Delayed Abdominal Flap for Upper Extremity Soft Tissue Coverage.

Unlike other body parts, the upper extremity has critical structures close to the skin, making soft tissue injuries more complex. These injuries can result from various causes, including trauma and necrotizing soft tissue infections, necessitating reconstruction. Historically, pedicled flaps from the groin and abdomen were commonly used for upper extremity reconstruction, but they had limitations, such as the need for flap division and debulking, patient discomfort, and stiffness. Free flap reconstruction has become the preferred method, but it still faces challenges like patient and facility issues, the absence of recipient vessels after injury, and multi-surface wounds. This case report describes a 67-year-old patient with a severe necrotizing soft tissue infection in the right upper extremity. After multiple debridement procedures, the patient underwent hand amputation and soft tissue coverage using an abdominal wall-based flap. The objectives of achieving stable soft tissue coverage while preserving maximal length of the upper extremity were successfully achieved, and the patient expressed satisfaction with the outcomes. Inadequate management of upper extremity wounds can lead to amputation and psychological distress. The reconstructive ladder is used to approach upper extremity soft tissue defects, with free tissue transfer being the standard for larger defects. However, abdominal flaps still have indications when free tissue transfer is not feasible or contraindicated. It is imperative that plastic surgeons have these techniques in their armamentarium to provide a service to the ever more complex patient with an upper extremity wound.

Prompt Management of Airbag Burn Injuries Leads to Optimized Patient Outcomes: A Pilot Study.

BACKGROUND: Dual airbags are required to be installed and available for use in all motor vehicles since 1997. The National Highway Traffic Safety Administration reported that 50,457 lives were saved by airbags from 1987 to 2017; however, airbag deployment can cause injuries, including thermal and chemical burns, hyperpigmentation, and dysaesthesia. There is little information available in the literature regarding differences in outcomes between promptly visiting a plastic surgeon and waiting for treatment, especially as an injury may not be immediately apparent or patients may not know that airbag burn injuries may be delayed in presenting. METHODS: This is a retrospective cohort pilot study conducted among 14 patients who presented to a plastic surgeon between January 1, 2019 and June 30, 2022 owing to injuries from airbag deployment. An early visit was considered ≤30 days, and a late visit was >30 days. Other variables collected included age, sex, Fitzpatrick skin type, smoking status, comorbidities, type of injury, injury site, pain status, hyper/hypopigmentation, dysaesthesia, epithelialization, and improvements in pain, pigmentation, and dysaesthesia from treatment. RESULTS: The mean age was 36.0 years (standard deviation (SD) 17.9). The majority were female (85.7%), non-smokers (87.5%), and not diabetic (75.0%). Only six patients (42.9%) visited their doctor within one month of injury. Most patients experienced dysaesthesia (85.7%) and pain (71.4%). Thirteen of the 14 patients had hyperpigmentation or hyperemia, and one had hypopigmentation. Full or slight epithelialization was seen in 35.7%, and nine of the 14 patients had no epithelialization. Ongoing issues were a factor for 64.3% of these patients; 42.9% had ongoing issues with hyperpigmentation. A full recovery was seen in 28.6% of the patients. The patients who saw the plastic surgeon by day 30 or less (early) from the time of injury had a 66.7% improvement in pigmentation and 33.3% resolution in pain. Of those who went to the surgeon beyond 30 days (late), 25% had improvement in pigmentation and 37.5% had resolution of pain. Improvement in dysaesthesia occurred in both groups, but those who saw the plastic surgeon early had 33.3% resolution, while 37.5% of those who went late improved. Of those who went late to the surgeon, only 12.5% had epithelialization, while 66.7% of those who went within 30 days showed signs of (full or slight) epithelialization. CONCLUSION: Patients involved in motor vehicle collisions (MVCs) should be informed of the delayed fashion in which airbag burns can develop. An ostensibly mild burn may portend long-term consequences, especially if such injuries are not addressed in a prompt manner. Our study demonstrates how airbag burn injuries and their sequelae are best addressed with early care.

Single-Stage Externalized Locked Plating for Treatment of Unstable Meta-Diaphyseal Tibial Fractures.

