Introduction. Acetabular dysplasia cause hip joint osteoarthritis(OA) by change hip mechanism. However, to our best knowledge, no studies have been published using prospectively collected data from asymptomatic young age volunteers, precise radiographic method. The purpose of this study is to evaluate the prevalence of hip dysplasia in asymptomatic Korean population as one of the most important risk factor of hip OA. Materials & Methods. From December 2014 to March 2015, we investigated prospectively collected retrospectively reviewed data of 200 asymptomatic volunteers 400 hips in age between 18 and 50 years recruited from our institution. Pelvic radiographs were taken and all radiographs were reviewed by 2 experienced orthopedic surgeons. Lateral center-edge angle(LCEA), Sharp angle, Tonnis angle and acetabular width-depth ratio were measured. We analyzed the statistical differences of these values between sex by Mann-Whitney U test and independent t-test. Pearson's correlation coefficient was used to measure the relationship between dysplasia parameters. Results. On the Pelvic AP view, 60 of the 400 hips (15%) were dysplastic hip as LCEA <20°. In 146 male hips, 17 hips (11.6%) were LCEA <20°. In 254 female hips, 43 hips(16.9%) were LCEA <20°. There was no strong correlation of LCEA with other measurements. Conclusion. There are large number of asymptomatic dysplastic hips in Asian population compared previously investigated

Introduction. Total knee arthroplasty (TKA) is one of the most successful surgeries to relieve pain and dysfunction caused by severe arthritis. However, it is a still big problem that there is a possibility of death in pulmonary embolism (PE) after TKA. We previously reported that there was more incidence of asymptomatic PE than estimated in general by detail examinations. But it was difficult to whom we decided to perform additional examinations except the patients with some doubtful symptoms. Therefore, we investigated detail of PE patients after primary TKA to find out anything key point in PE. Methods. Consecutive ninety-nine patients who underwent primary TKA from January 2015 to March 2018 were applied. There were 23 male and 76 females included, and the mean age was 73.7 years old. There were 96 cases of osteoarthritis, 2 cases of osteonecrosis and one of rheumatoid arthritis. A single knee surgery team performed all operations with cemented type prostheses and air tourniquet during operation. There were 35 cases of one-staged bilateral TKA and 64 of unilateral TKA. Detail examinations with contrast enhanced CT (CE-CT) and venous ultrasonography (US) were performed at the 3rd day after surgery. Next, we applied ultra sound cardiogram (UCG) to the patients diagnosed as PE by CE-CT, we checked right ventricular overload (RVO) to treat PE. These images were read by a single senior radiologist team. Results. CE-CT was performed in 87 patients (87.8%) and US was in all patients. The incidence of deep vein thrombosis (DVT) was 67 patients (67.6%), and all of these was distal type DVT. PE was 17 patients (17.1%), and each of patients had no symptoms. RVO was detected in 5 patients (5.0%), and two of them (2.0%) had decreased SpO2 in early 90% perioperative period. All patients did not change rehabilitation protocol and progress was good until discharge. Conclusion. We investigated consecutive 99 patients for DVT/PE after primary TKA using CE-CT and venous US. And we performed UCG to PE patients. One of the important findings to decide detail examination for asymptomatic PE was decrease in SpO2 during early perioperative period. It might be the only finding except symptom. We also have to be more aware about high incidence of asymptomatic PE and more careful to the patients after TKA to prevent complications. For any figures or tables, please contact authors directly

Total knee arthroplasty (TKA) has been shown to improve knee joint function during gait post-operatively. However, there is considerable patient to patient variability, with most gait mechanics metrics not reaching asymptomatic levels. To understand how to target functional improvements with TKA, it is important to identify an optimal set of functional metrics that remain deficient post-TKA. The purpose of this study was to identify which combination of knee joint kinematics and kinetics during gait best discriminate pre-operative gait from postoperative gait, as well as post-operative from asymptomatic. Seventy-three patients scheduled to receive a TKA for severe knee osteoarthritis underwent 3D gait analysis 1 week before and 1 year after surgery. Sixty asymptomatic individuals also underwent analysis. Eleven discrete gait parameters were extracted from the gait kinematic and kinetic waveforms, as previously defined (Astephen et al., J Orthop Res., 2008). Stepwise linear discriminant analyses were used to determine the sets of parameters that optimally separated pre-operative from post-operative gait, and post-operative from asymptomatic gait. Cross-validation was used to quantify group classification error. Knee flexion angle range, knee adduction moment first peak, and gait velocity were included in the optimal discriminant function between the pre- and post-operative groups (P<0.05), with relatively equal standardised canonical coefficients (0.567, −0.501, 0.565 respectively), and a total classification rate of 74%. A number of metrics were included in the discriminant function to optimally separate post-operative and asymptomatic gait function, including the knee flexion angle range, peak stance knee flexion angle, minimum late stance knee extension moment, minimum mid-stance knee adduction moment, and peak knee internal rotation moment (P<0.05). The mid-stance knee adduction moment had the largest standardised canonical coefficients in the function, and 89.5% of cases were correctly classified. Separation of pre and post-operative gait patterns included only three parameters, suggesting that current standard of care TKA significantly improves only walking velocity, knee flexion angle range, and the peak value of the knee adduction moment. A number of gait metrics, which were included in the discriminant function between post-operative and asymptomatic gait, could benefit from further improvement either through rehabilitation or design. With almost 90% classification, separation of post-operative gait function from asymptomatic levels is significant. The consolidation of knee joint function during gait into single, discrete discriminant scores allows for an efficient summary representation of patient-specific (or implant-specific) improvement in gait function from TKA surgery

