The management of comminuted metaphyseal fractures is a technical challenge and satisfactory outcomes of such fixations often remain elusive. The small articular fragments and bone loss often make it difficult for standard fixation implants for proper fixation. We developed a novel technique to achieve anatomical reduction in multiple cases of comminuted metaphyseal fractures at different sites by employing the cantilever mechanism with the help of multiple thin Kirschner wires augmented by standard fixation implants. We performed a retrospective study of 10 patients with different metaphyseal fractures complicated by comminution and loss of bone stock. All patients were treated with the help of cantilever mechanism using multiple Kirschner wires augmented by compression plates. All the patients were operated by the same surgeon between November 2020 to March 2021 and followed up till March 2023. Surgical outcomes were evaluated according to the clinical and radiological criteria. A total of 10 patients were included in the study. Since we only included patients with highly unstable and comminuted fractures which were difficult to fix with traditional methods, the number of patients in the study were less. All 10 patients showed satisfactory clinical and radiological union at the end of the study with good range of motion. One of the patient in the study had post-operative wound complication which was managed conservatively with regular dressings and oral antibiotics. Comminuted metaphyseal fractures might differ in pattern and presentation with every patient and there can be no standard treatment for all. The cantilever technique of fracture fixation is based on the principle of cantilever mechanism used in bridges and helps achieve good anatomical reduction and fixation. It provides a decent alternative when standard modes of fixation don't give desired result owing to comminuted nature of fractures and deficiency of bone stock

This study aimed to determine if multiple failed closed reductions (CRs) prior to fixation of distal radius fracture is associated with the odds of complication-related reoperation up to two years post fracture. We identified all distal radius fracture patients aged 18 or older between the years of 2003-2016 in Ontario, Canada from linked administrative databases. We used procedural and fee codes to identify patients who underwent primary outpatient surgical fixation between 8 and 14 days post fracture, and grouped patients by the number of CRs they underwent prior to definitive fixation. We excluded patients who underwent fixation within 7 days of their fracture to exclude more complex fracture types and/or patients who required more immediate surgery. We grouped patients according to the number of CRs they underwent prior to definitive fixation. We used intervention and diagnostic codes to identify reoperations within two years of fixation. We used multi-level multivariable logistic regression to compare the association between the number of CRs and reoperation while accounting for clustering at the surgeon level and adjusting for other relevant covariables. We performed an age-stratified analysis to determine if the association between the number of CRs and reoperation differed by patient age. We identified 5,464 patients with distal radius fractures managed with outpatient fixation between 8 and 14 days of their fracture. A total of 1,422 patients (26.0%) underwent primary surgical fixation (mean time to fixation 10.6±2.0 days), while 3,573 (65.4%) underwent secondary fixation following one failed CR (mean time to fixation 10.1±2.2 days, time to CR 0.3±1.2 days), and 469 (8.6%) underwent fixation following two failed CRs (mean time to fixation 10.8±2.2 days, time to first CR 0.0±0.1 days, time to second CR 4.7±3.0 days). The CR groups had higher proportions of female patients compared to the primary group, and patients who underwent two failed CRs were more likely to be fixed with a plate (vs. wires or pins). The unadjusted proportion of reoperations was significantly higher in the group who underwent two failed CRs (7.5%) compared to those who underwent primary fixation (4.4%), and fixation following one failed CR (4.9%). Following covariable adjustment, patients who underwent two failed CRs had a significantly higher odds of reoperation (odds ratio [OR] 1.72 [1.12-2.65]) compared to those who underwent primary fixation. This association appeared to worsen for patients over the age of 60 (OR 3.93 [1.76-8.77]). We found no significant difference between the odds of reoperation between patients who underwent primary fixation vs. secondary fixation following one failed CR. We found that patients with distal radius fractures who undergo multiple CRs prior to definitive fixation have a significantly higher odds of reoperation compared to those who undergo primary fixation, or fixation following a single CR. This suggests that surgeons should offer fixation if indicated following a single failed CR rather than attempt multiple closed reductions. Prospective studies are required to confirm these findings