(1) Background: Unstable meta-diaphyseal tibial fractures represent a heterogeneous group of injuries. Recently, good clinical results have been reported when applying a technique of externalized locked plating in appropriate cases, highlighting its advantage in terms of less additional tissue injury compared with conventional methods of fracture fixation. The aims of this prospective clinical cohort study were, firstly, to investigate the biomechanical and clinical feasibility and, secondly, to evaluate the clinical and functional outcomes of single-stage externalized locked plating for treatment of unstable, proximal (intra- and extra-articular) and distal (extra-articular), meta-diaphyseal tibial fractures. (2) Methods: Patients, who matched the inclusion criteria of sustaining a high-energy unstable meta-diaphyseal tibial fracture, were identified prospectively for single-stage externalized locked plating at a single trauma hospital in the period from April 2013 to December 2022. (3) Results: Eighteen patients were included in the study. Average follow-up was 21.4 ± 12.3 months, with 94% of the fractures healing without complications. The healing time was 21.1 ± 4.6 weeks, being significantly shorter for patients with proximal extra- versus intra-articular meta-diaphyseal tibial fractures, p = 0.04. Good and excellent functional outcomes in terms of HSS and AOFAS scores, and knee and ankle joints range of motion were observed among all patients, with no registered implant breakage, deep infection, and non-union. (4) Conclusions: Single-stage externalized locked plating of unstable meta-diaphyseal tibial fractures provides adequate stability of fixation with promising clinical results and represents an attractive alternative to the conventional methods of external fixation when inclusion criteria and rehabilitation protocol are strictly followed. Further experimental studies and randomized multicentric clinical trials with larger series of patients are necessary to pave the way of its use in clinical practice.

Augmented screwdrivers can increase the performance of orthopaedic surgeons compared with use of normal screwdrivers.

Orthopaedic screws insertion can be trivialised as a simple procedure, however it is frequently performed poorly. Limited work exists defining how well surgeons insert screws or whether augmented screwdrivers can aid surgeons to reduce stripping rates and optimise tightness. We aimed to establish the performance of surgeons inserting screws and whether this be improved with screwdriver augmentation. 302 orthopaedic surgeons tightened 10 non-locking screws to what they determined to be optimum tightness into artificial bone sheets. The confidence in the screw purchase was given (1-10). A further 10 screws were tightened, using an augmented screwdriver that indicated when a predetermined optimum tightness was reached. The tightness for unstripped insertions under normal conditions and with the augmented screwdriver were 81% (95% CI 79-82%)(n = 1275) and 70% (95% CI 69-72%)(n = 2577) (p < 0.001). The stripping rates were 58% (95% CI 54-61%) and 15% (95% CI 12-17%) respectively (p < 0.001). The confidences when using the normal and augmented screwdrivers respectively were 7.2 and 7.1 in unstripped insertions and 6.2 and 6.5 in stripped insertions. Performance improved with an augmented screwdriver, both in reduced stripping rates and greater accuracy in detecting stripping. Augmenting screwdrivers to indicate optimum tightness offer potentially enormous clinical benefits by improving screw fixation.

Non-linear explicit micro-FE models accurately predict axial pull-out force of cortical screws in human tibial cortical bone.

Screws are the most frequently used implants for treatment of bone fractures and play an essential role in determining fixation stability. Robust prediction of the bone-screw interface failure would enable development of improved fixation strategies and implant designs, ultimately reducing failure rates and improving outcomes of bone fracture treatments. This study aimed to compare the accuracy of micro-computed tomography image based bone volume measures, linear micro-finite element (FE) and non-linear micro-FE simulations in predicting pull-out force of 3.5 mm screws in human cadaveric tibial cortical bone. Axial pull-out experiments were performed in forty samples harvested from a single human tibia to measure ultimate force, which was correlated with bone volume around the screw and the predictions by both linear micro-FE and non-linear explicit micro-FE models. Correlation strength was similar for bone volume around the screw (R2 = 0.866) and linear micro-FE (R2 = 0.861), but the explicit non-linear micro-FE models were able to capture the experimental results more accurately (R2 = 0.913) and quantitatively correctly. Therefore, this technique may have potential for future in silico studies aiming at implant design optimization.

Screw tightness and stripping rates vary between biomechanical researchers and practicing orthopaedic surgeons.