INTRODUCTION:. Acetabular retroversion has been implicated as a risk factor for the development of early hip osteoarthritis. In clinical practice standard osseous signs such as the cross-over sign (COS) and the posterior wall sign (PWS) are widely used to establish the diagnosis of acetabular retroversion on plain radiographs. Despite standardized radiological evaluation protocols, an increased pelvic tilt can lead to a misdiagnosis of acetabular retroversion in AP radiographs and 2D MR or CT scans. Previous studies have shown that the elimination of observer bias using a standardized methodology based on 3D-CT models and the anterior pelvic plane (APP) for the assessment of COS and PWS results in greater diagnostic accuracy. Using this method a prevalence of 28% for COS and 24% for PWS has been found in a cohort of patients with symptoms indicative of FAI, however the prevalence of both signs in asymptomatic adults remains unknown. This study therefore sought to establish the prevalence of the COS and PWS in relation to the APP in an asymptomatic population using a reliable and accurate 3 D-CT based assessment. METHODS:. A large pool of consecutive CT scans of the pelvis undertaken in our department for conditions unrelated to disorders of the hip was available for analysis. Scans in subjects with a Harris hip score of less than 90 points were excluded leaving a sample of 100 asymptomatic subjects (200 hips) for this study. A previously established 3D analysis method designed to eliminate errors resulting from variations in the position and orientation of the pelvis during CT imaging was applied to determine in order to assess the prevalence of the COS and PWS in relation to the APP. Here, the acetabuli were defined as retroverted if either the COS, PWS or both were positive. RESULTS:. From the total of 200 hips a positive COS was identified in 24% (48/200) and a positive PWS was detected in 6.5% (13/200) relative to the APP using the CT data. A. In male adults a COS was observed in 25.4% (29/114) and a PWS in 10.5% (12/114). In female adults a COS were observed in 22.1% (19/86) and a PWS in 1.2% (1/86). DISCUSSION:. The high incidence of acetabular retroversion observed using an accurate 3D-CT based methodology shows that this anatomic configuration might not differ in frequency between asymptomatic individuals and patients with symptomatic FAI. Patients presenting with hip pain and evidence of FAI should therefore be subjected to strict diagnostic scrutiny, as the presence of a COS and/or PWS shows a poor correlation with the presence of symptomatic disease. In our collective of asymptomatic adults the COS showed a higher incidence than the PWS. Additionally a deficiency of the posterior acetabular wall was rare in asymptomatic adults compared to FAI patients. Therefore, the question whether an abnormal acetabular version does indeed lead to the development of osteoarthritis in all patients warrants further study. Although an association between osteoarthritis and femuro-acetabular impingement is believed to exist, long-term epidemiological studies are needed to establish the natural history of these anatomical configurations

The aim of this prospective study was to determine the prevalence of bone marrow oedema (BME) in asymptomatic knees of athletes and to investigate the factors associated with appearance of BME in this group. A total of 25 asymptomatic athletes who competed at an international, national or county level during their most recent sport season were recruited in this study and had MRI scan of both knees (n=50). MRI scans were reported independently by two experienced musculoskeletal radiologists. Statistical analysis included Cohen's kappa test to identify inter-observer agreement for MRI diagnosis of bone marrow oedema and multiple logistic regression model to identify the factors associated with BME on MRI scan. There was very good agreement between radiologists for diagnosis of BME (Kappa = 0.896). Seven participants (28%) were found to have BME. Six of the participants had BME in unilateral knees and one participant had BME in bilateral knees. The commonest location of BME was medial femoral condyle (62.5%) The amount of time spent in preseason training (34-38 weeks) was significantly associated with appearance of BME (P=0.048). BME seems to be common in asymptomatic athletes and one should realize that this finding might not be related to the clinical complaints of the patients. The results of the present study show that there is a training effect associated with BME. Knowing what is a ‘normal’ or ‘abnormal’ scan is important for a competitive athlete, as erroneously diagnosing BME as the underlying cause of athletes' symptoms could lead to decreased playing time or inappropriate therapy

