Percutaneous bone grafting in the treatment of the delayed union and non-union of tibial fractures

Effect of platelet-rich plasma on fracture healing

Bone has the ability to completely regenerate under normal healing conditions. Although fractures generally heal uneventfully, healing problems such as delayed union or nonunion still occur in approximately 10% of patients. Optimal healing potential involves an interplay of biomechanical and biological factors. Orthopedic implants are commonly used for providing the necessary biomechanical support. In situations where the biological factors that are needed for fracture healing are deemed inadequate, additional biological enhancement is needed. With platelets being packed with granules that contain growth factors and other proteins that have osteoinductive capacity, local application of platelet concentrates, also called platelet-rich plasma (PRP) seems an attractive biological to enhance fracture healing. This review shows an overview of the use PRP and its effect in enhancing fracture healing. PRP is extracted from the patient's own blood, supporting that its use is considered safe. Although PRP showed effective in some studies, other studies showed controversial results. Conflicts in the literature may be explained by the absence of consensus about the preparation of PRP, differences in platelet counts, low number of patients, and absence of a standard application technique. More studies addressing these issues are needed in order to determine the true effect of PRP on fracture healing.

Minimally Invasive Percutaneous Plate Osteosynthesis (MIPPO) Combined with Onionskin-Like Autologous Bone Grafting: A New Technique for Treatment of Tibial Nonunion

BACKGROUND Established tibial nonunions rarely heal without secondary intervention; revision surgery is the most common intervention. Herein, we evaluated the clinical outcomes of patients with tibial nonunion treated with a new technique - minimally invasive percutaneous plate osteosynthesis (MIPPO) - combined with a new onionskin-like autologous bone grafting method. MATERIAL AND METHODS From 2010 to 2013, 18 patients with tibial nonunions (average bone defect: 9.5 mm) were treated with MIPPO technology combined with onionskin-like autologous bone grafting. Indices for clinical evaluation included operative time, fluoroscopy time, blood loss, hospital stay, healing time, postoperative complaints, radiographic performances, the Short Musculoskeletal Function Assessment (SMFA) questionnaire, and the American Orthopedic Foot & Ankle Society (AOFAS) ankle-hindfoot score. RESULTS The average operation and fluoroscopy times for tibial nonunion were 65 min and 15.5 s, respectively, with a total blood loss of 107.7 mL. The mean duration of hospital stay was 12.8 days. The mean follow-up time was 11.9 months, and all patients achieved radiologically confirmed bony healing in an average time of 13.1 weeks. No lower-leg deformity, fixation failure, infection, and vascular, or nerve injuries were recorded in any patient, and only 4 patients complained of slight limb pain upon total weight-bearing at the end of follow-up. The SMFA and AOFAS ankle-hindfoot scores of patients were graded excellent in 14 (77.8%) and good in 4 (22.2%), indicating high functional recovery. CONCLUSIONS MIPPO technology combined with onionskin bone grafting is an efficient method to treat patients with tibial nonunion, especially for patients with poor soft tissue condition.

Cationic Substitutions in Hydroxyapatite: Current Status of the Derived Biofunctional Effects and Their In Vitro Interrogation Methods

High-performance bioceramics are required for preventing failure and prolonging the life-time of bone grafting scaffolds and osseous implants. The proper identification and development of materials with extended functionalities addressing socio-economic needs and health problems constitute important and critical steps at the heart of clinical research. Recent findings in the realm of ion-substituted hydroxyapatite (HA) could pave the road towards significant developments in biomedicine, with an emphasis on a new generation of orthopaedic and dentistry applications, since such bioceramics are able to mimic the structural, compositional and mechanical properties of the bone mineral phase. In fact, the fascinating ability of the HA crystalline lattice to allow for the substitution of calcium ions with a plethora of cationic species has been widely explored in the recent period, with consequent modifications of its physical and chemical features, as well as its functional mechanical and in vitro and in vivo biological performance. A comprehensive inventory of the progresses achieved so far is both opportune and of paramount importance, in order to not only gather and summarize information, but to also allow fellow researchers to compare with ease and filter the best solutions for the cation substitution of HA-based materials and enable the development of multi-functional biomedical designs. The review surveys preparation and synthesis methods, pinpoints all the explored cation dopants, and discloses the full application range of substituted HA. Special attention is dedicated to the antimicrobial efficiency spectrum and cytotoxic trade-off concentration values for various cell lines, highlighting new prophylactic routes for the prevention of implant failure. Importantly, the current in vitro biological tests (widely employed to unveil the biological performance of HA-based materials), and their ability to mimic the in vivo biological interactions, are also critically assessed. Future perspectives are discussed, and a series of recommendations are underlined.

