Injectable calcium phosphate in the treatment of distal radial fractures

Improved cytocompatibility and antibacterial properties of zinc-substituted brushite bone cement based on β-tricalcium phosphate

For bone replacement materials, osteoconductive, osteoinductive, and osteogenic properties are desired. The bacterial resistance and the need for new antibacterial strategies stand among the most challenging tasks of the modern medicine. In this work, brushite cements based on powders of Zinc (Zn) (1.4 wt%) substituted tricalcium phosphate (β-TCP) and non-substituted β-TCP were prepared and investigated. Their initial and final phase composition, time of setting, morphology, pH evolution, and compressive strength are reported. After soaking for 60 days in physiological solution, the cements transformed into a mixture of brushite and hydroxyapatite. Antibacterial activity of the cements against Enterococcus faecium, Escherichia coli, and Pseudomonas aeruginosa bacteria strains was attested. The absence of cytotoxicity of cements was proved for murine fibroblast NCTC L929 cells. Moreover, the cell viability on the β-TCP cement containing Zn²⁺ ions was 10% higher compared to the β-TCP cement without zinc. The developed cements are perspective for applications in orthopedics and traumatology.

Clinical impact of high-profile animal-based research reported in the UK national press

OBJECTIVES

We evaluated animal-based biomedical 'breakthroughs' reported in the UK national press in 1995 (25 years prior to the conclusion of this study). Based on evidence of overspeculative reporting of biomedical research in other areas (eg, press releases and scientific papers), we specifically examined animal research in the media, asking, 'In a given year, what proportion of animal research "breakthroughs"' published in the UK national press had translated, more than 20 years later, to approved interventions?'

METHODS

We searched the Nexis media database (LexisNexis.com) for animal-based biomedical reports in the UK national press. The only restrictions were that the intervention should be specific, such as a named drug, gene, biomedical pathway, to facilitate follow-up, and that there should be claims of some clinical promise.

MAIN OUTCOME MEASURES

Were any interventions approved for human use? If so, when and by which agency? If not, why, and how far did development proceed? Were any other, directly related interventions approved? Did any of the reports overstate human relevance?

RESULTS

Overspeculation and exaggeration of human relevance was evident in all the articles examined. Of 27 unique published 'breakthroughs', only one had clearly resulted in human benefit. Twenty were classified as failures, three were inconclusive and three were partially successful.

CONCLUSIONS

The results of animal-based preclinical research studies are commonly overstated in media reports, to prematurely imply often-imminent 'breakthroughs' relevant to human medicine.

Adipose-Derived Stem Cells in Bone Tissue Engineering: Useful Tools with New Applications

Adipose stem cells (ASCs) are a crucial element in bone tissue engineering (BTE). They are easy to harvest and isolate, and they are available in significative quantities, thus offering a feasible and valid alternative to other sources of mesenchymal stem cells (MSCs), like bone marrow. Together with an advantageous proliferative and differentiative profile, they also offer a high paracrine activity through the secretion of several bioactive molecules (such as growth factors and miRNAs) via a sustained exosomal release which can exert efficient conditioning on the surrounding microenvironment. BTE relies on three key elements: (1) scaffold, (2) osteoprogenitor cells, and (3) bioactive factors. These elements have been thoroughly investigated over the years. The use of ASCs has offered significative new advancements in the efficacy of each of these elements. Notably, the phenotypic study of ASCs allowed discovering cell subpopulations, which have enhanced osteogenic and vasculogenic capacity. ASCs favored a better vascularization and integration of the scaffolds, while improvements in scaffolds' materials and design tried to exploit the osteogenic features of ASCs, thus reducing the need for external bioactive factors. At the same time, ASCs proved to be an incredible source of bioactive, proosteogenic factors that are released through their abundant exosome secretion. ASC exosomes can exert significant paracrine effects in the surroundings, even in the absence of the primary cells. These paracrine signals recruit progenitor cells from the host tissues and enhance regeneration. In this review, we will focus on the recent discoveries which have involved the use of ASCs in BTE. In particular, we are going to analyze the different ASCs' subpopulations, the interaction between ASCs and scaffolds, and the bioactive factors which are secreted by ASCs or can induce their osteogenic commitment. All these advancements are ultimately intended for a faster translational and clinical application of BTE.

Radiographic and Histological Analysis of a Synthetic Bone Graft Substitute Eluting Gentamicin in the Treatment of Chronic Osteomyelitis

Introduction: Managing chronic osteomyelitis can be challenging and attention to the osseous dead-space left following resection is an important part of successful treatment. We assess radiographic bone healing following implantation of a gentamicin-eluting synthetic bone graft substitute (gBGS) used at chronic osteomyelitis (cOM) resection. We also describe histological carrier changes from biopsies in nine cases at various time points. Methods: This was a retrospective review of a prospectively collected consecutive series of 163 patients with Cierny-Mader Type III or IV cOM who underwent single-stage excision, insertion of gBGS and definitive soft-tissue closure or coverage. Bone defect filling was assessed radiographically using serial radiographs. Nine patients had subsequent surgery, not related to infection recurrence, allowing opportunistic biopsy between 19 days and two years after implantation. Results: Infection was eradicated in 95.7% with a single procedure. 138 patients had adequate radiographs for assessment with minimum one-year follow-up (mean 1.7 years, range 1.0-4.7 years). Mean void-filling at final follow-up was 73.8%. There was significantly higher void-filling in metaphyseal compared to diaphyseal voids (mean 79.0% versus 65.6%; p=0.017) and in cases with good initial interdigitation of the carrier (mean 77.3% versus 68.7%; p=0.021). Bone formation continued for more than two years in almost two-thirds of patients studied (24/38; 63.2%). Histology revealed active biomaterial remodelling. It was osteoconductive with osteoblast recruitment, leading to the formation of osteoid, then woven and lamellar bone on the substrate's surface. Immunohistochemistry demonstrated osteocyte specific markers, dentine matrix protein-1 and podoplanin within the newly formed bone. Conclusion: This antibiotic-loaded biomaterial is effective in managing dead-space in surgically treated cOM with a low infection recurrence rate (4.3%) and good mean bone void-filling (73.8%). The radiographic resolution of the bone defect is associated with bone formation, as supported by histological analysis.

What happens to the posterior comminution in extra-articular fractures of the distal radius treated with volar locking plates?

