Calcium phosphate ceramics as bone graft substitutes in filling bone tumor defects

Background:

Synthetic bio-inert materials are currently used as an alternative to autogenous bone graft. Calcium hydroxyapatite (HA) and Beta tri-calcium phosphate (β-TCP), which belong to the calcium phosphate ceramics group, are biocompatible and osteo-conductive. The purpose of this study is to analyse the use of HA and β-TCP in their ceramic forms as a bone graft substitute in filling bone voids after curettage of benign bone tumors.

Materials and Methods:

Twenty-four patients in the age range of 3.5-55 years (mean 14.3 years) having benign bone tumors with bone defects were filled with bone graft substitute following curettage. In 20 patients bone defects were filled with block/granules of HA ceramic and in four with β-TCP. Fibular strut graft was packed with HA in four patients. The patients were followed up for an average of 18 months (range 12-36 months).

Results:

The functional status of the patients at follow-up was evaluated and compared with preoperative functional status. Early incorporation of graft substitutes became evident radiologically between 6 and 10 weeks (Stage I). Complete incorporation (Stage III) was observed in an average of nine months (6-18 months). Clinical healing was observed before radiological healing. The average time taken to return to preoperative function was 14 weeks. There was no recurrence of lesion or growth retardation.

Conclusion:

Calcium hydroxyapatite and β-TCP are excellent bone graft substitutes for autogenous bone graft in filling voids after curettage of benign bone tumors.     

Repair of long bone defects with demineralized bone matrix and autogenous bone composite

Background:

Repair of diaphyseal bone defects is a challenging problem for orthopedic surgeons. In large bone defects the quantity of harvested autogenous bone may not be sufficient to fill the gap and then the use of synthetic or allogenic grafts along with autogenous bone becomes mandatory to achieve compact filling. Finding the optimal graft mixture for treatment of large diaphyseal defects is an important goal in contemporary orthopedics and this was the main focus of this study. The aim of this study is to investigate the efficacy of demineralized bone matrix (DBM) and autogenous cancellous bone (ACB) graft composite in a rabbit bilateral ulna segmental defect model.

Materials and Methods:

Twenty-seven adult female rabbits were divided into five groups. A two-centimeter piece of long bone on the midshaft of the ulna was osteotomized and removed from the rabbits’ forearms. In group 1 (n=7) the defects were treated with ACB, in group 2 (n=7) with DBM, and in group 3 (n=7) with ACB and DBM in the ratio of 1:1. Groups 4 and 5, with three rabbits in each group, were the negative and positive controls, respectively. Twelve weeks after implantation the rabbits were sacrificed and union was evaluated with radiograph (Faxitron), dual-energy x-ray absorptiometry (DEXA), and histological methods (decalcified sectioning).

Results:

Union rates and the volume of new bone in the different groups were as follows: group 1 - 92.8% union and 78.6% new bone; group 2 - 72.2% union and 63.6% new bone; and group 3 - 100% union and 100% new bone. DEXA results (bone mineral density [BMD]) were as follows: group 1 - 0.164 g/cm², group 2 - 0.138 g/cm², and group 3 - 0.194 g/cm².

Conclusions:

DBM serves as a graft extender or enhancer for autogenous graft and decreases the need of autogenous bone graft in the treatment of bone defects. In this study, the DBM and ACB composite facilitated the healing process. The union rate was better with the combination than with the use of any one of these grafts alone.     

Curettage of benign bone tumors and tumor like lesions: A retrospective analysis

Background:

Curettage is one of the most common treatment options for benign lytic bone tumors and tumor like lesions. The resultant defect is usually filled. We report our outcome curettage of benign bone tumors and tumor like lesions without filling the cavity.

Materials and Methods:

We retrospectively studied 42 patients (28 males and 14 females) with benign bone tumors who had undergone curettage without grafting or filling of the defect by any other bone graft substitute. The age of the patients ranged from 14 to 66 years. The most common histological diagnosis was that of giant cell tumor followed by simple bone cyst, aneurysamal bone cyst, enchondroma, fibrous dysplasia, chondromyxoid fibroma, and chondroblastoma and giant cell reparative granuloma. Of the 15 giant cell tumors, 4 were radiographic grade 1 lesions, 8 were grade 2 and 3 grade 3. The mean maximum diameter of the cysts was 5.1 (range 1.1-9 cm) cm and the mean volume of the lesions was 34.89 cm³ (range 0.94-194.52 cm³). The plain radiographs of the part before and after curettage were reviewed to establish the size of the initial defect and the rate of reconstitution, filling and remodeling of the bone defect. Patients were reviewed every 3 monthly for a minimum period of 2 years.

