Improvement of the bone-pin interface strength in osteoporotic bone with use of hydroxyapatite-coated tapered external-fixation pins. A prospective, randomized clinical study of wrist fractures

No effect of hydroxyapatite-coated sliding hip screw threads on screw migration in the femoral head/neck of pertrochanteric fractures: a randomized controlled trial using radiostereometric analysis

INTRODUCTION

Cut-out is the most frequently reported mechanical failure of internal fixation of pertrochanteric fractures. The purpose of this study was to examine if hydroxyapatite-coated screw thread on a sliding hip screw (SHS) could reduce screw migration within the femoral head in patients with stable pertrochanteric fractures.

MATERIALS AND METHODS

In a double-blinded randomized controlled study, 37 patients at mean age 78 (range 56-96), with pertrochanteric fracture (Evans I, II, IV) received surgery with a SHS with a hydroxyapatite-coated or a non-coated lag screw thread. Radiostereometry and standard radiographs were obtained 1 day, 6 weeks, 3- and 6 months post-operatively to evaluate screw and fracture migration and fracture reposition. The two groups were combined to describe fracture migration.

RESULTS

There was similar and small screw migration in the femoral head between the two groups at 6 weeks, 3- and 6 months (p > 0.12). Fracture migration occurred predominantly in the first 6 weeks, where fracture impaction was 5.95 mm (CI 95% 2.87 to 9.04) and anterior rotation of the femoral head was -2.94° (CI 95% - 5.22 to - 0.66). Migration of the fracture (total translation) correlated to the post-operative fracture reposition (p = 0.002), but not significantly to screw migration (p = 0.09). Neither screw total translation (rho 0.06, p = 0.79) nor fracture total translation (rho 0.04, p = 0.77) correlated with bone mineral density.

CONCLUSION

There was no clinical benefit of hydroxyapatite coating on lag screw migration in this patient cohort. Migration of the pertrochanteric fractures was higher with poor fracture reposition but fractures generally stabilized after 6 weeks follow-up. The study was registered at ClinicalTrials.gov (NCT05677061).

LEVEL OF EVIDENCE II

Patient-blinded prospective randomized study. Trial registration number The study was registered at ClinicalTrials.gov (NCT05677061).

Avoiding iatrogenic vascular injury in tibial external fixation with half pins. An in-vivo study based on CT angiography

BACKGROUND

External fixation is an important tool in the management of variety of tibial fractures. Appropriate half pin insertion is important, to provide stable fixation without compromising the surgical field for definitive surgical procedures, and avoiding further damage to the important structures of the traumatized limb. There is paucity of literature about the optimal trajectories and safe corridors for half pins insertion based on in vivo studies. The available studies are based on anatomic atlases, cadaveric studies or half pin related complications.The aim of the current study is to present the findings of CT angiograms, in patients with external fixation of tibia, to enhance our understanding of optimal trajectories in safe corridors for half pins insertion.

MATERIAL AND METHODS

We performed a retrospective study of patients with external fixators on the tibia, who had undergone CT angiogram as part of pre-operative planning for orthoplastic reconstructive procedures. The relationship between the tips of the fixator half pins and named vessels of the leg were analyzed, pins within 5 mm of a named vessel were considered to be a risk of causing iatrogenic injury.

RESULTS

A total 51 patients, with in situ temporizing external fixators, with 134 half pins in different segments of the tibia were analyzed. More than 5 mm of penetration beyond the far cortex was noted in 47%, while in another 16% of pins penetration was more than 10 mm beyond the cortex. A tip to vessel distance (TVD) of 5 mm or less was noted in 28/134 (21%) of the pins, which highlights potential risk to the neurovascular bundles of the leg.

CONCLUSION

Risk of iatrogenic injury to neurovascular structures from half pin insertion can be reduced by meticulous use of fluoroscopy, by avoiding penetration beyond the far cortex, and avoiding exiting with half pins on the lateral surface in the distal 1/3rd of segment II of tibia. Moreover observing optimal trajectories and safe corridors for pin insertion, and selection of appropriate type of half pin can mitigate the risk to these structures.

Role of coatings and materials of external fixation pins on the rates of pin tract infection: A systematic review and meta-analysis

BACKGROUND

Infection at the pin tract is a frequent and feared complication of external fixators (EF). The type of pin material and coatings have been regarded as possibly influencing infection rates. Over the last 20 years, few prospective clinical studies and systematic reviews addressed the role of coated pins on the rate of pin site infection in human clinical studies.

AIM

To assess the EF literature over the past 20 years on the clinical benefits of pins manufactured from varied materials and coating systems and their possible role in pin tract infection rates.

METHODS

We performed a systematic review according to the PRISMA and PICOS guidelines using four scientific platforms: PubMed, LiLacs, SciELO, and Cochrane. We searched the literature for related publications over the past 20 years.

RESULTS

A literature search yielded 29 articles, among which seven met the inclusion criteria. These studies compared stainless-steel pins and pins coated with hydroxyapatite (HA), titanium and silver. The pin tract infection definitions were arbitrary and not standardized among studies. Most studies included a low number of patients in the analysis and used a short follow-up time. Three meta-analyses were carried out, comparing stainless steel vs silver pins, stainless steel vs HA-coated pins, and titanium vs HA-coated pins. None of this analysis resulted in statistically significant differences in pin tract infection rates.

CONCLUSION

Currently, no clinical evidence supports the advantage of EF pins manufactured with materials other than stainless steel or coated over uncoated pins in reducing the rates of pin tract infections. A standardized definition of pin tract infection in external fixation is still lacking.

An Assessment of Randomized Controlled Trial Quality in The Journal of Bone & Joint Surgery: Update from 2001 to 2013

BACKGROUND

The quality of reporting of randomized controlled trials (RCTs) published in The Journal of Bone & Joint Surgery (JBJS) from 1988 to 2000 was previously analyzed. The purpose of this current study was to analyze the quality of reporting of RCTs published in JBJS from 2001 to 2013 to identify trends over time and potential areas of improvement for future clinical trials.

METHODS

A manual search of the JBJS database identified RCTs published between January 2001 and December 2013. Quality assessments, using the Detsky quality-of-reporting index (Detsky score), a modified Cochrane risk-of-bias tool, and abstraction of relevant data identifying predictors of quality, were conducted.

RESULTS

A total of 5,780 publications were identified in JBJS from 2001 to 2013, with 285 RCTs (4.9%), representing an increase from the prior 13-year period. The overall mean transformed Detsky score (and standard error) increased significantly (p < 0.001) from 68.1% ± 1.67% to 76.24% ± 0.72%. The percentage of multicenter RCTs decreased from 67% to 31%. The percentage of positive trials also decreased from 80% to 50.5%, as did the mean sample size (212 to 166). Regression analysis indicated that trials with an epidemiologist as the first author and nonsurgical trials were significantly associated (p = 0.001) with a higher overall trial quality score. The categories of the lowest mean methodology scores were randomization and concealment, eligibility criteria, and reasons for patient exclusion, as identified with the Detsky score, and patient and assessor blinding, as identified with the risk-of-bias assessment.