Few epidemiological studies from Asian countries have addressed this issue and reported that FAI is less prevalent in Asian population. The purpose of this study was to determine the prevalence of radiographic hip abnormalities associated with FAI in asymptomatic Korean volunteers. The authors hypothesized that the prevalence of FAI in Korean population would not be less than that in western population. Two hundred asymptomatic volunteers with no prior hip surgery or childhood hip problems underwent three-view plain radiography (pelvis anteroposterior (AP) view, Sugioka view, and 45° Dunn view) of both hips. Cam lesions were defined as the presence of the following signs on each views: pistol-grip deformity, osseous bump at the femoral head-neck junction, flattening of the femoral head-neck offset, or alpha angle >50°. Pincer lesions were determined by radiographic signs, including crossover sign, posterior wall deficient sign, or lateral center-edge (CE) angle >40°. Only positive cases agreed by both observers were defined as true FAI-related deformities. There were 146 male and 254 female hips, with a mean age of 34.7 years. On pelvis AP view, the prevalence of pistol grip deformity, bump, flattening, and alpha angle >50° was 1.3% (male 3.4%, female 0%), 0.8% (male 2.1%, female 0%), 0.8% (male 2.1%, female 0%), and 1.0% (male 2.7%, female 0%), respectively. On Sugioka view, the prevalence of bump, flattening, and alpha angle >50° was 9.8% (male 14.4%, female 7.1%), 13.5% (male 20.5%, female 9.4%), and 14.0% (male 26.7%, female 6.7%), respectively. On 45° Dunn view, the prevalence of bump, flattening, and alpha angle >50° was 8.0% (male 14.4%, female 4.3%), 17.5% (male 27.4%, female 11.8%), and 27.5% (male 44.5%, female 17.7%), respectively. The prevalence of cam lesion which was identified on at least one radiograph was 42.5% (male 62.3%, female 31.1%). The prevalence of cam lesion which was identified on ≥2 radiographs was 19.3% (male 30.8%, female 12.6%). The prevalence of cam type FAI (at least one cam lesion) was 2.0% (male 5.5%, female 0%) on pelvis AP view, 25.8% (male 37.0%, female 19.3%) on Sugioka view, and 35.8% (male 55.5%, female 24.4%) on 45° Dunn view. On pelvis AP view, the prevalence of crossover sign, posterior wall sign, and CE angle >40° was 20.0% (male 23.3%, female 18.1%), 20.8% (male 22.6%, female 19.7%), and 2.0% (male 2.7%, female 1.6%), respectively. The prevalence of pincer type of FAI (at least one pincer lesion) was 23.0% (male 27.4%, female 20.5%). In asymptomatic Korean volunteers, the prevalence of cam type FAI was low on AP pelvis radiographs, whereas the prevalence of cam type FAI on Sugioka and 45° Dunn view was found to be comparable to that previously reported in Western populations. The prevalence of pincer type FAI in asymptomatic Korean volunteers was also comparable that in Western populations and was similar in both gender. Considering the high prevalence of FAI morphologic features on plain radiographs in asymptomatic Korean populations, it is also important to determine whether FAI is a cause of hip pain when considering surgery in Asian patients

Purpose. There is a postulated association between increased serum metal ions and pseudotumour formation in patients with metal-on-metal hip replacements. The primary aim of this study was to assess the prevalence of pseudotumour in 31 asymptomatic patients with a large femoral head (LFH) metal-on-metal hip implant. This was compared to the prevalence of pseudotumour in 20 matched asymptomatic patients with a hip resurfacing (HRA) and 24 matched asymptomatic patients with a standard metal-on-polyethylene (MOP) total hip. A secondary objective was to assess possible correlation between increased serum metal ions and pseudotumour formation. Method. Ultrasound examination of the three groups was performed at a minimum follow up of two years. Serum metal ions were measured in the metal-on-metal LFH and HRA groups at a minimum of two years. Results. There were 10 (32%) solid or cystic masses in the LFH group with a mean size of 89.3 (8 to 437) cm3. In the HRA group there were five (25%) masses with a mean size of 41.6 (6 to 119) cm3. In the MOP group there was one cystic mass measuring 9.8 cm3. Median serum cobalt and chromium ion levels in the LFH group were 4.50 gL (interquartile range, 2.38 to 7.47) and 2.82 gL (interquartile range, 1.48 to 3.18) compared to 0.83 gL (interquartile range, 0.65 to 1.12) and 1.08 gL (interquartile range, 0.78 to 1.31) in the HRA group. Conclusion. This study demonstrates a significantly higher prevalence of pseudotumours in patients with large head metal-on-metal total hips. The higher levels of metal ions in this group suggest that elevated metal ions may lead to pseudotumour formation