Extra-articular fractures of the distal radius with posterior displacement are typically treated with volar locking plates. However, this fixation method does not address the posterior comminution, which seems to have no impact on the final result. The purpose of this study was to determine the fate of the posterior comminution. This was a retrospective study of 22 patients over 50 years old with a distal radius fracture. A preoperative computed tomography (CT) scan was performed to evaluate the comminution. All fractures were fixed with a volar locking plate. All patients underwent a bone density scan. Patients were reviewed at 6 months post-operative to determine their clinical, radiological and functional outcomes. The CT scan was performed again to determine the fate of the comminution. At 6 months post-operative, 82% of patients had an oval metaphyseal defect. The mean volume of this defect was 1.86 mL. The contents of this defect most closely resembled fat. There was no statistical link between the defect's volume and the various parameters studied. On the other hand, the defect's density was positively related to the functional outcome and negatively related to the patients' body mass index. Because of the compression experienced by the cancellous bone, a distal metaphyseal defect often persists after consolidation in dorsally displaced distal radius fractures. The posterior comminution is ultimately of little consequence.

Is calcium phosphate augmentation a viable option for osteoporotic hip fractures?

The use of calcium phosphate bone cement has been described to allow for retention of reduction. Therefore, we evaluated whether augmentation with resorbable calcium phosphate could improve fracture stability in osteoporotic hip fractures. The results showed that augmentation with calcium phosphate cement significantly improved the stability of intertrochanteric fractures.

INTRODUCTION

The aim with this study was to measure whether augmentation with resorbable calcium phosphate cement could improve fracture stability in osteoporotic hip fractures.

METHODS

We retrospectively reviewed 82 patients who underwent closed reduction and internal fixation with proximal femoral nail (PFN) for unstable intertrochanteric fractures between 2014 and 2017. In 42 of 82 patients, patients were treated with a PFN alone (group I). These patients were compared with 40 patients for whom the same device combined with calcium phosphate cement for augmentation was used (group II). Questionnaire surveys or telephone interviews were conducted and patients completed a self-report Harris hip score (HHS) and visual analog scale (VAS) scores. Radiographic outcomes including mean sliding distance of screw, femoral shortening, and varus collapse were compared. Postoperative complications were compared.

RESULTS

Clinical outcomes at 6 months after surgery were equivalent in both groups. Screw sliding, femoral shortening, and varus collapse were all significantly reduced in the cemented group at the last follow-up (p < 0.001, p = 0.005, p < 0.001, respectively). A total of 9 (21%) complications occurred in group I. In contrast, 2 (5%) complications were seen in group II (p = 0.029).

CONCLUSIONS

Augmentation with calcium phosphate cement significantly improved the stability of intertrochanteric fractures fixed with a PFN and reduced overall failure rates. We believe augmentation with resorbable calcium phosphate cement for osteoporotic hip fractures is a reasonable option in selected patients.

Nanomedicine for safe healing of bone trauma: Opportunities and challenges

Historically, high-energy extremity injuries resulting in significant soft-tissue trauma and bone loss were often deemed unsalvageable and treated with primary amputation. With improved soft-tissue coverage and nerve repair techniques, these injuries now present new challenges in limb-salvage surgery. High-energy extremity trauma is pre-disposed to delayed or unpredictable bony healing and high rates of infection, depending on the integrity of the soft-tissue envelope. Furthermore, orthopedic trauma surgeons are often faced with the challenge of stabilizing and repairing large bony defects while promoting an optimal environment to prevent infection and aid bony healing. During the last decade, nanomedicine has demonstrated substantial potential in addressing the two major issues intrinsic to orthopedic traumas (i.e., high infection risk and low bony reconstruction) through combatting bacterial infection and accelerating/increasing the effectiveness of the bone-healing process. This review presents an overview and discusses recent challenges and opportunities to address major orthopedic trauma through nanomedical approaches.

Dorsal Plating of Unstable Distal Radius Fractures Using a Bio-Absorbable Plating System and Bone Substitute

This study reports the results of open reduction and internal fixation of 26 unstable, intraarticular, dorsally displaced fractures of the distal radius using a bio-absorbable dorsal distal radius (Reunite) plate and calcium phosphate (Biobon) bone substitute. The bio-absorbable plate has the advantage of being low profile, easily contourable and angularly stable. In the majority of cases, this plate produces functional results comparable with metal plates. The Gartland and Werley score was excellent or good in 21 patients. The theoretical advantage over metal plates is in eliminating the need to remove the plate and hence the need for a second operation if implant-related extensor tenosynovitis occurs. Inflammatory tissue reaction to the degradation products of the plate is a potential concern, although the co-polymer ratio used in this plate appears to have reduced the severity of this reaction, which was seen in two patients in this series. The reduction was lost in five patients with severe dorsal comminution. Following this experience, we do not recommend this plating system for fractures with a metaphyseal gap of greater than 7 mm following reduction.

A prospective study of percutaneous balloon kyphoplasty with calcium phosphate cement in traumatic vertebral fractures: 10-year results

STUDY DESIGN

This is a prospective study to investigate the clinical and radiological results 10 years after percutaneous balloon kyphoplasty and cement augmentation with calcium phosphate cement (CPC) in traumatic vertebral fractures type A.

OBJECTIVES

Evaluation of a 10-year follow-up with radiological and computed tomography results, calculated by 2 independent radiologists, VAS, Roland Morris score, Oswestry Disability Index (ODI) score and Denis work scale and clinical examination in patients with traumatic compression fractures type A, who were treated with a balloon kyphoplasty with CPC (Calcibon™ from Biomed).

METHODS

In this study, we evaluated 21 patients (8 female and 13 male) clinically and radiologically 10 years postoperative and compared them with the same group of 28 patients we operated between August 2002 and August 2003 for traumatic vertebral fractures type A with balloon kyphoplasty and CPC. Over the 10 years, 7 patients were lost to follow-up. 3 of them were not clinically impaired but did not want to participate in the study and 4 patients were untraceable. All 21 patients underwent standard X-ray (standing) and a CT. We measured the volume of the cement, the resorption the last 10 years and the disc height in the CT and the segmental and vertebral kyphosis angle in the X-ray and compared them with the X-ray (standing) and CT done directly postoperatively. To assess the pain level we used the VAS, ODI score, Roland Morris score and the Denis work scale and compared them with the same scores we recorded in the past.