Two stage reconstruction versus bone transport in management of resistant infected tibial diaphyseal nonunion with a gap

INTRODUCTION

Infected nonunion of the tibial diaphysis poses one of the most challenging scenarios. There is no clear cut guidelines for cases of infected diaphyseal nonunion with bony defects of ≤6 cm.

MATERIALS AND METHODS

A retrospective comparative study was conducted on 30 patients who sustained resistant infected tibial diaphyseal nonunion with bony defect of ≤6 cm. The 30 patients were the sum of two groups; group I (16 patients, mean age 33.6 years) which included all patients, who underwent two stage reconstructions, and Group II patients (14 patients, mean age 29.5 years) who were managed by application of Ilizarov ring external fixator in a single stage surgery. Union was judged both clinically and radiologically. A scoring system comprising dual functional and bony grading was employed to evaluate the final results of both groups.

RESULTS

The results of both groups regarding the size of the resultant bony defect, the time to union, and the postoperative limb length discrepancy showed no statistically significant differences. Group II patients needed postoperative plastic reconstruction procedures significantly more than group I patients (p = 0.019). Similarly, group II patients exhibited more complications than group I patients (p = 0.003). Regarding both clinical and bony grading, the results of group I showed superiority to group II results with the only significant difference being the preservation of the preoperative range of motion of both ankle and subtalar joints (p = 0.072).

CONCLUSIONS

The use of two stage reconstruction in cases of resistant infected tibial diaphyseal nonunion gives comparable results to the Ilizarov ring external fixator in cases associated with bony defects within the confines of 6 cm with superiority in preservation of ankle and subtalar joints range of motion.

Direct comparison of current cell-based and cell-free approaches towards the repair of craniofacial bone defects - A preclinical study

For craniofacial bone defect repair, several alternatives to bone graft (BG) exist, including the combination of biphasic calcium phosphate (BCP) biomaterials with total bone marrow (TBM) and bone marrow-derived mesenchymal stromal cells (MSCs), or the use of growth factors like recombinant human bone morphogenic protein-2 (RhBMP-2) and various scaffolds. Therefore, clinicians might be unsure as to which approach will offer their patients the most benefit. Here, we aimed to compare different clinically relevant bone tissue engineering methods in an "all-in-one" study in rat calvarial defects. TBM, and MSCs committed or not, and cultured in two- or three-dimensions were mixed with BCP and implanted in bilateral parietal bone defects in rats. RhBMP-2 and BG were used as positive controls. After 7 weeks, significant de novo bone formation was observed in rhBMP-2 and BG groups, and in a lesser amount, when BCP biomaterials were mixed with TBM or committed MSCs cultured in three-dimensions. Due to the efficacy and safety of the TBM/BCP combination approach, we recommend this one-step procedure for further clinical investigation.

STATEMENT OF SIGNIFICANCE

For craniofacial repair, total bone marrow (BM) and BM mesenchymal stem cell (MSC)-based regenerative medicine have shown to be promising in alternative to bone grafting (BG). Therefore, clinicians might be unsure as to which approach will offer the most benefit. Here, BM and MSCs committed or not were mixed with calcium phosphate ceramics (CaP) and implanted in bone defects in rats. RhBMP-2 and BG were used as positive controls. After 7 weeks, significant bone formation was observed in rhBMP-2 and BG groups, and when CaP were mixed with BM or committed MSCs. Since the BM-based procedure does not require bone harvest or cell culture, but provides de novo bone formation, we recommend consideration of this strategy for craniofacial applications.

Recent biological trends in management of fracture non-union

Bone regeneration is a complex, well-orchestrated physiological process of bone formation, which can be seen during normal fracture healing, and is involved in continuous remodelling throughout adult life. Currently, there is a plethora of different strategies to augment the impaired or “insufficient” bone-regeneration process, including the “gold standard” autologous bone graft, free fibula vascularised graft, allograft implantation, and use of growth factors, osteoconductive scaffolds, osteoprogenitor cells and distraction osteogenesis. Improved “local” strategies in terms of tissue engineering and gene therapy, or even “systemic” enhancement of bone repair, are under intense investigation, in an effort to overcome the limitations of the current methods, to produce bone-graft substitutes with biomechanical properties that are as identical to normal bone as possible, to accelerate the overall regeneration process, or even to address systemic conditions, such as skeletal disorders and osteoporosis. An improved understanding of the molecular and cellular events that occur during bone repair and remodeling has led to the development of biologic agents that can augment the biological microenvironment and enhance bone repair. Orthobiologics, including stem cells, osteoinductive growth factors, osteoconductive matrices, and anabolic agents, are available clinically for accelerating fracture repair and treatment of compromised bone repair situations like delayed unions and nonunions. A lack of standardized outcome measures for comparison of biologic agents in clinical fracture repair trials, frequent off-label use, and a limited understanding of the biological activity of these agents at the bone repair site have limited their efficacy in clinical applications.

