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Essay: Fracture union

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Management of trauma has always been one of the surgical subsets in which oral and maxillofacial surgeons over the years. The mandibular body is a parabola-shaped curved bone composed of external and internal cortical layers surrounding a central core of cancellous bone. The goals of treatment, are to restore proper function by ensuring union of the fractured segments and re-establishing pre-injury strength; to restore any contour defect that might arise as a result of the injury and to prevent infection at the fracture site. Since the time of Hippocrates, it has been advocated that immobilisation of fractures to some degree or another is advantageous to their eventual union. The type and extent of immobility vary with the form of treatment and may play an essential part in the overall result. In common fractures, a certain amount of time is required before bone healing can be expected to occur. This reasonable time may vary according to age, species, breed, bone involved, level of the fracture, and associated soft tissue injury.

Delayed union, by definition, is present when an adequate period has elapsed since the initial injury without achieving bone union, taking into account the above variables. The fact that a bone is delayed in its union does not mean that it will become nonunion. Classically the stated reasons for a delayed union are problems such as small reduction, inadequate immobilisation, distraction, loss of blood supply, and infection. Inadequate reduction of a fracture, regardless of its cause, may be a prime reason for delayed union or nonunion. It usually leads to instability or poor immobilisation. Also, a small reduction may be caused by superimposition of soft tissues through the fracture area, which may delay healing.

Nonunion defined as the cessation of all reparative processes of healing without a bony union. Since all of the factors discussed under delayed union usually occur to a more severe degree in nonunion, the differentiation between delayed and nonunion is often based on radiographic criteria and time. In humans, failure to show any progressive change in the radiographic appearance for at least three months after the period during which regular fracture union would be thought to have occurred is evidence of nonunion. Malunion is defined as a healing of the bones in an abnormal position; Malunions can be classified as functional or nonfunctional. Functional malunions are usually those that have small deviations from normal axes that do not incapacitate the patient. A minimum of at least nine months has to elapse since the initial injury, and there should be no signs of healing for the final three months for the diagnosis of fracture nonunion. There are a few different classification systems of nonunions, but nonunions are most commonly divided into two categories of hypervascular nonunion and avascular nonunion. In hypervascular nonunions, also known as hypertrophic nonunion, fracture ends are vascular and are capable of biological activity. Here is evidence of callus formation around the fracture site and it is thought to be in response to excessive micromotion at the fracture site. Avascular nonunions, also known as atrophic nonunion, are caused by avascularity, or inadequate blood supply of the fracture ends. There is no or minimal callus formation, and fracture line remains visible . is nonunion requires natural enhancement in addition to adequate immobilisation to heal.

Treatment of mandibular aims in achieving the bony union, right occlusion, preserve IAN and mental nerve function, to prevent malunion and to attain optimal cosmesis. Rigid plate and screw fixation have the advantage of allowing the patient to return to the role without the need of 4–6 weeks of IMF; but the success of rigid fixation depends upon accurate reduction. During adaptation of manipulating in a champys line of osteosynthesis in symphysis region, even main bar applied to the tooth for proper occlusion, but still, the bone fragments overlap bone prominence. Gaps will be present. To achieve bone contact for healing various method are devices for the same to hold the fracture segments together like Towel clamps, Modified towel clamps. Stress patterns generated by Synthes reduction forceps, orthodontic brackets, allis forceps, manual reduction, elastics internal traction reduction, bone holding forceps, tension wire method and vacuum splints, as without which there is always a gap and inability to fix using mini plate intraoperatively. Proper alignment and reduction are essential for mastication, speech, and normal range of oral motion.