RESULTS

The VAS score demonstrated an increase over time from a mean of 1 (0-5) at the 2-year follow-up to 2.3 (0-8) at the 10-year follow-up. The Roland Morris disability score also increased over time from 2 (0-8) 2 years postoperative to a mean of 3.6 (0-18) at the 10 years follow-up. We recognized no complications and no reoperations were necessary. We recognized an increase of the median value for the vertebral kyphosis angle about 1° (0°-4°) (p < 0.0001). The median value of the disc height diminution over the 10 years was 0.7 mm (0-3.9) (p < 0.0001). For the anterior wall of the fractured VB the decrease of the median value was about 1 mm (0-3) (p < 0.0001) and for the posterior wall it was 0 mm (0-2) (p < 0.0039). So the beck index decreased from 0.80 (0.65-0.97) to 0.77 (0.62-0.97) at the 10-year follow-up, which means a decrease of the median value of 0.03 (0-0.07) (p < 0.0039). We noticed a median value for the cement volume of 4.2 cc (2.0-8.6) postoperative and at the 10-year follow-up of 3.2 cc (1.3-7.8), which means a resorption of the cement volume about 22.9 % (0.8-55.5 %) (p < 0.0001).

CONCLUSIONS

In our 10-year follow-up, we did not recognize any high loss of correction of the vertebral and segmental kyphosis angle. We also did not recognize a high diminution of the disc height without degeneration of the disc over the last 10 years. There was a partial resorption of the cement but not as much as we expected with variable bone formation. In summary, the long follow-up about 10 years of kyphoplasty show us very good clinical and radiological results and in our opinion we consider this to be a treatment option for traumatic selected vertebral type A fractures also in young patients.

The use of bone cement in difficult distal radius fractures

BACKGROUND

The lack of structural support remains a challenge in the treatment of comminuted distal radius fractures. Calcium phosphate and calcium sulfate bone cement has been used in other fracture locations in addition to fixation and has been shown to allow for retention of reduction in difficult cases.

METHODS

A case-control retrospective review of 34 consecutive distal radius fractures treated with surgery was performed with the patients classified by Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification. Complications and postoperative radiographs were evaluated.

RESULTS

Cement was used in the most difficult cases. Radial height was retained in both groups. Volar tilt was significantly better in the cement group. There were no significant differences between the case and control groups for any complication. No complications related to the use of the cement were found.

CONCLUSIONS

The use of bone cement as an adjunct to fixation of distal radius fractures seems to include minimal risks and may afford a technical advantage in maintaining reduction during surgery for difficult fractures. Since there is an aspect of fracture difficulty that we cannot control for by using radiographic assessment alone, cement may provide an advantage over fixation without cement, despite similar outcomes. Bone cement can be part of the "tool box" for difficult distal radius fractures. Further study is necessary to define the technical advantages and limitations of each particular cement product.

Injectable hydrogel incorporating with nanoyarn for bone regeneration

Traditional bone grafting requires an open surgical approach to the graft application sites with the attendant complications of a large surgical scar, increased pain and a longer post-operative recovery. To overcome these limitations, there is a great need for the development of better bone graft substitutes. In this study, we developed a novel injectable system which was a biomimetic bone substitute consisted of Poly (L-lactide-co-ε-caprolactone) (P(LLA-CL)) nanoyarns suspended in type I collagen hydrogel (Col). A dynamic liquid support system was employed to fabricate continuous P(LLA-CL) nanoyarns. The electrospun long nanoyarns were chopped into short nanoyarns before they were incorporated into Col. The result of rheological evaluation showed that the mechanical property of Col was enhanced after the nanoyarns were incorporated into it. The mixture of Col and nanoyarn could be smoothly injected out of 16 gauge needle. In vitro study showed that human mesenchymal stem cells (hMSCs) proliferated well on Col with nanoyarns. Alkaline phosphatase activity and osteocalcin expression of hMSCs on hydrogel with nanoyarns were much higher than those on control groups. This study highlights the potential of using a novel injectable biomimetic scaffold for bone regeneration.

The 100 top-cited classic papers in hand surgery

The number of citations that a published article has received reflects the importance that paper has on that area of practice. In hand surgery, it is unknown which journal articles are cited most frequently. The purpose of this study was to identify and analyze the characteristics of the top 100 papers in the field of hand surgery. The 100 most cited papers were identified in the following journals; the Journal of Hand Surgery (American volume), the Journal of Hand Surgery (European volume), the Journal of Hand Surgery (British and European volume), The Scandinavian Journal of Plastic and Reconstructive and Hand Surgery, Hand Clinics, and the Journal of Plastic Surgery and Hand Surgery. The articles were ranked in order of the number of citations received. These classic 100 papers were analyzed for article type, their journal distribution, as well as geographic and institutional origin.

Fixation of distal radius fractures in adults: a review

In patients for whom function is a priority, anatomic reduction and stable fixation are prerequisites for good outcomes. Several therapeutic options exist, including orthopedic treatment and internal fixation with pins (intra- and extrafocal), external fixation which may or may not bridge the wrist, and different internal fixation techniques with dorsal or palmar plates using or not, locking screws. Arthroscopy may be necessary in case of articular fracture. In the presence of significant metaphyseal bone defects, filling of the comminution with phosphocalcic cements provides better graft stability. The level of evidence is too low to allow recommending one type of fixation for one type of fracture; and different fixation options to achieve stable reduction exist, each with its own specific complications. With the new generations of palmar plate, secondary displacement is becoming a thing of the past.

[Anatomy and biomechanics of distal radius fractures: a literature review]

Distal radius fractures remain the most frequent fractures in the adult. Associated osteoporosis increases morbidity risk (secondary displacement is the most frequent) and mortality risk (in women older than 60). Severity of the fracture and functional results are related to the bone mineral density. Anatomy has been recently revisited with better description of palmar and dorsal aspects in order to avoid material-related complications. Standard postero-anterior, lateral and oblique radiographs of the wrist show the fracture and the displacement. CT scan is warranted if conventional X-rays are insufficient to show the articular surface. The involvement of the metaphysis (comminution), the epiphysis (articular fracture) and the ulna is different in each case and each fracture is an association of these three components. The MEU classification describes the fracture with sufficient inter-observer reliability and intra-observer reproducibility to be a useful tool for treatment and prognosis. The PAF system is used to propose the most appropriate treatment for each patient. Anatomical reduction and stable fixation are associated with good functional results but in high demanding patients.