Less than full circumferential fusion of a tibial nonunion is sufficient to achieve mechanically valid fusion--proof of concept using a finite element modeling approach

BACKGROUND

Although minimally invasive approaches are widely used in many areas of orthopedic surgery nonunion therapy remains a domain of open surgery. Some attempts have been made to introduce minimally invasive procedures into nonunion therapy. However, these proof of concept studies showed fusion rates comparable to open approaches never gaining wider acceptance in the clinical community. We hypothesize that knowledge of mechanically relevant regions of a nonunion might reduce the complexity of percutaneous procedures, especially in complex fracture patterns, and further reduce the amount of cancellous bone that needs to be transplanted. The aim of this investigation is to provide a proof of concept concerning the hypothesis that mechanically stable fusion of a nonunion can be achieved with less than full circumferential fusion.

METHODS

CT data of an artificial tibia with a complex fracture pattern and anatomical LCP are converted into a finite element mesh. The nonunion area is segmented. The finite element mesh is assigned mechanical properties according to data from the literature. An optimization algorithm is developed that reduces the number of voxels in the non union area until the scaled von Mises stress in the implant reaches 20% of the maximum stress in the implant/bone system that occurs with no fusion in the nonunion area at all.

RESULTS

After six iterations of the optimization algorithm the number of voxels in the nonunion area is reduced by 96.4%, i.e. only 3.6% of voxels in the non union area are relevant for load transfer such that the von Mises stress in the implant/bone system does not exceed 20% of the maximal scaled von Mises stress occurring in the system with no fusion in the non union area at all.

CONCLUSIONS

The hypothesis that less than full circumferential fusion is necessary for mechanical stability of a nonunion is confirmed. As the model provides only qualitative information the observed reduction of fusion area may not be taken literally but needs to be calibrated in future experiments. However this proof of concept provides the mechanical foundation for further development of minimally invasive approaches to delayed union and nonunion therapy.

The effect of sterilization methods on the osteoconductivity of allograft bone in a critical-sized bilateral tibial defect model in rabbits

Clinically, allogeneic bone graft is used extensively because it avoids the donor site morbidity associated with autograft. However, there are concerns over the optimal sterilization method to eliminate immunological risks whilst maintaining the biological efficacy of the graft. This study compared the effect of Supercritical fluid (SCF) treatment and gamma irradiation at 25 kGy on the osteoconductivity of allograft bone in a bilateral critical sized defect rabbit model. Osteoconductivity was evaluated at 2 and 4 weeks using X-ray, CT, histology (qualitative and quantitative) and immunohistochemistry (Alkaline Phosphatase and Cathepsin-K). Both grafts were well tolerated and osteoconductive. At 2 weeks, there was decreased bone volume and density in the gamma irradiated graft compared to the SCF treated graft, corresponding with a greater inflammatory response histologically and increased Cathepsin-K expression. Catabolic activity predominated at 4 weeks, with both grafts undergoing significant resorption and remodeling inside the defect. Alkaline Phosphatase expression was greater in the SCF group at both time points indicative of a more anabolic response. Allograft bone sterilized with either gamma irradiation or SCF treatment was osteoconductive and capable of healing a critical sized tibial defect in a rabbit. Gamma irradiated allografts elicited an acute inflammatory reaction when implanted which may increase the amount of graft resorption compared to the SCF treated bone.

Bone tissue engineering: recent advances and challenges

The worldwide incidence of bone disorders and conditions has trended steeply upward and is expected to double by 2020, especially in populations where aging is coupled with increased obesity and poor physical activity. Engineered bone tissue has been viewed as a potential alternative to the conventional use of bone grafts, due to their limitless supply and no disease transmission. However, bone tissue engineering practices have not proceeded to clinical practice due to several limitations or challenges. Bone tissue engineering aims to induce new functional bone regeneration via the synergistic combination of biomaterials, cells, and factor therapy. In this review, we discuss the fundamentals of bone tissue engineering, highlighting the current state of this field. Further, we review the recent advances of biomaterial and cell-based research, as well as approaches used to enhance bone regeneration. Specifically, we discuss widely investigated biomaterial scaffolds, micro- and nano-structural properties of these scaffolds, and the incorporation of biomimetic properties and/or growth factors. In addition, we examine various cellular approaches, including the use of mesenchymal stem cells (MSCs), embryonic stem cells (ESCs), adult stem cells, induced pluripotent stem cells (iPSCs), and platelet-rich plasma (PRP), and their clinical application strengths and limitations. We conclude by overviewing the challenges that face the bone tissue engineering field, such as the lack of sufficient vascularization at the defect site, and the research aimed at functional bone tissue engineering. These challenges will drive future research in the field.