Results:

Most of the bone defects completely reconstituted to a normal appearance while the rest filled partially. Two patients had preoperative and three had postoperative fractures. All the fractures healed uneventfully. Local recurrence occurred in three patients with giant cell tumor who were then reoperated. All other patients had unrestricted activities of daily living after surgery. The rate of bone reconstitution, risk of subsequent fracture or the incidence of complications was related to the size of the cyst/tumor at diagnosis. The benign cystic bone lesions with volume greater than approximately 70 cm³ were found to have higher incidence of complications.

Conclusion:

This study demonstrates the natural healing ability of bone without filling with bone grafts or bone graft substitutes. In selected sizes and locations of the benign lytic tumors and tumor like lesions extended curettage alone can be sufficient.     

Percutaneous autologus bone marrow injection in the treatment of delayed or nonunion

Background:

Bone marrow is a source of osteoprogenitor cells that are key elements in the process of bone formation and fracture healing. The purpose of the study was to ascertain the osteogenic potential of autologous bone marrow grafting and its effectiveness in the management of delayed union and nonunion.

Materials and Methods:

Twenty-eight patients with delayed union and three with nonunion of fracture of the long bones were treated with this procedure. Of these 28 cases, two patients had fracture shaft femur, one had fracture shaft ulna and 25 patients had tibial shaft fractures. The average time duration between procedure and injury was 25 weeks (range 14-53 weeks). The bone marrow was aspirated from the anterior iliac crest and injected percutaneously at the fracture site. The procedure was carried out as an outpatient procedure. All but five cases required one injection of bone marrow.

Results:

Union was observed in 23 cases. The average time of healing after the procedure was 12 weeks (range 7-18 weeks).

Conclusion:

The technique of percutaneous autologous bone marrow injection provides a very safe, easy and reliable alternative to open bone grafting, especially for early intervention in fracture healing process.     

The GDF5 mutant BB-1 enhances the bone formation induced by an injectable,poly(l-lactide-co-glycolide) acid (PLGA) fiber-reinforced,brushite-forming cement in a sheep defect model of lumbar osteopenia

Background Context

Targeted delivery of osteoinductive bone morphogenetic proteins (eg, GDF5) in bioresorbable calcium phosphate cement (CPC), potentially suitable for vertebroplasty and kyphoplasty of osteoporotic vertebral fractures, may be required to counteract augmented local bone catabolism and to support complete bone regeneration. The biologically optimized GDF5 mutant BB-1 may represent an attractive drug candidate for this purpose.

Evaluation of a biodegradable graft substitute in rabbit bone defect model

Objective:

To evaluate a new biodegradable copolymer calcium sulfate/poly amino acid (CS/PAA) as a graft substitute for the repair of the surgically created cancellous bone defects in rabbits and its biological properties in vivo.

Materials and Methods:

Cancellous bone defects were created by drilling holes in the unilateral lateral aspect of the femoral condyle of New Zealand white rabbits. Three groups were assigned: Group A rabbits were grafted with 80% CS/PAA and group B rabbits were grafted with 95% CS/PAA as two treatment groups; group C was sham-operation control group. To study the osteogenic capability in vivo, specimens were harvested at 4, 8, 12, and 16 weeks after implantation and were evaluated by gross assessment, X-ray, histological examination, and histomorphometry. In order to identify the molecular mechanism of bone defect repair, the expression of bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) was detected using Western blot at 4 weeks.

Results:

Group A and group B showed more vigorous and rapid repair leading to regeneration of cancellous bone than sham-operation control group on gross observation, radiology, and histomorphometry. There was no significant difference between groups A and B. Morphological observation and histological examination showed that the copolymers degraded in sync with the new bone formation process. The expression of BMP-2 and VEGF in implantation groups was higher than that in control group by western blot.

Conclusion:

These findings demonstrated that the novel biodegradable copolymers can repair large areas of cancellous bone defects. With its controllable degradation rate, it suggests that CS/PAA may be a series of useful therapeutic substitute for bone defects.     

