Injectable macroporous naturally-derived apatite bone cement as a potential trabecular bone substitute

In this study, we have formulated a novel apatite bone cements derived from natural sources (i.e. eggshell and fishbone) with improved qualities that is, porosity, resorbability, biological activity, and so forth. The naturally-derived apatite bone cement (i.e. FBDEAp) was prepared by mixing hydroxyapatite (synthesized from fishbone) and tricalcium phosphate (synthesized from eggshell) as a solid phase with a liquid phase (a dilute acidic blend of cement binding accelerator and biopolymers like gelatin and chitosan) with polysorbate (as liquid porogen) to get a desired bone cement paste. The prepared cement paste sets within the clinically acceptable setting time (≤20 min), easily injectable (>85%) through hands and exhibits physiological pH stability (7.3-7.4). The pure apatite phased bone cement was confirmed by x-ray diffraction and Fourier transform infrared spectroscopy analyses. The FBDEAp bone cement possesses acceptable compressive strength (i.e. 5-7 MPa) within trabecular bone range and is resorbable up to 28% in simulated body fluid solution within 12 weeks of incubation at physiological conditions. The FBDEAp is macroporous in nature (average pore size ~50-400 μm) with interconnected pores verified by SEM and micro-CT analyses. The FBDEAp showed significantly increased MG63 cell viability (>125% after 72 h), cell adhesion, proliferation, and key osteogenic genes expression levels (up to 5-13 folds) compared to the synthetically derived, synthetic and eggshell derived as well as synthetic and fishbone derived bone cements. Thus, we strongly believe that our prepared FBDEAp bone cement can be used as potential trabecular bone substitute in orthopedics.

Fabrication of injectable antibiotic-loaded apatitic bone cements with prolonged drug delivery for treating post-surgery infections

Antibiotic-loaded bioactive bone substitutes are widely used for treating various orthopedic diseases and prophylactically to avoid post implantation infection. Calcium deficient hydroxyapatite (also known as apatitic bone cement) is a potential bioactive bone substitute in orthopedics due to its chemical composition similar to that of natural bone minerals. In this study, fabrication of mannitol (a solid porogen) incorporated injectable synthetic (Syn) and eggshell derived (ESD) apatitic bone cements loaded with antibiotics (gentamicin/meropenem/ rifampicin/vancomycin) was investigated. The release kinetics of the antibiotics were studied by fitting them with different kinetic models. All the antibiotics-loaded apatitic bone cements set within clinically accepted setting time (20 ± 2 min) and with good injectability (>70%). The antibiotics released from these bone cements were found to be controlled and sustained throughout the study time. Weibull and Gompertz (applies in least initial burst and sustain drug release rate models) were the best models to predict the release behavior. They cements had acceptable compressive strength (6-10 MPa; in the range of trabecular bone) and were biodegradable (21%-27% within 12 weeks of incubation) in vitro in simulated body fluids at physiological conditions. These bone cements showed excellent antibacterial activity from day 1 onwards and no bacterial colony was found from day 3 onwards. The viability of MG63 cells in vitro after 72 h was significantly higher after 24 h (i.e., ~110%). The cells were well attached and spread over the surface of the cements with extended morphology. The ESD antibiotic-loaded apatitic bone cements showed better injectability, degradation and cytocompatibility compared when compared to Syn antibiotic-loaded apatitic bone cements. Thus, we believe that the ESD antibiotic-loaded apatitic bone cements are suitable as potential injectable bone substitutes to avoid post-operative implant associated and other acute or chronic bone infections.

Fabrication of macroporous apatite bone cements for non-load bearing orthopedic applications

Calcium deficient hydroxyapatite (CDHA)-based apatite forming bone cements are well known for their bioactivity and bioresorbability. The formulation of CDHA-based cements with improved macroporosity, injectability, and resorbability has been investigated. The solid phase consists of nanocrystalline hydroxyapatite (HA) and tricalcium phosphate (β-TCP). The liquid phase is diluted acetic acid with disodium hydrogen phosphate as binding accelerator along with gelatin and chitosan to improve the injectability. A porogen agent either mannitol (as solid porogen) or polysorbate (as liquid porogen) is also used to improve the porosity. All combined in fine-tuned composition results in optimal bone cements. The cement sets within the clinically preferred setting time (≤20 min) and injectability (>70%) and also stable at physiological pH (i.e., ~7.3-7.4). The XRD and FT-IR analysis confirmed the formation of CDHA phase on day 7 when the after-set cement immersed under phosphate buffer solution (PBS) at physiological conditions. The cements were found to have acceptable compressive strength for trabecular bone substitute. The cements were macroporous in nature with average pore size between 50 and 150 μm and were interconnected as confirmed by SEM, micro-CT and MIP analysis. The prepared cements are degradable up to 22% and 19% in simulated body fluid and PBS respectively within 10 weeks of immersion at physiological conditions. The cements exhibit higher viability (%) (>110%) with L929 and MG63 cells compared to the control after 3 days of incubation. They also show increased proliferation, well spreading and extended filopodia with MG63 cells. Overall, the developed apatite forming bone cements seems to be suitable for low or non-load bearing orthopedic applications.