CONCLUSIONS

The quantity and quality of published RCTs in JBJS have increased in the 2001 to 2013 time period compared with the previous time period. Although these improvements are encouraging, trends to smaller, single-center trials were also observed. To efficiently determine the efficacy of orthopaedic treatments and limit bias, high-quality randomized trials of appropriate sample size and rigorous design are needed.

Use of Polyphenol Tannic Acid to Functionalize Titanium with Strontium for Enhancement of Osteoblast Differentiation and Reduction of Osteoclast Activity

Implant anchorage remains a challenge, especially in porous osteoporotic bone with high osteoclast activity. The implant surface is modified with osteogenic molecules to stimulate osseointegration. Strontium (Sr) is known for its osteogenic and anti-osteoclastogenic effects. In this study, Sr was immobilized on a titanium (Ti) surface using bioinspired polyphenol tannic acid (pTAN) coating as an ad-layer (Ti-pTAN). Two separate coating techniques were employed for comparative analysis. In the first technique, Ti was coated with a tannic acid solution containing Sr (Ti-pTAN-1Stp). In the second method, Ti was first coated with pTAN, before being immersed in a SrCl2 solution to immobilize Sr on Ti-pTAN (Ti-pTAN-2Stp). Ti-pTAN-1Stp and Ti-pTAN-2Stp augmented the alkaline phosphatase activity, collagen secretion, osteocalcin production and calcium deposition of MC3T3-E1 cells as compared to those of Ti and Ti-pTAN. However, osteoclast differentiation of RAW 264.7, as studied by TRAP activity, total DNA, and multinucleated cell formation, were decreased on Ti-pTAN, Ti-pTAN-1Stp and Ti-pTAN-2Stp as compared to Ti. Of all the substrates, osteoclast activity on Ti-pTAN-2Stp was the lowest. Hence, an economical and simple coating technique using pTAN as an adlayer preserved the dual biological effects of Sr. These results indicate a promising new approach to tailoring the cellular responses of implant surfaces.

Bioinspired polydopamine and polyphenol tannic acid functionalized titanium suppress osteoclast differentiation: a facile and efficient strategy to regulate osteoclast activity at bone-implant interface

Osseointegration of metallic implants in porous osteoporotic bone remains a challenge. Surface modification of implants to reduce peri-implant osteoclastic bone resorption was explored in the study. Bioinspired polydopamine (pDOP) and polyphenol tannic acid (pTAN) are nature-derived universal coating systems that have emerged either as a sole coating or ad-layer for biomolecular conjugation on different biomaterials. The effects pDOP and pTAN on osteoclast development have not been reported before. In this study, osteoclast development was investigated on titanium (Ti) substrates coated with pDOP (Ti-pDOP) and pTAN (Ti-pTAN). The results showed that Ti-pDOP and Ti-pTAN coating reduced tartrate-resistant acid phosphatase activity and osteoclast cell number as compared with pristine Ti. Intriguingly, the reduction was higher on Ti-pTAN than on Ti-pDOP. Economical and biocompatible tannic acid serves as a superior coating in decreasing osteoclast activity when compared with that of pDOP coating and could be used to modulate osteoclast activity at bone-implant interfaces.

Initial clinical trial of pins coated with fibroblast growth factor-2-apatite composite layer in external fixation of distal radius fractures

Background

Pin tract infection and loosening are major complications and challenges in the treatment of fractures by external fixation. To address this issue, we developed titanium pins coated with a fibroblast growth factor 2 (FGF-2)-apatite composite layer. The purpose of this initial clinical trial is to clarify the safety and feasibility of using these pins for the external fixation of distal radius fractures.

Methods

Unstable, displaced fractures of the distal radius that were medically suitable for external fixation were treated using external fixation pins coated and uncoated with an FGF-2-apatite composite layer. The coated pin group (n = 5) comprised 5 women (average age, 70.4 ± 5.9 years), whereas the uncoated pin group (n = 10) comprised 8 women and 2 men (average age, 64.4 ± 11.7 years). The average duration of external fixation was 40.8 ± 1.3 and 41.6 ± 2.1 days for the coated and uncoated pin groups, respectively.

Results

All patients achieved fracture union. One patient in the uncoated group had severe pin tract infection on the day of pin extraction. No pin loosening or difficulty in pin removal was observed in either group. Bacterial growth was present in 5% and 25% of the pin sites in the coated and uncoated groups, respectively (p = 0.059). No adverse events such as tumor formation were observed for more than 2 years after surgery in the coated pin group.

Conclusions

This study clarified the safety and feasibility of using pins coated with an FGF-2-apatite composite layer for the external fixation of distal radius fractures.

Biomedical Coatings to Improve the Tissue-Biomaterial Interface

One of the most important factors determining the degree of tissue interaction of an implanted device is the property of its surface. Thus, great importance is given to chemical and morphological characteristics of biomaterial surfaces to improve biocompatibility, cell migration, proliferation and differentiation, mechanical stability and endogenous tissue ingrowth.

In order to obtain new and healing stimulating properties, it is possible to apply a coating or more generally a surface treatment to the surface of a prosthetic device. One of the most versatile methods for coating is thermal spray technology. This paper considers the principle of thermal spray processes and their application in the biomedical field, namely the coatings used for orthopedic prostheses and dental implants. Among thermal spray processes, plasma spray as well as High Velocity Oxygen Fuel (HVOF) processes will be particularly considered and their most important aspects will be illustrated.

Segmental Bone Loss Reconstruction Using Ring Fixation

Ring fixation is a powerful tool in the treatment of bone defects. The ability to create high-quality, biologically normal new bone of even massive proportions using distraction osteogenesis is a major reason for its success. In addition, ring fixation provides the ability to limit the risk of deep infection, improves flexibility in limb length control and alignment, and increases soft tissue coverage options. The drawbacks of ring fixation include long frame times, pin problems, risk of joint contractures, and difficult usage in areas with a large soft tissue envelope such as the thigh. Significant advancements such as hydroxyapatite coated pins, internal cable transport, multifocal transport, and combined techniques with internal fixation have helped increase the effectiveness of ring fixator use by minimizing many of the drawbacks. At present, ring fixation provides the most effective means of treatment for large bone defects in many clinic situations.