In vitro comparative study of white and dark polycaprolactone trifumarate in situ cross-linkable scaffolds seeded with rat bone marrow stromal cells

OBJECTIVE

Dark poly(caprolactone) trifumarate is a successful candidate for use as a bone tissue engineering scaffold. Recently, a white polymeric scaffold was developed that shows a shorter synthesis time and is more convenient for tissue-staining work. This is an in vitro comparative study of both the white and dark scaffolds.

METHODS

Both white and dark poly(caprolactone) trifumarate macromers were characterized via Fourier transform infrared spectroscopy before being chemically cross-linked and molded into disc-shaped scaffolds. Biodegradability was assessed by percentage weight loss on days 7, 14, 28, 42 and 56 (n = 5) after immersion in 10% serum-supplemented medium or distilled water. Static cell seeding was employed in which isolated and characterized rat bone marrow stromal cells were seeded directly onto the scaffold surface. Seeded scaffolds were subjected to a series of biochemical assays and scanning electron microscopy at specified time intervals for up to 28 days of incubation.

RESULTS

The degradation of the white scaffold was significantly lower compared with the dark scaffold but was within the acceptable time range for bone-healing processes. The deoxyribonucleic acid and collagen contents increased up to day 28 with no significant difference between the two scaffolds, but the glycosaminoglycan content was slightly higher in the white scaffold throughout 14 days of incubation. Scanning electron microscopy at day 1 [corrected] revealed cellular growth and attachment.

CONCLUSIONS

There was no cell growth advantage between the two forms, but the white scaffold had a slower biodegradability rate, suggesting that the newly synthesized poly(caprolactone) trifumarate is more suitable for use as a bone tissue engineering scaffold.

An osteoconductive, osteoinductive, and osteogenic tissue-engineered product for trauma and orthopaedic surgery: how far are we?

The management of large bone defects due to trauma, degenerative disease, congenital deformities, and tumor resection remains a complex issue for the orthopaedic reconstructive surgeons. The requirement is for an ideal bone replacement which is osteoconductive, osteoinductive, and osteogenic. Autologous bone grafts are still considered the gold standard for reconstruction of bone defects, but donor site morbidity and size limitations are major concern. The use of bioartificial bone tissues may help to overcome these problems. The reconstruction of large volume defects remains a challenge despite the success of reconstruction of small-to-moderate-sized bone defects using engineered bone tissues. The aim of this paper is to understand the principles of tissue engineering of bone and its clinical applications in reconstructive surgery.

Calcium phosphate bone cement: a possible alternative to autologous bone graft. A radiological and biomechanical comparison in rat tibial bone

BACKGROUND

Donor site morbidity is a problem after autologous bone transplantation. An injectable CaP bone cement indicates properties similar to bone.

MATERIALS AND METHODS

Double osteotomies on rat tibias were performed. The intercalated segments were avascular (10), vascular (10), or avascular with Norian SRS(®) CaP bone cement replacing cancellous bone (10). Controls were non-operated contralateral tibias (15). All osteotomies were stabilised with an intra-medullary nail. After 8 weeks, all rats were killed. The harvested tibias were compared using X-ray, DEXA scanning, microCT scans and a biomechanical torsional test.

RESULTS

No difference in healing processes or biomechanical results has been found between the avascular bone graft, vascular bone graft and CaP bone cement groups.

CONCLUSION

The injectable CaP bone cement confirms its similarities to bone, implying that it can be used as an adjunct to secure bone fragments and as a possible alternative to autologous bone transplantation in clinical practice.

Effect of calcium phosphate bone cement augmentation on volar plate fixation of unstable distal radial fractures in the elderly

BACKGROUND

Calcium phosphate bone cement increases the stability of implant-bone constructs in patients with an osteoporotic fracture. The purpose of this randomized study was to determine whether augmentation of volar locking plate fixation with calcium phosphate bone cement has any benefit over volar locking plate fixation alone in patients older than sixty-five years of age who have an unstable distal radial fracture.

METHODS

Forty-eight patients (fifty unstable distal radial fractures) were recruited for this study. The mean patient age was seventy-three years. Surgical procedures were randomized between volar locking plate fixation alone (Group 1) and volar locking plate fixation with injection of calcium phosphate bone cement (Group 2). The patients were assessed clinically at three and twelve months postoperatively. Clinical assessments included determinations of grip strength, wrist motion, wrist pain, modified Mayo wrist scores, and Disabilities of the Arm, Shoulder and Hand (DASH) scores. Radiographic evaluations were performed immediately postoperatively and at one year following surgery. The adequacy of the reduction was assessed by measuring radial inclination, volar angulation, and ulnar variance.

RESULTS

The two groups were comparable with regard to age, sex, fracture type, injury mechanism, and bone mineral density. No significant differences were observed between the groups with regard to the clinical outcomes at the three or twelve-month follow-up examination. No significant intergroup differences in radiographic outcomes were observed immediately after surgery or at the one-year follow-up visit. Furthermore, no complication-related differences were observed, and there were no nonunions.

CONCLUSIONS

Augmentation of metaphyseal defects with calcium phosphate bone cement after volar locking plate fixation offered no benefit over volar locking plate fixation alone in elderly patients with an unstable distal radial fracture.

Bone substitutes in the Netherlands - a systematic literature review

Autologous bone grafting is currently considered as the gold standard to restore bone defects. However, clinical benefit is not guaranteed and there is an associated 8-39% complication rate. This has resulted in the development of alternative (synthetic) bone substitutes. The aim of this systematic literature review was to provide a comprehensive overview of literature data of bone substitutes registered in the Netherlands for use in trauma and orthopedic surgery. Brand names of selected products were used as search terms in three available databases: Embase, PubMed and Cochrane. Manuscripts written in English, German or Dutch that reported on structural, biological or biomechanical properties of the pure product or on its use in trauma and orthopedic surgery were included. The primary search resulted in 475 manuscripts from PubMed, 653 from Embase and 10 from Cochrane. Of these, 218 met the final inclusion criteria. Of each product, structural, biological and biomechanical characteristics as well as their clinical indications in trauma and orthopedic surgery are provided. All included products possess osteoconductive properties but differ in resorption time and biomechanical properties. They have been used for a wide range of clinical applications; however, the overall level of clinical evidence is low. The requirements of an optimal bone substitute are related to the size and location of the defect. Calcium phosphate grafts have been used for most trauma and orthopedic surgery procedures. Calcium sulphates were mainly used to restore bone defects after tumour resection surgery but offer minimal structural support. Bioactive glass remains a potential alternative; however, its use has only been studied to a limited extent.

