibiae and femora of each cadaver. Two different sizes (12- and 14-mm diameter) of the RIA system were used. After a medial parapatellar incision was made at the knee, antegrade and retrograde reaming were performed in the tibiae and femur to harvest bone graft.

RESULTS

A significantly greater quantity of bone graft was harvested from the femora (27 ± 12 g) than the tibiae (17 ± 9 g) (p = 0.007).

CONCLUSIONS

On the basis of our present results, harvesting intramedullary bone graft with the RIA system appears to be an innovative technique for bone grafting in limb reconstruction. A significantly greater quantity of bone graft was harvested from the femora than the tibiae (p = 0.007). No significant differences among age, sex, body weight, bone length, or BMI were observed. Our results showed that a sufficient quantity in weight of autogenous bone graft could be obtained using the RIA system.

Revision of a nonunited subtrochanteric femoral fracture around a failed intramedullary nail with the use of RIA products, BMP-7 and hydroxyapatite: a case report

INTRODUCTION

Femoral subtrochanteric fractures are commonly treated using intramedullary devices. Failure of the implant and subsequent nonunion is still an issue, however, and limited evidence exists regarding the most appropriate treatment.

CASE PRESENTATION

We report the case of an 80-year-old Caucasian woman with a subtrochanteric fracture originally treated using a trochanteric gamma nail which failed, resulting in a nonunion and fracture of its proximal end. The nonunion was revised with the removal of the broken trochanteric gamma nail, application of a condylar blade plate, ipsilateral Reamer/Irrigator/Aspirator autografting, recombinant human bone morphogenetic protein-7 and injectable hydroxyapatite cement. The fracture united fully at ten months following revision surgery, with no signs of femoral head avascular necrosis at 18-month follow-up.

CONCLUSION

The essential requirements for success when revising a nonunited fracture are to provide anatomical reduction, mechanical stability, bone defect augmentation and biological stimulation to achieve healing. Current advances in molecular biology, such as recombinant human bone morphogenetic protein-7, and biotechnology such as the Reamer/Irrigator/Aspirator system and hydroxyapatite injectable cement can improve patient outcomes over the use of our traditional revision techniques.