Introduction:. One of the complications occurring after total knee arthroplasty (TKA) is venous thromboembolism (VTE). The current screening techniques for VTE are venography, lower extremity vascular ultrasound, pulmonary scintigraphy, and contrast-enhanced computed tomography (CT). Although venography and lower extremity vascular ultrasound can detect deep venous thrombosis (DVT) in the lower extremities, pulmonary thrombosis poses a diagnostic problem. We performed contrast-enhanced CT screening for DVT and pulmonary embolism (PE) after TKA, and assessed the efficacy of the following prophylactics for VTE: fondaparinux, enoxaparin, and edoxaban. Materials and Methods:. Subjects included 219 patients (260 knees) undergoing TKA at our hospital between April 2007 and November 2012. The 260 subject knees were divided as follows: group C, 31 cases in which DVT prophylactics were not used (April 2007 to October 2008); group F, 107 cases receiving fondaparinux 2.5 mg/day (July 2007 to October 2009); group ENO, 87 cases receiving enoxaparin 2000–4000 IU/day (November 2009 to October 2011); and group EDO, 35 cases receiving edoxaban 15–30 mg/day (November 2011 to November 2012). Contrast-enhanced CT images were obtained from the pulmonary apex to the foot for diagnosis of VTE. Groups were compared for incidence of symptomatic PE, asymptomatic PE, DVT-negative asymptomatic PE, DVT-positive asymptomatic PE, and DVT. Results:. Incidence of symptomatic PE tended to be lower in group ENO than in group C (p = 0.067), but no statistically significant differences in asymptomatic PE were observed between any groups (Figure 1). DVT-negative asymptomatic PE (Figure 2) was present in 2 cases in group C (6.5%), 14 cases in group F (13.1%), 3 cases in group ENO (3.4%), and 2 cases in group EDO (5.7%) (Figure 1). Patients diagnosed with symptomatic PE presented only with mild clinical symptoms and physical findings. As a result, PE was not suspected from clinical findings alone. The diagnosis of symptomatic PE was confirmed by the presence of thrombosis in the pulmonary artery on contrast-enhanced CT (Figure 3). Conclusion:. Asymptomatic PE is not prevented by prophylaxis after TKA. Contrast-enhanced CT screening is effective for identifying asymptomatic VTE, especially asymptomatic PE

Background. The knee is the commonest joint to be affected by osteoarthritis, with the medial compartment commonly affected. Knee osteoarthritis is commonly bilateral, yet symptoms may initially present unilaterally. Higher knee adduction moment has been associated with the development and progression of medial compartment knee osteoarthritis. Objectives. To assess the effect of lateral wedge insoles on the asymptomatic knee of patients with unilateral symptoms of medial compartment knee osteoarthritis. Methods. Twenty patients were assessed using a 3D optoelectronic tracking system, with 16 infrared camera, passive markers and four force platforms. Three different insoles were tested; a standard control shoe, the Boston lateral wedge insole (inclined at 5° throughout the full length of the insole) and the Salford insole (inclined at 5° throughout the full length of the insole, with medial arch support). A minimum of 5 trials per each insole were used. Kinetic and kinematic data were collected and processed using Qualysis Track Manager ® and Visual 3D™. Results. There was a significant reduction in knee adduction moment for both the Salford and Boston insoles as compared to the control shoe. This was 9.5–14.2% for the asymptomatic side, and 5.8–10.7% for the symptomatic side for the Salford and Boston insoles respectively. Although the reduction was larger on the asymptomatic side, this was not statistically significant. Patients reported significant reduction in pain with both Salford and Boston insoles as compared to the control shoe, and found the Salford insole to be the most comfortable. Stride length and walking speed was significantly higher with the Salford insole. Conclusions. This study confirms the effect of lateral wedge insoles on reducing knee adduction moment in patients with medial compartment osteoarthritis, in both the symptomatic and asymptomatic knees. Long-term follow-up studies are required to confirm the effect of treating the asymptomatic side on disease progression

