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Femoro-acetabular impingement (FAI) is a common cause of hip pain in young adults. The condition can result in labral tears, articular cartilage lesions and eventual osteoarthritis of the hip. FAI results from an abnormal bony sha...
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Femoro-acetabular impingement (FAI) is a common cause of hip pain in young adults. The condition can result in labral tears, articular cartilage lesions and eventual osteoarthritis of the hip. FAI results from an abnormal bony shape of the femoral head / neck or the acetabular rim or both, which causes contact (impingement) between the neck and acetabular rim during movement of the hip joint. Two different mechanisms are described, although a combination of the two mechanisms is frequent. Cam impingement is caused by an abnormality of the femoral head and neck; principally a reduction in offset between the head and the neck. Pincer impingement is caused by an abnormality on the acetabular side, with either excessive retroversion of the acetabulum or an unduly prominent anterior wall. Either problem is associated with the development of chondral lesions (especially in the acetabulum) and labral pathology.Patients with FAI usually present with deep groin pain exacerbated by hip flexion. X-rays typically show an anterior impingement bump on the anterior femoral neck on a horizontal beam lateral, abnormalities of head/neck offset or an excessively prominent anterior acetabular wall. Surgery is the treatment of choice and this involves open or arthroscopic bony resection to improve femoral head-neck clearance with either resection or refixation of the damaged labrum. Both the femoral head/neck junction and the acetabular rim may require bony resection. Such surgery yields good symptomatic relief, but whether the surgery prevents the development of osteoarthritis in the hip in the long term is currently unknown.
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Ankle impingement syndromes are a well-recognized cause of chronic ankle symptoms in both the elite athletic and general population. They comprise several distinct clinical entities with associated radiologic findings. Originally ...
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Ankle impingement syndromes are a well-recognized cause of chronic ankle symptoms in both the elite athletic and general population. They comprise several distinct clinical entities with associated radiologic findings. Originally described in the 1950s, advances in magnetic resonance imaging (MRI) and ultrasonography have allowed musculoskeletal (MSK) radiologists to further their understanding of these syndromes and the range of imaging-associated features. Many subtypes of ankle impingement syndromes have been described, and precise terminology is critical to carefully separate these conditions and thus guide treatment options. These are divided broadly into intra-articular and extra-articular types, as well as location around the ankle. Although MSK radiologists should be aware of these conditions, the diagnosis remains largely clinical, with plain film or MRI used to confirm the diagnosis or assess a surgical/treatment target. The ankle impingement syndromes are a heterogeneous group of conditions, and care must be taken not to overcall findings. The clinical context remains paramount. Treatment considerations are patient symptoms, examination, and imaging findings, in addition to the patient's desired level of physical activity.
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Jet impingement and low-temperature damage are potential risks of accidental release during the transportation and storage of liquid CO_2. An experimental system was built to investigate the characteristics of jet impingement of l...
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Jet impingement and low-temperature damage are potential risks of accidental release during the transportation and storage of liquid CO_2. An experimental system was built to investigate the characteristics of jet impingement of liquid CO_2. The effects of orifice size and impinging distance on the impinging force of the jet and temperature of the target surface were investigated at 2.3 MPa and 5 MPa, with orifice sizes from 2 to 4.84 mm and impinging distances from 0.25 to 1.5 m. A jet impingement model was established considering the initial pressure, orifice size, impinging distance and impingement area. The experimental results indicated that dry-ice attached on the plate surface, reducing the surface temperature to - 90 ℃ and improving the impinging force to 44.54 N with decreasing impingement distance. The variation in initial pressure had a more pronounced effect on the impinging force than on the impinging temperature, while the impingement distance had more influence on the impinging temperature than the orifice size and initial pressure. The results calculated with the model agreed well with the experimental results with an error of nearly less than 20%. The model was also used to analyse the effects of the initial pressure, liquid mass fraction, orifice size, impingement distance and impingement area on the release rate and impingement force.
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Introduction The mechanical conflict in symptomatic femoroacetabular impingement can lead to early osteoarthritis. However, radiographic impingement morphology is often seen in asymptomatic individuals. Long-term observation regar...