In Vitro Findings of Titanium Functionalized with Estradiol via Polydopamine Adlayer

To improve orthopedic implant fixation and reduce post-operative complications, osteogenic molecules are delivered locally by immobilizing them on the surface of implants, which will modulate the biology of cell attachment and differentiation on the implant surface. Estradiol, a natural steroid hormone, maintains bone metabolism by decreasing bone resorption. It either directly or indirectly affects osteoclasts. In this work, estradiol was immobilized on a titanium surface by polydopamine adlayer. Immobilization of estradiol was confirmed by X-ray electron spectroscopy (XPS), immunofluorescence staining and enzyme-linked immunosorbent assay (ELISA). Estradiol-modified substrates enhanced alkaline phosphatases activity (ALP) and calcium deposition of osteoblasts. However, these substrates did not decrease tartrate-resistant acid phosphatase (TRAP) activity and actin ring formation of the osteoclast. The scanning electron microscopic (SEM) images of estradiol-modified substrates showed the formation of estradiol crystals, which decreased the potency of immobilized estradiol. Despite having a successful immobilization of estradiol via the polydopamine technique, the bioavailability and potency of coated estradiol is reduced due to crystallization, suggesting that this is not a suitable system for localized estradiol delivery as tested in vitro here. Consequently, other suitable platforms have to be explored for immobilizing estradiol that will prevent crystal formation while preserving the biological activity.

Tantalum-coated pedicle screws enhance implant integration

Because titanium alloy (Ti) has the natural advantage of a low elastic modulus, it has become the most commonly used material for the manufacturing of pedicle screws. However, its poor shear strength and osteogenic ability are undesirable properties. The superior osteoinductivity demonstrated by tantalum (Ta) in oral and maxillofacial surgery and joint surgery leads us to assume that the tantalum-coated pedicle screws may have better osteogenic properties and bone anchoring strength. To verify this hypothesis, MC3T3-E1 cells and human mesenchymal stem cells (hBMSCs) were seeded on the surface of Ta and Ti disks to compare the effects of two different metals on cell adhesion, proliferation, and differentiation. At the same time, we observed the inhibitory effect of Ta on osteoclasts. As an in vivo study, conventional Ti pedicle screws and Ta-coated screws were implanted in bilateral pedicles of Bama pigs. The results showed that compared to titanium, tantalum promoted greater cell adhesion and proliferation and improved the level of hBMSC mineralization, and Ta-coated screws exerted an inhibitory effect on osteoclasts. More importantly, we found that the effect of tantalum on osteogenic differentiation was mediated through the Wnt/β-catenin and TGF-β/smad signaling pathways. Ta-coated screws significantly promoted trabecular bone growth compared with Ti as evidenced by micro-CT, histology and biomechanical examination. Our study clearly indicated that tantalum was a superior promoter of osteogenesis and proved that tantalum coating is an effective improvement for titanium alloy implants.

Definitive Management of Distal Tibia and Simple Plafond Fractures With Circular External Fixation

Obtaining optimal results in the treatment of extraarticular distal tibia fractures can be challenging. Plate and screw and intramedullary fixation have proven to be effective treatments, but are associated with significant complication rates when used for open fractures and patient with severe medical comorbidities. External fixation is a third alternative that is less often employed, but provides a very effective means of treatment. Circular external fixation offers great flexibility in obtaining anatomic alignment and stable fixation for even the most challenging distal tibia fractures. In addition, it provides advantages in limiting the risk of deep infection, dealing with bone loss, and obtaining soft tissue coverage. The greater ease of treatment and potential economic advantage in patient cohorts with low complication rates, such as closed fractures, supports the preferential use of internal fixation. However, circular external fixation may be the preferred treatment for patients with higher-grade open fractures, a poor soft tissue envelope with limited fixation options distally, and major comorbidities (diabetes, immune deficiency) with an associated high risk of complications.

Application of the skin and bone integrated pylon with titanium oxide nanotubes and seeded with dermal fibroblasts

BACKGROUND

Direct skeletal attachment of limb prostheses is associated with high rate of transcutaneous infection and loosening of the fixture in the medullary canal prompting for careful assessment of various means for enhancing the skin-device and bone-device interface. The skin and bone integrated pylon system constitutes a technological platform for different modifications being evaluated previously.

OBJECTIVES

The current study assessed the combination of nano-treatment skin and bone integrated pylon with its pre-seeding with dermal fibroblasts. We hypothesized that this combination will enhance cell interaction with skin and bone integrated pylon compared to nano-treatment and the fibroblast seeding when done separately.

STUDY DESIGN

The feasibility and safety of in-bone implantation of the skin and bone integrated pylon with nanotubes was investigated in vitro and in vivo in the animal model.

METHODS

TiO2 nanotubes were fabricated on the skin and bone integrated pylon, and the fibroblasts taken from rabbit's skin were cultured on the pylons before implantation.

RESULTS

The in vitro experiments demonstrated higher cellular density in the samples with a nanotubular surface than in the non-modified pylons used as control. There were no postoperative complications in any of the animals during the 6-month observation period. Subsequent scanning electron microscopy of the pylon extracted from the rabbit's femur showed the stable contact between the pylon and soft tissues in comparison to control samples where the patchy fibrovascular ingrowth was detected.

CONCLUSION

The promising results prompt further investigation of the integrative properties of the nanotextured skin and bone integrated pylon system seeded with dermal fibroblasts and its optimization for clinical application.

CLINICAL RELEVANCE

The study is devoted to the development of more safe and efficient technology of direct skeletal attachment of limb prostheses aimed in improving quality of life of people with amputations.

Standards of external fixation in prolonged applications to allow safe conversion to definitive extremity surgery: the Aachen algorithm for acute ex fix conversion

External fixation has become an important tool in orthopedic surgery. Technology has improved the design and material as well as the construct of the fixator. As most patients are converted from external fixation to definite stabilization during later clinical course, prevention of complications such as infection is of high importance. Based on the current literature, principles of temporary external fixation were summarized. We focused on minimizing the risk of infection and introduce a standardized algorithm how to proceed when converting from external to internal fixation, which also was examined for effectiveness.

External fixation in the elderly

Orthopaedic trauma is an increasingly common problem in geriatric patients. As demands of daily life and recreational activities are increasing in these patients, surgeons need to be able to manage geriatric fractures to achieve good functional results. Reduced bone quality in the elderly presents a considerable challenge and may preclude the use of established surgical stabilisation techniques that are performed in younger trauma patients. Furthermore, pre-existing medical conditions and considerable comorbidities in the elderly could complicate standard surgical procedures that younger patients would be offered. In this respect, application of external fixators represents a validated, minimally-invasive treatment opportunity. This review article summarises the use of external fixation in geriatric trauma patients for wrist fractures, proximal femoral fractures, pelvic fractures, and ankle fractures. Modern modifications, like pin coating with hydroxyapatite, and aspects of pin care will be discussed.

Bioabsorbable fish scale for the internal fixation of fracture: a preliminary study

Fish scales, which consist of type I collagen and hydroxyapatite (HA), were used to fabricate a bioabsorbable bone pin in this study. Fresh fish scales were decellularized and characterized to provide higher biocompatibility. The mechanical properties of fish scales were tested, and the microstructure of an acellular fish scale was examined. The growth curve of a myoblastic cell line (C2C12), which was cultured on the acellular fish scales, implied biocompatibility in vitro, and the morphology of the cells cultured on the scales was observed using scanning electron microscopy (SEM). A bone pin made of decellularized fish scales was used for the internal fixation of femur fractures in New Zealand rabbits. Periodic X-ray evaluations were obtained, and histologic examinations were performed postoperatively. The present results show good cell growth on decellularized fish scales, implying great biocompatibility in vitro. Using SEM, the cell morphology revealed great adhesion on a native, layered collagen structure. The Young's modulus was 332 ± 50.4 MPa and the tensile strength was 34.4 ± 6.9 MPa for the decellularized fish scales. Animal studies revealed that a fish-scale-derived bone pin improved the healing of bone fractures and degraded with time. After an 8-week implantation, the bone pin integrated with the adjacent tissue, and new extracellular matrix was synthesized around the implant. Our results proved that fish-scale-derived bone pins are a promising implant material for bone healing and clinical applications.

