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

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

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. 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. 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

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

Trigger finger is one of the most common problems presenting to hand clinics in the UK. Traumatic and compressive forces created through digital movement leads to thickening of the flexor tendon sheath. The most successful methods used to treat trigger finger are corticosteroid injection and surgical release. The ring, thumb and middle finger are the most frequently affected digits. The incidence of multiple digits being affected is between 20% and 24%, with a higher incidence in Diabetes Mellitus sufferers. We report a case of failed injection therapy in a patient with multiple trigger digits, review the literature and advocate the use of surgical release as a first line treatment option in those patients with multiply involved digits

Objectives. Modularity in total knee arthroplasty, particularly in revisions, is a common method to fit the implants to a patient's anatomy when additional stability or fixation is needed. In such cases, it may be necessary to employ multiple points of modularity to better match the anatomy. Taper junction strength at each of these levels is critical to maintain the mechanical stability of the implant and minimize micromotion. This effect of distributed assembly loads through multiple tapers and the resulting strength of the construct have not been previously evaluated on this revision tibial implant. The purpose of this study was to evaluate the possible dissipation of impaction force through multiple taper connections as compared to a single connection. Methods. Two different constructs representative of modular implants were studied: a construct with a single axial taper connection (Group A; representing implant-stem) was compared to a construct with an adaptor that included two, offset, modular taper connections (Group B; representing implant-adapter-stem). For Group A, the stem taper was assembled and impacted through the stem. For Group B, the two tapers of the adapter and stem were hand assembled with the mating components and impacted simultaneously through the stem. Assembly load for each construct was recorded. As shown in Figure 1, the constructs were then fixed in a mechanical test frame and an axial distraction force was applied to the end of the stem at a constant displacement rate of 0.075 mm/sec until taper separation or mechanical failure occurred. Force and displacement data were recorded at 50 Hz. Disassembly force was normalized to assembly force for each component. Minitab software was used to analyze the data using a t-test. Results. Separation occurred at the implant-stem interface for all components of Group A, without component fracture. Separation occurred at the adapter-stem interface for all components of Group B. There were neither component fractures nor separation of the implant-adapter interface. As seen in Figure 2, the disassembly force for Group A was greater than Group B (p = 0.456), likely due to the higher assembly forces. However, the ratio of these forces (disassembly/assembly) was greater for Group B than Group A, but not statistically significant (0.794 vs. 0.754 with p = 0.657). Discussion. There are no applicable standards for required taper disassembly strength. However, the results of this study indicate that the addition of a second taper connection and offset does not significantly change the static ratio of disassembly to assembly force of the studied constructs. Axial distraction forces vary with activity and constraint afforded by a particular prosthesis. Future work to further characterize the behavior of these constructs could include varying loading rate to determine if that affects the location of taper disassociation. A period of fatigue testing could also be added to evaluate the effect of cyclic loading on the taper connections

Image-guided spine surgery requires registration between the patient anatomy and the preoperative computed tomography (CT) image. We have previously developed an accurate and robust registration technique for this application by using intraoperative ultrasound to acquire patient anatomy and then registering the ultrasound images to the CT images by aligning the posterior vertebral surfaces extracted from both modalities. In this study, we validate our registration technique across 18 vertebrae on three porcine cadavers. We applied the ultrasound-registration technique on the thoracic and lumbar vertebrae of the porcine cadavers using both single sweeps and double orthogonal sweeps. For each sweep pattern at each vertebra, we also randomly simulated 100 different initial misalignments and registered each misalignment. The resulting registration transformations are compared to gold standard registrations to assess the accuracy and the robustness of the technique. Orthogonal-sweep acquisition was found to be the sweep-pattern that performed the best and yielded a registration accuracy of 1.65 mm across all vertebrae on all porcine cadavers. It was found that the target registration errors (TRE) stay relatively constant with increasing initial misalignment and that the majority (82.7%) of the registrations resulted in TREs below the clinically recommended 2 mm threshold. In addition, it was found that the registration accuracy varies by the sweep pattern and the vertebral level, but neighbouring vertebrae tend to result in statistically similar accuracy. We found that our ultrasound-CT registration technique yields clinically acceptable accuracy and robustness on multiple vertebrae across multiple porcine cadavers

Total Knee Arthroplasty (TKA) is an effective surgery performed for knee osteoarthritis. Despite this success up to 20% of patients are less than fully satisfied. Rotating platform (RP) bearings have demonstrated significant reduction in rates of wear in laboratory studies but thus far have failed to demonstrate a clinical difference compared to fixed bearing (FB) arthroplasty in patients. This may be due to studies limited by small sample size and single centre design. Additionally, no studies have utilised modern patient-reported outcome measures (PROMs) such as PKIP to investigate differences between these bearings.