Percutaneous autologous bone marrow injections for delayed or non-union of bones

PURPOSE

To evaluate 12 patients with delayed or nonunion of bones treated with bone marrow injections.

METHODS

6 men and 6 women aged 15 to 70 (mean, 45) years underwent bone marrow injections for delayed union (n=2) or atrophic non-union (n=10) of the ulna (n=6), femur (n=3), humerus (n=2), or metacarpal (n=1). Bone marrow was aspirated from the anterior iliac crest and injected to the delayed and non-union sites. Two injections were given for children and adolescents, and 3 for adults. The interval between the injections was 6 to 8 weeks. The amount of bone marrow injected was 30 to 40 ml for long bones and 20 ml for metacarpals.

RESULTS

Ten of the 12 delayed or non-union of bones healed after bone marrow injections. The mean time for callus formation was 5.8 (range, 3-10) weeks, for clinical union was 7 (range, 4-12) weeks, and for radiological union was 16 (range, 10-24) weeks.

CONCLUSION

Multiple injections of low-volume bone marrow can be used for treatment of delayed or non-union of bones.

Local erythropoietin injection in tibiofibular fracture healing

BACKGROUND

Erythropoietin (EPO), in addition to its function as an erythropoiesis regulator has a regenerative activity on some nonhematopoietic tissues. Animal studies have suggested a role for erythropoietin in bone healing.

OBJECTIVES

The present study aimed to evaluate the effects of local EPO injection in healing of tibiofibular fractures.

MATERIALS AND METHODS

In a prospective double blind study, 60 patients with tibiofibular fracture were divided to equal EPO or placebo groups, randomly. Patients received local injection of either EPO or a placebo to the site of fracture two weeks after surgical fixation. Patients were followed by clinical and radiographic examination to determine the union rate. The period of fracture union and incidence of nonunion were compared between the two groups.

RESULTS

The demographic data and types of fractures were similar in the both groups. The mean duration of the fracture union was 2.1 weeks shorter in those treated with EPO (P = 0.01). Nonunion was observed in 6 patients of the control group and 2 receiving EPO (P = 0.02). No patient experienced any adverse effect from local EPO injections.

CONCLUSIONS

EPO injection into the site of tibiofibular fractures may possibly accelerate healing.

Biologic adjuvants for fracture healing

Bone tissue has an exceptional quality to regenerate to native tissue in response to injury. However, the fracture repair process requires mechanical stability or a viable biological microenvironment or both to ensure successful healing to native tissue. An improved understanding of the molecular and cellular events that occur during bone repair and remodeling has led to the development of biologic agents that can augment the biological microenvironment and enhance bone repair. Orthobiologics, including stem cells, osteoinductive growth factors, osteoconductive matrices, and anabolic agents, are available clinically for accelerating fracture repair and treatment of compromised bone repair situations like delayed unions and nonunions. Preclinical and clinical studies using biologic agents like recombinant bone morphogenetic proteins have demonstrated an efficacy similar or better than that of autologous bone graft in acute fracture healing. A lack of standardized outcome measures for comparison of biologic agents in clinical fracture repair trials, frequent off-label use, and a limited understanding of the biological activity of these agents at the bone repair site have limited their efficacy in clinical applications.

Treatment of aseptic nonunion after intramedullary nailing fixation with locking plate

OBJECTIVE

To evaluate the safety and efficacy of locking plate combined with bone grafting in the treatment of aseptic nonunion following intramedullary nailing fixation of fractures of the long bones.

METHODS

Thirty-eight consecutive patients treated in our hospital between January 2004 and December 2006 were included in this retrospective study. The nonunions included 20 femurs, 15 tibias, and 3 humeri. The duration of non-union ranged from 6 to 84 months and 21 (55.3%) of them were located around the metaphysis of the affected long bones. There were 12 women and 26 men with a mean age of 39.2 years (range, 9-70 years). Locking plate combined with bone grafting was the procedure chosen to treat every case of nonunion in this series. The clinical outcomes were evaluated.