Single-stage implantation in the atrophic alveolar ridge of the mandible with the Norian skeletal repair system

Dental implants have played a part in rehabilitation of the jaws for more than 40 years, but in some cases they alone are inadequate because of extreme alveolar resorption. Correction may necessitate a two-stage procedure with additional interventions. We have made a preliminary study of the use of the Norian skeletal repair system (SRS), a carbonated calcium phosphate bone cement used to augment the alveolar ridge as a single-stage procedure, with the placement of implants. Ten edentulous patients with insufficient vertical bone in the interforaminal area were treated. After a horizontal osteotomy and crestal mobilisation of the alveolar ridge, implants were placed through the crestal part and fixed in the basal part of the mandible. Norian SRS was used to fill the gap created. The prostheses were inserted 3 months later. Forty implants were inserted. The follow up period was 60 months, and no fractures or dislocations developed. One of the implants was lost and there was one wound dehiscence, but no surgical intervention or revision was necessary. Radiographs showed good consolidation of the bony structure in all cases. We have described a reliable, single-stage procedure for augmentation and implantation in a highly atrophic alveolar crest. A 98% survival is comparable with those of other techniques. Further clinical trials are necessary to replicate these promising results.

Calcium phosphate-based composites as injectable bone substitute materials

A major weakness of current orthopedic implant materials, for instance sintered hydroxyapatite (HA), is that they exist as a hardened form, requiring the surgeon to fit the surgical site around an implant to the desired shape. This can cause an increase in bone loss, trauma to the surrounding tissue, and longer surgical time. A convenient alternative to harden bone filling materials are injectable bone substitutes (IBS). In this article, recent progress in the development and application of calcium phosphate (CP)-based composites use as IBS is reviewed. CP materials have been used widely for bone replacement because of their similarity to the mineral component of bone. The main limitation of bulk CP materials is their brittle nature and poor mechanical properties. There is significant effort to reinforce or improve the mechanical properties and injectability of calcium phosphate cement (CPC) and this review resumes different alternatives presented in this specialized literature.

Clinical and radiological results of calcium phosphate cement-assisted balloon osteoplasty for Colles' fractures in osteoporotic senile female patients

BACKGROUND

Distal radius fractures in osteoporotic senile female patients often used to be complicated with residual deformity, stiffness, and pain. Recently, however, adequate usage of a palmar locking plate or external fixation has led to fewer subsequent complications. The method proposed here deserves consideration because it is less invasive and more cost-effective.

METHODS

A total of 11 Colles' type fractures (AO type A2) in 11 patients (all female; mean age 78 years) were treated. After a closed reduction, the fractures were fixed by percutaneous pinning, as Kapandji previously described. Through a 5-mm longitudinal skin incision on the dorsoulnar aspect of the fracture site, the barrel of a disposable 1-ml syringe was inserted into the fracture site as a port. Next, a pediatric uromatic balloon was introduced into the fracture site and inflated by contrast medium. The balloon inflation enlarged the void of the fracture site. A compression bandage around the fracture site was applied before calcium phosphate cement injection with a cement gun through the port under an image intensifier. The functional and radiological results were evaluated. The mean follow-up period was 16 months (range 12-25 months).

RESULTS

All results were graded as good or excellent within 3 months, and all were graded as excellent at the final follow-up. The average duration of immobilization was 4 weeks with a short forearm cast. The overall postoperative correction loss in ulnar variance was 1.7 mm. Radial inclination and volar tilt showed no postoperative correction loss. The final volar tilt, radial inclination, and ulnar variance were comparable to those of the nonaffected side.

CONCLUSIONS

Calcium phosphate cement-assisted balloon osteoplasty is a less invasive procedure and can be clinically justified as a therapeutic option for a Colles' fracture in osteoporotic senile female patients.

Management of post-traumatic malunion of fractures of the distal radius

Distal radius malunions are a common cause of patient morbidity. This review of the literature surrounding distal radius malunion covers the demographics, pathologic anatomy, and indications for surgery, surgical techniques, and salvage options. Particular emphasis is placed on subject areas that have not been reviewed as extensively in previous articles, including: intra-articular malunion, computer-assisted techniques, bone graft alternatives, and volar fixed-angle plate osteosynthesis.

Osteotomy of dorsally displaced malunited fractures of the distal radius: no loss of radiographic correction during healing with a minimally invasive fixation technique and an injectable bone substitute

BACKGROUND AND PURPOSE

Malunion after a distal radius fracture can be treated with an osteotomy of the distal radius. Often autologous iliac crest bone graft is used to fill the gap, but this is associated with donor site morbidity. Instead of bone graft, we have used a slow-resorbing bone substitute in combination with a minimally invasive fixation technique.

PATIENTS AND METHODS

25 consecutive patients with a dorsal malunion after a distal radius fracture underwent an osteotomy. A TriMed buttress pin and a radial pin plate were used for fixation, and Norian SRS as bone substitute. The patients were followed for a minimum of 1 year and range of motion, grip strength, DASH scores, and the radiographic correction were measured.

RESULTS

Forearm rotation improved from 137 degrees to 155 degrees , flexion/extension from 102 degrees to 120 degrees , and radioul-nar deviation from 32 degrees to 43 degrees . Grip strength increased from 62% of the contralateral hand to 82%. DASH scores decreased from 36 to 23. Radiographically, all osteotomies but 1 healed and the radiographic correction achieved was consistent over the first year.

INTERPRETATION

Osteotomy of the distal radius is effective in increasing motion and grip strength after a malunited distal radial fracture. Patient satisfaction is high and subjective results measured with DASH are good. Using a bone substitute, the operation can be performed as an outpatient procedure and donor-site pain avoided. No loss of the radiographic correction achieved was noted during osteotomy healing.