Use of an Angled Blade Plate for 31A3 Intertrochanteric Fractures

BACKGROUND

A subgroup of pertrochanteric fractures-namely, the AO/OTA 31A3 fracture-continues to be a difficult problem to treat, even with cephalomedullary nails. We present the results for 26 patients with a 31A3 fracture treated with the angled blade plate.

METHODS

The records of 26 consecutive patients with a 31A3 fracture that was treated operatively with the angled blade plate device between 2007 and 2012 at our center were reviewed, and the patients were contacted for follow-up. The functional outcome (traumatic hip rating score) and radiographic outcome (the neck-shaft angle at the time of fixation and final follow-up) were obtained for 20 of the 26 patients at a minimum follow-up of 1 year.

RESULTS

All 26 patients had primary surgery. At final review, 2 patients had died and 4 had been lost to follow-up. Of the 4 patients lost to follow-up, 2 had revision of the fixation with the angled blade plate. Of the 20 patients with follow-up, 1 had malreduction and implant failure but eventually had healing after revision of the fixation with the angled blade plate. The mean traumatic hip rating score at the time of follow-up was 50.0 with 4, 14, and 2 patients having excellent, good, and failed outcomes, respectively. The mean neck-shaft angle at the time of final union was 126.16°, which was an average of 4° less than that on the unaffected side. However, this did not correlate with functional outcome. There was no significant difference between the immediate postoperative and final neck-shaft angles.

CONCLUSIONS

This study demonstrated that blade plate fixation for 31A3 fractures is associated with low rates of failure (15%), revision surgery (15%), and infection (15%), which are comparable with the results of nail fixation (range, 5% to 12%) and superior to those of sliding hip screw fixation. This large series demonstrates that the angled blade plate can be utilized for these complex fractures and should be part of the armamentarium for these injuries.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Efficacy and cost-effectiveness of universal pre-operative iron studies in total hip and knee arthroplasty

Background

The prevalence of anaemia in patients planned for total hip and knee arthroplasty is about 20%. Optimising pre-operative haemoglobin levels by iron supplementation has been shown to decrease transfusion rates, complications and associated morbidity. The need for universal screening with iron studies of all elective arthroplasty patients is not clearly defined at present.

Methods

Retrospective review of 2 sequential cohorts of patients undergoing primary hip or knee arthroplasty by a single surgeon at a single centre between January 2013 and December 2017. The first group of patients underwent pre-operative iron studies only if found to be anaemic, with a haemoglobin below 12g/dl. From January 2015, all patients irrespective of the presence of anaemia were screened with a complete iron profile before surgery. Patients with a confirmed iron deficiency were administered with intravenous iron prior to surgery. The 2 cohorts were compared with regard to blood transfusion rate post-operatively and cost efficiency for universal screening with iron studies.

Results

There was a net decrease in the allogenic blood transfusion rate from 4.76 to 2.92% when universal iron studies were introduced but the difference was not statistically significant. Obtaining universal pre-operative iron studies is cost neutral with the price of allogenic blood transfusion in a similar cohort. We also diagnosed 5 patients with occult malignancies.

Conclusions

Universal screening with pre-operative iron studies and iron infusion in elective arthroplasty patients may reduce allogenic blood requirements and is cost neutral. An additional benefit is the potential to diagnose asymptomatic malignancies. Further studies are required to show the true benefit of universal pre-operative iron screening.

Intravenous Mannitol reduces intracompartmental pressure following tibia fractures: A randomized controlled trial

PURPOSE

Impending compartment syndrome is a common event following closed tibia fractures, which can progress to sinister compartment syndrome. Fasciotomy is the only definitive treatment available, though it has its own drawbacks and complications. Medical management at present consists of limb elevation and adequate hydration. This study aims at determining whether intravenous administration of Mannitol reduced the intracompartmental pressure in patients with closed tibial fractures.

