Norian SRS versus external fixation in redisplaced distal radial fractures. A randomized study in 40 patients

What Is the Relative Effectiveness of the Various Surgical Treatment Options for Distal Radius Fractures? A Systematic Review and Network Meta-analysis of Randomized Controlled Trials

BACKGROUND

Many acceptable treatment options exist for distal radius fractures (DRFs); however, a simultaneous comparison of all methods is difficult using conventional study designs.

QUESTIONS/PURPOSES

We performed a network meta-analysis of randomized controlled trials (RCTs) on DRF treatment to answer the following questions: Compared with nonoperative treatment, (1) which intervention is associated with the best 1-year functional outcome? (2) Which intervention is associated with the lowest risk of overall complications? (3) Which intervention is associated with the lowest risk of complications requiring operation?

METHODS

Ten databases were searched from inception to July 25, 2019. Search and analysis reporting adhered to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Included studies were English-language RCTs that assessed at least one surgical treatment arm for adult patients with displaced DRFs, with less than 20% loss to follow-up. We excluded RCTs reporting on patients with open fractures, extensive bone loss, or ipsilateral upper extremity polytrauma. Seventy RCTs (n = 4789 patients) were included. Treatments compared were the volar locking plate, bridging external fixation, nonbridging external fixation, dynamic external fixation, percutaneous pinning, intramedullary fixation, dorsal plating, fragment-specific plating, and nonoperative treatment. Subgroup analyses were conducted for intraarticular fractures, extraarticular fractures, and patients with an average age greater than 60 years. Mean (range) patient age was 59 years (56 to 63) and was similar across all treatment groups except for dynamic external fixation (44 years) and fragment-specific plating (47 years). Distribution of intraarticular and extraarticular fractures was approximately equal among the treatment groups other than that for intramedullary fixation (73% extraarticular), fragment-specific plating (66% intraarticular) [13, 70], and dorsal plating (100% intraarticular). Outcomes were the DASH score at 1 year, total complications, and reoperation. The minimum clinically important different (MCID) for the DASH score was set at 10 points. The analysis was performed using Bayesian methodology with random-effects models. Rank orders were generated using surface under the cumulative ranking curve values. Evidence quality was assessed using Grades of Recommendation, Assessment, Development and Evaluation (GRADE) methodology. Most studies had a low risk of bias due to randomization and low rates of incomplete follow-up, unclear risk of bias due to selective reporting, and high risk of bias due to lack of patient and assessor blinding. Studies assessing bridging external fixation and/or nonoperative treatment arms had a higher overall risk of bias while studies with volar plating and/or percutaneous pinning treatment arms had a lower risk of bias.

RESULTS

Across all patients, there were no clinically important differences in terms of the DASH score at 1 year; although differences were found, all were less than the MCID of 10 points. Volar plating was ranked the highest for DASH score at 1 year (mean difference -7.34 [95% credible interval -11 to -3.7) while intramedullary fixation, with low-quality evidence, also showed improvement in DASH score (mean difference -7.75 [95% CI -14.6 to -0.56]). The subgroup analysis revealed that only locked volar plating was favored over nonoperative treatment for patients older than 60 years of age (mean difference -6.4 [95% CI -11 to -2.1]) and for those with intraarticular fractures (mean difference -8.4 [95% CI -15 to -2.0]). However, its clinical importance was uncertain as the MCID was not met. Among all patients, intramedullary fixation (odds ratio 0.09 [95% CI 0.02 to 0.84]) and locked volar plating (OR 0.14 [95% CI 0.05 to 0.39]) were associated with a lower complication risk compared with nonoperative treatment. For intraarticular fractures, volar plating was the only treatment associated with a lower risk of complications than nonoperative treatment (OR 0.021 [95% CI < 0.01 to 0.50]). For extraarticular fractures, only nonbridging external fixation was associated with a lower risk of complications than nonoperative treatment (OR 0.011 [95% CI < 0.01 to 0.65]), although the quality of evidence was low. Among all patients, the risk of complications requiring operation was lower with intramedullary fixation (OR 0.06 [95% CI < 0.01 to 0.85) than with nonoperative treatment, but no treatment was favored over nonoperative treatment when analyzed by subgroups.

CONCLUSION

We found no clinically important differences favoring any surgical treatment option with respect to 1-year functional outcome. However, relative to the other options, volar plating was associated with a lower complication risk, particularly in patients with intraarticular fractures, while nonbridging external fixation was associated with a lower complication risk in patients with extraarticular fractures. For patients older than 60 years of age, nonoperative treatment may still be the preferred option because there is no reliable evidence showing a consistent decrease in complications or complications requiring operation among the other treatment options. Particularly in this age group, the decision to expose patients to even a single surgery should be made with caution.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Bridging versus Nonbridging Dynamic External Fixation of Unstable Distal Radius Fractures in the Elderly with Polytrauma: A Randomized Study

Background  Despite the high prevalence of unstable distal radius fractures (DRFs), there is no consensus regarding the optimal method and treatment timing, especially for elderly patients with multiple associated injuries. Purpose  This study aimed to compare the grip strength achieved with two different methods for definitive dynamic external fixation of DRFs in elderly patients with polytrauma operated on within the first 24 hours. Methods  In this prospective randomized trial, 35 patients were assigned to undergo definitive external dynamic fixation of DRFs using the nonbridging (group A) or bridging (group B) method. The grip strength, range of motion (ROM), Disabilities of the Arm, Shoulder and Hand (QuickDASH) outcome measure, visual analog scale (VAS) score for pain, and radiographic characteristics were evaluated at 6 and 12 months. Results  At 12 months, no significant between-group difference was observed with respect to grip strength. All patients showed results in the third or fourth quartiles. The mean ROMs were 96.94 and 96.38% and the mean QuickDASH scores were 3.53 and 3.85 in groups A and B, respectively. The VAS scores were 1.60 and 1.85 in groups A and B, respectively. The overall complication rates were 13.3 and 15% in groups A and B, respectively. Initial fracture reduction was maintained in 86.67 and 95% of the patients in groups A and B, respectively. Conclusions  Both bridging and nonbridging external definitive dynamic fixation proved safe and reliable for the treatment of unstable DRFs in elderly patients with polytrauma. The grip strength results in both groups predicted the restoration of ability in elderly patients to perform activities of daily living independently.