Evaluation of a novel nanocrystalline hydroxyapatite paste and a solid hydroxyapatite ceramic for the treatment of critical size bone defects (CSD) in rabbits

The purpose of our study was to test the effectiveness of Ostim nanocrystalline hydroxyapatite paste and Cerabone ceramic by treating a critical size bone defect (CSD) on the right foreleg of a white New Zealand rabbit. Evaluation was carried out by comparing four groups each with a different CSD filling: an only OSTIM bone filling, an only Cerabone filling, an OSTIM-Cerabone combination, and a control group with no filling of the CSD. The results of this study display a rapid and uniform bone ingrowth following the CSD filling with Ostim. The histological and histomorphometrical data have shown similarly excellent results for both the Ostim and Cerabone-Ostim groups. The control group faired poorly in comparison, as three cases of non-union were observed and none of the defects were totally refilled with fresh bone within 60 days. The successful bone healing with osseous consolidation verifies the importance of the nanocrystalline hydroxyapatite in the treatment of metaphyseal osseous volume defects in the metaphyseal spongiosa.

Distal radius osteotomy in the elderly patient using angular stable implants and Norian bone cement

PURPOSE

To report our results after testing the combination of two technologies--angular-stable locking screw implants and Norian SRS cement--in corrective osteotomies of the distal radius in the elderly. This technique eliminates donor site bone-graft morbidity and expands the indications of corrective osteotomies to older patients with osteoporotic bone.

METHODS

Our retrospective series include 6 patients (5 women and 1 man) with an average age of 60 years. Three patients had corrections through a dorsal approach, 1 through a volar approach, and 2 through a combined approach. Two corrections included an intraarticular osteotomy. We used 2.4-mm volar T plates in patients approached volarly and 2.4-mm L and T plates for those approached dorsally; the osseous defect was filled with bone cement (Norian SRS). Range of motion and grip strength were measured at 16 months average follow-up. Standard wrist radiographs were taken to evaluate alignment and determine improvement. At final follow-up, patients completed the Modified Mayo Wrist score, the Modified Gartland and Werley score, and the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire.

RESULTS

There were no perioperative complications. All corrective osteotomies healed. One patient required a Darrach procedure at 6 months. The average wrist and forearm motion was 77% of the opposite side and grip strength 88% of the opposite side. The average total correction in the sagittal plane was 22 degrees with all patients returning to neutral or better alignment. The average ulnar variance improvement was 2 mm. Average postoperative DASH was 28 points; average Modified Mayo Wrist score was 68; and the Modified Gartland and Werley score averaged 9 points.

CONCLUSIONS

We believe that corrective osteotomy of the distal radius in the elderly using angular stable implants and Norian calcium phosphate cement is a safe and predictable surgical technique, even in patients with underlying osteoporosis. It eliminates donor site morbidity, and patient-rated outcome measures demonstrated acceptable daily living function return.

Effects of a magnesium adhesive cement on bone stability and healing following a metatarsal osteotomy in horses

OBJECTIVE

To compare biodegradable magnesium phosphate cement (Mg-cement), calcium phosphate cement (Ca-cement), and no cement on bone repair, biocompatibility, and bone adhesive characteristics in vivo in horses.

ANIMALS

8 clinically normal adult horses.

PROCEDURES

Triangular fragments (1-cm-long arms) were created by Y-shaped osteotomy of the second and fourth metatarsal bones (MTII and MTIV, respectively). Fragments were replaced in pairs to compare Mg-cement (MTII, n = 8; MTIV, 8) with Ca-cement (MTIV, 8) or with no cement (MTII, 8). Clinical and radiographic evaluations were performed for 7 weeks, at which time osteotomy sites were harvested for computed tomographic measurement of bone density and callus amount, 3-point mechanical testing, and histologic evaluation of healing pattern and biodegradation.

RESULTS

All horses tolerated the procedure without clinical problems. Radiographically, Mg-cement secured fragments significantly closer to parent bone, compared with Ca-cement or no treatment. Callus amount and bone remodeling and healing were significantly greater with Mg-cement, compared with Ca-cement or no cement. Biomechanical testing results and callus density among treatments were not significantly different. Significantly greater woven bone was observed adjacent to the Mg-cement without foreign body reaction, compared with Ca-cement or no cement. The Mg-cement was not fully degraded and was still adhered to the fragment.

CONCLUSIONS AND CLINICAL RELEVANCE

Both bone cements were biocompatible in horses, and Mg-cement may assist fracture repair by osteogenesis and fragment stabilization. Further studies are warranted on other applications and to define degradation characteristics.

Calcium phosphate cement-assisted balloon osteoplasty for a Colles' fracture on arteriovenous fistula forearm of a maintenance hemodialysis patient

We report a case of a Colles' fracture on the arteriovenous fistula forearm of a maintenance hemodialysis patient treated with percutaneous pinning with the aid of Chinese finger trap reduction combined with cavity creation using a pediatric uromatic balloon with calcium phosphate cement augmentation. Five months after surgery, the arteriovenous fistula was patent, and the range of motion, grip strength, and radiographic findings were comparable with a non-arteriovenous fistula forearm. Wrist x-rays showed a complete union of the distal radius with progressive absorption of the calcium phosphate cement.

Management of post-traumatic malunion of fractures of the distal radius

Distal radius malunions are a common cause of patient morbidity. This review of the literature surrounding distal radius malunion covers the demographics, pathologic anatomy, and indications for surgery, surgical techniques, and salvage options. Particular emphasis is placed on subject areas that have not been reviewed as extensively in previous articles, including: intra-articular malunion, computer-assisted techniques, bone graft alternatives, and volar fixed-angle plate osteosynthesis.