BACKGROUND: Screws are the most frequently inserted orthopaedic implants. Biomechanical, laboratory-based studies are used to provide a controlled environment to investigate revolutionary and evolutionary improvements in orthopaedic techniques. Predominantly, biomechanical trained, non-surgically practicing researchers perform these studies, whilst it will be orthopaedic surgeons who will put these procedures into practice on patients. Limited data exist on the comparative performance of surgically and non-surgically trained biomechanical researchers when inserting screws. Furthermore, any variation in performance by surgeons and/or biomechanical researchers may create an underappreciated confounder to biomechanical research findings. This study aimed to identify the differences between surgically and non-surgically trained biomechanical researchers' achieved screw tightness and stripping rates with different fixation methods. METHODS: Ten orthopaedic surgeons and 10 researchers inserted 60 cortical screws each into artificial bone, for three different screw diameters (2.7, 3.5 and 4.5 mm), with 50% of screws inserted through plates and 50% through washers. Screw tightness, screw hole stripping rates and confidence in screw purchase were recorded. Three members of each group also inserted 30 screws using an augmented screwdriver, which indicated when optimum tightness was achieved. RESULTS: Unstripped screw tightness for orthopaedic surgeons and researchers was 82% (n = 928, 95% CI 81-83) and 76% (n = 1470, 95% CI 75-76) respectively (p < 0.001); surgeons stripped 48% (872/1800) of inserted screws and researchers 18% (330/1800). Using washers was associated with increased tightness [80% (95% CI 80-81), n = 1196] compared to screws inserted through plates [76% (95% CI 75-77), n = 1204] (p < 0.001). Researchers were more accurate in their overall assessment of good screw insertion (86% vs. 62%). No learning effect occurred when comparing screw tightness for the first 10 insertions against the last 10 insertions for any condition (p = 0.058-0.821). Augmented screwdrivers, indicating optimum tightness, reduced stripping rates from 34 to 21% (p < 0.001). Experience was not associated with improved performance in screw tightness or stripping rates for either group (p = 0.385-0.965). CONCLUSIONS: Surgeons and researchers showed different screw tightness under the same in vitro conditions, with greater rates of screw hole stripping by surgeons. This may have important implications for the reproducibility and transferability of research findings from different settings depending on who undertakes the experiments.

Intracapsular Femoral Neck Fractures-A Surgical Management Algorithm.

Background and Objectives: Femoral neck fractures are common and constitute one of the largest healthcare burdens of the modern age. Fractures within the joint capsule (intracapsular) provide a specific surgical challenge due to the difficulty in predicting rates of bony union and whether the blood supply to the femoral head has been disrupted in a way that would lead to avascular necrosis. Most femoral neck fractures are treated surgically, aiming to maintain mobility, whilst reducing pain and complications associated with prolonged bedrest. Materials and Methods: We performed a narrative review of intracapsular hip fracture management, highlighting the latest advancements in fixation techniques, generating an evidence-based algorithm for their management. Results: Multiple different fracture configurations are encountered within the category of intracapsular hip fractures, with each pattern having different optimal surgical strategies. Additionally, these injuries typically occur in patients where further procedures due to operative complications are associated with a considerable increase in mortality, highlighting the need for choosing the correct index operation. Conclusions: Factors such as pathological causes for the fracture, pre-existing symptomatic osteoarthritis, patient's physiological age and fracture displacement all need to be considered when choosing optimal management.

Cement-a-TAN Temporary Proximal Femoral Replacement for Staged Joint Replacement - A Case Report.

INTRODUCTION: Infected non-unions of proximal femoral fractures are difficult to treat. If debridement and revision fixation is unsuccessful, staged revision arthroplasty may be required. Non-viable tissue must be resected; coupled with the introduction of an antibiotic-eluting temporary spacer before definitive reconstruction. Tissue microbiological diagnosis and targeted antibiotic therapy are required. In cases of significant proximal femoral bone loss, spacing options are limited. CASE REPORT: We present a case of a bisphosphonate-induced subtrochanteric fracture that progressed to infected non-union. Despite multiple washouts and two revision fixations, the infection remained active with an unfavorable antibiogram. The patient required staged revision arthroplasty including a proximal femoral resection. To improve function through maintaining leg length and offset, the Cement-a-TAN was fabricated. It is a custom-made antibiotic-eluting articulating temporary spacer. Using a trochanteric entry cephalocondylar nail as a scaffold, bone cement was molded around the nail to fashion an anatomical and patient-specific proximal femoral spacer. Following resolution of the infection, the Cement-a-TAN was removed and a proximal femoral arthroplasty was successfully performed. CONCLUSION: Cement-a-TAN is an excellent temporary spacing technique in staged proximal femoral replacement for infected non-union of the proximal femur where there has been significant bone loss. It preserves mobility and maintains leg length, offset, and periarticular soft-tissue tension, while offering good stability.