Knee alignment is a fundamental measurement in the assessment, monitoring and surgical management of patients with osteoarthritis [OA]. In spite of extensive research into the consequences of malalignment, our understanding of static tibiofemoral alignment remains poor with discrepancies in the reported weight-bearing characteristics of the knee joint and there is a lack of data regarding the potential variation between supine and standing (functional) conditions. In total knee arthroplasty [TKA] the lower limb alignment is usually measured in a supine condition and decisions on prosthesis placement made on this. An improved understanding of the relationship between supine and weight-bearing conditions may lead to a reassessment of current surgical goals. The purpose of this study was to explore the relationship between supine and standing lower limb alignment in asymptomatic, osteoarthritic and prosthetic knees. Our hypothesis was that the change in alignment of these three groups would be different. A non-invasive infrared position capture system (accuracy ±1° in both coronal and sagittal plane) was used to assess the knee alignment for 30 asymptomatic controls and 31 patients with OA, both before and after TKA. Coronal and sagittal mechanical femorotibial (MFT) angles in extension (negative values indicating varus in the coronal plane and hyperextension in the sagittal plane) were measured with each subject supine and in bi-pedal stance. For the supine test, the lower limb was supported at the heel and the subject told to relax. For the standing position subjects were asked to assume their normal stance. The change in alignment between these two conditions was analysed using a paired t-test for both coronal and sagittal planes. To quantify the change in 3D, vector plots of ankle centre displacement relative to the knee centre from the supine to standing condition were produced. Alignment in both planes changed significantly from supine to standing for all three groups. For the coronal plane the supine and standing measurements (in degrees, mean(SD)) were 0.1(2.5) and −1.1(3.7) in the asymptomatic group, −2.5(5.7) and −3.6(6) in the OA group and −0.7(1.4) and −2.5(2) in the TKA group. For the sagittal plane the numbers were −1.7(3.3) and −5.5(4.9); 7.7(7.1) and 1.8(7.7); 6.8(5.1) and 1.4((7.6) respectively. This change was most frequently towards relative varus and extension. Vector plots showed that the trend of relative varus and extension in stance was similar in overall magnitude and direction between the three groups. Knee alignment can change from supine to standing for asymptomatic and osteoarthritic knees, most frequently towards relative varus and hyperextension. The similarities between each group did not support our hypothesis. The consistent kinematic pattern for different knee types suggests that soft tissue restraints rather than underlying joint deformity may be more influential in dynamic control of alignment from lying to standing. In spite of some evidence suggesting a difference between supine and standing knee alignment a mechanical femorotibial (MFT) angle of 0° is a common intra-operative target as well as the desired post-operative weight-bearing alignment. These results indicated that arthroplasties positioned in varus intra-operatively could potentially become ‘outliers’ (>3° varus) when measured weight-bearing. Mild flexion contractures may correct when standing, reducing the need for intra-operative posterior release. These potential changes should be considered when positioning TKA components on supine limbs as post-operative functional alignment may be different

Introduction. Pseudotumors have been reported following metal-on-metal total hip arthroplasty (THA); however, the natural history and longitudinal imaging findings of pseudotumors have yet to be fully analyzed. Our hypothesis was that pseudotumor size might change over time following metal-on-metal THA. This hypothesis was studied longitudinally using magnetic resonance imaging (MRI). Materials and Methods. Screening for pseudotumors was performed using MRI after large-diameter metal-on-metal THA. Initial MRI was conducted at a mean of 36 months postoperatively. Follow-up MRI was performed at a mean of 20 months after the detection of 24 pseudotumors in 20 asymptomatic patients. Pseudotumors were classified as cystic, solid, and mixed types. Fourteen hips were characterized as cystic type and 10 hips were defined as mixed type. There were three men and 17 women with a mean age of 63 years. Pseudotumor size was determined on MRI by manually outlining the greatest size of the mass. Serum cobalt and chromium ion levels were measured in nine patients with unilateral THA at the time of MRI. Statistical analysis was performed using the Kruskal-Wallis test and chi square test to compare age, gender, BMI, head diameter, cup inclination, cup anteversion, and pseudotumor type among changes of pseudotumor size. We compared the pseudotumor size for the three groups (increase in size, no change, decrease in size) using Kruskal-Wallis test and Mann-Whitney U test. Wilcoxon signed-rank test was used to compare median serum metal ion levels over time. A p value < 0.05 was considered significant. This study was approved by the ethics committee of our institution, and all patients provided informed consent. Results. The mean pseudotumor size changed from 729 mm. 2. to 877 mm. 2. Among the 24 hips, pseudotumors increased in size (Fig. 1) in eight (three cystic and five mixed) and decreased in size in six (four cystic and two mixed). Ten hips showed no changes in size (seven cystic and three mixed). We found no significant differences between changes of pseudotumor size and patient characteristics. The mean initial size of pseudotumor was bigger in pseudotumors with increased in size (1002 ± 309 mm. 2. ) than in those with decreased in size (542 ± 295 mm. 2. , p = 0.020) or no change (622 ± 448 mm. 2. , p = 0.041). The median cobalt ion levels at initial MRI and follow-up MRI were 2.0 µg/L and 1.8 µg/L, respectively. The median chromium ion levels at initial MRI and follow-up MRI were 2.0 µg/L and 3.1 µg/L, respectively. No significant differences were observed between the levels of either metal at initial and subsequent MRI. Conclusions. The present results suggest that pseudotumors frequently change in size in asymptomatic patients, and our hypothesis was verified. The initial size of pseudotumor was bigger in pseudotumors with increased in size than in those with decreased in size or no change. And we might predict that bigger pseudotumors would tend to increase in size