Introduction. Femoral-shortening osteotomy for the treatment of leg length discrepancy is demanding technique. Many surgical technique and orthopaedic devises have been suggested to perform this procedure. Herein, we describe modified femoral shortening osteotomy over a nail, using a percutaneous multiple drill-hole osteotomy technique. Materials and Methods. We operated on six patients with LLD. Mean femoral shortening was 4.2 cm. Osteotomy was performed using a multiple drill-hole technique, and bone was stabilized using an intramedullary nail. Post-operative clinical and radiological data were reported. Results. Shortening was achieved, with a final LLD of < 1 cm in all patients. All patients considered the lengths of the lower limbs to be equal. No special surgical skills or instrumentation were needed. Intraoperative and post-operative complications were not recorded. Conclusions. Percutaneous femoral-shortening osteotomy over a nail using multiple drill-hole osteotomy technique was effective and safe in treating LLD

Renal Osteodystrophy is a type of metabolic bone disease characterized by bone mineralization deficiency due to electrolyte and endocrine abnormalities. Patients with chronic kidney disease (CKD) are more likely to experience falls and fractures due to renal osteodystrophy and the high prevalence of risk factors for falls. Treatment involves medical management to resolve the etiology of the underlying renal condition, as well as management (and prevention) of pathological fractures. A 66-year-old female patient, with severe osteoporosis and chronic kidney disease undergoing haemodialysis, has presented with multiple fractures along the years. She was submitted to bilateral proximal femoral nailing as fracture treatment on the left and prophylactically due to pathological bone injury on the right, followed by revision of the left nail with a longer one after varus angulation and fracture distal to the nail extremity. Meanwhile, the patient suffered a pathological fracture of the radial and cubital diaphysis and was submitted to conservative treatment with cast, with consolidation of the fracture. Posteriorly, she re-fractured these bones after a fall and repeated the conservative treatment. Clinical management: There is a multidisciplinary approach to manage the chronic illness of the patient, including medical management to resolve the etiology and consequences of her chronic kidney disease, pain control, conservative or surgical fracture management and prevention of falls. The incidence of chronic renal disease is increasing and the patients with this condition live longer than previously and are more physically active. Thus, patients may experience trauma as a direct result of increased physical activity in a setting of weakened pathologic bone. Their quality of life is primarily limited by musculoskeletal problems, such as bone pain, muscle weakness, growth retardation, and skeletal deformity. A multidisciplinary approach is required to treat these patients, controlling their chronic diseases, managing fractures and preventing falls

Aim. In severe cases of postoperative spinal implant infections (PSII) multiple revision surgeries may be needed. Little is known if changes of the microbiological spectrum and antibiotic resistance pattern occur between revision surgeries. Therefore, the aim of this study was to analyze the microbiological spectrum and antibiotic resistance pattern in patients with multiple revision surgeries for the treatment of PSII. Furthermore, changes of the microbiological spectrum, distribution of mono vs. polymicrobial infections, and changes of the antimicrobial resistance profile in persistent microorganisms were evaluated. Method. A retrospective analysis of a prospectively maintained single center spine infection database was performed with a minimum follow-up of 3 years. Between 01/2011 and 12/2018, 103 patients underwent 248 revision surgeries for the treatment of PSII. Overall, 20 patients (6 male/14 female) underwent 82 revisions for PSII (median 3; range 2–12). There were 55/82 (67.1%) procedures with a positive microbiological result. Microbiological analysis was performed on tissue and implant sonication fluid. Changes in microbial spectrum and antibiotic resistance pattern between surgeries were evaluated using Chi-Square and Fisher's exact test. Results. In total, 74 microorganisms (83.3% gram-positive; 10.8% gram-negative) were identified. The most common microorganisms were Staphylococcus epidermidis (18.9%) and Cutibacterium acnes (18.9%). All S. epidermidis identified were methicillin-resistant (MRSE). Overall, there were 15/55 (27.3%) polymicrobial infections. The microbiological spectrum changed in 57.1% (20/35) between the revision stages over the entire PSII period. In 42.9% (15/35) the microorganism persisted between the revision surgeries stages. Overall, changes of the antibiotic resistance pattern were seen in 17.4% (8/46) of the detected microorganisms comparing index revision and all subsequent re-revisions. Moreover, higher resistance rates were found for moxifloxacin and for ciprofloxacin at first re-revision surgery compared with index PSII revision. Resistances against vancomycin increased from 4.5% (1/23) at index PSII revision to 7.7% (2/26) at first re-revision surgery. Conclusions. Changes of the microbiological spectrum and the resistance pattern can occur in patients with severe PSII who require multiple revision surgeries. It is important to consider these findings in the antimicrobial treatment of PSII. The microbiological analysis of intraoperative tissue samples should be performed at every revision procedure for PSI