Reinforcement of calcium phosphate cement using alkaline-treated silk fibroin

BACKGROUND

Bone cement plays an important role in the treatment of osteoporotic vertebral compression fractures. Calcium phosphate cement (CPC) is a potential alternative to poly(methyl methacrylate), currently the gold standard of bone cements. However, the poor mechanical properties of CPCs limit their clinical applications. The objective of this study was to develop reinforced CPCs for minimally invasive orthopedic surgeries by compositing silk fibroin (SF) with α-tricalcium phosphate.

METHODS

SF solution was treated with calcium hydroxide and characterized by Zeta potential analyzer and Fourier transform infrared spectroscopy. The alkaline-treated SF (tSF) was com-posited with α-tricalcium phosphate to obtain tSF/CPC composite, which was characterized using mechanical tests, scanning electron microscopy, handling property and biocompatibility tests, and sheep vertebral augmentation tests.

RESULTS

Upon treatment with calcium hydroxide, larger SF particles and more abundant negative charge appeared in tSF solution. The tSF/CPCs exhibited a compact structure, which consisted of numerous SF -CPC clusters and needle-like hydroxyapatite (HAp) crystals. In addition, high transition rate of HAp in tSF/CPCs was achieved. As a result, the mechanical property of tSF/ CPC composite cements was enhanced remarkably, with the compressive strength reaching as high as 56.3±1.1 MPa. Moreover, the tSF/CPC cements showed good injectability, anti-washout property, and decent biocompatibility. The tSF/CPCs could be used to augment defected sheep vertebrae to restore their mechanical strength.

CONCLUSION

tSF/CPC may be a promising composite bone cement for minimally invasive orthopedic surgeries.

Similar 1-year subjective outcome after a distal radius fracture during the 10-year-period 2003-2012

Background and purpose - During the last decades, treatment of distal radius fractures (DRFs) has changed, with surgical intervention being more common and with new techniques. We investigated whether this change has influenced the subjective outcome. Here we report, year by year, the 1-year score after a DRF over a 10-year-period, using a patient-reported outcome measure. Patients and methods - Patients aged 18 years or more with a DRF between 2003 and 2012 were prospectively and consecutively registered in a longitudinal outcome database. 1 year after the fracture, all the patients were sent a validated subjective outcome questionnaire, the Disabilities of the Arm, Shoulder, and Hand (DASH). The lower the score (0-100), the better the outcome. Results - Between 2003 and 2012, 3,666 patients (2,833 of them women; mean age 62 (18-98) years) were included. 22% were operated and the rate remained constant over the years. The surgical methods shifted from external fixators (42%) and fragment-specific plates (45%) in 2003, to mainly volar locking plates (65%) in 2012. 70% of the patients responded to the 1-year DASH questionnaire. The median DASH score was 9 (IQR: 2-25) for the cohort, both in surgically treated patients (9 (IQR: 3-25)) and in non-surgically treated patients (9 (IQR 2-27)). Subgroup analysis showed a higher median DASH score for women than for men; for patients with AO type C fractures rather than type B or type A fractures; for patients with external fixation or fragment-specific fixation than for those who underwent surgery using volar locking plates; and for patients who were operated by a general orthopedic surgeon rather than a hand surgeon. Interpretation - The shift in surgical treatment had no influence on the subjective outcome for the cohort.

Fragment-Specific Fixation Versus Volar Locking Plates in Primarily Nonreducible or Secondarily Redisplaced Distal Radius Fractures: A Randomized Controlled Study

PURPOSE

To compare the patient-reported, clinical, and radiographic outcome of 2 methods of internal fixation in distal radius fractures.

METHODS

Fifty patients, mean age 56 years (range, 21-69 years) with primarily nonreducible or secondarily redisplaced distal radius fractures were randomized to open reduction internal fixation using volar locking plates (n = 25) or fragment-specific fixation (n = 25). The patients were assessed on grip strength, range of motion, patient-reported outcome (Quick Disabilities of the Arm, Shoulder, and Hand), pain (visual analog scale), health-related quality of life (Short Form-12 [SF-12]), and radiographic evaluation. Grip strength at 12 months was the primary outcome measure.

RESULTS

At 12 months, no difference was found in grip strength, which was 90% of the uninjured side in the volar plate group and 87% in the fragment-specific fixation group. No differences were found in range of motion and the median Quick Disabilities of the Arm, Shoulder, and Hand score was 5 in both groups. The overall complication rate was significant, 21% in the volar locking plate group, compared with 52% in the fragment-specific group.

CONCLUSIONS

In treatment of primarily nonreducible or secondarily redisplaced distal radius fractures, volar locking plates and fragment-specific fixation both achieve good and similar patient-reported outcomes, although more complications were recorded in the fragment-specific group.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic II.

Critical review: Injectability of calcium phosphate pastes and cements

Calcium phosphate cements (CPC) have seen clinical success in many dental and orthopaedic applications in recent years. The properties of CPC essential for clinical success are reviewed in this article, which includes properties of the set cement (e.g. bioresorbability, biocompatibility, porosity and mechanical properties) and unset cement (e.g. setting time, cohesion, flow properties and ease of delivery to the surgical site). Emphasis is on the delivery of calcium phosphate (CaP) pastes and CPC, in particular the occurrence of separation of the liquid and solid components of the pastes and cements during injection; and established methods to reduce this phase separation. In addition a review of phase separation mechanisms observed during the extrusion of other biphasic paste systems and the theoretical models used to describe these mechanisms are discussed.