Osseointegration by bone morphogenetic protein-2 and transforming growth factor beta2 coated titanium implants in femora of New Zealand white rabbits

Background:

Intramembranous bone formation is essential in uncemented joint replacement to provide a mechanical anchorage of the implant. Since the discovery of bone morphogenic proteins (BMPs) by Urist in 1965, many studies have been conducted to show the influence of growth factors on implant ingrowth. In this study, the influence of bone morphogenetic protein-2 (rhBMP-2) and transforming growth factor β2 (TGF-β2) on implant osseointegration was investigated.

Materials and Methods:

Thirty-two titanium cylinders were implanted into the femoral condyles of both hind legs of New Zealand White Rabbits. Four experimental groups were investigated: controls without coating, a macromolecular copolymer + covalently bound BMP-2, adsorbed BMP-2, and absorbed BMP-2+TGF-β2. All samples were analyzed by ex vivo high-resolution micro-computed-tomography after 28 days of healing. Bone volume per total volume (BV/TV) was recorded around each implant. Afterward, all samples were biomechanically tested in a pull-out setup.

Results:

The highest BV/TV ratio was seen in the BMP-2 group, followed by the BMP-2+TGF-β2 group in high-resolution micro-computed-tomography. These groups were significantly different compared to the control group (P < 0.05). Copolymer+BMP-2 showed no significant difference in comparison to controls. In the pull-out setup, all groups showed higher fixation strength compared to the control group; these differences were not significant.

Conclusions:

No differences between BMP-2 alone and a combination of BMP-2+TGF-β2 could be seen in the present study. However, the results of this study confirm the results of other studies that a coating with growth factors is able to enhance bone implant ingrowth. This may be of importance in defect situations during revision surgery to support the implant ingrowth and implant anchorage.     

Reconstruction of post-traumatic long bone defect with vascularised free fibula: A series of 28 cases

Introduction:

The severe long bone defects usually follow high-energy trauma and are often associated with a significant soft-tissue injury. The goal of management of these open long bone defects is to provide stable fixation with maintenance of limb length and soft-tissue coverage. The purpose of this article is to present the clinic-radiological outcome, complications and treatment of post-traumatic long bone defect with vascularised fibula transfer.

Materials and Methods:

Retrospective records of 28 patients were analysed who presented with post-traumatic long bone defects and in whom reconstruction with vascularised free fibula was done. Demographic data were recorded and clinical and radiological assessment was done.

Results:

Out of 28 patients in whom vascularised free fibula transfer was carried out three flaps were lost while non-union occur in three patients. Three patients developed a stress fracture of transferred free fibula in the post-operative period. Few of the patients experienced some problems in the donor leg; however, all of them improved in subsequent follow-up.

Discussion:

It is clearly evident from this study that timing of surgery plays an important role in the micro-vascular reconstruction in trauma cases. All the complication like flap loss, non-union or delayed union occur in patients in whom reconstruction was delayed.

Conclusion:

The free vascularised fibula graft is a viable method for the reconstruction of skeletal defects of more than 6 cm, especially in cases of scarred and avascular recipient sites or in patients with combined bone and soft-tissue defects. Results are best when the reconstruction is done within 1 week of trauma.KEY WORDS: Long bone defect, post-traumatic, vascularised free fibula     

Hydroxyapatite crystals as a bone graft substitute in benign lytic lesions of bone

Background:

Bone grafts are required to fill a cavity created after curettage of benign lytic lesions of the bone. To avoid the problems associated at donor site with autologous bone graft, we require allograft or bone graft substitutes. We evaluated the healing of lytic lesions after hydroxyapatite (HA) grafting by serial radiographs.

Materials and Methods:

Forty cases of benign lytic lesions of bone were managed by simple curettage and grafting using HA blocks. Commercially available HA of bovine origin (Surgiwear Ltd., Shahjahanpur, India) was used for this purpose. Mean duration of followup was 34.8 months (range 12–84 months). Mean patient age was 19.05 years (range 3–55 years). Radiological staging of graft incorporation was done as per criteria of Irwin et al. 2001.

Results:

In our series, two cases were in stage I. A total of 11 cases were in stage II and 27 were in stage III. Graft incorporation was radiologically complete by 15 months. Clinical recovery was observed before radiological healing. The average time taken to return to preoperative function was 3 months. Recurrence was observed in giant cell tumor (n = 3) and chondromyxoid fibroma (n = 1). There was no incidence of graft rejection, collapse, growth plate disturbances or antigenic response.