Introduction. Deformations of forearm with different degree of expression and functional restrictions of upper limb in children with hereditary multiple exostosis are formed in almost 80% of the cases. The question of indications for the selection and conduct of surgical procedure remains controversial, existing treatment methods and post-operative recovery methods for children need to be improved. Materials and Methods. The long-term outcomes of surgical treatment of 112 patients diagnosed with “Hereditary Multiple Exostosis” (HME) aged from 2 till 17 years old were researched. Evaluation of surgical treatment results was carried out in accordance with complaints, functional condition of the forearm, radiographs (taking into account reference lines and angles). Depending on the variant of deformation, the following surgical operations were performed: resection of bone-cartilage exostoses (in 20.5%); correction of forearm deformation with external fixator (in 79.5). In 14 cases, for a more accurate correction of deformity a hexapod frame was used. Results. Differentiated approach provided “good” anatomical and functional results in 55.6%; “satisfactory” results in 40.2%; “unsatisfactory” results in 4.2%. Postoperative complications in the form of non-union, pseudoarthrosis, delayed consolidation or neurological disorders were in 6.2%. Conclusions. The choice of surgical treatment is determined by the variant and severity of deformation. This approach allows to improve cosmetic and functional condition of forearm and adjacent joints. The use of hexapod allows to increase accuracy of correction of physiological axis of forearm bones

Flail chest and multiple rib fractures are common injuries in trauma patients. Several small randomized studies have suggested significant improvements in patient outcomes with surgical fixation, compared to nonoperative management, yet emerging population-level data report some conflicting results. The objectives of this study were to compare the results of surgical fixation and nonoperative management of multiple rib fractures and flail chest injuries and to assess whether effects varied by study design limitations, including risk of confounding by indication. A comprehensive search of electronic databases (Medline, Embase, Web of Science) was performed to identify randomized controlled trials and observational studies. Random effects models were used to evaluate weighted risk ratios (RR) and mean differences (MD). Risk of confounding by indication was assessed for each study (low, medium, and high risk), and this categorization was used to stratify results for clinical outcomes. Publication bias was assessed. Thirty-nine studies, with a total of 19,357 patients met inclusion criteria. Compared to nonoperative treatment, surgical fixation of flail chest and multiple rib fractures was associated with decreased risk of death (overall RR 0.40, 95% confidence interval (CI) 0.28–0.56), pneumonia (overall RR 0.70, 95% CI 0.52–0.93), tracheostomy (overall RR 0.62, 95% CI 0.41–0.93), and chest wall deformity (overall RR 0.16, 95% CI 0.06–0.42). However, many of the observational studies were at risk of confounding by indication, and results varied according to risk of confounding by indication. Differences in ventilator time, intensive care unit length of stay (LOS), hospital LOS, and return to work will be assessed (results pending). Compared to nonoperative treatment, surgical fixation of flail chest and multiple rib fractures is associated with improved clinical outcomes. Discrepancies between some study results may be due to confounding by indication. Additional prospective randomized trials and high-quality observational studies are required to overcome potential threats to validity and to expand on existing evidence around optimal treatment of these injuries