Arthroscopic fragment fixation using hydroxyapatite/poly-L-lactate Acid thread pins for treating elbow osteochondritis dissecans

BACKGROUND

Various procedures, such as arthroscopic debridement, osteochondral transplantation, and bone plug fixation, have been described for the treatment of osteochondritis dissecans (OCD) of the humeral capitellum. However, the use of hydroxyapatite/poly-L-lactate acid (HA/PLLA) thread pins to fix the osteochondral fragment in an OCD lesion is a recent development.

HYPOTHESIS

Adolescent throwing athletes would return to preinjury levels of function after arthroscopic osteochondral fragment fixation using HA/PLLA thread pins.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Enrolled in this prospective cohort study were 18 adolescent baseball players (mean age, 14.2 years; range 12-16, years) with elbow OCD who underwent arthroscopic fragment fixation with HA/PLLA thread pins between 2006 and 2009. All patients were affected on their dominant side. Plain radiographs taken before surgery showed an open physis in 13 patients (72%) and a closed physis in 5 patients (28%). During surgery, the condition of the OCD lesion was evaluated by use of the International Cartilage Research Society (ICRS) classification system; there were 5 grade II, 11 grade III, and 2 grade IV cases. Outcomes were assessed after 3 years (mean, 39 months; range, 36-50 months). Elbow function was measured using the Timmerman and Andrews score and the Mayo Elbow Performance Index. Return to sports activity was assessed as higher than preinjury, same level, lower level, or no return to sports.

RESULTS

The mean Timmerman and Andrews score improved significantly from 126.6±6.5 to 197.5±1.5, and the mean Mayo Elbow Performance Index improved significantly from 68.0±2.1 to 98.06±0.9 (P=.0001 for both). Mean elbow extension improved significantly from -10°±10.4° to -0.8°±5.2° (P=.006), and mean flexion improved significantly from 123.1°±17.9° to 138.6°±6.1° (P=.001). Three patients had a loss of extension greater than 5°. Five patients returned to a higher level of sports activity, 10 patients returned to the same level, and 2 patients returned to a lower level. A remaining patient did not return to baseball. In one patient, the lesion did not heal, resulting in fragmentation at 1 year after surgery. This patient consequently underwent revision arthroscopy to remove the lesion, and he eventually returned to sports at the same level of activity.

CONCLUSION

Arthroscopic fragment fixation using HA/PLLA thread pins provides a beneficial clinical outcome to adolescent baseball players with humeral capitellar OCD.

Treatment of intertrochanteric fractures in elderly highrisk patients: dynamic hip screw vs. external fixation

INTRODUCTION

Although the use of a dynamic hip screw (DHS) is considered to be the preferred treatment for intertrochanteric fractures, the external fixation device could produce clinical outcomes comparable to the outcomes obtained with conventional treatment. Furthermore, because external fixation is minimally invasive, we expected a lower rate of morbidity. Therefore, we compared the two treatments in a clinical trial of elderly patients with intertrochanteric fracture.

METHODS

60 elderly high-risk patients with an average age of 78 years were treated for intertrochanteric fracture, resulting from a low energy trauma. Patients were randomly divided in two groups regarding to treatment. In Group A the patients were treated with DHS, while in Group B were treated with external fixator.

RESULTS

The fixator was well accepted and no patient had significant difficulties while sitting or lying. The average intraoperative time was 73 min in Group A and 15 min in Group B (p<0.05). 27 patients of Group A need blood transfusion postoperatively and none in Group B (p<0.05). The mean duration of hospitalization in Group A and Group B was 8.4 and 2.2 days, respectively (p<0.05). 9 of patients Group B had pin-track infection grade 2 that all were treated by oral antibiotics. There were no differences in comorbidities, quality of reduction, screw cut out, bed sore and HHS between the two groups.

CONCLUSION

Treatment with external fixator is an effective treatment for intertrochanteric fractures in elderly highrisk patients. The advantages include quick and simple application, minimal blood loss, less radiation exposure, adequate fixation, pain reduction, early discharge from hospital, low costs and favourable functional outcomes.

Prevention of infection in external fixator pin sites

Infection in external fixator pins is known to be a significant problem, with incidences between 3% and 80% reported in the literature. An infection occurs when planktonic bacteria adhere to external fixator pins and subsequently produce a biofilm which protects the bacteria from host defences. The most commonly implicated organisms are Staphylococcus aureus and Staphylococcus epidermidis. Once an infection occurs, treatment is difficult. Systemic antibiotics have limited benefits and considerable side-effects. The only definitive management is removal of the pin. This review will consider the current and potential future strategies for reducing pin site infection. Techniques to prevent infection must prevent bacterial adhesion, allow good osteointegration and have a low toxicity. Current areas of interest reviewed are titanium-copper alloys, nanosilver coatings, nitric oxide coatings, chitosan coatings, chlorhexidine and iodine, hydroxyapatite and antibiotic coatings. At present there is no consensus on the prevention of pin site infection, and there is a paucity of randomized controlled trials on which to draw a conclusion. Whilst a number of these strategies have potential future use, many of the above strategies need further studies in animal models to ensure no cytotoxicity and prevention of osteointegration. Following this, well-designed randomized controlled clinical trials are required to give future ways to prevent external fixator pin site infections.

Hydroxyapatite-coated external fixation pins

The aim of this review is to report on studies of hydroxyapatite-coated external fixation pins as a solution to enhance pin fixation. In a highly loaded animal study, three tapered pin types were compared: Type A uncoated, Type B coated with hydroxyapatite and Type C coated with titanium. There was a 13-fold increase in the extraction torque of Type B pins compared with Type A, and a twofold increase compared with Type C pins. Extraction torque was significantly lower compared with the corresponding insertion torque in both Types A (p < 0.001) and C (p = 0.003). Conversely, with the hydroxyapatite-coated pins there was no difference between extraction and insertion torque. In a clinical study of 76 external fixation pins in 19 patients treated with hemicallotasis for osteoarthritis on the medial side of the knee, pin insertion and extraction torque forces were measured. The patients were randomized to be treated with either standard tapered pins or tapered pins coated with hydroxyapatite. Extraction torque of the hydroxyapatite-coated pins was higher than the extraction torque of the standard pins in both cancellous and cortical bone (p < 0.005). In a prospective, randomized clinical study of osteoporotic wrist fractures, extraction torque of the coated pins was higher than with standard pins (p < 0.0001). These studies demonstrate that with the use of hydroxyapatite-coated pins, no deterioration of pin fixation occurs, and that there is no significant pin loosening and infection, regardless of bone type and loading conditions.