RESULTS

All patients were followed up for 6-20 months (average 11.6 months). After locking plate fixation combined with bone grafting, union was achieved in all cases, the average healing time being 5.3 months (range, 4-8 months). Infection of the superficial incision occurred in three cases (7.9%) and delayed healing of the incision in one case, all of which healed with no further complications. The function of the adjacent joints was excellent to good in 30 patients (78.9%), fair in 7 (18.4%) and poor in 1 (2.6%) after follow-up.

CONCLUSION

Locking plate fixation combined with bone grafting is a highly effective treatment for aseptic nonunions of the long bones after intramedullary nailing fixation, especially in the case of metaphyseal nonunion.

Application of stem cells in orthopedics

Stem cell research plays an important role in orthopedic regenerative medicine today. Current literature provides us with promising results from animal research in the fields of bone, tendon, and cartilage repair. While early clinical results are already published for bone and cartilage repair, the data about tendon repair is limited to animal studies. The success of these techniques remains inconsistent in all three mentioned areas. This may be due to different application techniques varying from simple mesenchymal stem cell injection up to complex tissue engineering. However, the ideal carrier for the stem cells still remains controversial. This paper aims to provide a better understanding of current basic research and clinical data concerning stem cell research in bone, tendon, and cartilage repair. Furthermore, a focus is set on different stem cell application techniques in tendon reconstruction, cartilage repair, and filling of bone defects.

Efficacy of minimally invasive techniques for enhancement of fracture healing: evidence today

The successful treatment of nonunions represents a major challenge for orthopaedic surgeons. Lately, ongoing advances made in the field of molecular medicine and molecular biology have increased our understanding of the pathways and involvement of mediators surrounding the bone healing process. As a result, the surgeon's armamentarium has been increased in terms of options for intervention. This article aims to provide an overview of minimally invasive techniques applicable in the treatment of nonunions of fractures.

Fracture repair with ultrasound: clinical and cell-based evaluation

Fracture repair continues to be widely investigated, both within the clinical realm and at the fundamental research level, in part due to the fact that 5% to 10% of fractures result in either delayed union or nonunion, depending on the duration of incomplete healing. Beyond the temporal delay in repair, nonunions share the same unifying characteristic: all periosteal and endosteal repair processes have stopped and the fracture will not heal without surgical intervention. A less-invasive alternative method--low-intensity pulsed ultrasound--has shown promise as a treatment for delayed unions and nonunions and as a method to facilitate distraction osteogenesis. In this paper, we summarize the clinical effectiveness of low-intensity pulsed ultrasound with regard to fracture repair, treatment of nonunion, and distraction osteogenesis and we discuss the results of a multitude of published studies that have sought to elucidate the mechanisms behind that effectiveness through research on low-intensity pulsed ultrasound exposure on osteoblasts and osteoblast precursors. When evaluated clinically, low-intensity pulsed ultrasound was shown to enhance bone repair (most commonly noted as a decrease in healing time), although variations in patient population hindered a definitive claim to clinical effectiveness. In vitro cellular evaluation and in vivo studies on animal models have revealed an increase in cell proliferation, protein synthesis, collagen synthesis, membrane permeability, integrin expression, and increased cytosolic Ca(2+) levels as well as other increased indicators of bone repair in response to low-intensity pulsed ultrasound exposure. Many of the cellular responses to low-intensity pulsed ultrasound mirror the cellular responses to fluid-induced shear flow, suggesting a link between the two as one potential mechanism of action. The considerable amount of information that has been revealed about the behavior of osteoblasts under low-intensity pulsed ultrasound exposure suggests that the exact mechanism of action is complex. It is clear, however, that considerable progress is being made toward uncovering these mechanisms, which has served to encourage the use of low-intensity pulsed ultrasound in new applications. It is posited that successful noninvasive treatment strategies such as low-intensity pulsed ultrasound may be combined with other conventional and novel tissue-regeneration strategies to develop new treatments for large-scale bone defects.

The syringe technique for minimally invasive bone grafting

Standard techniques of bone grafting for nonunion involve extensive dissection of the soft tissues surrounding the nonunion site to gain exposure and facilitate placement of the graft. Successful minimally invasive grafting has been described; however, it can involve difficulties in graft placement or require the use of advanced, expensive technical equipment. We describe a simple, inexpensive technique in which the distal end of a standard syringe is trimmed to provide a conduit for minimally invasive delivery of bone graft material. Three illustrative case reports are discussed in which this technique achieved successful union without operative morbidity.