Compression during plate fixation has been shown to aid in the stability and healing process of a fracture site. The primary mechanism is thought to be due to increased contact of bony surfaces. Reduction forceps can hold large segments of bone together to increase surface contact while plate fixation is performed. An additional benefit of using reduction forceps is that a single operating surgeon can achieve plating of body fractures because the forceps hold the fracture in reduction while the plates and screws are placed. Reduction gaps of more than 1 mm between fracture segments result in secondary healing, which occurs in callus formation and increases the risk of a nonunion irrespective of any fixation method. Direct bone contact between the fracture segments promotes primary bone healing, which leads to earlier bone regrowth and stability across the fracture site. Gap healing takes place in stable or “quiet” gaps with a width more significant than the 200-μm osteonal diameter. Ingrowth of vessels and mesenchymal cells starts after surgery. Osteoblasts deposit osteoid on the fragment ends without osteoclastic resorption. The gaps are filled exclusively with primarily formed, transversely oriented lamellar bone. Replacement usually completed within 4 to 6 weeks. In the second stage, the transversely oriented bone lamellae replaced by axially orientated osteons, a process which is referred to as Haversian remodelling. Clinical experience shows that fractures that are not adequately reduced are at higher risk for malunion, delayed union and non-union and infection leading to further patient morbidity to achieve bone contact plate.

Studies by Choi et al. using silicon mandibular models have established the optimum position of the modified towel clamp–type reduction forceps relative to symphyseal and parasymphyseal fractures. Fractured models were reduced at three different horizontal levels: midway bisecting the mandible, 5 mm above midway, and 5 mm below midway. Besides, engagement holes were tested at distances of 10, 12, 14, and 16 mm from the fracture line. The models were subjected to heating up to 130°C for 100 minutes and then were cooled to room temperature. Stress patterns were then evaluated using a polariscope. Optimal stress patterns (defined as those distributed over the entire fracture site) were noted when the reduction forceps were placed at the midway or 5 mm below midway and at least 12 mm from the fracture line for symphyseal or parasymphyseal fractures and at least 16 mm for mandibular body fractures.

Shinohara et al. in 2006 used two modified reduction forceps for the symphyseal and parasymphyseal fractures. One was applied at the inferior border and another one in the subapical zone of the anterior mandible, to reduce lingual cortical bone sufficiently. In the other clinical studies, the reduction was achieved by using one clamp or forceps in the anterior and posterior region of the mandible.

One study describes that two monocortical holes were drilled, each 10 mm from the fracture line (Žerdoner and Žajdela, 1998). A second study describes monocortical holes at approximately 12 mm (Kluszynski et al., 2007) from the fracture line at midway down the vertical height of the mandible. The third study describes either monocortical or bicortical holes depending on difficulties. These difficulties are not described in detail. In this study, the distance of 5-8 mm from the fracture was chosen (Rogers and Sargent, 2000) at the inferior margin of the mandible.

Taglialatela Scafati et al., (2004) used elastic rubber bands stretched between screws placed across both sides of the fractured parts to reduce mandibular and orbit- maxillary fractures. Orthodontic rubber bands and two self-tapping monocortical titanium screws with 2 mm diameter and 9-13 mm length used. The heads of the screws protruded about 5 mm and the axis had to be perpendicular to the fracture line. It is similar in concept to other intraoperative methods of reduction used in orthopaedic or maxillofacial surgery such as the tension band technique or the Tension Wire Method (TWM), where EIT utilises rubber bands tightened between monocortical screws placed onto the fracture fragments

Vikas and Terrence Lowe in 2009 in their technical note on Modification of the elastic internal traction method for temporary inter-fragment reduction prior to internal fixation described a simple and effective modification of the Elastic Internal Traction method as previously described by Scafati et al.The modification utilizes 2 mm AO mono-cortical screws and elastomeric orthodontic chain (EOC) instead of elastic bands. 9–12mm length mono-cortical screws strategically placed to a depth of 4–5 mm approximately 7 mm either side of the fracture.

Based on studies by Smith at el in 1933 a series of 10 x 1 cm ‘turns’ of the elastic should resist a displacing force of between 30.-40 Newtons approximately.

Degala and Gupta, (2010) used comparable techniques for symphyseal, parasymphyseal and body fractures. Titanium screws with 2 mm diameter and 8 mm length were tightened at a distance of 10-20 mm from the line of fracture, and around 2 mm screw length remained above the bone to engage a 24 G wire loop. However, before applying this technique, they used IMF.

Rogers and Sargent in 2000 modified A standard towel by bending two ends of a clamp approximately 10 degrees outward and was done to prevent disengagement from the bone. Kallela et al. in 1996 modified a standard AO reduction forceps through shortening the teeth and made notches at the ends to grasp tightly in the drill holes. Shinohara et al. in 2006 used two modified reduction forceps: one was positioned at the inferior border and the other in the neutral subapical zone.