A non-randomised, prospective, multi-centre study was conducted across centres in Australia, United Kingdom and the United States from November 2012 to May 2015. Knee prosthesis included were the RP and FB models of the PFC Sigma Knee (Depuy, Synthes) and the ATTUNE Knee (Depuy, Synthes). Data was collected on pre-arthroplasty interventions, demographics and PROMs. PROMs included were the KOOS, OKS, EQ53DL and PKIP. Participants were followed-up for 2 years.

A total of 1,718 patients were recruited across 27 centres. 959 participants underwent a FB TKA, 759 participants underwent a RP TKA. No significant difference was found between RP and FB in change from baseline at 2 years across any parameter in all PROMs investigated at 2 years. Body Mass Index pre-operatively was the biggest indicator of change from baseline at 2 years.

Our data demonstrates similar improvements in the short-term in both RP and TKA across all PROMs. Patients reported similar scores in satisfaction, confidence, mobility and stability in the PKIP PROM for both RP and FB groups. We have not found any evidence to suggest that RP TKA is disadvantageous at 2 years, and this is reassuring for any surgeon looking to utilise this bearing type in practice.

Our data does not demonstrate a clinical advantage in RP TKA over FB TKA at 2 years in any PROM.

Thigh-calf contact force is the force acting on posterior side of the thigh and calf during deep knee flexion. It has been reported the force is important to analyze the kinetics of a lower limb and a knee joint. Some previous researches reported the measured thigh-calf contact force, however, the values varied among the reports. Furthermore, the reports indicated that there were large variations even in a single report. One of the reports tried to find the relationship between the magnitude of thigh-calf contact force and anthropometric measurement as height, weight or perimeter of the lower limb, however, there could not found clear correlations. We considered that the cause of the variations might be the difference of the posture. At heel-rise squatting posture, we can bend or stand upright the upper body. Therefore we tried to create the equation to estimate the thigh-calf contact force by multiple regression analysis, using the anthropometric and posture parameters as explanatory variables. We performed the experiment to measure thigh-calf contact force, joint angles and anthropometric information. Test subjects were 10 healthy male. First we measured their height, weight, perimeter of the thigh and muscle mass of the legs and whole body. Muscle mass was measured by body composition meter (BC-118E, Tanita Co., Japan). Then, test subjects were asked to squat with their heels lifted and with putting the pressure distribution sensor between thigh and calf. And they bent their upper body forward and backward. The pressure sensor to be used was ConfroMat System (Nitta Co., Japan). After that, we measured the joint angles of the hip, knee and ankle, and the angle between the floor and upper body using the videos taken during the experiment. Then, we created the equation to estimate the thigh-calf contact force by linear combination of the anthropometric values and joint angles. The coefficients were settled as to minimize the average error between measured and estimated values. Results are shown in Fig.1. Forces were normalized by the body weight of the test subjects. Because the horizontal axes show the measured and vertical axis show the estimated values, the estimation is accurate when the plots are near the 45-degree line. Average error was 0.11BW by using only physical values, 0.15BW by angles and 0.06BW using both values. And the maximum error was 0.69BW, 0.43BW and 0.32BW respectively. Thus we could estimate the thigh-calf contact force by multiple regressions, using both physical parameters and angles to indicate the posture. Using the equation, we would be able to analyze the kinetics of a lower limb by physical and motion measurement. Our future work might be increasing the number of subjects to consider the appropriateness, because the test subjects of this study were very limited

The purposes of this study were to investigate whether twins and multiple births have a higher incidence of Developmental Dysplasia of the Hip (DDH), and whether universal ultrasound scanning would be beneficial in this population. Methods. Records of all twin and multiple births between 1st January 2004 and 31st December 2008 at Addenbrooke's Hospital were obtained. Information regarding sex, gestation, birth weight, DDH risk factors, results of the neonatal hip examination and of any ultrasound scans were analysed. The incidence of DDH in singletons born during the same period was calculated from birth records and the DDH database. Results. Of the 990 twin and multiple births, 267 had ultrasound scans. Of those scanned, over 92% had a normal (bilateral Graf I) scan initially. Within the study cohort there was one case of DDH diagnosed on ultrasound and successfully treated with Pavlik harness. There were two cases of late presenting DDH, one at 8 months and one at 14 months old. Both had no risk factors, a normal neonatal examination and consequently had not had an ultrasound scan. Conclusion. In our study, twins did not have a significantly higher incidence of DDH compared to singletons. However, ultrasound screening of twins would have detected the two late presenting cases of DDH earlier. It remains to be seen whether universal scanning would be cost-effective