Prospective study of standalone balloon kyphoplasty with calcium phosphate cement augmentation in traumatic fractures

Prospective consecutive series cases study to investigate the clinical and radiological results of standalone balloon kyphoplasty and cement augmentation with calcium phosphate in traumatic fractures. Independent observer evaluation of radiological and computer tomography results, visual analogue scale (VAS), Roland-Morris score and complications with acute traumatic compression fractures type A, treated with a standalone balloon kyphoplasty and cement augmentation with calcium phosphate (Calcibon); follow-up time at a mean of 30 months (24-37 months). From August 2002 to August 2003, consecutive patients with traumatic compression fractures (Magerl type A) without neurological deficit underwent standalone kyphoplasty with Calcibon. We report here the pre-, post-operative and the follow-up results, applying the VAS (0-10) for pain rating, the Roland-Morris (0-24) disability score, CT-scan examination, detailed radiographic evaluation of vertebral body (VB) deformity and segmental kyphosis measurement. The pre-operative X-ray measurements, VAS and the 7 days Roland-Morris scores are compared with the post-operative and the 30 months follow-up findings. Twenty-eight patients with 33 treated fracture levels were included in this study. The mean initial vertebral deformity (VB kyphosis) was 17 degrees, corrected to a post-operative of 6 degrees. We noted a loss of correction at the follow-up in comparison to the post-operative standing X-ray at 24 h of 3 degrees vertebral deformity and 3 degrees segmental kyphosis. The VAS score demonstrates a decrease over time from a mean of 8.7-3.1 at 7 days and to 0.8 at the last follow-up. The Roland-Morris disability score demonstrates a similar improvement. We noticed no major complications related to the procedure. The mean cement resorption after 1 year was 20.3% (0.3-35.3%) and is related to the individual biological resorption process and is not predictable. All patients with vertebral fractures as sole medical problem were discharged within 48 h. All active patients returned to the same work within 3 months with the same working ability as before the accident. Standalone balloon kyphoplasty is a potential alternative mini-invasive technique to reduce the fractures. However, due to the intrinsic characteristic of calcium phosphate cement (Calcibon) we recommend the application of this biological cement for standalone reduction and stabilisation only in fractures type A1 and A3.1 in young patient. In case of higher destruction levels of the VB, we propose the utilisation of Calcibon associated with posterior instrumentation. Having regard to the pointed out indications, our preliminary results demonstrate a new possibility to treat this kind of fractures, allowing a rapid handling of pain, early discharge and return to normal activities.

Intra-articular calcium phosphate cement: Its fate and impact on joint tissues in a rabbit model

Clinical application of injectable ceramic cement in comminuted fractures revealed penetration of the viscous paste into the joint space. Not much is known on the fate of this cement and its influence on articular tissues. The purpose of this experimental study was to assess these unknown alterations of joint tissues after intra-articular injection of cement in a rabbit knee. Observation periods were from 1 week up to 24 months, with three rabbits per group. Norian SRS cement was injected into one knee joint, the contralateral side receiving the same volume of Ringers' solution. Light microscopic evaluation of histologic sections was performed, investigating the appearance of the cement, inflammatory reactions, and degenerative changes of the articular surface. No signs of pronounced acute or chronic inflammation were visible. The injected cement was mainly found as a single particle, anterior to the cruciate ligaments. It became surrounded by synovial tissues within 4 weeks and showed signs of superficial resorption. In some specimens, bone formation was seen around the cement. Degeneration of the articular surface showed no differences between experimental and control side, and no changes over time became apparent. No major degenerative changes were induced by the injected cement. The prolonged presence of cement still seems to make it advisable to remove radiologically visible amounts from the joint space.

Novel injectable calcium phosphate/chitosan composites for bone substitute materials

In this study, a novel injectable bone substitute material was developed which consists of chitosan, citric acid and glucose solution as the liquid phase, and tricalcium phosphate powder as the solid phase. This material was moldable because of its paste consistency after mixing. We used four groups of cement to investigate the mechanical properties and biocompatibility of the new biomaterial in vitro, which were named group A (10% citric acid), B (15% citric acid), C (20% citric acid) and D (25% citric acid). The setting times of the cements were 5-30 min. X-ray diffraction analysis showed that the products were hydroxyapatite (HA) and dicalcium phosphate anhydrous. When the concentration of citric acid was increased, the compressive strength of specimen increased. Through the simulated body fluid test, we observed the material was bioactive. Group D could induce Ca and P ions to deposit the surface group D quickly. These results indicated that the concentration of citric acid in the liquid component affected the mechanical properties and bioactivity of cements. The cell cultivation test showed that the cytocompatibility of the new biomaterial was good. The method for preparing the novel bone substitute material is simple. The starting material is more readily available and cheaper than HA, poly(methyl methacrylate), and so on. The cement could have good prospects for medical application.

Calcium phosphate cement for augmentation did not improve results after internal fixation of displaced femoral neck fractures: a randomized study of 118 patients

BACKGROUND

We wanted to evaluate whether augmentation with calcium phosphate cement can improve clinical and functional outcome following internal fixation of displaced femoral neck fractures.

PATIENTS

118 patients aged 60-98 years (95 women) were included. All patients were physically active and ambulatory before the fracture. Patients were randomized to treatment with closed reduction and fixation with two cannulated screws alone (controls: 60 patients) or screws combined with injection of calcium phosphate for augmentation around the screw threads and at the fracture site (augmented: 58 patients). All patients were allowed free weight bearing. Clinical and radiographic examinations were done by a physiotherapist directly after surgery, at 1 and 6 weeks, and at 6, 12 and 24 months.

RESULTS

24 patients, 14 augmented and 10 controls, died during the follow-up. There was 1 deep infection (augmented). Another 34 patients were reoperated with a total arthroplasty (20 in the augmented group and 14 controls) due to loss of reduction, nonunion or avascular necrosis (p = 0.1). There was no difference in pain or muscle strength between groups. Some activities of daily living (ADLs) were slightly better in the augmented patients during the first weeks, while there were no differences between groups later on.

INTERPRETATION

Due to a trend towards more reoperations in the augmented group, and only a temporary clinical improvement during the early rehabilitation, augmentation as we used it cannot be recommended.

Clinical use of a newly developed calcium phosphate cement (XSB-671D)

BACKGROUND

Several kinds of thermally processed hydroxyapatite have been commonly used for bone defects due to bone diseases or fractures instead of autologous bone grafts. However, these materials do not change in form during surgery and are not absorbed over a long period. To overcome this disadvantage, calcium phosphate bone cements (CPCs) have been developed and are already in use in clinical cases. These materials have merit in that to be formed in situ they are injectable and absorbable, but there are still problems with their handling and their hardening properties. A newly developed CPC called XSB-671D hardens earlier and is more resistant to body fluids than other CPCs. The purpose of this article is to verify the effectiveness, safety and usefulness of this CPC (XSB-671D) as a bone defect filler.

METHODS

We conducted clinical trials at five medical institutions based on a unified protocol in a total of 75 cases (30 males, 45 females). We observed the postoperative constitutional symptoms and local symptoms of the filling sites. The effectiveness of this material was evaluated by radiographs of the filled sites, and blood and urine were examined to evaluate any adverse effects.