Choi et al. in 2005 included two treatment groups (reduction forceps and IMF group) and used a scale of 1 to 3 to assess the accuracy of anatomic reduction in the radiographic image. A score of 1 indicated a poorly reduced fracture which required a second operation, while a score of 2 indicated a slight displacement but an acceptable occlusion. A score of 3 indicated a precise reduction. The reduction forceps group had a higher number of accurate anatomic alignments of the fractures than the IMF group.

New reduction forceps were developed by Choi et al., 2001; Choi et al., 2005 for mandibular angle fractures based on the unique anatomy of the oblique line and body; one end of the forceps designed for positioning in the fragment medial to the oblique line, and another end was placed in the distal fragment below the oblique line . The reduction-compression forceps of Scolozzi and Jaques, in 2008 was designed similar to standard orthopaedic atraumatic grasping forceps.

Zerdoner and Zajdela in 1998 used a combination of self-cutting screws and a repositioning forceps which has butterfly-like shaped prongs. First, two screws fastened on each side of the fracture line and then the reposition forceps is placed over the heads of the screws

The use of reduction forceps has known for many years in general trauma surgery, orthopaedic surgery and plastic surgery. In OMF surgery traditionally the dental occlusion was used to perform and check reduction of mandibular fractures. Notwithstanding this historical background, reduction forceps can be used in mandibular fractures as in any other fracture as long as there is sufficient space and as long as the fracture surface permits stable placement and withstands the forces created by such a forceps.

George concluded by saying that the use of IMF for the management of angle fractures of the mandible is unnecessary provided there is a skilled assistant present to help manually reduce the fracture site for plating.

Other fracture reduction methods such as traction wire or elastic tension on screws are simple to use in the area of anterior mandibular fractures. This method may cause a gap at the lingual side of the fracture as an effect of the resultant of the force exerted on the protruding screws (Ellis & Tharanon 1992, Cillo & Ellis 2007). This lingual gap can occur as well when using reduction forceps but as they grab inside the bone and when they are positioned at a distance of the fractures site of at least 8-10 mm this should be prevented ( Žerdoner & Žajdela 1998, Rogers & Sargent 2000, Kluszynski et al. 2015). Choi et al., (2003) even suggested that tips of repositioning forceps should be placed at least 12mm from each site of the fracture line in case of symphyseal and parasymphyseal fractures. In the mandibular body fractures, adequate stress pattern at the lingual site found at least 16 mm from the fracture line.

Traditional wiring is a potential source of ‘needlestick’ type injury in the contaminated environment of the oral cavity and represents a health risk to surgeons and assistants. Conventional elastic or rubber rings may be difficult to place, and large numbers often need to be applied to prevent displacement of the fragments from the wafer. Such elastic exerts a pull of approximately 250-500 g per ‘turn’ depending on its specification (De Genova et al., 1985), and multiple ‘turns’ around anchorage points increase the firmness of retention. It is resilient, and even if displaced by stretching, tends to return the segments to their correct location in the splint or wafer, whereas wire ties once pulled, or if inadequately tightened become passive and allow free movement. The chain is relatively expensive, but the ease of use and the rapidity and flexibility with which it can be applied and retrieved save valuable operating time. It can be cold sterilised if desired and is designed to retain its physical properties within the oral environment. On removal, unlike wires and elastic rings which easily break or tear and may be difficult to retrieve from the mouth or wound, it can be recovered in one strip and, as an additional check, the holes can. The force exerted by elastic modules is known to decrease over time (Wong, 1976) and the strength decays by 17-70% (Hershey & Reynolds, 1975; Brooks & Hershey, 1976) over the first 24 h, depending on the precise material and format of the chain, and whether it has been pre-stretched (Young & Sandrik, 1979; Brantley et al., 1979).