STATEMENT OF SIGNIFICANCE

Occurrence of phase separation of calcium phosphate pastes and cements during injection limits their full exploitation as a bone substitute in minimally invasive surgical applications. Due to lack of theoretical understanding of the phase separation mechanism(s), optimisation of an injectable CPC that satisfies clinical requirements has proven difficult. However, phase separation of pastes during delivery has been the focus across several research fields. Therefore in addition to a review of methods to reduce phase separation of CPC and the associated constraints, a review of phase separation mechanisms observed during extrusion of other pastes and the theoretical models used to describe these mechanisms is presented. It is anticipated this review will benefit future attempts to develop injectable calcium phosphate based systems.

Immediate effects of repetitive wrist extension on grip strength in patients with distal radial fracture

OBJECTIVE

To evaluate the immediate effect of repetitive wrist extension on grip strength in patients with distal radial fracture.

DESIGN

Interventional study.

SETTING

Patients who were admitted to a hospital department of occupational therapy.

PARTICIPANTS

Consecutive patients with a unilateral distal radial fracture (N=28).

INTERVENTION

Each patient was randomly allocated to either the experimental group (n=14) or the control group (n=14). The experimental group performed 30 repetitive wrist extensions with maximal isometric contraction of the extensors of their affected hands during a 6-minute intervention period, whereas the control group did not perform the exercise.

MAIN OUTCOME MEASURES

Grip strength was measured just before and after the intervention period. Pain during grip strength measurements was also quantified using the visual analog scale. Wrist extension strength was measured 10 minutes after the grip strength measurement.

RESULTS

Grip strength increased immediately after repetitive wrist extension in the experimental group, but it remained the same in the control group. Visual analog scale scores indicated that pain was relieved only in the experimental group. However, pain was unrelated to strength production.

CONCLUSIONS

The intervention used in this study might be useful during physical examination to reveal the potential grip strength of patients. The intervention may also be an effective warm-up training procedure in preparation for conventional grip-strengthening exercises.

Bone graft substitutes currently available in orthopaedic practice: the evidence for their use

We reviewed 59 bone graft substitutes marketed by 17 companies currently available for implantation in the United Kingdom, with the aim of assessing the peer-reviewed literature to facilitate informed decision-making regarding their use in clinical practice. After critical analysis of the literature, only 22 products (37%) had any clinical data. Norian SRS (Synthes), Vitoss (Orthovita), Cortoss (Orthovita) and Alpha-BSM (Etex) had Level I evidence. We question the need for so many different products, especially with limited published clinical evidence for their efficacy, and conclude that there is a considerable need for further prospective randomised trials to facilitate informed decision-making with regard to the use of current and future bone graft substitutes in clinical practice.

Open reduction and internal fixation versus external fixation for unstable distal radial fractures: a meta-analysis

PURPOSE

To compare the clinical outcomes of open reduction and internal fixation (ORIF) versus the ones of closed reduction and external fixation (EF) in the treatment of distal radial fractures.

METHODS

We performed a meta-analysis of randomized controlled trials that compared the clinical results of ORIF to EF in the treatment of distal radial fractures. A systemic retrieve from PubMed, EMBASE, OVID and Cochrane Collaboration CENTRAL database resulted in 11 studies with 824 patients. We thus performed data synthesis using RevMan (version 5.1).

RESULTS

Superior statistical differences were observed for DASH scores (at 3, 6 and 12 months follow-up) grip strength (at 3 months follow-up), volar tilt (at 12 months follow-up), flexion and supination (at 3 months follow-up), and extension (at 3 and 6 months follow-up) in ORIF patients group, compared with those in EF group. We also found a significantly higher risk of infection associated with EF. There was no significant difference in the incidence of malunion and median nerve dysfunction.

CONCLUSION

Regarding surgical fixation of unstable distal radius fractures, ORIF yields significantly better subjective outcome (DASH scores) the first year after operation, restoration of anatomic volar tilt, and forearm flexion and extension at the end of the follow-up period. However, EF results in higher incidence of infection compared to ORIF. ORIF is equal to EF for either grip strength, or range of motion of the injured wrist, or incidence of malunion or median nerve dysfunction at the end of the follow-up period.

LEVEL OF EVIDENCE

Level II. Therapeutic study.

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.

Bone graft substitutes: What are the options?

Currently, a number of bone grafting materials are available in the clinical setting to enhance bone regeneration, varying from autologous bone to several bone graft substitutes. Although autologous bone remains the "gold standard" for stimulating bone repair and regeneration, the morbidity from its harvesting and its restricted availability generated the need for the development of other materials or strategies either to substitute autologous bone graft or expand its limited supply. Bone graft substitutes can possess one or more components: an osteoconductive matrix, acting as a scaffold; osteoinductive proteins and other growth factors to induce differentiation and proliferation of bone-forming cells; and osteogenic cells for bone formation. Based on their distinct properties, all these bone grafting alternatives have specific indications, and can be used either alone or in combination. In this review, we summarise the available bone grafting materials, focussing mainly on the various bone substitutes and their characteristics, in an effort to specify the indications for their use.

The use of bone grafts and substitutes in the treatment of distal radius fractures

The interest in developing biomaterials to augment fracture healing continues to grow. New products promise early return to function with minimal morbidity; however, indications to use these products remain unclear. An ideal bone graft material stimulates bone healing and provides structural stability while being biocompatible, bioresorbable, easy to use, and cost-effective. This article reviews the biology of bone grafts and the clinical evidence in the use of bone graft substitutes for the treatment of distal radius fractures.