METHODS

This is a double blinded, randomized control trial done in a single tertiary care center in India. Forty-five patients were recruited between February 2012 and October 2012. Forty patients who presented to the emergency department with isolated, closed, high velocity, and proximal 2/3 tibia fractures were included in this study. Patients with contraindication to Mannitol were excluded. They were allocated into 2 groups by the investigator using computer generated randomization. The pressure in the anterior compartment of the leg was measured with a handheld Stryker pressure monitor. Then either 20% Mannitol or 0.9% normal saline as given intravenously in a blinded manner, based on the randomization. The intracompartmental pressure was measured at 0, 1 and 3 h after the infusion. The participant, investigator and statistician were masked to the group assessment.

RESULTS

There was no difference in intracompartmental pressures at 1 or 3 h, between the groups. However, in patients with the baseline of compartmental pressures ≥30 mmHg, Mannitol showed a marked reduction in pressure of 8.5 mmHg at 1 h compared to almost no change in pressure in the saline group. There were no adverse events with the use of Mannitol.

CONCLUSIONS

This preliminary study appears to show that Mannitol is useful in the management of the increased compartment pressure. The limitations of this study were that it only involved a small group of patients and the baseline pressures in both the groups were not comparable. More studies are required before the use of Mannitol as a standard of care in the management of compartment syndrome can be established.

Similar regeneration of articular cartilage defects with autologous & allogenic chondrocytes in a rabbit model

Background & objectives:

Articular cartilage defects in the knee have a very poor capacity for repair due to avascularity. Autologous chondrocyte transplantation (ACT) is an established treatment for articular cartilage defects. Animal studies have shown promising results with allogenic chondrocyte transplantation since articular cartilage is non-immunogenic. In addition to being economical, allogenic transplantation has less morbidity compared to ACT. This study was undertaken to compare ACT with allogenic chondrocyte transplantation in the treatment of experimentally created articular cartilage defects in rabbit knee joints.

Methods:

Cartilage was harvested from the left knee joints of six New Zealand white rabbits (R1-R6). The harvested chondrocytes were cultured to confluence and transplanted onto a 3.5 mm chondral defect in the right knees of 12 rabbits [autologous in 6 rabbits (R1-R6) and allogenic in 6 rabbits (R7-R12)]. After 12 wk, the rabbits were euthanized and histological evaluation of the right knee joints were done with hematoxylin and eosin and safranin O staining. Quality of the repair tissue was assessed by the modified Wakitani histological grading scale.

Results:

Both autologous and allogenic chondrocyte transplantation resulted in the regeneration of hyaline/mixed hyaline cartilage. The total histological scores between the two groups showed no significant difference.

Interpretation & conclusions:

Allogenic chondrocyte transplantation seems to be as effective as ACT in cartilage regeneration, with the added advantages of increased cell availability and reduced morbidity of a single surgery.

POWIFF- Prospective study of wrist internal fixation of fracture: A protocol for a single centre, superiority, randomised controlled trial to study the efficacy of the VRP (2.0) distal radius plate (Austofix) versus the VA-LCP (Depuy-Synthes) for distal radius fractures

Background

Distal radial fractures are one of the most common orthopaedic cases that present to the A&E department. Surgical intervention is warranted in displaced intraarticular fractures and fractures with more than the recommended angulation or shortening, and is most commonly treated with volarly placed fixed angle locking plates. The aim of this study is to determine and compare the efficacy of two different plates for surgical treatment of distal radius fractures. The VRP 2.0 is a new plate produced by the Austofix company and this system will be compared against the VA-LP (Variable angle-locking plate) produced by Depuy-Synthes which has been used as the standard treatment device.

Methods and Design

Patients between the ages of 18 and 80 presenting to the Royal Adelaide Hospital with isolated closed distal radial fractures will be invited to participate in this study. A total of 200 patients are required to provide 90% statistical power at a 5% alpha level to detect a difference of 11.5 points on the PRWE (Patient rated Wrist evaluation) score. The primary outcome measure will be the PRWE score while the secondary outcome measures will include the DASH score, EQ5D score, clinical range of movements, grip strength as well as patient perceived return of function at the wrist and time to resumption to work. These will be measured at 6 weeks, 3 months and 12 months. Radiographic indices including the radial tilt, length, volar inclination and plate prominence will also be measured. Complications will be recorded up to 12 months. Post hoc comparisons will be done using paired t tests. An intention to treat and a per protocol analysis will be done to compare the 2 groups.

Discussion

Distal radial fractures are increasingly being treated by internal fixation using volar locking plates. However, there is no prospective study to date comparing one plate against another in terms of outcome and complications. This study could provide more information about the best way to treat these injuries surgically.

Trial registration

The trial is registered with the Australia New Zealand Clinical Trials Registry (ANZCTR). Trial registration date-17/11/2016. Trial registration number-ACTRN12616001590459.