Symphysis, parasymphysis, and mandibular body can be differentiated from other regions of the mandible because of a ridge of compact cortical bone (alveolar ridge) located on its cranial aspect that allows for tooth-bearing. This horizontally oriented tooth-bearing portion then becomes vertically oriented to form its articulation with the cranium. The change in orientation occurs at the mandibular angle, and subsequently, the mandible continues as the mandibular body and condyle as it travels Along the entire course of the mandible are muscle attachments that place dynamic internal forces on the mandible. These muscles can be divided into two primary groups: muscles of mastication and suprahyoid muscles. The muscles of mastication include the medial and lateral pterygoids, the temporalis, and masseter muscles. Together these muscles aid in chewing by generating forces along the posterior aspects of the mandible (angle, ramus, coronoid process).

Furthermore, two of the muscles of mastication, the medial pterygoid and masseter muscles, combine to form the pterygomasseteric sling, which attaches at the mandibular angle. Conversely, the suprahyoid group (digastric, stylohyoid, mylohyoid, and geniohyoid) functions, in part, to depress the anterior mandible by applying forces to the mandibular symphysis, parasymphysis, and a portion of the body. Together, these muscle attachments act to place dynamic vectors of force on the mandible that, when in continuity, allow for proper mandibular function, but when in discontinuity, as occurs with mandible fractures, can potentially disrupt adequate fracture healing. Works of literature looking at the relationship between the timing of surgery and subsequent outcomes have demonstrated no difference in infectious nonunion complications between treatment within or after three days status postinjury but did find that complication because of technical errors increased after this time. As a result, the authors commented that if surgery was to commence or more days after the injury, a technically accurate surgery by the surgeon is necessitated to overcome factors such as tissue oedema and inflammation. In cases where a delay in treatment is necessary, consideration should be given for temporarily closed fixation to reduce fracture mobility and patient pain.

Treating mandibular fractures involves providing the optimal environment for bony healing to occur: adequate blood supply, immobilisation, and proper alignment of fracture segments. Plate length is generally determined to allow for the placement of more than one screw on either side of the fracture to nullify the dynamic forces that act on the mandible. In ideal conditions, three screws are placed on either side of the fracture segments to allow for assurance against inadequate stabilisation, with screws placed at least several millimetres from the fracture site. Proper plate thickness determined by the forces required to stabilise fractured bone segments. Options for stabilisation can be divided into either load-sharing fixation or load-bearing fixation. Mandible that would only require monocortical plates to allow for stable fixation along the symphysis, parasymphysis, and angle of the mandible. These regions have subsequently been called Champy’s lines of tension, with the superior portion of lines also referred to as the tension band of the mandible.

A study by George Dimitroulis in 2002 in which he gave Postreduction orthopantomograph scoring criteria. These radiographs were assessed using a score of from 1 to 3. A score of 3 given to radiologic evidence of an accurate anatomic reduction in the fracture site. A score of 2 assigned to reduced fractures that were slightly displaced but had a satisfactory occlusion. The lowest score of 1 was for poorly decreasing fractures that required a second operation to correct the poor alignment and unacceptable occlusion.

The assessment of fracture healing is becoming more and more critical because new approaches used in traumatology. The biology of fracture healing is a complex biological process that follows specific regenerative patterns and involves changes in the expression of several thousand genes. Although there is still much to be learned to comprehend the pathways of bone regeneration fully, the overall paths of both the anatomical and biochemical events have thoroughly investigated. These efforts have provided a general understanding of how fracture healing occurs. Following the initial trauma, bone heals by either direct intramembranous or indirect fracture healing, which consists of both intramembranous and endochondral bone formation. The most common pathway is incidental healing, since direct bone healing requires an anatomical reduction and rigidly stable conditions, commonly only obtained by open reduction and internal fixation. However, when such conditions achieved, the direct healing cascade allows the bone structure to immediately regenerate anatomical lamellar bone and the Haversian systems without any remodelling steps necessary It is helpful to think of the bone healing process in a stepwise fashion, even though in reality there is an excellent overlap among these different stages. In general, it is possible to divide this process into an initial hematoma formation step, followed by inflammation, proliferation and differentiation, and eventually ossification and remodelling. Shortly after a fracture occurs, the vascular injury to periosteum, endosteum, and the surrounding so tissue causes hypoperfusion in the adjacent area. The coagulation cascade is activated which leads to the formation of a hematoma rich in platelets and macrophages. Cytokines from these macrophages initiate an inflammatory response, including increased blood ow and vascular permeability at the fracture site. Mechanical and molecular signals dictate what happens subsequently. Fracture healing can occur either through direct intramembranous healing or more commonly through indirect or secondary healing. The significant difference between these two pathways is that direct healing requires absolute stability and lack of interfragmentary motion, whereas, in secondary healing, the presence of interfragmentary motion at the site of fracture creates relative stability. In secondary healing, this mechanical stimulation in addition to the activity of the inflammatory molecules leads to the formation of fracture callus followed by woven bone which eventually remodelled to lamellar bone. At a molecular level secretion of numerous cytokines and proinflammatory factors coordinate these complex pathways. Tumour necrosis factor-𝛼 (TNF-𝛼), interleukin-1 (IL-1), IL-6, IL-11, and IL-18 are responsible for the initial inflammatory response. ReRevascularisationan essential component of bone healing, s achieved through different molecular pathways requiring either angiopoietin or vascular endothelial growth factors (VEGF) ).EGF’s importance in the process of bone repair hahas shown any studies involving animal models. S the collagen matrix invaded blood vessels, the mineralisation the so callus occurs through the activity of osteoblasts resulting in hard callus, which is remodelled into lamellar bone. Inhibition of angiogenesis in rats with closed femoral fractures completely prevented healing and resulted in atrophic non-unions