Abstract. Introduction. Re-revision knee replacement (RR-KR) is complex surgery, with a significant impact on individual patients and health resource use. The aim of this study was to investigate early patient-relevant outcomes following RR-KR. Methodology:. 206 patients (250 knees) undergoing RR-KR were recruited from a major revision centre between 2015–2018. Patient-relevant outcomes assessed were: implant survivorship, complications (90-days), joint function and quality of life (final follow-up). Risk factors for further revision surgery at 1 year were investigated using multiple logistic regression. Results. Mean age at RR-KR was 69.0 years. Indications for RR-KR included: infection (n=171, 68.4%), aseptic loosening (n=25, 10.0%), and instability (n=24, 9.6%). Mean follow-up was 25.5 months. Kaplan Meier survivorship at 1 year was 71.3% (95% CI 64.1-77.3%). RR-KR for PJI had lower reoperation-free survival at 2 years compared to aseptic indications (55.7% versus 78.1%, p<0.05). 35 knees (14.0%) were readmitted within 90 days, the main indication being surgical site infection (54.3%, 4 superficial, 15 deep). At final follow-up, 44% of patients were dissatisfied with the outcome from RR-KR. Mean Oxford Knee Score was 25.1 (range 1–48). Median EQ-5D index was 0.648 (IQR 0.343-0.735). Risk factors for further revision surgery at 1 year were: PJI (OR 2.4;p<0.05) greater number of previous surgeries (OR 1.18;p<0.05) and higher Elixhauser score (OR 1.06;p<0.05). Conclusion. RR-KR was associated with high rates of early failure and post-operative complications. Infective indication for surgery, multiple previous surgeries and worse baseline patient comorbidity were associated to lower implant survivorship

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by progressive cartilage degradation, synovial membrane inflammation, osteophyte formation, and subchondral bone sclerosis. Pathological changes in cartilage and subchondral bone are the main processes in OA. In recent decades, many studies have demonstrated that activin-like kinase 3 (ALK3), a bone morphogenetic protein receptor, is essential for cartilage formation, osteogenesis, and postnatal skeletal development. Although the role of bone morphogenetic protein (BMP) signalling in articular cartilage and bone has been extensively studied, many new discoveries have been made in recent years around ALK3 targets in articular cartilage, subchondral bone, and the interaction between the two, broadening the original knowledge of the relationship between ALK3 and OA. In this review, we focus on the roles of ALK3 in OA, including cartilage and subchondral bone and related cells. It may be helpful to seek more efficient drugs or treatments for OA based on ALK3 signalling in future.

Aims

Intra-articular (IA) injection may be used when treating hip osteoarthritis (OA). Common injections include steroids, hyaluronic acid (HA), local anaesthetic, and platelet-rich plasma (PRP). Network meta-analysis allows for comparisons between two or more treatment groups and uses direct and indirect comparisons between interventions. This network meta-analysis aims to compare the efficacy of various IA injections used in the management of hip OA with a follow-up of up to six months.

Aim. As the populations of patients who have multiple prosthetic joints increase these years, the fate of a single joint periprosthetic joint infection in these patients is still unknown. Risk factors leading to a subsequent infection in another prosthetic joint are unclear. Our goal is to identify the risk factors of developing a subsequent infection in another prosthetic joint and describe the organism profile to the second prosthetic infection. Method. We performed a retrospective cohort study of all PJI cases underwent surgical intervention at our institute, a tertiary care referral center over 11 years, during January 2006 to December 2016. We identified 96 patients with periprosthetic joint infection who had another prosthetic joint in place at the time of presentation. The comorbidity, number of prosthetic joints, date and type of each arthroplasty, times of recurrent infection at each prosthetic joint with subsequent debridement or 2-stage resection arthroplasty, organisms from every infection episode, the outcome of each periprosthetic joint infection in these patients were analyzed. Results. During January 2006 to May 2017, we retrospective collected 294 PJI cases (159 hips, 135 knees) in our institute. Patients with single prosthetic joint were excluded and finally 96 patients were included. Of the 96 patients, 19 (19.79%) developed a periprosthetic joint infection in a second joint. The type of organism was the same as the first infection in 12 (63.16%) of 19 patients. The time to developing a second infection averaged 2.16 years (range, 0–9.3 years). The risk factors leading to a subsequent infection in another prosthetic joint are albumin level (< 3.5 mg/dl), long-term steroid usage (> 5mg/day, > 3 months), history of necrotizing fasciitis, history of invasive dental procedure (> Grade IV procedure), 3-stage resection arthroplasty or more, and PJI caused by vacomycin-resistent enterococcus (VRE). Conclusions. A PJI might predispose patients to subsequent PJI in another prosthesis. Patients and surgeons must be aware of the risk factors contribute to this devastating complication. Most organisms in the second PJI are identical to the first one, and we believe the bacteremia may be the pathogenesis, but need further proved. The preventive policy may be needed in the future for this population who has multiple prosthetic joints