Fixation of comminuted distal radius fractures with a mixture of calcium phosphate and calcium sulfate cement

Distal radius fracture alignment and stabilization can be a surgical challenge in the face of severe comminution and bone loss. We describe a technique using a calcium phosphate/sulfate bone cement, as an adjunct to internal fixation. This bone cement is biocompatible, osteoconductive, and sets quickly with an isothermic reaction. The use of bone cement eliminates the need for primary autologous bone grafting and allows for easier reduction and retention of reduction at the time of surgery. Bone cement is employed for the following purposes in comminuted fractures: (1) to fill a void due to lost or crushed cancellous bone, (2) to hold larger unstable fragments while hardware is placed, and (3) to retain fragments too small to take hardware. Available bone cements, studies involving the use of bone cement for distal radius fractures, indications, and surgical technique will be reviewed.

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.

Bioactive glass granules: a suitable bone substitute material in the operative treatment of depressed lateral tibial plateau fractures: a prospective, randomized 1 year follow-up study

Purpose of this study was to compare bioactive glass and autogenous bone as a bone substitute material in tibial plateau fractures. We designed a prospective, randomized study consisting of 25 consecutive operatively treated patients with depressed unilateral tibial comminuted plateau fracture (AO classification 41 B2 and B3).14 patients (7 females, 7 males, mean age 57 years, range 25-82) were randomized in the bioglass group (BG) and 11 patients (6 females, 5 males, mean age 50 years, range 31-82) served as autogenous bone control group (AB). Clinical examination of the patients was performed at 3 and 12 months, patients' subjective and functional results were evaluated at 12 months. Radiological analysis was performed preoperatively, immediately postoperatively and at 3 and 12 months. The postoperative redepression for both studied groups was 1 mm until 3 months and remained unchanged at 12 months. No differences were identified in the subjective evaluation, functional tests and clinical examination between the two groups during 1 year follow-up. We conclude that bioactive glass granules can be clinically used as filler material instead of autogenous bone in the lateral tibial plateau compression fractures.

Microstructure and biomechanical characteristics of bone substitutes for trauma and orthopaedic surgery

BACKGROUND

Many (artificial) bone substitute materials are currently available for use in orthopaedic trauma surgery. Objective data on their biological and biomechanical characteristics, which determine their clinical application, is mostly lacking. The aim of this study was to investigate structural and in vitro mechanical properties of nine bone substitute cements registered for use in orthopaedic trauma surgery in the Netherlands.

METHODS

Seven calcium phosphate cements (BoneSource®, Calcibon®, ChronOS®, Eurobone®, HydroSet™, Norian SRS®, and Ostim®), one calcium sulphate cement (MIIG® X3), and one bioactive glass cement (Cortoss®) were tested. Structural characteristics were measured by micro-CT scanning. Compression strength and stiffness were determined following unconfined compression tests.

RESULTS

Each bone substitute had unique characteristics. Mean total porosity ranged from 53% (Ostim®) to 0.5% (Norian SRS®). Mean pore size exceeded 100 μm only in Eurobone® and Cortoss® (162.2 ± 107.1 μm and 148.4 ± 70.6 μm, respectively). However, 230 μm pores were found in Calcibon®, Norian SRS®, HydroSet™, and MIIG® X3. Connectivity density ranged from 27/cm3 for HydroSet™ to 0.03/cm3 for Calcibon®. The ultimate compression strength was highest in Cortoss® (47.32 MPa) and lowest in Ostim® (0.24 MPa). Young's Modulus was highest in Calcibon® (790 MPa) and lowest in Ostim® (6 MPa).

CONCLUSIONS

The bone substitutes tested display a wide range in structural properties and compression strength, indicating that they will be suitable for different clinical indications. The data outlined here will help surgeons to select the most suitable products currently available for specific clinical indications.

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.

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.

Treatment of distal radius fractures

The clinical practice guideline is based on a systematic review of published studies on the treatment of distal radius fractures in adults. None of the 29 recommendations made by the work group was graded as strong; most are graded as inconclusive or consensus; seven are graded as weak. The remaining five moderate-strength recommendations include surgical fixation, rather than cast fixation, for fractures with postreduction radial shortening >3 mm, dorsal tilt >10 degrees , or intra-articular displacement or step-off >2 mm; use of rigid immobilization rather than removable splints for nonsurgical treatment; making a postreduction true lateral radiograph of the carpus to assess dorsal radial ulnar joint alignment; beginning early wrist motion following stable fixation; and recommending adjuvant treatment with vitamin C to prevent disproportionate pain.

Calcium phosphates: what is the evidence?

A number of different calcium phosphate compounds such as calcium phosphate cements and solid beta-tricalcium phosphate products have been introduced during the last decade. The chemical composition mimics the mineral phase of bone and as a result of this likeness, the materials seem to be remodeled as for normal bone through a cell-mediated process that involves osteoclastic activity. This is a major difference when compared with, for instance, calcium sulphate compounds that after implantation dissolve irrespective of the new bone formation rate. Calcium phosphates are highly biocompatible and in addition, they act as synthetic osteoconductive scaffolds after implantation in bone. When placed adjacent to bone, osteoid is formed directly on the surface of the calcium phosphate with no soft tissue interposed. Remodeling is slow and incomplete, but by adding more and larger pores, like in ultraporous beta-tricalcium phosphate, complete or nearly complete resorption can be achieved. The indications explored so far include filling of metaphyseal fracture voids or bone cysts, a volume expander in conjunction with inductive products, and as a carrier for various growth factors and antibiotics. Calcium phosphate compounds such as calcium phosphate cement and beta-tricalcium phosphate will most certainly be part of the future armamentarium when dealing with fracture treatment. It is reasonable to believe that we have so far only seen the beginning when it comes to clinical applications.

Open reduction and internal fixation compared to closed reduction and external fixation in distal radial fractures: a randomized study of 50 patients

BACKGROUND AND PURPOSE

In unstable distal radial fractures that are impossible to reduce or to maintain in reduced position, the treatment of choice is operation. The type of operation and the choice of implant, however, is a matter of discussion. Our aim was to investigate whether open reduction and internal fixation would produce a better result than traditional external fixation.