Conclusions:

We conclude that calcium HA is biologically acceptable bone graft substitute in the management of benign lytic lesions of bone.     

Open reduction and internal fixation of clavicular nonunions with allograft bone substitute

Background:

Biologic augmentation with allograft has shown equivalent healing rates to autograft in several nonunion models. No literature exists clearly demonstrating this in the clavicle. The purpose of this study was to evaluate the healing and complication rates of clavicle nonunions treated solely with open reduction and internal fixation (ORIF) and allograft.

Materials and Methods:

Nineteen clavicle nonunions treated with ORIF and allograft were evaluated retrospectively to assess healing rates and complications based on clinical symptoms and radiographic findings.

Results:

For the 19 patients included and treated with ORIF and allograft, clinical follow-up averaged 15 months. Seven patients were smokers. Although complete radiographic healing was achieved in only 68% of patients, clinical success occurred in 16 (84%) patients who demonstrated full range of motion and strength without pain. The three patients who did not demonstrate full radiographic healing were completely pain free. Five patients experienced complications (26%). Two underwent hardware removal due to persistent irritation after union. Three had a persistent painful nonunion. Each of these three patients was a smoker (P=0.08). Two proceeded to union after revision fixation. The other had hardware failure, which was removed, with a persistent nonunion and did not wish any further treatment.

Conclusion:

ORIF with allograft bone substitute is an acceptable treatment alternative to iliac crest bone graft for clavicle nonunions. However, we did not demonstrate equivalent healing rates to published results utilizing autograft. Smokers were identified to have a trend toward higher failure rates with ORIF augmented with allograft and therefore these patients may be better served by augmenting fixation with autograft.

Level of Evidence:

IV; retrospective comparative study.     

Bone healing after median sternotomy: A comparison of two hemostatic devices

Background

Bone wax is traditionally used as part of surgical procedures to prevent bleeding from exposed spongy bone. It is an effective hemostatic device which creates a physical barrier. Unfortunately it interferes with subsequent bone healing and increases the risk of infection in experimental studies. Recently, a water-soluble, synthetic, hemostatic compound (Ostene^®) was introduced to serve the same purpose as bone wax without hampering bone healing. This study aims to compare sternal healing after application of either bone wax or Ostene^®.

Methods

Twenty-four pigs were randomized into one of three treatment groups: Ostene^®, bone wax or no hemostatic treatment (control). Each animal was subjected to midline sternotomy. Either Ostene^® or bone wax was applied to the spongy bone surfaces until local hemostasis was ensured. The control group received no hemostatic treatment. The wound was left open for 60 min before closing to simulate conditions alike those of cardiac surgery. All sterni were harvested 6 weeks after intervention.Bone density and the area of the bone defect were determined with peripheral quantitative CT-scanning; bone healing was displayed with plain X-ray and chronic inflammation was histologically assessed.

Results

Both CT-scanning and plain X-ray disclosed that bone healing was significantly impaired in the bone wax group (p < 0.01) compared with the other two groups, and the former group had significantly more chronic inflammation (p < 0.01) than the two latter.

Conclusion

Bone wax inhibits bone healing and induces chronic inflammation in a porcine model. Ostene^® treated animals displayed bone healing characteristics and inflammatory reactions similar to those of the control group without application of a hemostatic agent.

     

Augmentation of bone healing in delayed and atrophic nonunion of fractures of long bones by partially decalcified bone allograft (decal bone)

Background:

Autograft from iliac crest is considered as gold standard for augmentation of bone healing in delayed and nonunion of fractures. Bone demineralized with 0.6N hydrochloric acid has shown to retain its osteoinductive capacity. We report the outcome of partially decalcified bone allograft (decal bone) in the treatment of delayed union and atrophic nonunions of bones.

Materials and Methods:

Twenty patients with clinicoradiological diagnosis of delayed union or atrophic nonunion of long bone fractures were included in this retrospective study. Patients at extreme of ages (<18 years and >60 years), pathological fractures, metabolic bone diseases, infected nonunion, hypertrophic nonunion and those having systemic illness like diabetes mellitus and on drugs that impair fracture healing were excluded from the study. Decal bone was prepared in the bone bank and maintained in department of orthopedics. Allografting was done in 20 patients of delayed union (9/20) and atrophic nonunion (11/20) of long bone fractures with mean age of 34 years (range 18–55 years). The bones involved were humerus (8/20), tibia (7/20) and femur (5/20). Fourteen patients underwent treatment in the form of internal fixation and allografting and six patients were operated with osteoperiosteal allografting.