Introduction. Sonicate fluid cultures (SFC) are more sensitive than conventional microbiological methods in identifying periprosthetic joint infections (PJI), because sonication enables a sampling of the causative bacteria directly from the surface of the endoprosthetic components. Because of their high sensitivity SFC can be positive while all other microbiological methods remain negative. It is therefore difficult to interpret a single SFC as being truly or falsely positive. The aim of this prospective study was to improve the interpretation of SFC in the diagnosis of PJI in patients after total hip arthroplasty through the use of multiple SFC. Material and methods. 102 patients of which 37 had a defined PJI according to the following criteria were included: intraarticular pus or a sinus tract, a periprosthetic membrane (PM) indicative of infection, or a positive microbiological culture in a minimum of 2 separate microbiological samples. A single positive microbiological sample was classified as false positive. In 35 patients multiple SFC were acquired from the separate endoprosthetic components. Results. Out of all individual diagnostic parameters SFC achieved the highest sensitivity with 89% and a specificity of 72%. PM was able to achieve a sensitivity of 78% for the detection of PJI. Out of the 35 patients with multiple SFC it was possible to newly diagnose a PJI in 3 cases solely through multiple isolations of the same bacterial species in SFC. In the same group it was also possible to exclude the suspicion of PJI in 3 cases, because only one of the multiple samples presented a bacterial isolation, while the other samples remained negative. When multiple SFC were employed it was possible to increase the sensitivity to 100% and the specificity to 85%. Conclusion. In our study SFC were the most sensitive diagnostic parameter for detection of PJI and our results show that it is possible to further increase the sensitivity and specificity of SFC when multiple samples are used. The acquisition of multiple SFC facilitate the diagnosis of PJI, since they are able to present the 2 positive bacterial isolations that are needed for making the diagnosis of PJI. Multiple SFC can help to solve the orthopaedic surgeon's diagnostic dilemma of having to interpret a single positive bacterial isolation by confirming the bacterial isolation in a second SFC sample

Introduction: A 2-stage approach is often employed to treat infected TJA. Success rates have been reported between 85–100%. Other authors favor multiple routine debridements (I& D) to lower the infection rate. This study compares the relative effectiveness of 2-, 3- and 4 stage treatment approaches. Methods: Between 1988 and 1998, all infected TJA at our institution were treated with a 2-, 3- or 4 stage approach. In the 2-stage approach, prosthesis removal was followed by 6 weeks of IV antibiotics and reimplantation. In the 3-stage approach, an additional I& D was added 5–7 days after prosthesis removal. In the 4-stage protocol, a third I& D was performed after completion of antibiotics. Negative cultures led to reimplantation. Positive cultures led to an additional 6-week course of antibiotics, and then repeat 3rd and 4th stages. Patients retained their components if free of infection, on chronic antibiotic suppression or after additional I& D. Patients were free of infection if no more treatment was needed. Results: 83 patients with infected TJA were treated. Average follow-up was 25 months. Of the 2 stage patients, 9/10 (90%) retained their components, and 7/10 (70%) was free of infection. Of the 3 stage patients, 32/37 (86%) retained their components, and 28/37 (76%) was free of infection. Of the 4 stage patients, 34/36 (94%) retained their prosthesis, and 30/36 (83%) was free of infection. Seventeen additional patients in the 4-stage group had positive cultures at the third stage. After additional treatment 13/17 (76%) retained their components and 12/17 (71%) was free of infection. No correlation was found between infection severity (gram positive vs. negative organisms; single vs multiple organisms) or initial diagnosis. Discussion. Our ten-year experience with infected THA suggests that multiple I& D are required for successful treatment. Repeat I& D assures a sterile wound, as tissue culture is more sensitive than aspiration. Importantly, persistent infection after three I& D and appropriate antibiotics led to poorer results, suggesting that other host factors may preclude these patients from reimplantation. Given the exorbitant costs of treating failed reimplantations, an additional routine I& D may in fact be cost-effective across an entire population of infected TJA patients. Further analysis will focus upon cemented versus cementless implants, cost-benefit ratios of multiple debridements, nutritional parameters, functional assessments of patients at latest follow-up, cost analysis, and the value of preoperative. Conclusion: We recommend a 4-stage approach to the treatment of infected THA