METHODS

50 patients with an unstable or comminute distal radius fracture were randomized to either closed reduction and bridging external fixation, or open reduction and internal fixation using the TriMed system. The primary outcome parameter was grip strength, but the patients were followed for 1 year with objective clinical assessment, subjective outcome using DASH, and radiographic examination.

RESULTS

At 1 year postoperatively, grip strength was 90% (SD 16) of the uninjured side in the internal fixation group and 78% (17) in the external fixation group. Pronation/supination was 150 degrees (15) in the internal fixation group and 136 degrees (20) in the external fixation group at 1 year. There were no differences in DASH scores or in radiographic parameters. 5 patients in the external fixation group were reoperated due to malunion, as compared to 1 in the internal fixation group. 7 other cases were classified as radiographic malunion: 5 in the external fixation group and 2 in the internal fixation group.

INTERPRETATION

Internal fixation gave better grip strength and a better range of motion at 1 year, and tended to have less malunions than external fixation. No difference could be found regarding subjective outcome.

WITHDRAWN: Surgical interventions for treating distal radial fractures in adults

BACKGROUND

Fracture of the distal radius is a common clinical problem, particularly in older white women with osteoporosis.

OBJECTIVES

To determine when, and if so what type of, surgical intervention is the most appropriate treatment for fractures of the distal radius in adults.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group specialised register (November 2002), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2003), MEDLINE (1966 to February 2003), EMBASE (1988 to 2003 Week 8), CINAHL (1982 to February 2003), the National Research Register (Issue 1, 2003), PEDro, conference proceedings and reference lists of articles. No language restrictions were applied.

SELECTION CRITERIA

Randomised or quasi-randomised clinical trials involving skeletally mature patients with a fracture of the distal radius, which compared surgical treatment with conservative treatment, different types of surgical intervention or the duration of immobilisation after surgery. The main categories of surgical intervention were external fixation, percutaneous pinning, open reduction and internal fixation, and the insertion of bone scaffolding materials.

DATA COLLECTION AND ANALYSIS

All trials, meeting the selection criteria, were independently assessed by both reviewers for methodological quality. Data were extracted for anatomical, functional and clinical outcomes (including complications). The trials were grouped into categories relating to the main comparisons and types of surgical intervention. Despite clear heterogeneity in the characteristics of comparable trials, pooling of data was undertaken where possible and appropriate.

MAIN RESULTS

Forty eight trials, examining 25 treatment comparisons, met the inclusion criteria of this review. These involved a total of 3371 mainly female and older patients with generally displaced, often comminuted and potentially or evidently unstable fractures. Nearly half of the trials compared surgery with plaster cast immobilisation. Summarising the outcomes was hampered by the variation between the studies in participant characteristics, interventions, quality of trial methodology and reporting, and outcome measurement. Surgical methods were usually associated with better anatomical appearance after fracture healing, but there was inadequate evidence to confirm that these had resulted in better functional and clinical outcomes for the patients.

AUTHORS' CONCLUSIONS

The 48 randomised trials do not provide robust evidence for most of the decisions necessary in the management of these fractures. Although, in particular, there is some evidence to support the use of external fixation or percutaneous pinning, their precise role and methods are not established. It is also unclear whether surgical intervention of most fracture types will produce consistently better long-term outcomes.There is a need for good quality evidence for the surgical management of these fractures.

Augmented pin fixation with Cortoss for an unstable AO-A3 type distal radius fracture in a patient with a manifest osteoporosis

Distal radius fractures are one of the most common fractures in the elderly females. In this article, we report a case of a distal radius fracture type AO-A3 with dorsal instability, in an older woman with manifest osteoporosis, treated with minimally invasive Cortoss composite and FFS-wires(R). A 63-year-old woman sustained an unstable distal radial fracture of her left wrist after falling from a kitchen step. She underwent an open reduction of the fracture and fixation with two crossed-fixation pins and Cortoss composite. Post-operative plaster cast immobilization was given for 2 weeks, after which the plaster cast and the fixation pins were removed. At 4 weeks follow-up, she had a good functional result of her left wrist, after 11 months there was a complete return of grip strength with also, except for the palmar flexion, a full return of function. We report here the first case of a successful surgical treatment with Cortoss composite of an AO-A3 type distal radius fracture.

Injectable bone cement augmentation for the treatment of distal radius fractures: a review

Fractures of the distal radius often occur as a result of low-energy trauma and are frequently seen in osteoporotic patients. Many biomechanical studies and clinical case series have been carried out to investigate the effects on the fractured bones of different fixation methods such as cast immobilization, percutaneous pins, external fixators, or open reduction with internal fixation. In addition, the use of different bone cements as stand-alone solutions or as an adjunct to the aforementioned fixation methods is described as one possible way of increasing the performance of the fixation by reducing secondary dislocation of the fragments and allowing more intensive rehabilitation of the patients. This review aims to provide an overview of some of the main issues under discussion and a critical evaluation of the different treatments.

Bone grafts and bone substitutes for treating distal radial fractures in adults

BACKGROUND

Surgical treatment of fractures of the distal radius can involve the implantation of bone scaffolding materials (bone grafts and substitutes) into bony defects that frequently arise after fracture reduction.

OBJECTIVES

To review the evidence from randomised controlled trials evaluating the implanting of bone scaffolding materials for treating distal radial fractures in adults.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (June 2007), the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and other databases, conference proceedings and reference lists. No language restrictions were applied.

SELECTION CRITERIA

Randomised or quasi-randomised controlled clinical trials evaluating the use of bone scaffolding for treating distal radial fracture in adults.

DATA COLLECTION AND ANALYSIS

Two people independently selected studies and undertook assessment and data collection.