RESULTS

The ratio of the cases determined to be "effective" or "better" among the 74 cases we found qualified was 97.3%, and XSB-671D was confirmed to be a highly effective material with beneficial effects of biocompatibility and osteoconduction as a bone defect filler. Additionally, there were no adverse effects caused by XSB-671D except one local skin reaction, which disappeared 2 weeks later; its safety was also thus verified.

CONCLUSIONS

We conclude that effective, safe treatment is possible using XSB-671D in cases requiring filling of a bone defect as well as those with serious osteoporosis.

Augmentation of intraarticular calcaneal fractures with injectable calcium phosphate cement: densitometry, histology, and functional outcome of 18 patients

Eighteen patients with intraarticular calcaneal fractures treated with open reduction and internal fixation and augmentation with an injectable carbonated apatite cement. Functional follow-up studies using the Zwipp Foot Score and densitometry were performed at 6-month intervals postoperatively. Histological samples of biopsies obtained at the time of hardware removal (6 months postoperatively) were also analyzed. The use of bone cement led to intermediate-term functional outcomes that were no better than those reported with conventional surgical procedures using bone graft. Patients demonstrated postoperative difficulties similar to those seen in other studies of this fracture, including pain, subtalar motion restrictions, peroneal impingement, and difficulties on uneven terrain and with toe- and heel-walking. However, compared to patients treated surgically without injectable carbonated apatite cement, full weight bearing on the affected extremity was regained at an average 4 weeks postoperatively. In addition, autogenous bone graft was not required to fill the osseous defect using this technique, minimizing morbidity and discomfort. During the present observation period of 3 years, only a slight decrease in the density of the peripheral zones of the cement block was observed. Histological examination revealed fibrous bone formation resulting from remodelling processes. Complete resorption and remodeling of the bone cement were not complete at 3 years. One patient developed a postoperative wound infection. Another displayed cement loosening secondary to failure of bony ingrowth.

Synthesis, material properties, and biocompatibility of a novel self-cross-linkable poly(caprolactone fumarate) as an injectable tissue engineering scaffold

A novel self-cross-linkable and biodegradable macromer, poly(caprolactone fumarate) (PCLF), has been developed for guided bone regeneration. This macromer is a copolymer of fumaryl chloride, which contains double bonds for in-situ cross-linking, and poly(epsilon-caprolactone), which has a flexible chain to facilitate self-cross-linkability. PCLF was characterized with Fourier transform infrared spectroscopy, 1H and 13C nuclear magnetic resonance spectroscopy, and gel permeation chromatography. Porous scaffolds were fabricated with sodium chloride particles as the porogen and a chemical initiation system. The PCLF scaffolds were characterized with scanning electron microscopy and micro-computed-tomography. The cytotoxicity and in vivo biocompatibility of PCLF were also assessed. Our results suggest that this novel copolymer, PCLF, is an injectable, self-cross-linkable, and biocompatible macromer that may be potentially used as a scaffold for tissue engineering applications.

Resorbable cement for the augmentation of internally-fixed unstable trochanteric fractures

We undertook a multicentre, prospective study of a series of 112 unstable trochanteric fractures in order to evaluate if internal fixation with a sliding screw device combined with augmentation using a calcium phosphate degradable cement (Norian SRS) could improve the clinical, functional and radiological outcome when compared with fractures treated with a sliding screw device alone. Pain, activities of daily living, health status (SF-36), the strength of the hip abductor muscles and radiological outcome were analysed.

Six weeks after surgery, the patients in the augmented group had significantly lower global and functional pain scores (p < 0.003), less pain after walking 50 feet (p < 0.01), and a better return to the activities of daily living (p < 0.05). At follow-up at six weeks and six months, those in the augmented group showed a significant improvement compared with the control group in the SF-36 score. No other significant differences were found between the groups. We conclude that augmentation with calcium phosphate cement in unstable trochanteric fractures provides a modest reduction in pain and a slight improvement in the quality of life during the course of healing when compared with conventional fixation with a sliding screw device alone.

Orthopaedics

Orthopaedic surgery is a large and expanding speciality. There are approximately five million clinic attendances each year in this country and musculo-skeletal complaints are the commonest presentation in General Practice. This review examines three key areas within orthopaedics, fracture management, sports medicine and the new subspeciality of minimally invasive orthopaedics and highlights areas of recent advancement, significant research and ongoing debate.

Fractures comminutives du radius distal traitées par ostéosynthèse et substitut osseux injectable

PURPOSE OF THE STUDY

Comminution is often neglected in patients presenting fractures of the distal radius. Use of injectable bone substitutes can fill the gap left by comminution, avoiding radial shortening and loss of prono-supination.

MATERIAL AND METHODS

Forty-eight patients with a distal fracture of the radius were treated by osteosynthesis and injectable cement between 1998 and 2001. These patients were reviewed at mean follow-up of 46 months (36-56). Dorsal displacement was present in all cases and the AO classification was A (n=26), B (n=15), C (n=7). Fixation was achieved with pins (n=32), posterior plate (n=14), and external fixator (n=2) before injection of the bone substitute. Outcome was evaluated with the Herzberg score, the Gartland and Werley score and DASH by an independent operator.

RESULTS

Four patients were lost to follow-up and five who developed a deformed callus after the initial osteosynthesis were excluded from the analysis. The Herzberg functional score reached 84 (range 54-100) and the Gartland and Werley radioclinical score was 4.6 (0-11) with 89% excellent and good outcomes. DASH was 23.6 (5.8-62.7). Ulnar variance was unchanged or changed less than 2 mm between the immediate postoperative period and last follow-up in 88% of patients. There was one carpal tunnel syndrome related to anterior cement leakage. Three biopsies were performed and revealed a "humid sand" aspect six months after injection as well as presence of osteoblasts within the bone substitute. There was no or very little resorption.

DISCUSSION

Several authors have demonstrated the biomechanical and functional effects of filling the comminution gap to avoid radial shortening. The first reported cases, then later prospective series, favored the use of injectable cements for patients with comminution. Cement used in our patients allowed preservation enables preservation of normal ulnar variance in addition to filling the gap. Like any bone substitute, it is an attractive alternative to other filling methods (ceramic graft) offering two advantages: adaptation to the bone defect and primary stability. This easy-to-use cement is resorbed slowly. Because of high cost, it may be reserved for patients with important functional needs.