Some military personnel are having Femoral Acetabular Impingement (FAI) surgery. The use of the alpha angle (AA) to help assess the diagnosis is common. Currently there are no standardised values available across a asymptomatic pre-arthritic population. Retrospective analysis of 200 consecutive individuals (400 hip joints) with ages 20 to 50, who had a CT performed between 1 Apr 2011 and 29 Nov 2011 due to abdominal pathology. The AA of Notzli was measured on the axial view. The mean AA value was 53.5 (95%CI 1.30) for Right hips and 53.4 (95% CI 1.31) for the left. In age 20–30 Right 52.6 (95%CI 3.5) the Left 52.0 (95%CI 2.9), 31–40 Right 53.9 (95%CI 2.5) Left 53.4 (95%CI 3.1), 41–50 Right 53.8 (95% CI 1.9) Left 53.2 (95% CI 1.8). Mean male Right 52.9 (95% CI 1.5) Left 53.2 (95%CI 1.9) Female Right 52.5 (95% CI 1.5) Left 49.9 (95% CI 1.6). 144/400 (37%) of patients had angle >55 degrees. Previous literature suggests an AA >55 degrees is diagnostic of FAI, we suggest that the AA is highly variable across age and sex and that >1/3rd of asymptomatic patients will have an AA that was previously regarded as abnormal

Introduction. The use of metal-on-metal (MOM) and modular total hip arthroplasty (THA) is associated with potentially serious complications including elevated serum metal ion levels, pseudotumor, cardiomyopathy and neurologic abnormalities. The primary aim of this analysis was to identify any associations between the presence of pseudotumor, serum metal ion levels, and specific dual modular implant components. Methods. We evaluated prospectively collected data from 49 patients, mean age 58.4 years, who underwent implantation of modular THA from 01/2004-01/2010. The collected data spanned a 5–11 year period from the time of index procedure. Serum metal ion levels, including titanium, cobalt and chromium, were collected in 2012 and 2015. Hip ultrasounds were performed on each patient by a trained musculoskeletal radiologist for evaluation of the presence of soft-tissue pseudotumor. Univariate nonparametric tests were used to compare the two groups: Fisher's exact tests for categorical variables, and Wilcoxon two-group tests for continuous variables. For the purposes of analysis, values that were below the level of detection (LOD) were set to half the LOD. All analyses were performed using SAS 9.4 (SAS Institute Inc, Cary, NC, USA). Statistical significance is set at p<0.05. Results. Eight of 49 patients (16.3%) had pseudotumors on ultrasound examination. The average size measured 35.05 cm3 (7.35 cm3 – 130.81 cm3). In patients without pseudotumor, the serum levels (ng/mL) of titanium, cobalt and chromium were 3.2 ± 2.7, 4.4 ± 5.7 and 3.4 ± 4.9 in 2012 and 3.6 ± 4.9, 11.3 ± 33.7 and 5.3 ± 10.8 in 2015, respectively. Patients with pseudotumor had titanium, cobalt and chromium levels of 3.5 ± 2.3, 8.4 ± 8.7 and 6.2 ± 9.4 in 2012 and 4.1 ± 3.4, 6.0 ± 4.5 and 5.1 ± 6.4 in 2015. The ratio of cobalt to chromium was 1.6 ± 1.3 in 2012 and 1.8 ± 1.2 in 2015 in patients without pseudotumor and 2.1 ± 1.2 and 1.9 ± 1.3 with patients with pseudotumor, respectively. There was no statistical correlation between the presence of pseudotumor and age, component pairings (stem, neck and cup) and any of the serum metal ion levels. Discussion/Conclusion. In this prospective cohort study the incidence of pseudotumor was 16.3% in asymptomatic patients with modular THA. The presence of pseudotumor did not correlate with component pairings, serum metal ion levels or cobalt to chromium ratios

Purpose. The importance of femoral head-neck morphology in the development of early hip osteoarthritis is recognized in femeroacetabular impingement (FAI), however no studies have examined FAI morphology in the developing hip, i.e. pre-closure of the proximal femoral physis. We developed a pilot project to study prevalence of CAM-type FAI hip morphology in both the pre- and post-closure proximal femoral physes of asymptomatic children using MR-imaging. We also examined biologic markers possibly related to FAI etiology, including Vitamin D metabolites, BMI, family history, and activity levels. Method. Recruitment included volunteers with asymptomatic lower extremities, and either pre- or post-closure of the proximal femoral physis. Males were 10–12 years (pre-closure) or 15–18 years (post-closure); females were 8–10 years or 14 18 years. Phlebotomy and urine sampling were used to assess metabolic markers. MRI of bilateral hips and a clinical exam including hip impingement tests were conducted. MR imaging assessment was independent and blinded and recorded using established parameters including alpha angles measured at both the 3:00 (anterior head-neck junction) and 1:30 (antero-superior head-neck junction) radial image positions. Results. Fifty-two volunteers were recruited (32 boys, 20 girls), of whom 44 had bilateral hips imaged (88 hips). Radiographic analysis showed no CAM-type morphology in pre-closure hips and 14% in post-closure hips, using established criteria (alpha > 50.5). The difference between alpha angle measurements at 3:00 and 1:30 positions (5.16) appears significant in developing hips. Conclusion. Results confirm our ability to recruit a cohort of asymptomatic children for the proposed methodology. Collected data found FAI in 14% of the closed-physes group and 0 % in the open physes group suggesting possible physeal closure importance. The difference between 3:00 and 1:30 alpha angle measurements was significantly less than in published adult figures, further suggesting a developmental role in CAM-Type FAI. This is the first published attempt to assess CAM-type FAI morphology in the developing hip. Preliminary data suggests the period just prior to physeal closure may have significant etiological implications. New parameters for imaging angles are suggested. The study results will guide future cohort study designs