Introduction. The bone defect reconstruction is the first step of successful primary or revision TKA in case of large bone defect. If the defect is not reconstructed adequately, we can neither preserve knee joint function nor guarantee long survival of the implant. Allogeneic bone graft is known to be the treatment of choice in large defect. However the surgical technique is demanding and incorporation failure is constant issue of the allogeneic bone graft. We propose new bone defect reconstruction technique using multiple screws and cement. Material and method. From April 2012 to April 2014, 12 patients with large defect which could not be reconstructed with metal augment were involved in this study. The bone defect type was 10 cases of 2A and 2 cases of 2B according to AORI (Anderson Orthopedic Research Institute) classification. The defect was reconstructed with multiple screws and cementing technique by single surgeon (WS Cho). Average follow-up period was 15 months. (24 ∼ 1 month). Result. We analyzed 6 patients whose follow-up periods were more than 12 months. Average ROM was 107' and clinical scores were 86 by HSS, 93 by KS and 11 by WOMAC respectively. No complications such as infection and loosening were developed. Mean surgical time was 1 hour and 57 minutes. Conclusion. In short term follow-up, cementing technique using multiple screws can be a solution for large bone defect reconstruction

Introduction: Aggressive fibromatosis is a benign but locally aggressive process. It arises from musculo-aponeurotic tissues, and invades locally without respect for tissue planes, surrounding vessels and nerves, which makes treatment of local recurrences difficult. Aims: Our aim is to review our experience in the management of aggressive fibromatosis, focussing on the cases of multiple recurrences, as well as to evaluate the need for disabling surgery. Material and methods: We present the series of 33 patients (15 male and 18 female) diagnosed of aggressive fibromatosis treated between 1993 and 2003; the follow-up period was no less than two years. The locations were shoulder girdle (8), lower extremity (8), upper extremity (6), gluteus (5), paravertebral (4) and thorax (2). There were 6 cases with 3 or more episodes of local recurrences; in these cases, depending on location and size, and considering high surgical morbidity, associations of radiotherapy, chemotherapy and hormone therapy were given, avoiding disabling surgery. Results: With an average follow-up of 32 months (25 to 50), there were no deaths and, in the 6 cases of multiple recurrences, there were no amputations. The control MRI demonstrated stability of the process in 5 out of 6 cases, and minimum growth without clinical correlation in the other one. In the other 27 cases, there were 14.8% surgical treated local recurrences, with no need for amputation. Conclusion: We consider that cases of multiple recurrences of aggressive fibromatosis benefit from adjuvant treatment (radiotherapy, chemotherapy and hormone therapy), avoiding disabling surgery, which is unnecessary following our criteria. This requires strict clinical and radiological control