Surgeon perception of cancellous screw fixation

OBJECTIVES

The ability of surgeons to optimize screw insertion torque in nonlocking fixation constructs is important for stability, particularly in osteoporotic and cancellous bone. This study evaluated screw torque applied by surgeons during synthetic cancellous fixation. It evaluated the frequency with which screws were stripped by surgeons, factors associated with screw stripping, and ability of surgeons to recognize it.

METHODS

Ten surgeons assembled screw and plate fixation constructs into 3 densities of synthetic cancellous bone while screw insertion torque and axial force were measured. For each screw, the surgeon recorded a subjective rating as to whether or not the screw had been stripped. Screws were then advanced past stripping, and stripped screws were identified by comparing the insertion torque applied by the surgeon to the measured stripping torque.

RESULTS

Surgeons stripped 109 (45.4%) of 240 screws and did not recognize stripping 90.8% of the time when it occurred. The tendency to strip screws was highly variable among individual surgeons (stripping ranging from 16.7% to 83.3%, P < 0.0001) and did not correlate with synthetic bone density in the range tested (P = 0.186) nor with the ranking of surgeons as resident or attending surgeon (P = 0.437). Screws that were correctly recognized as stripped retained a mean 55.0% of maximum torque, less than when stripping was not recognized (79.6%, P = 0.005).

CONCLUSIONS

Surgeon perception is not reliable at preventing and detecting screw stripping at clinical torque levels in synthetic cancellous bone. Less aggressive insertion or standardized methods of insertion may improve the stability of nonlocking screw and plate constructs.

Pin site care for preventing infections associated with external bone fixators and pins

BACKGROUND

Metal pins are used to apply skeletal traction or external fixation devices in the management of orthopaedic fractures. These percutaneous pins protrude through the skin, and the way in which they are treated after insertion may affect the incidence of pin site infection. This review set out to summarise the evidence of pin site care on infection rates.

OBJECTIVES

To assess the effect on infection rates of different methods of cleansing and dressing orthopaedic percutaneous pin sites.

SEARCH METHODS

In September 2013, for this third update, we searched the Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL.

SELECTION CRITERIA

We evaluated all randomised controlled trials (RCTs) that compared the effect on infection and other complication rates of different methods of cleansing or dressing orthopaedic percutaneous pin sites.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the citations retrieved by the search strategies for reports of relevant RCTs, then independently selected trials that satisfied the inclusion criteria, extracted data and undertook quality assessment.

MAIN RESULTS

A total of eleven trials (572 participants) were eligible for inclusion in the review but not all participants contributed data to each comparison. Three trials compared a cleansing regimen (saline, alcohol, hydrogen peroxide or antibacterial soap) with no cleansing (application of a dry dressing), three trials compared alternative sterile cleansing solutions (saline, alcohol, peroxide, povidone iodine), three trials compared methods of cleansing (one trial compared identical pin site care performed daily or weekly and the two others compared sterile with non sterile techniques), one trial compared daily pin site care with no care and six trials compared different dressings (using different solutions/ointments and dry and impregnated gauze or sponges). One small blinded study of 38 patients found that the risk of pin site infection was significantly reduced with polyhexamethylene biguanide (PHMB) gauze when compared to plain gauze (RR 0.23, 95% CI 0.12 to 0.44) (infection rate of 1% in the PHMB group and 4.5% in the control group) but this study was at high risk of bias as the unit of analysis was observations rather than patients. There were no other statistically significant differences between groups in any of the other trials.

AUTHORS' CONCLUSIONS

The available trial evidence was not extensive, was very heterogeneous and generally of poor quality, so there was insufficient evidence to be able to identify a strategy of pin site care that minimises infection rates. Adequately-powered randomised trials are required to examine the effects of different pin care regimens, and co-interventions - such as antibiotic use - and other extraneous factors must be controlled in the study designs.

Treatment of non-unions with bone defects: which option and why?

Bone defects associated with non-unions occur as a result of the initial insult or as a consequence of bone excision following non-union development. Historically management of this clinical scenario consisted mainly of amputation, which provided a short recovery period but a significant loss of limb function. Today treatment has evolved and multiple options are available for reconstruction of the bone defect. Broadly these are: bone shortening with lengthening later or bone transport and 'docking' (distraction osteogenesis based techniques); the use of vascularised and non-vascularised bone grafts; bone substitutes; stem cells; growth factors; scaffolds and gene therapy.

Effects of Ti2448 half-pin with low elastic modulus on pin loosening in unilateral external fixation

The objective of this study was to compare the benefits of titanium 2448 (Ti2448) half-pin and titanium-6 aluminium-4 vanadium (TAV) half-pin on reducing pin loosening during external fracture fixation. Although having similar strength, Ti2448 half-pin had even lower elastic modules (33 GPa) when compared with TAV half-pin (110 GPa), which was similar to that of cortical bone (20 GPa). In the external fixation of tibial model fractures and canine cadaveric tibia fractures, Ti2448 half-pin had greater recoverable deformation and less stress concentration at the pin-bone interface in compression, torsion, and four-points bending test. Then, tibial fractures were created in 24 dogs and stabilized with four half-pins of either Ti2448 or TAV in each animal. At 4 and 8 weeks postoperatively, fracture healing and pin loosening was assessed by radiographic grading scale. The scores of Ti2448 group were significantly higher than those of TAV group. Micro-CT analysis also indicated larger quantity and higher quality of newly formed bone at pin-bone interface in Ti2448 group. Histology observation showed the newly formed bone integrated well into the threads of Ti2448 half-pins. In contrast, there was a layer of necrotic tissue between the bone tissue and TAV half-pin at pin-bone interface in TAV group. The extraction torque values of Ti2448 half-pins near the fracture line were significantly higher than those TAV pins. In conclusion, the Ti2448 half-pin with low elastic modulus could enhance osseointegration and reduce pin loosening when compared with TAV half-pin. It is a promising biomaterial for constructing external fixation system in clinical application.

Clinical benefit of hydroxyapatite-coated pins compared with stainless steel pins in external fixation at the wrist: a randomised prospective study

BACKGROUND

The purpose of this study was to determine the clinical benefit of hydroxyapatite (HA)-coated pins compared with standard stainless steel pins in external fixators applied for unstable fractures of the distal radius.

METHODS

A total of 40 patients (160 pins) with unstable wrist fractures were randomised for uniplanar fixator treatment with the use of identically designed, commercially available pins either composed of stainless steel (steel group) (n = 20) or coated by hydroxyapatite (HA group) (n = 20). Each pin site was clinically evaluated concerning erythema and grade of drainage as well as pain intensity (numeric rating scale (NRS) 0–10) and, additionally, radiological assessment was performed concerning pin-loosening/infection as well as fracture healing at T1 (Ø18 days), T2 (Ø44 days) and T3 (Ø65 days). In case of pintrack complication, the patient was followed continuously. The need for intensified pin-site care, oral or intravenous antibiotic medication, re-admission for additional surgery and premature fixator removal was documented. Bone mineral density (BMD) was determined by dual energy X-ray absorptiometry. At fixator removal (T2), the pin-extraction strength was measured by the use of an electronic torque wrench.