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Introduction The mechanical conflict in symptomatic femoroacetabular impingement can lead to early osteoarthritis. However, radiographic impingement morphology is often seen in asymptomatic individuals. Long-term observation regarding the risk of developing osteoarthritis in these individuals is lacking. Our study addressed the following questions: Does femoroacetabular impingement morphology increase the risk for development of osteoarthritis after at least 25 years? If yes, which radiographic parameter is the most predictive? Does the level of activity influence the risk for development of osteoarthritis? Are PROM influenced by the grade of osteoarthritis in this population? Methods We investigated 51 (32 male, 19 female) patients for whom AP pelvis and Dunn view radiographs were available with a minimum follow-up of 25 years. Alpha angle in AP pelvis and Dunn view radiographs, femoral torsion in Dunn view, lateral center edge angle, cross-over sign, posterior wall sign and prominence of ischial spine sign in AP pelvis radiographs were determined. On the follow-up radiographs, osteoarthritis was graded. Tegner Score for the time of the index radiograph was evaluated. Harris Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index were assessed at latest follow-up. Results The mean follow-up was 43 years (range 25-58). Cam impingement morphology showed to increase the risk for development of osteoarthritis: Alpha angles of >= 55 degrees on AP pelvis and Dunn view radiographs were associated risk factors and showed an OR of 1.05 (p = 0.002) and 1.10 (p = 0.001), respectively. Abnormal femoral torsion and acetabular retroversion were not risk factors for osteoarthritis. Tegner Score at index presentation, HHS and WOMAC Score did not correlate with the grade of osteoarthritis. Conclusion This study showed that cam impingement morphology in young patients raises the risk for development of hip osteoarthritis by 5-10% in a long-term follow-up with a minimum of 25 years, thus its contribution was small.
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Femoroacetabular impingement (FAI) is widely understood to be an underlying etiology of injuries to the ace-tabular labrum and cartilage in the adult hip, although somewhat less attention has previously been spent on its incidence...
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Femoroacetabular impingement (FAI) is widely understood to be an underlying etiology of injuries to the ace-tabular labrum and cartilage in the adult hip, although somewhat less attention has previously been spent on its incidence in the pediatric and adolescent populations. Initially recognized as a consequence of periacetabular osteotomies performed for developmental dysplasia of the hip, it can also be because of a number of other disorders or to a developmental process causing irregular bony growth. The adolescent presenting with FAI is athletic, particularly in endeavors placing excessive stress on the hip and surrounding soft tissues. The pain is characterized as sharp, localized around the anatomic femoral head location, and may be associated with catching or popping. Complete physical examination includes full range of motion testing, as a hallmark of FAI is restriction and pain with internal rotation. Special tests include the anterior impingement test, the FABER test, and the dial test. Imaging includes anteroposterior pelvic and cross-table lateral radiographs and magnetic resonance imaging. Treatment in all patients is 6 weeks of conservative therapy. If patients see no improvement with conservative treatment, they may be candidates for hip arthroscopy. Arthroscopic treatment of FAI includes rim trimming for pincer lesions, osteoplasty for cam decompression and labral detachment, and repair or reconstruction for labral tears. Studies have shown improvements in the modified Harris Hip Score and the Hip Outcomes Score postoperatively. As FAI is diagnosed most frequently in athletes, and it is estimated that 30 to 45 million adolescents 6 and 18 years old are involved in sports, it is becoming imperative to identify factors that may predict its development, study treatments, and improve outcomes.
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Hypermobility, or joint hyperlaxity, can result from inherited connective tissue disorders or from micro- or macrotrauma to a joint. The supraphysiologic motion of the hip joint results in capsuloligamentous damage, and these pati...
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Hypermobility, or joint hyperlaxity, can result from inherited connective tissue disorders or from micro- or macrotrauma to a joint. The supraphysiologic motion of the hip joint results in capsuloligamentous damage, and these patients have a propensity to develop femoroacetabular impingement syndrome (FAIS) and labral injury. In this review, the recent literature evaluating the definitions, history, incidence, genetics, and histology of hypermobile disorders is investigated. We then review the clinical evaluation, natural history, and resulting instability for patients presenting with a hypermobile hip. Lastly, treatment options and outcomes will be highlighted.