Multiple ligament deficiency in knees is usually the aftermath of high velocity trauma and leads to complex multidirectional instability, that can in turn greatly compromise the patient’s functional level if left untreated. The aim of this study is to evaluate the mid- and long-term functional outcome of patients who underwent complex reconstruction for multiple ligament deficiency. Twenty-nine patients (21 male and 8 female) with an average age of 35.54 years (range 17–60) underwent arthroscopic or arthroscopically assisted multiple ligament reconstruction at an average of 2.1 years following their initial knee injury. Thirteen of them sustained a multiple ligament injury following an RTA, 11 during sports and 5 following a fall from a height. They were followed for a period of 13 to 108 months (average: 45.8) and functionally evaluated according to Clancy’s criteria. The functional outcome was excellent in five patients (17.2%), good in ten (34.5%), fair in twelve (41.4%), while two reconstructions resulted in a failure (6.9%). Eleven patients returned to sporting activities and all but three returned to work, although sometimes in lighter duties. Arthroscopic multiple ligament reconstruction is a complex and technically demanding procedure that should be carried out in specialised units. Although it rarely results in a “normal” knee, it offers in most cases a stable as well as functional knee

Introduction. Improper seating during head/stem assembly can lead to unintended micromotion between the femoral head and stem taper—resulting in fretting corrosion and implant failure. There is no consensus—either by manufacturers or by the surgical community—on what head/stem taper assembly method maximizes modular junction stability in total hip arthroplasty (THA). A 2018 clinical survey found that orthopedic surgeons prefer applying one strike or three, subsequent strikes when assembling head/stem taper. However, it has been suggested that additional strikes may lead to decreased interference. Additionally, the taper surface finish—micro-grooves—has been shown to affect taper interference and may be influenced by assembly method. Objective. The objective of this study was to employ a novel, micro-grooved finite element (FEA) model of the hip taper interface and assess the role of head/stem assembly method—one vs three strikes—on modular taper junction stability. Methods. A two-dimensional, axisymmetric model representative of a CoCrMo femoral head taper and Ti6Al4V stem taper was created using median geometrical measurements taken from over 100 retrieved implants. Surface finish—micro-grooves—of the head/stem taper were modeled using a sinusoidal function with amplitude and period corresponding to median retrieval measurements of micro-groove height and spacing, respectively (“smooth” stem taper: height=2µm, spacing=50µm; “rough” stem taper: height=11µm, spacing=200µm; head taper: height=2µm, spacing=50µm). All models had a 3’ (0.05°), proximal-locked angular mismatch between the tapers. To simulate modular assembly during surgery, multiple dynamic loads (4kN, 8kN, and 12kN) were applied to the femoral head taper as either one or three sequence of strikes. The input load profile (Figure 1) used for both cases was collected from surgeons assembling an experimental setup with a three-dimensional load sensor. Models were assembled and meshed in ABAQUS Standard (v 6.17) using four-node linear hexahedral, reduced integration elements. Friction was modeled between the stem and head taper using surface-to-surface formulation with penalty contact (µ=0.2). A total of 12 implicit, dynamic simulations (3 loads x 2 assembly sequences x 2 stem taper surface finishes) were run, with 2 static simulations at 4kN for evaluating inertial effects. Outcome variables included contact area, contact pressure, equivalent plastic strain, and pull-off force. Results. As expected, increasing assembly load led to increased contact area, pressures, and plasticity for both taper finishes. Rough tapers exhibited less total contact area at each loading level as compared to the smooth taper. Contact pressures were relatively similar across the stem taper finishes, except the 3-strike smooth taper, which exhibited the lowest contact pressures (Figure 2) and pull-off forces. The models assembled with one strike exhibited the greatest contact pressures, pull-off forces, and micro-groove plastic deformation. Conclusion. Employing 1-strike loads led to greater contact areas, pressures, pull-off forces, and plastic deformation of the stem taper micro-grooves as compared to tapers assembled with three strikes. Residual energy may be lost with subsequent assembly strikes, suggesting that one, firm strike maximizes taper assembly mechanics. These models will be used to identify the optimal design factors and impaction method to maximize stability of modular taper junctions. For any figures or tables, please contact authors directly