Results:

Nineteen patients achieved union in mean time of 14.9 weeks range (range 8–20 weeks). Eight patients had serous discharge from the operative site that subsided in 11 days (range 4–21 days). One patient had pus discharge that required repeat debridement and antibiotics for 6 weeks. The fracture healed in 16 weeks.

Conclusion:

The partially decalcified bone allograft is an effective modality for augmentation of bone healing without complication associated with autograft like donor site morbidity, increased blood loss and increase in the surgical time.     

Long bone reconstruction using multilevel lengthening of bone defect fragments

Purpose

This paper presents experimental findings to substantiate the use of multilevel bone fragment lengthening for managing extensive long bone defects caused by diverse aetiologies and shows its clinical introduction which could provide a solution for the problem of reducing the total treatment time.

Methods

Both experimental and clinical multilevel lengthening to bridge bone defect gaps was performed with the use of the Ilizarov method only.

Results

The experimental findings and clinical outcomes showed that multilevel defect fragment lengthening could provide sufficient bone formation and reduction of the total osteosynthesis time in one stage as compared to traditional Ilizarov bone transport. The method of multilevel regeneration enabled management of critical-size defects that measured on average 13.5 ± 0.7 cm in 78 patients.

Conclusions

The experimental and clinical results proved the efficiency of the Ilizarov non-free multilevel bone plasty that can be recommended for practical use.     

Experimental posterolateral spinal fusion with beta tricalcium phosphate ceramic and bone marrow aspirate composite graft

Background:

Beta tricalcium phosphate is commonly used in metaphyseal defects but its use in posterolateral spinal fusion remains controversial. There are very few published animal studies in which use of beta tricalcium phosphate has been evaluated in the posterolateral lumbar arthrodesis model. Hence we conducted a study to evaluate the potential of composite graft of beta tricalcium phosphate and bone marrow aspirate in comparison to autologous bone graft, when used for posterolateral spinal fusion.

Materials and Methods:

Single level posterolateral lumbar fusion was performed in 40 adult male Indian rabbits, which were assigned randomly into one of the four groups based on graft materials implanted; a) 3 gm beta tricalcium phosphate plus 3 ml bone marrow aspirate (Group I); b) 3 ml bone marrow aspirate alone (Group II); c) 3 gm beta tricalcium phosphate (Group III) and d) 3 gm autologous bone graft (Group IV). Each group had 10 rabbits. Half of the rabbits were sacrificed by injecting Phenobarbitone intraperitoneally after eight weeks and the remaining after 24 weeks, and were evaluated for fusion by X-rays, computed tomography (CT) scans, manual palpation test and histology.

Results:

Beta tricalcium phosphate used with bone marrow aspirate produced best results when compared to other groups (P =.0001). When beta tricalcium phosphate was used alone, fusion rates were better as compared to fusion achieved with autologous iliac crest bone graft though statistically not significant (P =0.07). Autologous bone graft showed signs of new bone formation. However, the rate of new bone formation was comparatively slow.

Conclusion:

Composite graft of beta tricalcium phosphate and bone marrow aspirate can be used as an alternative to autologous iliac crest bone graft.     

Autograft reconstructions for bone defects in primary total knee replacement in severe varus knees

Background:

Large posteromedial defects encountered in severe varus knees during primary total knee arthroplasty can be treated by cementoplasty, structural bone grafts or metallic wedges. The option is selected depending upon the size of the defect. We studied the outcome of autograft (structural and impaction bone grafting) reconstruction of medial tibial bone defects encountered during primary total knee replacement in severe varus knees.

Materials and Methods:

Out of 675 primary varus knees operated, bone defects in proximal tibia were encountered in 54 knees. Posteromedial defects involving 25-40% of the tibial condyle cut surface and measuring more than 5 mm in depth were grafted using a structural graft obtained from cut distal femur or proximal tibia in 48 knees. For larger, peripheral uncontained vertical defects in six cases, measuring >25 mm in depth and involving >40% cut surface of proximal tibial condyle, impaction bone grafting with a mesh support was used.