Purpose. With the advent of newer diagnostic imaging tools, the reported prevalence of acute pulmonary embolism (PE) following total hip (THA) and total knee (TKA) arthroplasty appears to be increasing. However, the true prevalence and clinical relevance of these events are unclear. Our study was designed to evaluate the results of routine multi-detector computed tomography (MDCT) in this patient population in the early postoperative period. Method. We prospectively performed MDCT scans on 48 consecutive THA/TKA patients on the first postoperative day in 2009. Patients underwent routine postoperative care and data were collected regarding the development of symptoms such as tachycardia, fever, chest pain, or shortness of breath. Scans were kept blinded and read at the end of study recruitment for the diagnosis of acute PE. Results. Our cohort included 27 TKA patients and 21 THA patients. None of the 48 patients had any symptoms of PE. Among the TKR patients, 11 (41%) of the CT scans were read as positive for acute PE compared with 1 (5%) of the THR patients (p=0.004). All of the patients diagnosed with asymptomatic PE were discharged from hospital without treatment for venous thromboembolism (VTE) and without developing any clinical symptoms suggestive of VTE. One TKA patient, who had a negative CT scan on the first postoperative day, was diagnosed with symptomatic PE the following day. Conclusion. Our study demonstrates a high rate of abnormal MDCT early following lower extremity arthroplasty, the clinical significance of which may be benign. This finding is also important in the interpretation of MDCT obtained after a clinical suspicion of PE in these patients

Aims

The risk to patients and healthcare workers of resuming elective orthopaedic surgery following the peak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been difficult to quantify. This has prompted governing bodies to adopt a cautious approach that may be impractical and financially unsustainable. The lack of evidence has made it impossible for surgeons to give patients an informed perspective of the consequences of elective surgery in the presence of SARS-CoV-2. This study aims to determine, for the UK population, the probability of a patient being admitted with an undetected SARS-CoV-2 infection and their resulting risk of death; taking into consideration the current disease prevalence, reverse transcription-polymerase chain reaction (RT-PCR) testing, and preassessment pathway.

Iliopsoas tendonitis occurs in up to 30% of patients after hip resurfacing arthroplasty (HRA) and is a common reason for revision. The primary purpose of this study was to validate our novel computational model for quantifying iliopsoas impingement in HRA patients using a case-controlled investigation. Secondary purpose was to compare these results with previously measured THA patients. We conducted a retrospective search in an experienced surgeon's database for HRA patients with iliopsoas tendonitis, confirmed via the active hip flexion test in supine, and control patients without iliopsoas tendonitis, resulting in two cohorts of 12 patients. The CT scans were segmented, landmarked, and used to simulate the iliopsoas impingement in supine and standing pelvic positions. Three discrete impingement values were output for each pelvic position, and the mean and maximum of these values were reported. Cup prominence was measured using a novel, nearest-neighbour algorithm. The mean cup prominence for the symptomatic cohort was 10.7mm and 5.1mm for the asymptomatic cohort (p << 0.01). The average standing mean impingement for the symptomatic cohort was 0.1mm and 0.0mm for the asymptomatic cohort (p << 0.01). The average standing maximum impingement for the symptomatic cohort was 0.2mm and 0.0mm for the asymptomatic cohort (p << 0.01). Impingement significantly predicted the probability of pain in logistic regression models and the simulation had a sensitivity of 92%, specificity of 91%, and an AUC ROC curve of 0.95. Using a case-controlled investigation, we demonstrated that our novel simulation could detect iliopsoas impingement and differentiate between the symptomatic and asymptomatic cohorts. Interestingly, the HRA patients demonstrated less impingement than the THA patients, despite greater cup prominence. In conclusion, this tool has the potential to be used preoperatively, to guide decisions about optimal cup placement, and postoperatively, to assist in the diagnosis of iliopsoas tendonitis