Variations in non-locking screw insertion conditions generate unpredictable changes to achieved fixation tightness and stripping rates.

BACKGROUND: Screws are the most commonly inserted orthopaedic implants. However, several variables related to screw insertion and tightening have not been evaluated. This study aimed firstly to assess the effect of insertion variables on screw tightness, secondly to improve methodologies used by researchers when testing screw insertion techniques and thirdly to assess for any learning or fatigue effects when inserting screws. METHODS: Two surgeons tightened a total of 2280 non-locking, 3.5 mm cortical screws, with 120 screws inserted to what they felt to be optimum tightness whilst varying each of the following factors: different screwdrivers for measuring torque, screwdriver orientation, gloves usage, dominant/non-dominant hand usage, awareness to the applied torque (blinded, unblinded and re-blinded), four bone densities and seven cortical thicknesses. Screws were tightened to failure to determine stripping torque, which was used to calculate screw tightness - ratio between stopping and stripping torque. FINDINGS: Screw tightness increased with glove usage, being blinded to the applied torque and with denser artificial bone and with thinner cortices. Considering all the insertions performed, the two surgeons stopped tightening screws at difference values of tightness ((77% versus 66% (p < 0.001)). A learning effect was observed with some parameters including sterile gloves usage and non-dominant hand application. INTERPRETATION: Different insertion conditions frequently changed screw tightness for both surgeons. Given the influence of screw tightness on fixation stability, the variables investigated within this study should be carefully reported and controlled when performing biomechanical testing alongside practicing screw insertion under different conditions during surgical training.

Influence of pilot hole diameter in cancellous screw fixation in a reduced density animal bone model.

BACKGROUND: Screw fixation in osteoporotic bone is clinically challenging. Screw failure rates are growing due to an increasing prevalence of osteoporosis. To address this, biomechanical models are needed to recreate the bone clinically encountered alongside the development of new operative techniques. The first aim of this study was to test whether the use of a smaller than recommended pilot-hole diameter improved pull-out strength for cancellous screws, with the second aim to create a model of low-density porcine bone for biomechanical testing. METHODS: Thirty porcine tibiae were cut into transverse metaphyseal sections of 20 mm thickness. Bone density was altered using 0.15 M Hydrochloric acid, and measured and pre- and post-demineralisation using HRµCT. Seventy-two screw areas were randomised to either 2.5 mm or 1.5 mm pilot holes and to either be normal or reduced density. Maximum axial pull-out strength was measured. FINDINGS: Demineralisation reduced bone density by 12% (p < 0.0001) and 11% (p < 0.0001) for 2.5 mm and 1.5 mm pilot hole diameters respectively. Pull-out strength reduced by 50% (p = 0.0001) and 44% (p < 0.0001) following demineralisation for both 2.5 mm and 1.5 mm pilot hole diameters. Pull-out strength increased by 51% (p = 0.0008) when inserting screws into 1.5 mm pilot holes in low density bone, and by 28% (p = 0.027) in normal bone. INTERPRETATION: Porcine bone can be demineralised to model low density cancellous bone. This novel model showed that pullout force is significantly reduced in lower density screw holes, but that this reduction can be mitigated by reducing pilot hole diameter for cancellous screws.

Stripping torques in human bone can be reliably predicted prior to screw insertion with optimum tightness being found between 70% and 80% of the maximum.