If the gap between bone ends is less than 0.01 mm and interfragmentary strain is less than 2%, the fracture unites by so-called contact healing. Under these conditions, cutting cones are formed at the ends of the osteons closest to the fracture site. The tips of the cutting cones consist of osteoclasts which cross the fracture line, generating longitudinal cavities at a rate of 50–100 μm/day. The primary bone structure is then gradually replaced by longitudinal revascularized osteons carrying osteoprogenitor cells which differentiate into osteoblasts and produce lamellar bone on each surface of the gap. This lamellar bone, however, is laid down perpendicular to the long axis and is mechanically weak. This initial process takes approximately 3 and eight weeks, after which a secondary remodelling resembling the contact healing cascade with cutting cones takes place. Although not as extensive as endochondral remodelling, this phase is necessary to fully restore the anatomical and biomechanical properties of the boneDirect bone healing first described in radiographs after complete anatomical repositioning and stable fixation. Its features are lack of callus formation and disappearance of the fracture lines. Danis (1949) described this as soudure autogène (autogenous welding). Callus-free, direct bone healing requires what is often called “stability by interfragmentary compression” (Steinemann, 1983).

Contact healing of the bone means healing of the fracture line after stable anatomical repositioning, with perfect interfragmentary contact and without the possibility for any cellular or vascular ingrowth. Cutting cones can cross this interface from one fragment to the other by remodelling the Haversian canal. Haversian canal remodelling is the primary mechanism for restoration of the internal architecture of compact bone. Contact healing takes place over the whole fracture line after perfect anatomical reduction, osteosynthesis, and mechanical rest. Contact healing is only seen directly beneath the miniplate. Gap healing takes place in stable or “quiet” gaps with a width more significant than the 200-μm osteonal diameter. In- growth of vessels and mesenchymal cells starts after surgery. Osteoblasts deposit osteoid on the fragment ends without osteoclastic resorption. The gaps are filled exclusively with primarily formed, transversely oriented lamellar bone. Replacement usually completed within 4 to 6 weeks. In the second stage, the transversely oriented bone lamellae replaced by axially orientated osteons, a process which referred to as Haversian remodelling. After ten weeks the fracture is replaced by newly reconstructed cortical bone. Gap healing is seen, for example, on the inner side of the mandible after miniplate osteosynthesis. Gap healing plays a vital role in direct bone healing. Gaps are far more extensive than contact areas. Contact areas, on the other hand, are essential for stabilisation by interfragmentary friction. Contact areas protect the gaps against deformation. Gap healing was seen far from the plate.