RESULTS

Two pin-track infections requiring daily pin-site care and oral antibiotics occurred in the HA group (2.6%) compared with four in the steel group (5.3%) (p = 0.601) and although a trend towards a superior performance of HA pins was detectable, the majority of clinical pin-site-parameters were comparable in both groups. At the end of the fixator therapy, the HA group showed a non-significant lower rate of loose pins (n(steel group) = 9; n(HA group) = 6; p = 0.864) and both hydroxyapatite-coated pins showed at the radius a significantly stronger pin-bone bonding measured by the torque wrench (p(proximal radius pin) = 0.007; p(distal radius pin) = 0.031). Except for elderly patients of the steel group (p = 0.018), all demographic-, health- and injury-related data including BMD were not correlated to any type of pin-site complication in both groups (p > 0.05). Since all fracture healed uneventfully without any type of additional surgery, the number of patients suffering clinically relevant pin-related complications showed no significant difference between both groups (p = 0.707).

CONCLUSIONS

The use of HA-coated pins compared with standard stainless-steel pins in external fixation for unstable wrist fractures yields only a trend towards a superior clinical outcome.

The influence of hydroxyapatite coating of external fixator pins on pin loosening and pin track infection: a systematic review

OBJECTIVE

The primary objective of this systematic review of published randomised controlled trials was to evaluate whether there was a clinical benefit in terms of pin loosening and pin track infection, or deep infection, associated with hydroxyapatite coating of external fixator pins. The secondary objective was to evaluate whether there was a clinical benefit in terms of loss of alignment or malunion associated with hydroxyapatite coating of external fixator pins.

METHODS

Studies included were identified by a PubMed search for relevant randomised controlled trials on the 20th of December 2007. A systematic review was performed.

RESULTS

All of the studies concluded that there was significantly less pin loosening in the HA-coated groups although the definition of loosening was based on different criteria. However, there was insufficient evidence to properly evaluate the clinical benefit in terms of the numbers needed to treat to avoid premature pin removal. There was also insufficient evidence to evaluate whether any clinical benefit is gained by using HA-coated pins with respect to deep infection and malunion.

CONCLUSION

A well designed large randomised controlled trial is required to determine the numbers needed to treat with HA-coated pins to reduce the incidence of clinically relevant pin loosening, axial deformity and pin track or deep infection.

Distal radius fractures

Distal radius fractures are a common injury, particularly in the elderly population. Severity of these fractures is directly related to the bone mineral density of the patient, and clinical results are dependent on this parameter as well. In terms of treatment, several options exist. Nonoperative management consists of closed treatment with casting. Operative treatment options include intrafocal pinning, nonbridging and bridging external fixation, arthroscopic-assisted external fixation, and various methods of open reduction internal fixation. When operative intervention is indicated, considerations include the characteristics of the fracture and the experience of the surgeon with the treatment modalities.

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.

Can we improve fixation and outcomes? Use of bone substitutes

Hip fractures secondary to osteoporosis are common in the elderly. Stabilizing these fractures until union is achieved is a challenge due to poor bone stock and insufficient purchase of the implant to the bone. The reported high rate of complications has prompted extensive research in the development of fixation techniques. Furthermore, manipulation of both the local fracture environment in terms of application of growth factors, scaffolds, and mesenchymal cells and the systemic administration of agents promoting bone formation and bone strength has been considered as a treatment option with promising results. There are only a few evidence-based studies reporting on fixation augmentation techniques. This article reports on the efficacy of bone graft substitutes for the fixation of hip fractures, in particular calcium phosphates, which have been used as granules, cements, and implant coatings.

Functional assessment in patients with osteoporotic wrist fractures treated with external fixation: a review of randomized trials

INTRODUCTION

Osteoporosis is a chronic and progressive condition that leads to decreased bone mass and skeletal fragility which may result in fractures, disability, pain, deformity and even death. Fractures of the wrist are the most common symptomatic fracture related to osteoporosis in which up to 80% of the persons with this fracture type have low bone mass. External fixation is minimally-invasive and is used in particular for the treatment of displaced, unstable fractures.

OBJECTIVE

The present systematic review will present functional outcome assessment in randomized controlled trials in the aged with distal radius fractures and treated with external fixation.

MATERIALS AND METHODS

Multiple databases including Medline, EMBASE, CINAHL, AMED and OVID Healthstar were searched. MESH headings such as: "Radius fractures" or "wrist injuries" were used in combination with "randomized controlled trials". Studies were included if the surgical treatment was external fixation, mean patient age was 50 years and over, and were in the English language.

RESULTS

The primary focus of wrist outcome assessments in patients treated with external fixation were based on traditional measures such as wrist range of movement and grip strength reflecting the need to shift the focus in future protocols towards measuring a patient's functional ability, measuring the difficulty of task performance and compensatory mechanisms. Furthermore, it is essential to take into account more evidence of instrument development before clinicians can reliably choose the best measure to assess the aged treated with external fixation.

Pin site care for preventing infections associated with external bone fixators and pins

BACKGROUND

Metal pins are used to apply skeletal traction or external fixation devices in the management of orthopaedic fractures. These pins protrude through the skin (described as 'percutaneous') and the way in which they are treated after insertion may affect the incidence of pin site infection. This review set out to summarise the evidence on the effect of pin site care on infection rates.

OBJECTIVES

To assess the effect on infection rates of different methods of cleansing and dressing orthopaedic percutaneous pin sites.

SEARCH STRATEGY

For this first update the following electronic databases were searched: the Wounds Group Specialised Trials Register (searched June 2008); CENTRAL (2008, Issue 2); Ovid Medline (1950 to May 2008), Ovid EMBASE (1980 to May 2008) and Ovid CINAHL (1982 to May 2008). In addition, reference lists of review articles and relevant trials were also searched and some handsearching undertaken.

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing the effect on infection and other complication rates of different methods of cleansing or dressing orthopaedic percutaneous pin sites were evaluated.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the citations retrieved by the search strategies for reports of relevant RCTs, independently selected trials that satisfied the inclusion criteria, extracted data and undertook quality assessment.

MAIN RESULTS

For this first update an additional five trials were identified, in total six trials (349 participants) were eligible for inclusion in the review. Three trials compared a cleansing regimen with no cleansing, 2 trials compared cleansing solutions, 1 trial compared identical pin site care performed daily or weekly and 4 trials compared dressings. One of these trials reported that infection rates were lower (9%) with a regimen that included cleansing with half strength hydrogen peroxide and application of Xeroform dressing when compared with other regimens with different cleansing and dressing regimens (rates >26%) but this may be a chance difference. There was no evidence of a difference between groups in any of the other trials. No trials were identified that compared any dressing versus no dressing or different massage regimens.