Results:

Bone grafts incorporated in 54 knees in 6 months. There was no graft collapse or stress fractures, loosening or nonunion. The average followup period was 7.8 years (range 5-10 years). We observed an average postoperative increase in the Knee Society Score from 40 to 90 points. There was improvement in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores in terms of pain, stiffness and physical function during activities of daily living.

Conclusion:

Bone grafting for defects in primary total knee is justified as it is biological, available then and is cost effective besides preserving bone stock for future revisions. Structural grafts should be used in defects >5 mm deep and involving 25-40% of the cut proximal tibial condyle surface. For larger peripheral vertical defects, impaction bone grafting contained in a mesh should be done.     

Coracoid bone graft osteolysis after Latarjet procedure: A comparison study between two screws standard technique vs mini-plate fixation

Aims:

One of the reason for Latarjet procedure failure may be coracoid graft osteolysis. In this study, we aimed to understand if a better compression between the coracoid process and the glenoid, using a mini-plate fixation during the Latarjet procedure, could reduce the amount of coracoid graft osteolysis.

Materials and Methods:

A computed tomography scan analysis of 26 prospectively followed-up patients was conducted after modified Latarjet procedure using mini-plate fixation technique to determine both the location and the amount of coracoid graft osteolysis in them. We then compared our current results with results from that of our previous study without using mini-plate fixation to determine if there is any statistical significant difference in terms of corcacoid bone graft osteolysis between the two surgical techniques.

Results:

The most relevant osteolysis was represented by the superficial part of the proximal coracoid, whereas the deep part of the proximal coracoid graft is least involved in osteolysis and has best bone healing. The current study showed a significant difference only for the deep part of the distal coracoid with our previous study (P < 0.01).

Discussion:

To our knowledge, there are no studies in literature that show the causes of coracoid bone graft osteolysis after Latarjet procedure.

Conclusion:

Our study suggests that there is a significant difference only for the deep part of the distal coracoid in terms of osteolysis. At clinical examination, this difference did not correspond with any clinical findings.

Level of Evidence:

Level 4.

Clinical Relevance:

Prospective case series, Treatment study.     

Bone formation in rabbit's leg muscle after autologous transplantation of bone marrow-derived mesenchymal stem cells expressing human bone morphogenic protein-2

Background:

To test whether autologous transplantation of bone marrow-derived mesenchymal stem cells (BM-MSCs) expressing human bone morphogenic protein-2 (hBMP-2) can produce bone in rabbit leg muscles.

Materials and Methods:

MSCs were isolated from BM of the iliac crest of rabbits and then infected with lentiviral vectors (LVs) bearing hBMP-2 and green fluorescent protein under the control of the cytomegalovirus (immediate early promoter). Differentiation of transduced MSCs to osteoblasts in vitro was evaluated with an alkaline phosphatase activity assay and immuohistochemistry against osteoblast specific markers. MSCs expressing hBMP-2 were placed in an absorbable gelatin sponge, which was then transplanted into the gastrocnemius of rabbits from which MSCs were isolated. Bone formation was examined by X-ray and histological analysis.

Results:

LVs efficiently mediated hBMP-2 gene expression in rabbit BM-MSCs. Ectopic expression of hBMP in these MSCs induced osteoblastic differentiation in vitro. Bone was formed after the MSCs expressing hBMP-2 were transplanted into rabbit muscles.

Conclusion:

Ectopic expression of hBMP-2 in rabbit MSCs induces them to differentiate into osteoblasts in vitro and to form a bone in vivo.     

Decal bone matrix as a local antibiotic delivery vehicle in a MRSA-infected bone model: An experimental study

Background:

Polymethyl methacrylate (PMMA) antibiotic beads though have proved their utility as a local antibiotic delivery system, however, there are limitations. Decalcified bone matrix (DBM) as a vehicle of antibiotics can serve the purpose, provided a minimum inhibitory concentration is sustained. Healing of the defect and avoiding the second surgery is another advantage. We studied the DBM as the delivery vehicle for vancomycin in controlling the methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis as well as healing of the cavity simultaneously in an experimental study.

Materials and Methods:

An in vitro study was conducted to optimize vancomycin impregnation in the DBM. For the in vivo study, a unicortical defect was created in the metaphysis of the distal femur in 18 rabbits. After contaminating the defect with MRSA, rabbits were divided into three groups. Group I (eight limbs) received no graft. Defects in group II (11 limbs) were filled with plain DBM chips and in group III (14 limbs), cavities were implanted with vancomycin-impregnated decal bone chips. Rabbits were assessed by clinical, radiological, histological, gross examination and bacterial load assay. High Performance Liquid Chromatography HPLC analysis of vancomycin in group III was done to assess the concentration in DBM chips.