Femoroacetabular impingement (FAI) deformities are a potential precursor to hip osteoarthritis and an important contributor to non-arthritic hip pain. Some hips with FAI deformities develop symptoms of pain in the hip and groin that are primarily position related. The reason for pain generation in these hips is unclear. Understanding potential impingement mechanisms in FAI hips will help us understand pain generation. Impingement between the femoral head-neck contour and acetabular rim has been proposed as a pathomechanism in FAI hips. This proposed pathomechanism has not been quantified with direct measurements in physiological postures. Research question: Is femoroacetabular clearance different in symptomatic FAI hips compared to asymptomatic FAI and control hips in sitting flexion, adduction, and internal rotation (FADIR) and squatting postures?. We recruited 33 participants: 9 with symptomatic FAI, 13 with asymptomatic FAI, and 11 controls from the Investigation of Mobility, Physical Activity, and Knowledge Translation in Hip Pain (IMAKT-HIP) cohort. We scanned each participant's study hip in sitting FADIR and squatting postures using an upright open MRI scanner (MROpen, Paramed, Genoa, Italy). We quantified femoroacetabular clearance in sitting FADIR and squatting using beta angle measurements which have been shown to be a reliable surrogate for acetabular rim pressures. We chose sitting FADIR and squatting because they represent, respectively, passive and active maneuvers that involve high flexion combined with internal/external rotation and adduction/abduction, which are thought to provoke impingement. In the squatting posture, the symptomatic FAI group had a significantly smaller minimum beta angle (−4.6º±15.2º) than the asymptomatic FAI (12.5º ±13.2º) (P= 0.018) and control groups (19.8º ±8.6º) (P=0.001). In the sitting FADIR posture, both symptomatic and asymptomatic FAI groups had significantly smaller beta angles (−9.3º ±14º [P=0.010] and −3.9º ±9.7º [P=0.028], respectively) than the control group (5.7º ±5.7º). Our results show loss of clearance between the femoral head-neck contour and acetabular rim (negative beta angle) occurred in symptomatic FAI hips in sitting FADIR and squatting. We did not observe loss of clearance in the asymptomatic FAI group for squatting, while we did observe loss of clearance for this group in sitting FADIR. These differences may be due to accommodation mechanisms in the active, squatting posture that are not present in the passive, sitting FADIR posture. Our results support the hypothesis that impingement between the femoral head-neck contour and acetabular rim is a pathomechanism in FAI hips leading to pain generation

Discoid meniscus (DM) is a congenital variant of the knee joint that involves morphological and structural deformation, with potential meniscal instability. The prevalence of the Discoid Lateral Meniscus (DLM) is higher among the Asians than among other races, and both knees are often involved. Meniscal pathology is widely prevalent in the adult population, secondary to acute trauma and chronic degeneration. The true prevalence in children remains unknown, as pathologies such as discoid menisci often go undiagnosed, or are only found incidentally. A torn or unstable discoid meniscus can present with symptoms of knee pain, a snapping or clicking sensation and/or a decrease in functional activity, although it is not known if a specific presentation is indicative of a torn DM. While simple radiographs may provide indirect signs of DLM, magnetic resonance imaging (MRI) and arthroscopy is essential for diagnosis and treatment planning. Asymptomatic patients require close follow-up without surgical treatment, while patients with symptoms often require surgery. Partial meniscectomy is currently considered the treatment of choice for DLM. For children are more likely to achieve better results after partial meniscectomy

Complex acetabular reconstruction for oncology and bone loss are challenging for surgeons due to their often hostile biological and mechanical environments. Titrating concentrations of silver ions on implants and alternative modes of delivery allow surgeons to exploit anti-infective properties without compromising bone on growth and thus providing a long-term stable fixation. We present a case series of 12 custom acetabular tri-flange and custom hemipelvis reconstructions (Ossis, Christchurch, New Zealand), with an ultrathin plasma coating of silver particles embedded between layers of siloxane (BioGate HyProtect™, Nuremberg, Germany). At the time of reporting no implant has been revised and no patient has required a hospital admission or debridement for a deep surgical site infection. Routine follow up x-rays were reviewed and found 2 cases with loosening, both at their respective anterior fixation. Radiographs of both cases show remodelling at the ilium indicative of stable fixation posteriorly. Both patients remain asymptomatic. 3 patients were readmitted for dislocations, 1 of whom had 5 dislocations within 3 weeks post-operatively and was immobilised in an abduction brace to address a lack of muscle tone and has not had a revision of their components. Utilising navigation with meticulous implant design and construction; augmented with an ultrathin plasma coating of silver particles embedded between layers of siloxane with controlled and long-term generation of silver ion diffusion has led to outstanding outcomes in this series of 12 custom acetabular and hemipelvis reconstructions. No patients were revised for infection and no patients show signs of failure of bone on growth and incorporation. Hip instability remains a problem in these challenging mechanical environments and we continue to reassess our approach to this multifaceted problem