MAIN RESULTS

Ten heterogenous trials involving 874 adults with generally unstable fractures were grouped into six comparisons. No trial had proven allocation concealment. Four trials (239 participants) found implantation of bone scaffolding (autogenous bone graft (one trial); Norian SRS - a bone substitute (two trials); methylmethacrylate cement (one trial)) improved anatomical outcomes compared with plaster cast alone; and two found it improved function. Reported complications of bone scaffolding were transient discomfort resulting from extraosseous deposits of Norian SRS; with surgical removal of one intra-articular deposit. One trial (323 participants) comparing bone substitute (Norian SRS) versus plaster cast or external fixation found no difference in functional or anatomical outcomes at one year. Statistically significant complications in the respective groups were extraosseous Norian SRS deposits and pin track infection. One trial (48 participants with external fixation) found that autogenous bone graft did not significantly change outcome. There was one serious donor-site complication. One trial (21 participants) found some indication of worse outcomes for hydroxyapatite bone cement compared with Kapandji's intrafocal pinning. Three trials (180 participants) found bone scaffolding (autogenous bone graft (one trial); Norian SRS (one trial); methylmethacrylate cement (one trial)) gave no significant difference in functional outcomes but some indication of better anatomical outcomes compared with external fixation. Most reported complications were associated with external fixation; extraosseous deposits of Norian SRS occurred in one trial. One trial (93 participants with dorsal plate fixation) found autografts slightly improved wrist function compared with allogenic bone material but with an excess of donor site complications.

AUTHORS' CONCLUSIONS

Bone scaffolding may improve anatomical outcome compared with plaster cast alone but there is insufficient evidence to conclude on functional outcome and safety; or for other comparisons.

Augmentation of posterior wall acetabular fracture fixation using calcium-phosphate cement: a biomechanical analysis

OBJECTIVE

This study investigates if the use of calcium phosphate cement as an adjunct to internal fixation for posterior wall acetabular fracture will result in acute restoration of joint loading parameters to the intact condition.

METHODS

Ten fresh-frozen cadaveric pelves were used for this investigation. Simulated abductor mechanism was used to load the hip. Pressure-sensitive film was used to measure contact area and pressure within the anterior, superior, and posterior regions of the acetabulum for all experimental conditions. The hips were loaded under the following 4 conditions: 1) intact; 2) following posterior wall osteotomy; 3) following reduction and standard internal fixation; and 4) following reduction of the posterior wall using calcium phosphate cement, as a grout, in addition to internal fixation. A posterior wall fracture was created along an arc of 40-90 degrees about the acetabular rim. Extensometers were utilized to measure posterior wall fragment micromotion under conditions 3 and 4 above. Statistical analysis was performed using multivariate analysis of variance to assess the significance of the difference among and between conditions simultaneously for each region. Fragment motion data were analyzed using a 2-tailed t test.

RESULTS

Fragment micromotion was reduced to 78 microm superiorly and 46 microm inferiorly with the use of calcium phosphate cement (P < 0.05). Creation of a posterior wall defect resulted in increased load in the superior acetabulum (1201N) as compared to the intact condition (902N, P = 0.024). Following reduction and internal fixation, the load distributed to the superior acetabulum (1132N) was not statistically different from the displaced condition. Following the addition of calcium phosphate cement, the load seen at the superior region of the acetabulum (883N) was less than fixation without calcium phosphate cement and was not different from the intact state (P = 0.85).

CONCLUSION

The use of calcium-phosphate cement as a fracture grout with internal fixation resulted in a partial restoration of joint loading parameters toward the intact state. Further work will be needed to determine if similar types of augmented articular fixation may result in a clinical benefit.

Synthetic bone scaffolds and fracture repair

Synthetic scaffolding has been used in the treatment of bone defects and fractures for over 100 years. They remain a critical tool in the treatment of large-volume bone defects, and their role as potential substitues for human bone graft continues to expand. Various materials are used commercially to produce osteoconductive scaffolds including ceramics (both bioactive and bioinert) and select polymers, all of which offer distinct advantages and dissadvantages. While currently used principally as osteoconductive conduits for growth, the role of bone-graft substitues in fracture treatment is likely to change, as biomaterial research moves towards utilizing current and future scaffold materials as delivery systems for biologic fracture treatments.

Mechanical evaluation of fracture fixation augmented with tricalcium phosphate bone cement in a porous osteoporotic cancellous bone model

OBJECTIVE

The purpose of this study was to examine the effects of resorbable bone cement on screw and plate-screw fracture fixation in a porous osteoporotic bone model.

METHODS

Experiment 1: Screw pullout strength was assessed for 4 sets of 4.5-mm cortical screws inserted into a synthetic osteoporotic cancellous bone model, including screws inserted without cement augmentation (control), screws augmented with tricalcium phosphate (TCP) bone cement (Norian SRS; Synthes USA, Paoli, PA), and screws augmented with polymethylmethacrylate. Experiment 2: The effects of cement augmentation on plate-screw fixation strength were examined by performing cantilever bending tests on 4 sets of 8 plate-screw constructions, including nonaugmented and TCP-augmented standard and locked screw-plate constructions in a similar bone model.

RESULTS

Experiment 1: Cement augmentation with both TCP and polymethylmethacrylate increased screw pullout strength from a porous osteoporotic cancellous bone model by about 4-fold (P < 0.05), and there was no significant difference between the 2 cements (P > 0.1). Experiment 2: Fixation strength was 1.5 times higher for locked plates compared with standard plates when neither was augmented with cement (P = 0.07). Cement augmentation with TCP improved fixation strength by 3.6 times for a standard plate-screw construction (P < 0.05) and 3.3 times for a locked plate-screw construction (P < 0.05). The most stable construction was the TCP-augmented locked plate, in which a 5-fold increase was observed compared with that of standard plates without TCP (P < 0.05).

CONCLUSIONS

This study indicates augmenting screws with TCP cement during osteosynthesis improves fixation strength in an osteoporotic cancellous bone model.

CLINICAL RELEVANCE

: In fracture situations in which osteoporotic bone makes screw and screw-plate fixation tenuous, screw augmentation with TCP cement should be considered as adjunct treatment.