Ultrasound is unable to penetrate cortical bone, but there is evidence that it can detect callus formation before radiographic changes are visible. Moed conducted a larger prospective study which showed that ultrasound findings at 6 and nine weeks have a 97% positive predictive value (95% CI: 0.9-1) and 100% sensitivity in determining fracture healing in patients with acute tibial fractures treated with locked intramedullary nailing [52]. Time to the determination of healing was also shorter using ultrasound (6.5 weeks) compared to a nineteen-week average of radiographic data (𝑃 < 0.001). Ultrasound has additional advantages over other imaging modalities including lower cost, no ionising radiation exposure, and bisnoninvasive. HHowever, ts use and interpretation of findings are thought to be highly dependent on operator’s expertise. Furthermore, thick layers of such tissue can obscure an adequate view of bones with ultrasound. CT scans showed some advantages over radiographs in early detection of fracture healing in radius fractures. A limitation of CT is a beam-hardening artefact from internal and external fixation. Ultrasound is unable to penetrate cortical bone, but there is evidence that it can detect callus formation before radiographic changes are visible. The author concluded that When used to evaluate hindfoot arthrodeses, plain radiographs may be misleading. CT provides a more accurate assessment of the healing, and we have devised a new system to quantitate the fusion mass. In seven cases MDCT led to operative treatment while on X-ray the treatment plan was undecided. Bhattacharyya et al. examined the evaluation of tibial fracture union by CT scan and determined an ICC of 0.89, which even indicates excellent agreement. These studies suggest that using CT scan has high inter-observer reliability, better than the inter-observer reliability of plain radiography. According to the authors, interobserver reliability of MDCT scan is not higher than conventional radiographs for determining non-union. However, an MDCT scan did lead to a more invasive approach in equivocal cases.MDCT provides superior diagnostic accuracy to panoramic radiography and has been to characterise mandibular fracture locations with greater certainty. Because of the high soft tissue contrast, MDCT may reveal the relation of a bone fragment and adjacent muscle, needing and the existence of some foreign bodies in traumatic injury. So in cases of severe injuries of soft tissue, an MDCT is mandatory. A 33% CT fusion ratio threshold could accurately discriminate between clinical stability and instability By 36 weeks, healing was essentially complete according to both modalities, although there still were small gaps in the callus detectable on computed tomography but not on plain films. Authors concluded by stating that Computed tomography may be of value in the evaluation of fractures of long bones in those cases in which clinical examination and plain radiographs fail to give adequate information as to the status of healing. A study in 2007 used a PET scan with Fluoride ion in the assessment of bone healing in rats with femur fractures. Fluoride ion deposits in regions of the bone with high osteoblastic activity and high rate of turnover, such as endosteal and periosteal surfaces. They concluded that Fluoride ion PET could potentially play an essential part in the assessment of fracture healing given its ability to quantitatively monitor metabolic activity and provide an objective evaluation of fracture repair. 18F-fluoride PET imaging, which is an indicator of osteoblastic activity in vivo, can identify fracture nonunions early point and may have a role in the assessment of longitudinal fracture healing. PET scans using 18F-FDG were not helpful in differentiating metabolic activity between successful and delayed bone healing. Moghaddam et al. conducted a prospective cohort study to assess changes in serum concentrations of a few serologic markers in normal and delayed fracture healing. He was able to show significantly lower levels of tartrate-resistant acid phosphatase 5b (TRACP 5b) and C-terminal cross-linking telopeptide of type I collagen (CTX) in patients who developed non-unions compared to patients with normal healing. TRACP 5b is a direct marker of osteoclastic activity and bone resorption, while CTX is an indirect measure of osteoclastic activity by reflecting collagen degradation Secretion of many of the cytokines and biologic markers is also influenced by other factors. For example, systemic levels of TGF-𝛽 were found to vary based on smoking status, age, gender, diabetes mellitus, and chronic alcohol abuse at different time points. On plain radiography, it is difficult to distinguish between desired callus formation and pseudoarthrosis. Therefore CT is an essential objective diagnostic tool to determine healing status. Computed tomography (CT) is superior to plain radiography in the assessment of union and visualising of fracture in the presence of abundant callus or overlaying cast. There have been studies to test the accuracy and efficacy of computed tomography in the assessment of fracture union in clinical settings. Bhattacharyya et al. showed that computed tomography has 100% sensitivity for detecting nonunion; however, it’s limited by a low specificity of 62%. Three of the 35 patients in the study were misdiagnosed as tibial nonunion based on CT scan findings but were healed when the fracture was visualised during surgical intervention. Seventy-seven studies involved the use of clinical criteria to define fracture union. The most common clinical standards were the absence of pain or tenderness (49%), the lack of pain or tenderness on palpation or physical examination (39%), and the ability to bear weight. The most common radiographic definitions of fracture-healing in studies involving the use of plain radiographs were bridging of the fracture site by callus, trabeculae, or bone (53%); bridging of the fracture site at three cortices (27%), and obliteration of the fracture line or cortical continuity (18%). Most commonly reported criteria for radiographic assessment of fracture union according to the location of the fracture. Two studies did not involve the use of plain radiographs to assess fracture-healing. In the study in which computed, tomography was used, the union defined as bridging of >25% of the cross-sectional area at the fracture site. In the study in which ultrasound was used, a union defined as the complete disappearance of the intramedullary nail on ultrasound imaging at six weeks or progressive removal of the intramedullary nail with the formation of periosteal callus between six and nine weeks following treatment.