AIMS: To devise a method to quantify and optimize tightness when inserting cortical screws, based on bone characterization and screw geometry. METHODS: Cortical human cadaveric diaphyseal tibiae screw holes (n = 20) underwent destructive testing to firstly establish the relationship between cortical thickness and experimental stripping torque (Tstr), and secondly to calibrate an equation to predict Tstr. Using the equation's predictions, 3.5 mm screws were inserted (n = 66) to targeted torques representing 40% to 100% of Tstr, with recording of compression generated during tightening. Once the target torque had been achieved, immediate pullout testing was performed. RESULTS: Cortical thickness predicted Tstr (R2 = 0.862; p < 0.001) as did an equation based on tensile yield stress, bone-screw friction coefficient, and screw geometries (R2 = 0.894; p < 0.001). Compression increased with screw tightness up to 80% of the maximum (R2 = 0.495; p < 0.001). Beyond 80%, further tightening generated no increase in compression. Pullout force did not change with variations in submaximal tightness beyond 40% of Tstr (R2 = 0.014; p = 0.175). CONCLUSION: Screw tightening between 70% and 80% of the predicted maximum generated optimum compression and pullout forces. Further tightening did not considerably increase compression, made no difference to pullout, and increased the risk of the screw holes being stripped. While further work is needed for development of intraoperative methods for accurate and reliable prediction of the maximum tightness for a screw, this work justifies insertion torque being considerably below the maximum.Cite this article: Bone Joint Res 2020;9(8):493-500.

Cement augmentation of calcar screws may provide the greatest reduction in predicted screw cut-out risk for proximal humerus plating based on validated parametric computational modelling: Augmenting proximal humerus fracture plating.

AIMS: Fixation of osteoporotic proximal humerus fractures remains challenging even with state-of-the-art locking plates. Despite the demonstrated biomechanical benefit of screw tip augmentation with bone cement, the clinical findings have remained unclear, potentially as the optimal augmentation combinations are unknown. The aim of this study was to systematically evaluate the biomechanical benefits of the augmentation options in a humeral locking plate using finite element analysis (FEA). METHODS: A total of 64 cement augmentation configurations were analyzed using six screws of a locking plate to virtually fix unstable three-part fractures in 24 low-density proximal humerus models under three physiological loading cases (4,608 simulations). The biomechanical benefit of augmentation was evaluated through an established FEA methodology using the average peri-screw bone strain as a validated predictor of cyclic cut-out failure. RESULTS: The biomechanical benefit was already significant with a single cemented screw and increased with the number of augmented screws, but the configuration was highly influential. The best two-screw (mean 23%, SD 3% reduction) and the worst four-screw (mean 22%, SD 5%) combinations performed similarly. The largest benefits were achieved with augmenting screws purchasing into the calcar and having posteriorly located tips. Local bone mineral density was not directly related to the improvement. CONCLUSION: The number and configuration of cemented screws strongly determined how augmentation can alleviate the predicted risk of cut-out failure. Screws purchasing in the calcar and posterior humeral head regions may be prioritized. Although requiring clinical corroborations, these findings may explain the controversial results of previous clinical studies not controlling the choices of screw augmentation.

Surgical performance when inserting non-locking screws: a systematic review.

Billions of screws are inserted by surgeons each year, making them the most commonly inserted implant. When using non-locking screws, insertion technique is decided by the surgeon, including how much to tighten each screw. The aims of this study were to assess, through a systematic review, the screw tightness and rate of material stripping produced by surgeons and the effect of different variables related to screw insertion.Twelve studies were included, with 260 surgeons inserting a total of 2793 screws; an average of 11 screws each, although only 1510 screws have been inserted by 145 surgeons where tightness was measured - average tightness was 78±10% for cortical (n = 1079) and 80±6% for cancellous screw insertions (n = 431).An average of 26% of all inserted screws irreparably damaged and stripped screw holes, reducing the construct pullout strength. Furthermore, awareness of bone stripping is very poor, meaning that screws must be considerably overtightened before a surgeon will typically detect it.Variation between individual surgeons' ability to optimally insert screws was seen, with some surgeons stripping more than 90% of samples and others hardly any. Contradictory findings were seen for the relationship between the tightness achieved and bone density.The optimum tightness for screws remains unknown, thus subjectively chosen screw tightness, which varies greatly, remains without an established target to generate the best possible construct for any given situation. Work is needed to establish these targets, and to develop methods to accurately and repeatably achieve them. Cite this article: EFORT Open Rev 2020;5:26-36. DOI: 10.1302/2058-5241.5.180066.

[68Ga]Ga-P16-093 as a PSMA-Targeted PET Radiopharmaceutical for Detection of Cancer: Initial Evaluation and Comparison with [68Ga]Ga-PSMA-11 in Prostate Cancer Patients Presenting with Biochemical Recurrence.