Objective. The optimal dosage and timing of tranexamic acid in total hip arthroplasty (THA) still is undetermined. Previous studies showed the hyper-fibrinolysis would last for 18 hours after surgery. The study aimed to examine the efficacy and safety of multiple bolus of intravenous TXA on hidden blood loss and inflammation response following primary THA. Methods. 150 patients were randomly divided into three groups to receive single bolus of 20 mg/kg IV-TXA before skin incision (Group A), or another bolus of 1 g IV-TXA 3 hours later (Group B), or another two boluses of 1g IV-TXA 3 hours and 6 hours later (Group C). All patients received a standard perioperative enhanced recovery protocol. The primary outcomes was hidden blood loss. Other outcome measurements such as hemoglobin level, total blood loss, transfusion rate, inflammation markers (CRP, IL-6), VAS pain score, length of hospital stay (LOH) and venous thromboembolism (VTE) were also compared. Results. The hidden blood loss in group C was 402.13 ± 225.97 ml, which was less than that in group A (679.28±277.16 ml, p< 0.001) and group B (560.62±295.22 ml, p= 0.010). However, such difference was not detected between group A and B (p= 0.072). The mean value of total blood loss in group A, B and C were 1090.78±251.41, 979.42±247.89, 768.71±180.19 ml, respectively, with a significant intergroup difference (p <0.001). The Hb drop on postoperative day (POD) 3 in group A, B and C was 30.82±6.31, 27.16±6.83, 21.98±3.72 g/L, and the difference between groups was significant (p <0.001). Only one patients received red blood cell transfusion. The mean level of CRP in group C was lower than that in group A and B on POD 2 (p= 0.000, p= 0.034), POD 3 (p= 0.000, p= 0.014). The serum level of IL-6 in group C was lower than group A on POD 1, POD 2 and POD 3 (p=0.017, p=0.023, p= 0.005; respectively). The patients in group C had slightly less postoperative pain. The LOH in group C was shorter than those in group A (p= 0.023). No episodes of VTE or other adverse events occurred in any patient. Conclusion. Multiple boluses of IV-TXA can effectively reduce hidden blood loss following primary THA. What is the most important is that, by adding another boluses of IV-TXA, patients can gain a smaller decline of Hb, less postoperative inflammation response, less pain and shorter length of hospital stay

Introduction. Femoro-acetabular impingement (FAI) is a common source of impaired motion of the hip, often attributed to the presence of an aspherical femoral head. However, other types of femoral deformity, including posterior slip, retroversion, and neck enlargement, can also limit hip motion. This study was performed to establish whether the “cam” impinging femur has a single deformity of the head/neck junction or multiple abnormalities. Materials and Methods. Computer models of 71 femora (28 normal and 43 “cam” impinging) were prepared from CT scans. Morphologic parameters describing the dimensions of the head, neck, and medullary canal were calculated for each specimen. The anteversion angle, alpha angle of Notzli, beta angle of Beaulé, and normalized anterior heads offset were also calculated. Average dimensions were compared between the normal and impinging femora. Results. Compared to the normal controls, the impinging femora had wider necks (AP: 15.2 vs 13.3 mm, p<0.0001), larger heads (diameter: 48.3mm vs 46.0mm, p=0.032) and decreased head/neck ratios (1.60 vs 1.74, p=0.0002). However, there was no difference in neck/shaft angle (125.7° vs 126.5°, p=0.582) or anteversion angle (8.70 vs 8.44°, p=0.866). Most significantly, 53% of impinging femora also had a significant posterior slip (>2mm), compared to only 14% of normal controls. Average head displacements for the two groups were: FAI: 1.93mm vs Normals: 0.78mm (p<0.0001). Conclusions. The CAM impinging femur has many abnormalities apart from the “bump” at the head/neck junction. These femora have increased neck width and head/neck ratio, a smaller spherical bearing surface, and reduced neck offset from the medullary canal. Therefore, surgical treatment limited to localized re-contouring of the head–neck profile may fail to address significant components of the underlying abnormality