Objectives. Several genome-wide association studies (GWAS) of bone mineral density (BMD) have successfully identified multiple susceptibility genes, yet isolated susceptibility genes are often difficult to interpret biologically. The aim of this study was to unravel the genetic background of BMD at pathway level, by integrating BMD GWAS data with genome-wide expression quantitative trait loci (eQTLs) and methylation quantitative trait loci (meQTLs) data. Method. We employed the GWAS datasets of BMD from the Genetic Factors for Osteoporosis Consortium (GEFOS), analysing patients’ BMD. The areas studied included 32 735 femoral necks, 28 498 lumbar spines, and 8143 forearms. Genome-wide eQTLs (containing 923 021 eQTLs) and meQTLs (containing 683 152 unique methylation sites with local meQTLs) data sets were collected from recently published studies. Gene scores were first calculated by summary data-based Mendelian randomisation (SMR) software and meQTL-aligned GWAS results. Gene set enrichment analysis (GSEA) was then applied to identify BMD-associated gene sets with a predefined significance level of 0.05. Results. We identified multiple gene sets associated with BMD in one or more regions, including relevant known biological gene sets such as the Reactome Circadian Clock (GSEA p-value = 1.0 × 10. -4. for LS and 2.7 × 10. -2. for femoral necks BMD in eQTLs-based GSEA) and insulin-like growth factor receptor binding (GSEA p-value = 5.0 × 10. -4. for femoral necks and 2.6 × 10. -2. for lumbar spines BMD in meQTLs-based GSEA). Conclusion. Our results provided novel clues for subsequent functional analysis of bone metabolism, and illustrated the benefit of integrating eQTLs and meQTLs data into pathway association analysis for genetic studies of complex human diseases. Cite this article: W. Wang, S. Huang, W. Hou, Y. Liu, Q. Fan, A. He, Y. Wen, J. Hao, X. Guo, F. Zhang. Integrative analysis of GWAS, eQTLs and meQTLs data suggests that multiple gene sets are associated with bone mineral density. Bone Joint Res 2017;6:572–576

Purpose: We present a 12 year follow up of a patient who presented with a multiple plexiform schwannoma of the median nerve with multiple recurrences, where it was possible to salvage the limb. Patients and Methods: Multiple plexiform Schwannomas are rare nerve sheath tumours. In this case the tumour presented as a soft non-tender swelling in the palm of a child. On exploration the lesion was found to involve the median nerve from the digital nerves to the antecubital fossa. Histology confirmed a plexiform schwannoma. The tumour was locally very aggressive with multiple recurrences initially in the median nerve and ulnar nerves and later in the nerve grafts used following excision of the primary tumour. We present a pictorial review of the mode of presentation of the tumour; discuss different modalities used for limb salvage and the differential diagnosis of this rare tumour. Conclusion: There are very few reports of PS involving main nerve trunks and none describe the long term follow-up. We report a twelve year follow up of a PS involving the main nerve trunks of the upper limb with salvage despite multiple recurrences. The clinical course of the tumour is presented up to the age of sixteen where the growth tumour appears to have regressed

Forearm deformity is common in Hereditary Multiple Exostoses, for which multiple surgical treatments exist. Acute ulnar lengthening has been described in the literature, though in small numbers and not independent of adjunctive procedures. We hypothesise that acute ulnar lengthening as a primary procedure is safe and effective in correcting forearm deformity. Seventeen ulnas in 13 patients had acute ulnar lengthening for HME associated forearm deformity, over an eight-year period. Radiographic parameters were assessed and compared preoperatively and postoperatively. Mean follow-up was 27 months. Complications and revisions were noted. The mean pre-operative ulnar variance, 12.4mm (range 6.1 – 16.5), was significantly reduced post-operatively to a mean 4.6mm (p=<0.00001). A significant acute difference was achieved in carpal slip, (mean change of −2.2mm, p=0.02) but no significant change was seen with regard to radial bowing (p=0.98) or radial articular angle (p=0.74). There were three episodes of recurrence requiring revision. There were no major complications. Significant radiographic improvements in forearm and wrist alignment were seen with acute ulnar lengthening. Complications were infrequent. Recurrence rates in the skeletally immature patients are comparable to that reported with gradual lengthening techniques. Acute ulnar lengthening for forearm deformity associated with HME, has been demonstrated to be a safe, reproducible and effective surgical procedure