Electronic supplementary material

The online version of this article (10.1186/s12891-018-2052-4) contains supplementary material, which is available to authorized users.

Characteristics of postoperative weight bearing and management protocols for tibial plateau fractures: Findings from a scoping review

OBJECTIVE

To identify and describe the characteristics of existing practices for postoperative weight bearing and management of tibial plateau fractures (TPFs), identify gaps in the literature, and inform the design of future research.

METHODS

Seven electronic databases and clinical trial registers were searched from inception until November 17th 2016. Studies were included if they reported on the surgical management of TPFs, had a mean follow-up time of ≥1year and provided data on postoperative management protocols. Data were extracted and synthesized according to study demographics, patient characteristics and postoperative management (weight bearing regimes, immobilisation devices, exercises and complications).

RESULTS

124 studies were included involving 5156 patients with TPFs. The mean age across studies was 45.1 years (range 20.8-72; 60% male), with a mean follow-up of 34.9 months (range 12-264). The most frequent fracture types were AO/OTA classification 41-B3 (29.5%) and C3 (25%). The most commonly reported non-weight bearing time after surgery was 4-6 weeks (39% of studies), with a further 4-6 weeks of partial weight bearing (51% of studies), resulting in 9-12 weeks before full weight bearing status was recommended (55% of studies). Loading recommendations for initial weight bearing were most commonly toe-touch/<10kg (28%), 10kg-20kg (33%) and progressive (39%). Time to full weight bearing was positively correlated with the proportion of fractures of AO/OTA type C (r=0.465, p=0.029) and Schatzker type IV-VI (r=0.614, p<0.001). Similar rates of rigid (47%) and hinged braces were reported (58%), most frequently for 3-6 weeks (43% of studies). Complication rates averaged 2% of patients (range 0-26%) for abnormal varus/valgus and 1% (range 0-22%) for non-union or delayed union.

CONCLUSIONS

Postoperative rehabilitation for TPFs most commonly involves significant non-weight bearing time before full weight bearing is recommended at 9-12 weeks. Partial weight bearing protocols and brace use were varied. Type of rehabilitation may be an important factor influencing recovery, with future high quality prospective studies required to determine the impact of different protocols on clinical and radiological outcomes.

Valgus osteotomy for nonunion and neglected neck of femur fractures

Nonunion neck of femur can be a difficult problem to treat, particularly in the young, and is associated with high complication rates of avascular necrosis due to the precarious blood supply and poor biomechanics. The various treatment options that have been described can be broadly divided according to the aim of improving either biology or biomechanics. Surgeries aimed at improving the biology, such as vascularized fibula grafting, have good success rates but require high levels of expertise and substantial resources. A popular surgical treatment aimed at improving the biomechanics-valgus intertrochanteric osteotomy-optimizes conditions for fracture healing by converting shear forces across the fracture site into compressive forces. Numerous variations of this surgical procedure have been developed and successfully applied in clinical practice. As a result, the proximal femoral orientation for obtaining a good functional outcome has evolved over the years, and the present concept of altering the proximal femoral anatomy as little as possible has arisen. This technical objective supports attaining union as well as a good functional outcome, since excessive valgus can lead to increased joint reaction forces. This review summarizes the historical and current literature on valgus intertrochanteric osteotomy treatment of nonunion neck of femur, with a focus on factors predictive of good functional outcome and potential pitfalls to be avoided as well as controversies surrounding this procedure.

Retrograde Intramedullary Nailing for Recurrent Fracture in Congenital Pseudarthrosis of the Tibia

We present the case of a 23-year-old male with congenital pseudarthrosis of the tibia, who had undergone treatment with Ilizarov ring fixation and had experienced 4 episodes of repeat fracture. He had associated type 1 neurofibromatosis, and his radiographs confirmed a type 6 Boyd's congenital pseudarthrosis of the left tibia, with concomitant arthritic ankle and subtalar joints. He was treated successfully with retrograde intramedullary nailing of the tibia and autologous bone grafting. At his final follow-up visit at 3 years postoperatively, he displayed complete union with no repeat fractures.

Recurrent peripheral embolism following nonunion of the clavicle

Vascular complications in closed clavicular fractures are uncommon, with an incidence of only 0.4%. Subclavian artery injury can present acutely or can have a delayed presentation with arm ischemia. We report the case of an undetected subclavian pseudoaneurysm in a patient with a nonunion fracture clavicle who was referred with persistent ischemia following attempted brachial embolectomy at another center, along with a review of literature to support the hypothesis that in addition to repair of the aneurysm, treatment of the psuedarthrosis by fixation of the clavicle is essential.