Cement augmentation in fracture treatment

Surgical treatment of fractures close to joints, especially in osteoporotic patients, is often associated with problems to obtain adequate strength of the bone-implant construct as well as sufficient purchase for screws in the weak bone. One way to address this increasing problem is through the development of new metal implants specifically designed for fixation of fractures in osteopenic bone. An alternative strategy is to develop methods for augmentation of the weak bone that surrounds the metal implant. In most instances augmentation is achieved by using injectable cement to reinforce the bone. Conventional PMMA provides good strength but due to several drawbacks it has never gained general acceptance for fracture augmentation. More recently several injectable cements based on calcium-phosphate, calcium-sulphate or bioglass has been developed for augmentation of fractures in the extremities as well as for vertebral compressive fractures in the spine. On the basis of biomechanical studies and the clinical experience so far, cement augmentation will enable faster rehabilitation, as the strength of the cement makes it possible to allow full weight-bearing earlier than conventional metal implants alone. More clinical studies are needed in order to refine the surgical technique, develop cement types aimed for fracture treatment and define the most appropriate indications and limitations of augmentation for fracture repair. The purpose of this article is to review the possible use of augmentation as a technique in the treatment of fractures in the extremities as well as in the spine.

Grafting of tibial bone defects in knee replacement using Norian skeletal repair system

INTRODUCTION

The authors have been using Norian skeletal repair system (SRS) to repair cancellous bone defects in knee replacements since 1999. Norian SRS is injectable, biocompatible calcium phosphate cement with a high mechanical strength. This product is similar to the mineral phase of bone and should undergo gradual remodeling with time. We present our experience with this bone substitute in a total of 13 knee replacement surgeries.

MATERIALS AND METHODS

This included three unicompartmental knee replacements (UKR), two bilateral UKR following tibial plateau fractures, five revisions of UKR to total knee replacements (TKR), two TKR revisions and one hinged knee prosthesis for significant deformity. Full weight bearing was permitted as soon as tolerated in all patients. Patients were evaluated at the latest follow-up using both the Knee Society Score (KSS) and GIUM (Italian UKR Users Group) knee scores.

RESULTS

At the latest follow-up, no poor results were seen with an improvement between pre-operative and post-operative knee scores in all cases. There was no evidence of bone loss or post-operative deformity. Complete compound resorption was seen in the first 4 cases.

CONCLUSIONS

The authors state that Norian SRS is a practical alternative as bone grafting in knee replacement surgery for type 1 and 2 bone defects.

Management of segmental bony defects: the role of osteoconductive orthobiologics

Our knowledge about, and the availability of, orthobiologic materials has increased exponentially in the last decade. Although previously confined to the experimental or animal-model realm, several orthobiologics have been shown to be useful in a variety of clinical situations. As surgical techniques in vascular anastomosis, soft-tissue coverage, limb salvage, and fracture stabilization have improved, the size and frequency of bony defects (commensurate with the severity of the initial injury) have increased, as well. Because all methods of managing segmental bony defects have drawbacks, a need remains for a readily available, void-filling, inexpensive bone substitute. Such a bone substitute fulfills a permissive role in allowing new bone to grow into a given defect. Such potential osteoconductive materials include ceramics, calcium sulfate or calcium phosphate compounds, hydroxyapatite, deproteinized bone, corals, and recently developed polymers. Some materials that have osteoinductive properties, such as demineralized bone matrix, also display prominent osteoconductive properties.

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.

Biomechanical testing of the fractured distal radius treated with a new bone cement--is it strong enough?

This study evaluates the in vitro ability of CAP, a bone graft substitute with osteointegration and osteoconductive properties, to restore the anatomy and strength of fractured distal radii. Ten pairs of cadaveric radii were imaged and tested to failure, simulating a fracture. The radii were reconstructed using CAP and were re-fractured and sequentially imaged. The deformities of the bones were determined through computerised evaluation of the radiographs. Radiographic analysis showed that CAP is capable of restoring the anatomy of the distal radius. The load and work required to fracture intact radii were compared to those required to fracture the reconstructed radii. The load to fracture was similar in the two situations. The work to fracture, however, was higher with reconstructed radii, suggesting that these are stronger than the original bones. Our study supports the hypothesis that CAP is capable of restoring the original anatomy and dimensions of the distal radius and re-establishing its mechanical strength.

Calcium phosphate cement in musculoskeletal tumor surgery

BACKGROUND AND OBJECTIVES

Calcium phosphate cement (CPC) is an injectable biocompatible bone substitute that has been used for various applications in orthopedic surgery. However, no extensive clinical studies of the use of CPC to fill bone cavities after curettage of musculoskeletal tumors have been reported. The present study reviewed the results for 56 musculoskeletal tumors treated by curettage and CPC implantation.

METHODS

Assessment was based on clinical examination and radiographic findings. Variables for clinical assessment included pain, limb function, and complications. Median follow-up was 18.5 months (range 6-47 months).

RESULTS

One patient experienced post-operative fractures. Three patients displayed local recurrence. One patient developed post-operative superficial wound infection, and two patients with large bony defect exhibited non-infectious serous discharge. No serious adverse effects such as deep venous thrombosis, pulmonary embolism were encountered. In all cases, CPC was radiographically well adapted to the surrounding host bone as of final follow-up.

CONCLUSIONS

CPC appears to offer a useful bone substitute for the treatment of musculoskeletal tumors. As the follow-up period for this study was short, further long-term follow-up studies are needed.

Bone substitutes: an update

Autograft is considered ideal for grafting procedures, providing osteoinductive growth factors, osteogenic cells, and an osteoconductive scaffold. Limitations, however, exist regarding donor site morbidity and graft availability. Allograft on the other hand, posses the risk of disease transmission. Synthetic graft substitutes lack osteoinductive or osteogenic properties. Composite grafts combine scaffolding properties with biological elements to stimulate cell proliferation and differentiation and eventually osteogenesis. We present here an overview of bone grafts and graft substitutes available for clinical applications.