AUTHORS' CONCLUSIONS

There is insufficient evidence for a particular strategy of pin site care which minimises infection rates. Adequately powered randomised trials are required to examine the effects of different pin care regimens and co interventions such as antibiotic use and other extraneous factors must be controlled in the study designs.

Chitosan-coated stainless steel screws for fixation in contaminated fractures

Stainless steel screws and other internal fixation devices are used routinely to stabilize bacteria-contaminated bone fractures from multiple injury mechanisms. In this preliminary study, we hypothesize that a chitosan coating either unloaded or loaded with an antibiotic, gentamicin, could lessen or prevent these devices from becoming an initial nidus for infection. The questions investigated for this hypothesis were: (1) how much of the sterilized coating remains on the screw with simulated functional use; (2) is the unloaded or loaded chitosan coating bacteriostatic and biocompatible; and (3) what amount and rate does an antibiotic elute from the coating? In this study, the gentamicin eluted from the coating at a detectable level during 72 to 96 hours. The coating was retained at the 90% level in simulated bone screw fixation and the unloaded and loaded chitosan coatings had encouraging in vitro biocompatibility with fibroblasts and stem cells and were bacteriostatic against at least one strain of Staphylococcus aureus. The use of an antibiotic-loaded chitosan coating on stainless steel bone screws and internal fixation devices in contaminated bone fracture fixation may be considered after optimization of antibiotic loading and elution and more expanded in vitro and in vivo investigations with other organisms and antibiotics.

Use of chlorhexidine-impregnated patch at pin site to reduce local morbidity: the ChIPPS Pilot Trial

Pin tract infection is one of the most common complications associated with the use of external fixation. While some studies have identified the potential benefit of chlorhexidine gluconate-impregnated polyurethane dressings to reduce the incidence of catheter-related bloodstream infections, we are unaware of any published studies that evaluate the effectiveness of similar technologies in reducing the risk for external-fixation-related pin tract infections. Therefore, the purpose of this study was to evaluate the effectiveness of chlorhexidine gluconate-impregnated polyurethane dressing in reducing percutaneous-device-related skin colonisation and local infections. In this initial retrospective cohort, data were abstracted for two groups of consecutive patients undergoing surgery involving external fixation at an interdisciplinary foot and ankle surgical unit. All patients received surgical treatment of their foot/ankle pathology along with application of a hybrid external fixator. Twenty patients (45% male, age 54.5 +/- 3.69 years) received chlorhexidine gluconate-impregnated polyurethane dressing and twenty (55% male, age 55.8 +/- 3.22 years) received standard pin care. There was a significantly higher rate of pin tract infection in patients who received standard pin care compared with those who received chlorhexidine gluconate-impregnated polyurethane dressings (25% versus 0%, P = 0.047). There was no significant difference in any of the descriptive study characteristics (age, gender, diabetes and presence of neuropathy). The results of this initial study suggest that chlorhexidine gluconate-impregnated polyurethane dressing may be effective to reduce the incidence of pin tract infections and help decrease morbidity associated with external fixation.

Quantification of bone strength by intraoperative torque measurement: a technical note

INTRODUCTION

Bone strength describes the resistance of bone against mechanical failure. Bone strength depends on both the amount of bone and the bone's quality, and the bone strength may be looked upon as a relevant parameter to judge an osteosynthesis' stability. Information about bone strength was barely available intraoperatively in the past. The previous work of our group reported on development and laboratory evaluation of mechanical torque measurement as a method for the intraoperative quantification of bone strength. With the clinical series presented here we intend to verify that the im gesamten Text DensiProbe instrumentation for intraoperative torque measurement and the related measurement method are eligible for intraoperative use based on the following criteria: application of the method may not create complications, the measurement can be performed by the surgeon himself and may only cause a limited increase in the procedure time.

PATIENTS AND METHODS

From December 2006 until May 2007 ten patients with a pertrochanteric femoral fracture or a lateral femoral neck fracture eligible for stabilization with DHS were included in the study after having received informed consent. Any medication and comorbidity that might have influenced bone quality or bone mineral density (BMD) in these patients was documented. Bone strength was intraoperatively measured with DensiProbe. Complications that were obviously related with torque measurement were documented as well as any deviation from the suggested procedure; 6 and 12 weeks postoperative follow-up included clinical and radiological examination. The time required for torque measurement, the overall operating time and the number of persons present in the operating room were protocolled. BMD values of the contralateral femoral neck were postoperatively assessed by dual energy X-ray absorptiometry (DEXA) and compared to intraoperative peak torque values measured by DensiProbe.

RESULTS

No major complication was observed during intraoperative application of DensiProbe by trained surgeons. The unintended extraction of the guide wire together with the torque measurement probe was reported only once and is looked upon as a minor complication. Fracture healing was uneventful in all patients. The mean time for torque measurement was 2.35 +/- 0.9 min accounting for 2.2 +/- 1.1% of total surgery time. The presence of an additional person was not required to perform torque measurement but to protocol the data. There was a tendency towards correlation between BMD values of the femoral neck and intraoperative peak torque values.

DISCUSSION

The data presented clearly indicate that the DensiProbe instrumentation and measurement principle are eligible for routine intraoperative use by trained surgeons. Interpretation of possible correlations between BMD values measured by means of DEXA and the Peak Torque values assessed by DensiProbe has to be considered very carefully, because BMD and Peak Torque analyse bone at a different scale. Only within the framework of a multicenter study it will be possible to include a sufficient number of patients for calculation of the methods' predictive value towards implant failure and to verify acceptance of the method by the surgeons.

Inferior fixation with a new pin design for external fixation: a randomized study in 50 patients operated on by the hemicallotasis technique

BACKGROUND AND PURPOSE

Tibial osteotomy by the hemicallotasis technique (HCO) requires strong pin fixation. We compared pin fixation in HCO using a new self-drilling XCaliber pin (Orthofix) with optimized thread and tip design, with the commonly used standard pin (Orthofix).

PATIENTS AND METHODS

50 patients, mean age 51 (35-66) years, to be treated by HCO were randomized to standard pins or XCaliber pins. In the metaphyseal bone, hydroxyapatite-coated (HA-coated) pins were used in both types of pins. In the diaphyseal bone, non-coated pins were used. The torque forces for insertion and extraction (in Nm) were measured.

RESULTS

The insertion torque was higher for both the proximal and distal standard pins (2.1 Nm (SD 0.9) and 7.0 Nm (1.3), respectively) than for the XCaliber pins (1.3 Nm (0.8) and 3.6 Nm (1.4)). The extraction torque force was higher for the proximal standard pins (4.3 Nm (3.1)) than for the proximal XCaliber pins (1.5 Nm (1.7)) (p < 0.001). The extraction torque for the distal standard pins was 1.9 Nm (2.0) and for the distal XCaliber pins it was 1.4 Nm (1.1).