Plain radiography is the most common way in which fracture union assessed, and a substantial number of studies defined fracture union by radiographic parameters alone. Hammer et al. combined cortical continuity, the loss of a visible fracture line, and callus size in a scale to assess fracture- healing radiographically but found conventional radiographic examination challenging to correlate with fracture stability and could not conclusively determine the state of the union. In animal models, cortical continuity is a good predictor of fracture torsional strength, whereas the callus area is not. Also, clinicians cannot reliably determine the concentration of a healing fracture by a single set of radiographs and are unable to rank radiographs of healing fractures in order of strength. Therefore, we rely heavily on a radiographic method without proven validity for predicting bone strength in the assessment of fracture union.

Computed tomography eliminates the problem of overlapping structures and allows axial sections to limit imaging of bone bridging CT directly in the evaluation. However, in fractures treated with external fixators, CT can determine the increasing amount of callus formation, which indicates favourable fracture healing . in this study CT was correlated with fractionmetry in the assessment of fracture healing of tibial shaft fractures. The amount of callus was serially quantified and correlated with fractionmetry . after axial imaging, two equal slices at two points of the fracture were analysed 1, 6, 12, 18 weeks after stabilisation. The principal fracture line was selected for longitudinal measurement because maximum callus formation was expected at that level . a rectangular region of interact within 200-2000 and 700-2000 HU. The callus was measured automatically after marking the area of interest. Multiple measurements after repositioning the limb were performed to evaluate the short-term precision of the method. The new formation of callus indicated stability of the fracture healing on CT after 12 weeks. Although the amount of callus is only an indirect indicator of fracture union, CT was able to assess the fracture stability. The ROC analysis showed that an increase > 50% of callus formation after 12 weeks indicated stability with a sensitivity of 100% and a specificity of 83 %.

In the study in which computed, tomography used, the union was defined as bridging of >25% of the cross-sectional area at the fracture site. In the study in which ultrasound was used, the union was defined as the complete disappearance of the intramedullary nail on ultrasound imaging at six weeks or progressive removal of the intramedullary nail with the formation of periosteal callus between six and nine weeks following treatment. One hundred and twenty-three studies proved to be eligible. Union was defined by a combination of clinical and radiographic criteria in 62% of the reviews, from radiographic criteria only in 37%, and by clinical tests just 1%. Twelve different approaches were used to define fracture union clinically, and the most common rule was the absence of pain or tenderness at the fracture site during weight-bearing. In studies involving the use of plain radiographs, eleven different approaches were used to define fracture union, and the most common criterion was bridging of the fracture site.