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.

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.

The Use of Novabone and Norian in Cranioplasty: A Comparative Study

Bone replacement products have enhanced the ease of reconstructing bone while improving morbidity related to bone harvest. Although these products are successfully used, studies of bone healing and biomechanical strength are lacking. We aimed to compare how Norian CRS (cranial replacement substance) and Novabone C/M heal in a cranial defect. Adult New Zealand rabbits underwent removal of a critical size cranial defect. The defect was filled with Novabone (n = 8), Novabone plus demineralized bone matrix (n = 8), or Norian (n = 8), or it was left empty (n = 8). Rabbits were euthanized at 8 weeks. Cranial specimens were harvested and soft radiographs, contact microradiographs, and biomechanical testing were done. Soft radiographs revealed opacification like adjacent bone with Novabone, which was augmented when Novabone was combined with demineralized bone matrix. Norian maintained an opaque appearance. The control group did not heal. Contact microradiographs demonstrated bone within the healing defect with Novabone, which was augmented by demineralized bone matrix. Norian was not replaced with bone but served as a scaffold for bone formation. Biomechanical indentation testing demonstrated that the stiffness of Norian was the highest. Novabone plus demineralized bone matrix had a higher stiffness than Novabone alone. All experimental groups had a statistically significant difference compared with Norian. None of the groups achieved the strength of unoperated native bone. Studying two popular products, we found evidence that Novabone was incorporated into cranial bone, regenerating the bone. Novabone healed at a faster rate, creating a stronger product, with demineralized bone matrix. The biomechanical strength of the healed defect was higher in the Norian group, because the bone cement remained solid and was not incorporated, unlike crania reconstructed with Novabone.

Degradable injectable bone cement in maxillofacial surgery: indications and clinical experience in 27 patients

BACKGROUND

A carbonated apatite cement (NORIAN SRS) was used as a bone mineral substitute for the calvaria or viscerocranium in 27 patients. It has the consistency of a paste and hardens at physiologic pH and body temperature due to dahllite crystallization, which has the stoichiometric formula Ca(8.8)(HPO(4))(0.7)(PO(4))(4.5)(CO(3))(0.7)(OH)(1.3).

MATERIAL AND METHODS

The cement was used for posttraumatic bone defects in the orbital, periorbital or malar regions (nine patients), posttraumatic deformities of the frontal bone (six patients), tumour-dependent bony defects of the calvaria (two patients) and posttraumatic or cystic defects of the mandible (five patients). In another five patients, the material was used to augment the atrophic anterior mandible in combination with the insertion of dental implants. Follow-up varied between 6 and 40 months (mean: 29 months).

RESULTS

There was no inflammatory reaction surrounding the implanted material. There was no sign of infection in any of the patients and only one case of partial wound dehiscence with superficially exposed material. The defect fillings and augmentations were successful in all patients. None of the 19 dental implants which were inserted in combination with the material showed any sign of infection or loosening. Also, there was no loosening of the implants after loading (mean follow-up: 15 months). From the check-up radiographs, the material could be seen as a dense, radio-opaque structure. There were no material fractures or dislocations. Radiologically, the material seemed to be completely replaced by bony tissue after 30 months.

CONCLUSION

Our 5-year clinical experience suggests that the material is a suitable bone mineral substitute for cranio-maxillofacial surgery especially for moderate-sized defects of the calvaria and forehead bone. It has advantages over preformed, solid bone substitute materials, and, due to its initial plasticity and eventual great compressive strength, it can also stabilize dental endosseous implants in the atrophic mandible.

Augmentation expérimentale de la résistance du radius distal ostéoporotique par un ciment phosphocalcique

Diagnosis and treatment of osteoporosis are focused on demineralisation but bone mineral density is not directly correlated with bone strength. As with every material, the mechanical strength of bone depends upon its Young's modulus and its cross-sectional moment of inertia. In the clinical situation, bone strength can be quantified using peripheral quantitative computed tomography imaging (pQCT), a non-invasive imaging method, which allows calculation of a strength index. In this study, we tried to increase the fracture threshold of the distal radius by directly increasing bone strength rather than density. Twenty wrists in 10 cadavers were filled percutaneously with a calcium phosphate cement. Fluoroscopy and pQCT were performed twice, once before cementing and again 24 h after cement crystallisation to hydroxyapatite. We obtained measurements of trabecular and total bone density, and also stress strain index (SSI). Our results showed that trabecular bone density increased by a factor of 2.85, whereas total bone density increased by 1.61 and SSI by 1.99. Fluoroscopy showed two small leaks of cement at the point of injection. This study demonstrated that percutaneous injection of calcium phosphate cement increased distal radius strength, and consequently its fracture threshold. This technique could be employed in the future to prevent the occurrence of fractures in osteoporotic patients.

Bone graft for revision hip arthroplasty: biology and future applications

Revision total hip arthroplasty often presents surgeons with difficult bone loss problems. The selection of an appropriate bone graft is influenced by the size of the bone defect, the location, the biology of the bone graft site, and whether the graft is required for structural support. Autogenous bone graft remains the gold standard bone graft material but there only is a limited amount available and there is morbidity associated with the harvesting of these grafts. The most frequently used bone graft materials include autogenous iliac crest bone graft, cancellous allograft chips, demineralized bone matrix, and bulk structural allografts (femoral head, distal or proximal femoral allograft, whole acetabuli, and femoral strut grafts). It often is difficult to determine on plain radiographs whether nonstructural grafts actually incorporate into the host bone. Recently, attention has focused on the use of new materials for bone grafting including: new demineralized bone matrices, ceramics, autologous platelet concentrates, recombinant proteins, and stem cells. The purpose of this review was to assess the biologic potential of these nonstructural grafts in revision hip arthroplasty and their limitations. Are these agents actually incorporating into host bone? Future bone graft options, including tissue engineering and gene therapy will be discussed briefly.