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In the present study, we compared the thermal performance of the two types of impinging jets: confined and unconfined impinging jets. In order to obtain the thermal characteristics of impinging jets, experimental investigations fo...
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In the present study, we compared the thermal performance of the two types of impinging jets: confined and unconfined impinging jets. In order to obtain the thermal characteristics of impinging jets, experimental investigations for air and water are conducted. The effects of dimensionless pumping powers (P_(pump)~* = 1.35 × 10~(10) - 4 × 10~(13)) on the Nusselt number are considered. The focus is on the cases where the nozzle-to-plate spacing is equal to or less than one nozzle diameter (H/d ≤ 1). The results show that the thermal performance of the confined jet is similar to that of the unconfined jet under a fixed pumping power condition, while the thermal performance of the confined jet is 20-30% lower than that of the unconfined jet under a fixed flow rate condition. Based on the experimental results, generalized correlations for the stagnation and average Nusselt numbers for both confined and unconfined impinging jets are presented as a function of the dimensionless pumping power and the Prandtl number.
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Purpose Extra-articular hip impingement syndromes encompass a group of conditions that have previously been an unrecognised source of pain in the hip and on occasion been associated with intra-articular hip impingement as well. As...
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Purpose Extra-articular hip impingement syndromes encompass a group of conditions that have previously been an unrecognised source of pain in the hip and on occasion been associated with intra-articular hip impingement as well. As arthroscopic techniques for the hip continue to evolve, the importance of these conditions has been recognised recently and now form an important part of the differential of an individual presenting with hip pain. The aim of this article, therefore, is to provide the reader with an evidence-based and comprehensive update of these syndromes.
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Purpose Anatomic tunnel placement in ACL reconstruction is crucial to restore knee function. The aims of this study were to (i) evaluate the accuracy of tunnel placement for primary state-of-the-art ACL reconstruction, and (ii) ex...
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Purpose Anatomic tunnel placement in ACL reconstruction is crucial to restore knee function. The aims of this study were to (i) evaluate the accuracy of tunnel placement for primary state-of-the-art ACL reconstruction, and (ii) examine the correlation between incorrect tunnel placement, graft appearance, and notch impingement. Methods In this retrospective study, all patients underwent primary single-bundle ACL reconstruction with independent drilling of the femoral and tibial tunnels according to anatomical landmarks. The accuracy of tunnel placement and the rate of notch impingement were analysed with MRI. The study cohort was subdivided according to the morphology of the graft: intact, degeneration, and re-rupture. The objective outcome was evaluated with the IKDC objective score, and the subjective outcomes were evaluated with the IKDC subjective score, the Lysholm knee score, the KOOS, and the Tegner activity scale score. Results Eighty-seven consecutive patients with a mean follow-up of 3.8 +/- 1.4 years were evaluated. There was no significant difference among the groups concerning the baseline characteristics. The re-rupture rate was 9.2%. The position of the femoral tunnel was correct in 92% of the patients, and the position of the tibial tunnel was correct in 93% of the patients. In the intact group, impingement was not found in any of the cases, whereas the rate of impingement in the degeneration (65%) and re-rupture (80%) groups was significantly higher than that in the intact group (p < 0.001). The risk of impingement was more likely with femoral (71% vs. 13%,p < 0.001) or tibial (100% vs. 11%,p < 0.001) malpositioning. The objective IKDC score was A in 52 patients (60%), B in 26 patients (30%), and C in 9 patients (10%). The average subjective IKDC score, Lysholm score, and KOOS were comparable in the intact and degeneration groups but significantly lower in the patient group with newly diagnosed re-ruptures (p = 0.05). The Tegner activity scale score was comparable in all three groups. Conclusion Even though the accuracy of femoral tunnel placement in modern single-bundle ACL reconstruction is greater, the risk of malpositioning and graft impingement remains. In our patient cohort, there was a clear correlation between ACL graft impingement, degenerative changes in MRI, and incorrect tunnel positioning. The surgeon must focus on accurate tunnel placement specific to individual patient anatomy.
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