PURPOSE: This study was undertaken to evaluate radiation dosimetry for the prostate-specific membrane antigen targeted [68Ga]Ga-P16-093 radiopharmaceutical, and to initially assess agent performance in positron emission tomography (PET) detection of the site of disease in prostate cancer patients presenting with biochemical recurrence. PROCEDURES: Under IND 133,222 and an IRB-approved research protocol, we evaluated the biodistribution and pharmacokinetics of [68Ga]Ga-P16-093 with serial PET imaging following intravenous administration to ten prostate cancer patients with biochemical recurrence. The recruited subjects were all patients in whom a recent [68Ga]Ga-PSMA-11 PET/X-ray computed tomography (CT) exam had been independently performed under IND 131,806 to assist in decision-making with regard to their clinical care. Voided urine was collected from each subject at ~ 60 min and ~ 140 min post-[68Ga]Ga-P16-093 injection and assayed for Ga-68 content. Following image segmentation to extract tissue time-activity curves and corresponding cumulated activity values, radiation dosimetry estimates were calculated using IDAC Dose 2.1. The prior [68Ga]Ga-PSMA-11 PET/CT exam (whole-body PET imaging at 60 min post-injection, performed with contrast-enhanced diagnostic CT) served as a reference scan for comparison to the [68Ga]Ga-P16-093 findings. RESULTS: [68Ga]Ga-P16-093 PET images at 60 min post-injection provided diagnostic information that appeared equivalent to the subject's prior [68Ga]Ga-PSMA-11 scan. With both radiopharmaceuticals, sites of tumor recurrence were found in eight of the ten patients, identifying 16 lesions. The site of recurrence was not detected with either agent for the other two subjects. Bladder activity was consistently lower with [68Ga]Ga-P16-093 than [68Ga]Ga-PSMA-11. The kidneys, spleen, salivary glands, and liver receive the highest radiation exposure from [68Ga]Ga-P16-093, with estimated doses of 1.7 × 10-1, 6.7 × 10-2, 6.5 × 10-2, and 5.6 × 10-2 mGy/MBq, respectively. The corresponding effective dose from [68Ga]Ga-P16-093 is 2.3 × 10-2 mSv/MBq. CONCLUSIONS: [68Ga]Ga-P16-093 provided diagnostic information that appeared equivalent to [68Ga]Ga-PSMA-11 in this limited series of ten prostate cancer patients presenting with biochemical recurrence, with the kidneys found to be the critical organ. Diminished tracer appearance in the urine represents a potential advantage of [68Ga]Ga-P16-093 over [68Ga]Ga-PSMA-11 for detection of lesions in the pelvis.

Non-locking screw insertion: No benefit seen if tightness exceeds 80% of the maximum torque.

BACKGROUND: Millions of non-locking screws are manually tightened during surgery each year, but their insertion frequently results in overtightening and damage to the surrounding bone. We postulated that by calculating the torque limit of a screw hole, using bone and screw properties, the risk of overtightening during screw insertion could be reduced. Additionally, predicted maximum torque could be used to identify optimum screw torque, as a percentage of the maximum, based on applied compression and residual pullout strength. METHODS: Longitudinal cross-sections were taken from juvenile bovine tibial diaphyses, a validated surrogate of human bone, and 3.5 mm cortical non-locking screws were inserted. Fifty-four samples were used to define the association between stripping torque and cortical thickness. The relationship derived enabled prediction of insertion torques representing 40 to 100% of the theoretical stripping torque (Tstr) for a further 170 samples. Screw-bone compression generated during insertion was measured, followed immediately by axial pullout testing. FINDINGS: Screw-bone compression increased linearly with applied torque up to 80% of Tstr (R2 = 0.752, p < 0.001), but beyond this, no significant further compression was generated. After screw insertion, with all screw threads engaged, more tightening did not create any significant (R2 = 0.000, p = 0.498) increase in pullout strength. INTERPRETATION: Increasing screw tightness beyond 80% of the maximum did not increase screw-bone compression. Variations in torques below Tstr, did not affect pullout forces of inserted screws. Further validation of these findings in human bone and creation of clinical guidelines based on this research approach should improve surgical outcomes and reduce operative costs.