INTERPRETATION

The commonly used standard pin gives stronger fixation during the treatment of HCO.

Different methods of external fixation for treating distal radial fractures in adults

BACKGROUND

Fracture of the distal radius is a common injury. A surgical treatment is external fixation, where metal pins inserted into bone on either side of the fracture are then fixed to an external frame.

OBJECTIVES

To evaluate the evidence from randomised controlled trials comparing different methods of external fixation for 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 of articles. No language restrictions were applied.

SELECTION CRITERIA

Randomised or quasi-randomised controlled clinical trials which compared different methods of external fixation in adults with a distal radial fracture.

DATA COLLECTION AND ANALYSIS

All review authors independently performed study selection. Two authors independently assessed the included trials and performed data extraction.

MAIN RESULTS

Nine small trials involving 510 adults with potentially or evidently unstable fractures, were grouped into five comparisons. The interventional, clinical and methodological heterogeneity of trials precluded data pooling. Only one trial had secure allocation concealment. Two trials comparing a bridging (of the wrist) external fixator versus pins and plaster external fixation found no significant differences in function or deformity. One trial found tendencies for more serious complications but less subsequent discomfort and deformity in the fixator group. Three trials compared non-bridging versus bridging fixation. Of the two trials testing uni-planar non-bridging fixation, one found no significant differences in functional or clinical outcomes; the other found non-bridging fixation significantly improved grip strength, wrist flexion and anatomical outcome. The third trial found no significant findings in favour of multi-planar non-bridging fixation of complex intra-articular fractures. One trial using a bridging external fixator found that deploying an extra external fixator pin to fix the 'floating' distal fragment gave superior functional and anatomical results. One trial found no evidence of differences in clinical outcomes for hydroxyapatite coated pins compared with standard uncoated pins. Two trials compared dynamic versus static external fixation. One trial found no significant effects from early dynamism of an external fixator. The poor quality of the other trial undermines its findings of poorer functional and anatomical outcomes for dynamic fixation.

AUTHORS' CONCLUSIONS

There is insufficient robust evidence to determine the relative effects of different methods of external fixation. Adequately powered studies could provide better evidence.

Fixation of HA-coated unicortical locking screws in a sheep gap model: a comparative biomechanical study

OBJECTIVES

To evaluate whether fixing a locking compression plate (LCP) with hydroxyapatite (HA)-coated screws provides improved biomechanical fixation and healing compared with standard screws under loaded conditions.

METHODS

Ten sheep were randomly divided into 2 groups. A resection osteotomy of 8 mm was performed in the sheep's right tibiae. Five tibiae were fixed with a 9-hole LCP and 8 standard unicortical locking screws (Group Non-HA), and 5 tibiae were fixed with a 9-hole LCP and 8 HA-coated unicortical locking screws (Group HA). All screws were implanted at the same insertion torque of 4000 Nmm. Three months after surgery, all the sheep were euthanized. Bone segments after screw removal were randomly chosen from each group for histologic analysis (Group Non-HA=5, Group HA=5).

RESULTS

Mean screw extraction torque was 438+/-288 Nmm in Group Non-HA (n=40) and 2317+/-657 Nmm in Group HA (n=40) (P<0.0005). The tibial torque resistance of the resected tibiae was 24+/-8 Nm in Group Non-HA (n=5) and 31+/-3 in Group HA (n=5) (P=0.045). In Group Non-HA, histology showed bone resorption and fibrous tissue encapsulation in all the samples, but this was not found in any of the Group HA samples.

CONCLUSIONS

This study shows that an LCP with HA-coated screws provides improved biomechanical fixation than an LCP with similar standard screws as shown by a 5-fold greater screw extraction torque (P<0.0005). Furthermore, the higher tibial torque resistance is potentially beneficial for improved gap healing, as shown by higher tibial torque resistance.

The radiographic classification of the bone-screw interface in paediatric tibial lengthening

Bone-screw loosening in monolateral external fixators is a significant problem. This study classifies the radiographic appearance of the bone-screw interface and predicts which screws will become loose and those that will remain solidly fixed to bone. Five radiographic features were identified at the bone-screw interface. The classification of these features was validated using interobserver and intraobserver studies. The reliability of the classification was improved by image enhancement with simple filters. Some radiographic features predicted which screws would eventually become loose, allowing the clinician to make earlier management decisions regarding the adjustment of screws.

Contemporary evaluation and treatment of distal radius fractures

Distal radius fractures are among the most common fractures encountered by orthopedic surgeons. Because of many fracture patterns and types, it has been difficult to develop a comprehensive classification. Treatment options vary depending on injury severity and stability of the fracture reduction. Closed reduction and immobilization can be used for stable fractures. Common surgeries include pinning with and without external fixation and open reduction and internal fixation. Technological advances such as locking and fixed angle plates have made the volar approach feasible. Dorsal plating with low profile plates and fragment-specific techniques can be successful in treating distal radius fractures. Following fracture reduction and stabilization, assessment of distal radioulnar joint stability is essential and must be stabilized when necessary.

Alendronate improves screw fixation in osteoporotic bone

BACKGROUND

Animal studies have demonstrated the efficacy of the use of bisphosphonates to enhance screw fixation in bone. In this prospective, randomized study of pertrochanteric fractures treated with external fixation, we tested whether systemic administration of bisphosphonates would improve the fixation of hydroxyapatite-coated screws implanted in osteoporotic bone.

METHODS

Sixteen consecutive patients with a pertrochanteric fracture were selected. Inclusion criteria were female gender, an age of at least sixty-five years, and a bone mineral density T-score of less than -2.5 standard deviations. Exclusion criteria included bisphosphonate treatment during the two-year period prior to the fracture. Fractures were fixed with a pertrochanteric fixator and four hydroxyapatite-coated pins. Two pins were implanted in the femoral head (pin positions 1 and 2), and two were placed in the femoral diaphysis (pin positions 3 and 4). The patients were randomized either to therapy with alendronate for a three-month postoperative period (Group A) or to no therapy (Group B). The Group-A patients received an oral dose of 70 mg of alendronate per week. The fixators were removed after three months.

RESULTS

All of the fractures healed, and no loss of reduction, nonunion, or delayed union was observed. The combined mean extraction torque (and standard deviation) of the pins implanted at positions 1 and 2 (cancellous bone) was 2558 +/- 1103 N/mm in Group A and 1171 +/- 480 N/mm in Group B (p < 0.0005). The combined mean extraction torque of the pins implanted at positions 3 and 4 (cortical bone) was 4327 +/- 1720 N/mm in Group A and 4075 +/- 1022 N/mm in Group B.

CONCLUSIONS

These data show that weekly systemic administration of alendronate improves pin fixation in cancellous bone in elderly female patients with osteoporosis. We observed a twofold increase in extraction torque with the pins implanted in cancellous bone. These results support the use of alendronate in the treatment of osteoporotic pertrochanteric fractures to improve screw fixation in the femoral head.