Results:

In group I, the infection persisted throughout the period of the study. Group II showed the fulminated infection at the grafted site with DBM chips sequestrating out. Vancomycin-impregnated decal chips in group III did not show any sign of infection and eventually incorporated. The bacterial load study showed a progressive load change and HPLC revealed an effective antibiotic concentration up to 3 weeks in both in vitro and in vivo.

Conclusion:

Decal bone chips were effective as the local antibiotic delivery vehicle in preventing the MRSA osteomyelitis model. It eluted vancomycin significantly and the graft uptake was also excellent. Allogeneic decal grafts eliminated the need for second surgery and acted as an excellent delivery vehicle for antibiotics.     

Spectrum of primary bone grafting in cranio maxillofacial trauma at a tertiary care centre in India

Background:

In past several years, traumas following road traffic accidents and other causes have increased, owing to an increase in mechanization and pace of life. These patients frequently have complicated injuries involving soft tissue and the craniofacial skeleton. Assessment of bony injuries and loss of portions of facial skeleton and their management has proved to be a challenge to the reconstructive surgeon.

Aims:

Primary bone grafting of craniofacial skeletal injuries provides an opportunity for one stage correction of bony defects. The varied spectrum of primary bone grafts for management of craniomaxillofacial injuries are evaluated in this study.

Materials and Methods:

Patients with a history of acute trauma resulting in facial skeletal injuries with or without bone loss were included in the study. Primary bone grafting was undertaken in situations requiring contour correction, replacement of skeletal losses and for rigid fixation of fracture segments. Olecranon, Iliac crest, ribs, Vascularized as well as nonvascularized outer table calvarial grafts and nonvascularized inner table calvarial grafts were used in this study.

Results:

Sixty two patients of craniomaxillofacial injury following trauma requiring primary bone grafting were considered in this study. Fifty seven percent of patients (n=32) required primary bone grafting for replacement of bone loss while bone grafting for contour correction was done in twenty three patients. The parietal calvaria overlying the non-dominant hemisphere was used as a source of bone graft in forty-nine patients. Nearly ninety-two percent of the patients were satisfied with the results of primary bone grafting.

Conclusions:

Functional and aesthetic assessment of each of these patients, managed with primary bone grafting revealed a low rate of disabilities and high percentage of satisfaction in this study.     

Monitoring of fracture healing by electrical conduction: A new diagnostic procedure

Background:

Electrical stimulation of fractures has been reported to enhance fracture healing. X-rays are normally used to assess union of fractures. Electrical conduction is not tried as a tool to study fracture healing. The current study focuses on electrical conduction as a diagnostic tool to assess fracture healing and new bone formation. The aim was to find if electrical resistance across the fracture can be used as a tool to study fracture healing which can be verified with simultaneous radiographs.

Materials and Methods:

A prospective study was conducted where 12 open fractures of tibia, including two with bone defects were evaluated. They were debrided and four-carbon ring Ilizarov external fixators were applied. Their healing was followed with clinical assessment and periodical X-rays till the endpoint of fracture union and then the rings were removed. In addition, all these cases also had application of electrical voltage in the range of 0.1–1.0 V DC in 0.1 V increments, across the two wires on either side of fracture. The output current was recorded by an ammeter connected in series. Resistance calculated for various voltages was plotted as a graph for the period of fracture treatment and the characteristics were studied. This graph was compared with the appearance of new bone in the X-rays.

Results:

In all cases, when the above graph stabilized, in the consecutive recordings, the X-rays showed healing (bridging callus) matching the curve and the patient was able to load the limb. The time of stabilization of this graph for a specific voltage was different in individual cases. However, for a given case, the resistance characteristics were the same for the entire voltage range of 0.1–1.0 V.

Conclusion:

If the resistance versus day curve stabilizes on the consecutive recordings, we can predict that the fracture is in the process of healing. This stabilization period also matched the patients’ ability to comfortably load the limb and also the radiographs which showed bridging callus (healing). If this is used as a positive criterion for fracture healing in future, the radiation exposure by X-rays shall be less.