Screw configuration in proximal humerus plating has a significant impact on fixation failure risk predicted by finite element models.

BACKGROUND: Proximal humeral fractures occur frequently, with fixed angle locking plates often being used for their treatment. No current quantitative evidence for the effect of different screw configurations exists, and the large number of variations makes biomechanical testing prohibitive. Therefore, we used an established and validated finite element osteosynthesis test kit to quantify the effect of variations in screw configuration on predicted failure risk of PHILOS plate fixation for unstable proximal humerus fractures. METHODS: Twenty-six low-density humerus models were osteotomized to create malreduced unstable 3-part fractures that were virtually fixed with PHILOS plates. Twelve screw configurations were simulated: 6 using 2 screw rows, 4 using 3 rows, and 1 with either 8 or 9 screws. Three physiological loading cases were modeled and an established finite element analysis methodology was used. The average peri-screw bone strain, previously demonstrated to predict fatigue cutout failure, was used to compare the different configurations. RESULTS: Significant differences in peri-screw strains, and thus predicted failure risk, were seen with different combinations. The 9-screw configuration demonstrated the lowest peri-screw strains. Fewer screw constructs showed lower strains when placed further apart. The calcar screws (row E) significantly (P < .001) reduced fixation failure risk. CONCLUSION: Screw configurations significantly impact predicted cutout failure risk for locking plate fixations of unstable proximal humerus fractures in low-density bone. Although requiring clinical corroboration, the result of this study suggests that additional screws reduce peri-screw strains, the distance between them should be maximized whenever possible and the calcar screws should be used.

The influence of screw length on predicted cut-out failures for proximal humeral fracture fixations predicted by finite element simulations.

BACKGROUND: The aim of this study was to identify the effect of screw length on predictions of fixation failure in three-part proximal humeral fractures using a finite element-based osteosynthesis modelling toolkit. METHODS: A mal-reduced unstable three-part AO/OTA 11-B3.2 fracture with medial comminution was simulated in forty-two digitally processed proximal humeri covering a spectrum of bone densities and fixed with the PHILOS plate using three distal and six proximal locking screws. Four test groups were generated based on the screw tip to joint surface distance (TJD), with all proximal screws being shortened from 4 mm TJD to be 8, 12 or 16 mm TJD. Average bone strains around the screw tips, correlating with biomechanical cyclic cut-out-type failure, were evaluated in three physiological loading protocols representing simple shoulder motions. Six further groups were tested, where five of the proximal screws were inserted to 4 mm TJD and the sixth screw to 8 mm TJD. RESULTS: Exponential increases in the predicted risk of fixation failure were seen with increased tip-to-joint distances (p < 0.001). When one of the proximal screws was placed 8 mm from the joint, with the remaining five at 4 mm distance, significant increases (p < 0.001) were registered in the strains around the screw tips in all except the two superior screws. This effect was maximal around the calcar screws (p < 0.001) and for lower density samples (p < 0.001). CONCLUSIONS: These results suggest that longer screws provide reduced risk of cut-out failure, i.e. distalisation and/or varisation of the head fragment, and thus may decrease failure rates in proximal humeral fractures treated with angular stable plates. These findings require clinical corroboration and further studies to investigate the risk of screw perforation.

Low Rates of Survival Seen in Orthopedic Patients Receiving In-Hospital Cardiopulmonary Resuscitation.