Introduction. Instability after total knee arthroplasty (TKA) represents, in excess of, 7% of reasons for implant failure. This mode of failure is correlated with soft-tissue imbalance, and has continued to be problematic despite advances in implant technology. Thus, understanding the options available to execute safe and effective soft-tissue release is critical to mitigating future complications due to instability. This study aimed to use intraoperative sensors to evaluate a multiple needle puncturing technique (MNPT), in comparison with traditional transection-based release, to determine its biomechanical and clinical efficacy. Methods. Seventy-five consecutive, cruciate-retaining TKAs were performed, as part of an 8-site multicenter study. All procedures were performed with the use of an intraoperative sensor to ensure quantitative balance, as per previously reported literature. Of the 75-patient cohort, 50 patients were balanced with the MNPT; 20 patients were balanced with traditional transection. All patients were followed out to 1-year, and administered KSS, WOMAC, and satisfaction. Alignment and ROM was captured for all patients, pre-operatively and at the 1-year follow-up interval. Results. All patient joints could be released to a balanced joint state, regardless of technique used. There was no significant difference between the two groups (MNPT vs. transection), pre-operatively, with respect to range of motion or alignment (114° MNPT; 114° transection). At 1-year, post-operatively, there was no significant difference in WOMAC score, KSS scores, satisfaction, or ROM (Respectively: 13.1 MNPT vs. 14.6 transection; 174.9 MNPT vs.176.5 transection; 31.7 “Very Satisfied” MNPT vs. 32.2 “Very Satisfied” transection; 124° MNPT vs. 125° transection). No adverse outcomes related to balancing technique have been reported. Discussion. Instability contributes to the current 2.7 billion dollar TKA revision burden in the United States. Understanding the efficacy of different techniques in soft-tissue balancing may help to mitigate unfavorable complications. In this study, it was found that the MNPT is just as safe and effective at achieving soft-tissue balance as transectional release techniques, and showed no deviation from the achievement of optimal post-operative outcomes at 1-year. This technique, when used with intraoperative sensors to quantify joint balance, may thereby offer a more controlled way to release soft-tissue, incrementally, to achieve precise balance

Objective. The optimal positioning of the acetabular component is a relevant prognostic factor in total hip arthroplasty (THA). Because of substantial errors of manual technique in cup placement even with experienced surgeon, computer aided navigation system has been developed in recent years. However, existence of the hardware around acetabulum likely deteriorates the accuracy of the navigation system, namely in revision THA case and postoperative status of pelvic fracture. Here we report a case who we successfully performed THA using CT based navigation system although there were multiple hardware around acetabulum due to osteosynthesis for the previous pelvic fracture. Case presentation. A forty-one years old man presented with intolerable hip pain with severe radiographic osteoarthritic findings in left hip joint. He had sustained left pelvic fracture and posterior hip dislocation due to traffic accident and undergone osteosynthesis using multiple plates and screws when he was forty years old. However, progressive collapsing of femoral head and acetabulum occurred. Then, we indicated THA for his situation and planned to apply the CT based navigation system (Stryker CT based hip Ver.1.1 softwear and Cart II system). Preoperative workup revealed incomplete union of posterior and superior acetabular wall and we had to retain plates and screws for the stable fixation of acetabular cup. The existence of the hardware made it complicated to perform three dimensional planning and templating. Meticulous surface editing of pelvis to exclude the metal artifact and fibrocartilagenous tissue was needed to achieve accurate surface registration. In the operation room, we had to use unusual way of registration to complete two steps of registration. In the first step (roughly matching between patient's physical pelvic surface and edited pelvic surface in work station using corresponding 5 points), we utilized head of screw and hole of the plate which we could easily identify intraoperatively, in addition to ASIS and innominate groove. In the second step (strict matching using more than 30 points of pelvic surface), we had to identify the pelvic bony surface, as excluding the metal surface and fibrocartilagenous tissue such as fracture callus. These efforts enabled us to accomplish substantial accuracy of registration with RMS of 0.5 mm. Final cup orientation at the end of surgery was 41° of inclination and 25° of anteversion. Postoperative CT scan revealed that cup placement angle was 40° of inclination and 25° of anteversion, almost identical with intraoperative value. Conclusion. Our experience showed that CT based navigation system provided accurate placement of the acetabular component in a case having multiple hardware as well as in normal primary THA. Although we need additional efforts such as meticulous preoperative planning, extra operation time, CT based navigation system has great advantages to minimize the mal-placement of the cup in complicated case