Several factors predispose a patient to be nonunion of bones, including mechanical instability, loss of blood supply, and infections. Bone production has been estimated to occur within 15 weeks after osteotomy; complete bone healing may take 3–6 months or even longer. The reliability of conventional radiographs for the determination of fracture healing has questioned in previous studies. CT has been used for the monitoring of bone production and fracture healing, and its advantages over conventional radiography in early fracture healing have reported. To avoid stairstep artefacts in CT, the isotropic or near-isotropic resolution is necessary and has become attractive with the introduction of MDCT scanners. Experimental studies have shown that MDCT reduces stairstep artefacts with multiplanar reconstruction when compared with single-detector CT From these data, authors reconstructed thin axial slices with 50% overlap to yield near-isotropic voxels (almost identical to the length of the voxel in the x, y, and z-axes) for further processing. This allows 2D and 3D reconstructions with a resolution similar to the source images that form the basis of good-quality multiplanar reconstructions (MPRs). MPRs reconstructed from contiguous axial slices ranging from 1.5 to 3 mm thick, depending on the anatomic region. Orthogonal to the fracture or arthrodesis plane. Fusion of osseous structures was scored with a semiquantitative approach for both techniques (MDCT, digital radiography) as complete (c), partial (p), and no bone bridging (0). Definitions of fusion were as follows: full, bone bridges with no gap; partial, some bone bridges with gaps between; and no bridging, no osseous bridges. Two musculoskeletal radiologists assessed all MDCT examinations and digital radiographs in a consensus interpretation.

Conventional tomography has been used for many years for the evaluation of the postoperative spine after posterior spinal arthrodesis. Thin-section tomography had good correlation with surgery in the diagnosis of pseudarthrosis after fusions for scoliosis and was superior to anteroposterior, lateral, and oblique radiography. However, conventional tomography also suffers from certain disadvantages. The standard linear movement is mechanically easy to produce but will give rise to rather thick tomographic sections and a short blurring path (the length of the tomographic section). If thinner parts are required, more complex movements are needed. Because conventional tomography does not entirely blur out all distracting structures, the inherent lack of sharpness of the traditional tomographic image could assess bone bridges problematic. Thinner sections of conventional tomography, in particular, suffer from greater background blur. In dentistry radiology, the technique is called orthopantomography and is still widely used, although for practical reasons other conventional tomographic methods have been mostly replaced by CT, and the commercial availability of traditional tomography scanners has decreased substantially.

CT eliminates the blurring problem of conventional tomography and increases the perceptibility of fracture healing. MDCT has the advantage that the X-ray beam passes through the whole volume of the object in a short time, and, when using isotropic or near-isotropic resolution, volumetric imaging with the reconstruction of arbitrary MPRs is useful. The CT technique also has an essential impact on the severity of artefacts, with high milliampere-second and high peak kilovoltage settings leading to the reduction of artefacts. With MDCT and low pitches, the high tube current is achieved, which is the basis for good-quality MPRs. With 16-MDCT scanners, the trend is first to reconstruct an overlapping secondary raw data set and then to obtain MPRs of axial, coronal, or arbitrarily angulated sections with a predefined section width. Bone bridges are high-contrast objects and are reliably detected on 1.5- to 3-mm-thick MPRs, depending on the anatomic region, with thicker MPRs preferable for the lumbar spine and somewhat thinner MPRs superior for the hand region

The use of computed tomography (CT) scanning technology improves anatomical visualisation by offering three-dimensional reconstructions of bony architecture and has contributed to the assessment of healing in certain fractures. However, CT scans and plain radiographs detect mineralised bone formation, which is the late manifestation of the fracture healing process.

Moreover, CT scans demonstrate low specificity in the diagnosis of fracture nonunions in long bones

MRI has not been useful in evaluating delayed fracture healing in the long bones. Scintigraphic studies with 99mTc-labeled compounds have also been used to assess carpal bones; however, multiple studies have demonstrated no significant differences in tracer uptake between tibia fractures that usually heal and those that form nonunions.

In our study 48 patients were divided equally into two groups: group A (study group) and group B (control group) based on reduction method to compare the accuracy of reduction and bone healing of mandible fractures using elastic guided reduction v/s bone reduction forceps. Where both groups were evaluated based on sex, type of mandible fracture, confined or nonconfined , intermaxillary fixation method , type of reduction method used , postoperative opg scores , and ct scan assessment scores after 6 weeks for lingual , buccal cortices and medullary bone , calculation of fusion percentage using ct scan , and development of any late post-op complication .

So based on sex, fracture types, intermaxillary fixation method, late post-op complications post-op opg assessment scoring, ct scan assessment scoring fusion percentage results were nil significant (P <0.5). Whereas based on the confined or non-confined type of fractures results were substantial Which denotes that use of bone holding forceps for non confined type of fracture (P 0.011)


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