INTRODUCTION: Despite awareness of overall poor survival rates following cardiopulmonary resuscitation (CPR), some orthopedic patients with significant comorbidities continue to have inappropriate resuscitation plans. Furthermore, in certain injury groups such as patients with hip fractures, survival outcome data are very limited; current discussions regarding resuscitation plans may be inaccurate. This study assesses survival in orthopedic patients following CPR, to inform decision-making between physicians, surgeons, and patients. METHODS: A dual center, retrospective cohort study was performed analyzing all orthopedic admissions that received CPR over a 25-month period, with a minimum of 1 year follow-up. National Cardiac Arrest Audit data, "mortality and morbidity" meeting records, National Hip Fracture Databases, and electronic notes were analyzed. Survival duration was measured, alongside reason for admission, location CPR occurred, and initial rhythm encountered. RESULTS: Thirty-two patients received CPR over the 25-month period (median age: 83; range: 30-96). Three (9%) of 32 patients survived to discharge. Only 1 of the 26 patients older than 65 years survived to discharge. Fifteen (47%) of 32 had hip fractures, where 4 (27%) of 15 of this group survived 24 hours; none survived to discharge. When recorded, 22 (92%) of 24 initially had a nonshockable rhythm. DISCUSSION: Cardiopulmonary resuscitation was conceptualized as a treatment for reversible cardiopulmonary causes. When used in trauma and orthopedic patients, especially older and/or hip fracture patients, it seldom led to hospital discharge. Different admission practices such as "front door" orthogeriatric reviews may explain the contrast in usage of CPR between the hospitals. CONCLUSION: Survival rates following CPR were very low, with it proving specifically ineffective in hip fracture patients. Although every decision about resuscitation should be patient centered and individualized, this study will allow clinicians to be more realistic about outcomes from CPR, particularly in the hip fracture group.

Importance of locking plate positioning in proximal humeral fractures as predicted by computer simulations.

Multifragmented proximal humeral fractures frequently require operative fixation. The locking plates commonly used are often placed relative to the greater tuberosity, however no quantitative data exists regarding the effect of positional changes. The aim of the study was to establish the effects from variations in proximal-distal PHILOS humeral plate positioning on predicted fixation failure risk. Twenty-one left-sided low-density virtual humeri models were created with a simulation framework from CT data of elderly donors and osteotomized to mimic an unstable three-part malreduced AO/OTA 11-B3.2 fracture with medial comminution. A PHILOS plate with either four or six proximal screws was used for fixation. Both configurations were modelled with plate repositioning 2 and 4 mm distally and proximally to its baseline position. Applying a validated computational model, three physiological loading situations were simulated and fixation failure predicted using average strain around the proximal screws-an outcome established as a surrogate for cycles to failure. Varying the craniocaudal plate position affected the peri-implant strain for both four and six-screw configurations. Even though significant changes were seen only in the latter, all tests suggested that more proximal plate positioning results in decreased peri-screw strains whereas distalizing creates increases in strain. These results suggest that even a small distal PHILOS plate malpositioning may reduce fixation stability. Plate distalization increases the probability of being unable to insert all screws within the humeral head, which dramatically increases the forces acting on the remaining screws. Proximal plate shifting may be beneficial, especially for constructs employing calcar screws. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Study protocol for a randomised controlled trial of consenting processes and their effects on patient decision-making when undergoing spinal injections: the Risks In Spinal Consenting for Surgery (RISCS) trial.

INTRODUCTION: There are major differences between legal and medical approaches to informed consent. Medically, consent is obtained prospectively for an intended procedure, to inform the patient of choices, risks and benefits, and to manage expectations. Legally, consent is reviewed retrospectively, usually following unmet expectations and/or the occurrence of complications. Recent legal cases relating to clinical negligence define the establishment of causation and breach of duty related to informed consent. However, there is no prospective evidence to validate the current judicial perspectives on causation and thus clinical negligence. The aim of this randomised controlled trial (RCT) is to investigate whether variations in consenting processes for the same procedure lead to changes in patient decision-making related to consent for that procedure. METHODS AND ANALYSIS: The Risks In Spinal Consenting for Surgery trial is a single-centre, non-inferiority RCT, where 220 patients, aged over 18 years, receiving an elective, day case spinal injection, will be randomised to either a 'legally styled' consent form with 55 risks identified in the world literature, or a 'medically styled' consent form with the 13 serious or most common risks usually quoted by reference to specialist society guidelines. Following explanation of the medical reasons for considering an injection therapy and consent to the trial, participants will be randomly allocated to one of two groups (1:1). The patients are then given the opportunity to discuss any concerns relating to the procedure and/or risks with a single specialist practitioner. The primary outcome will be rates of consent withdrawal due to the risks explained. Secondary outcomes include scores from the State-Trait Anxiety Inventory, Visual Analogue Scale, EuroQol 5-dimension questionnaire and Oswestry Disability Index. ETHICS AND DISSEMINATION: Results will be presented in peer-reviewed journals and at international conferences. This study is approved by the Health Research Authority: REC 16/SC/0510. TRIAL REGISTRATION NUMBER: ISRCTN67513618; Pre-results.