Short-term Dislocation Research Articles

Dynamic change of acetabular component position in total hip arthroplasty based on the spinopelvic classification: a prospective radiographic study

PurposeRecent studies have proposed optimizing the position of the acetabular component based on spinal deformity and stiffness classification to avoid mechanical complication after total hip arthroplasty (THA). The aim of this study was to characterize the dynamic changes in cup alignment post-THA based on the spinopelvic classification and to evaluate the efficacy of cup placement of preventing dislocation.MethodsThis prospective study included a total of 169 consecutive patients awaiting THA who were classified into four groups based on spinal deformity (pelvic incidence minus lumbar lordosis) and spinal stiffness (change in sacral slope from the standing to seated positions). The cups were aligned based on the group with fluoroscopy. Additionally, postoperative radiographic inclination (RI), radiographic anteversion (RA) in standard anteroposterior radiograph, and lateral anteinclination (AI) in sitting and standing positions were measured. The cumulative incidence of dislocation was evaluated at a follow-up two years post-THA.ResultRA was significantly greater in the group with normal spine alignment and stiff spine than in other groups (P = 0.0006), and AI in the sitting position was lower than in other groups (P = 0.012). Standing AI did not significantly differ between the groups. One posterior dislocation occurred during the study period (0.6%).ConclusionAI in the sitting position was lower in patients with normal spinal alignment and stiff spine despite larger RA in the standard anteroposterior radiographs. Consequently, with more anteversion in the normal spinal alignment and stiff spine group, spinopelvic parameters can help guide cup placement to prevent short-term dislocation post-THA.

The administration of acetazolamidum for the symptom prophylaxis of an acute mountain sickness when short-term dislocation from middle mountains to highlands takes place

The development of mountain sickness symptoms is one of the limiting factors of successful physical performance in middle mountains and highlands. Among drugs with established effectiveness for the prophylaxis of an acute mountain sickness carbonic anhydrase inhibitor acetazolamidum is also viewed, but at presence there is no universal approach to this issue and drug dosage regimen for its administration have not been elaborated. Aim. А comprehensive analysis of acetazolamidum being administered in the range of effective doses has been carried out. Methods. During the experiment the effect of acetazolamidum on physical performance and resistance of rats to an acute hypobaric hypoxia when administered in the range of effective doses (20, 40 and 80 mg/kg) was studied. During full-scale approbation the effect of acetazolamidum in various dosages on adaptation processes in the course of a rapid dislocation from middle mountains to highlands (glade Azau-the Elbrus mountain) was assessed. Results. The undertaken study showed that the administration of acetazolamidum to rats beginning from a daily dosage 20 mg/kg, that corresponds to human intake of 250 mg of the drug, promotes significant increase of survival time of rats following acute hypoxic exposure as well as growth of an animal performance ability factor under hypoxia. Conclusion. In the course of full-scale approbation it was established that prophylactic intake of acetazolamidum in examined doses prevents the development of symptoms of an acute mountain sickness when rapid dislocation from middle mountains (2300 m) to highlands (5000 m) takes place in the background of physical activity according to the results of sportsmen’s performance of Lake Louise test. (For citation: Vetryakov OV, Bykov VN, Fateev IV, Khalimov YS. The administration of acetazolamidum for the symptom prophylaxis of an acute mountain sickness when short-term dislocation from middle mountains to highlands takes place. Reviews on Clinical Pharmacology and Drug Therapy. 2018;16(2):42-48. doi: 10.17816/RCF16242-48).

The Portuguese Empire and the Lusophone Postcolony as Diasporas

The Portuguese-Speaking Diaspora is an ambitious repository for a selective yet extraordinarily wide-ranging assembly of cultural artifacts drawn from the entire history of the Portuguese empire and Lusophone postcolony. Within the chronological expanse ranging from 1415 to (roughly) 2015, the book stages a storytelling enterprise of encyclopedic breadth and scope, skillfully intertwining historical accounts with brief vignettes and longer analyses of a wide array of artistic objects, from literary works to maps, paintings, decorative arts, sculpture, and cinema. Given the study’s broad definition of diasporic experience (which encompasses a variety of often nonpermanent or short-term dislocations) and its guiding focus on “imperially produced hybridity that is characteristic of lusophone culture” (72), the book is best read as a lively history of hybrid cultural processes and legacies of the Portuguese empire rather than as a sustained reflection on the diasporic condition as such.

Accuracy of applicator tip reconstruction in MRI-guided interstitial 192Ir-high-dose-rate brachytherapy of liver tumors

Background and purposeTo evaluate the reconstruction accuracy of brachytherapy (BT) applicators tips in vitro and in vivo in MRI-guided 192Ir-high-dose-rate (HDR)-BT of inoperable liver tumors. Materials and methodsReconstruction accuracy of plastic BT applicators, visualized by nitinol inserts, was assessed in MRI phantom measurements and in MRI 192Ir-HDR-BT treatment planning datasets of 45 patients employing CT co-registration and vector decomposition. Conspicuity, short-term dislocation, and reconstruction errors were assessed in the clinical data. The clinical effect of applicator reconstruction accuracy was determined in follow-up MRI data. ResultsApplicator reconstruction accuracy was 1.6±0.5mm in the phantom measurements. In the clinical MRI datasets applicator conspicuity was rated good/optimal in ⩾72% of cases. 16/129 applicators showed not time dependent deviation in between MRI/CT acquisition (p>0.1). Reconstruction accuracy was 5.5±2.8mm, and the average image co-registration error was 3.1±0.9mm. Vector decomposition revealed no preferred direction of reconstruction errors. In the follow-up data deviation of planned dose distribution and irradiation effect was 6.9±3.3mm matching the mean co-registration error (6.5±2.5mm; p>0.1). ConclusionApplicator reconstruction accuracy in vitro conforms to AAPM TG 56 standard. Nitinol-inserts are feasible for applicator visualization and yield good conspicuity in MRI treatment planning data. No preferred direction of reconstruction errors were found in vivo.

Improving the Accuracy of Acetabular Component Orientation: Avoiding Malpositioning

Many factors such as poor visualization, greater patient size, inaccuracies of mechanical guides, and changes in patient positioning during surgery can negatively impact acetabular component positioning1. Improper orientation contributes to an increased dislocation rate, limb-length discrepancy, component impingement, bearing surface wear, and revision surgery. Acetabular malpositioning also contributes to altered hip biomechanics, pelvic osteolysis, and acetabular component migration2-8. Despite the established definitions of acetabular safe zones, a recent analysis of United States Medicare total hip arthroplasty data revealed dislocation rates during the first six postoperative months to be 3.9% for primary arthroplasty and 14.4% for revision arthroplasty9. A recent report cited instability and dislocation as accounting for 22.5% of revision cases10. The use of larger femoral head sizes in primary total hip arthroplasty has increased dramatically in recent years with the introduction of alternative bearings and has reduced the short-term dislocation rate by almost one-half from 1998 to 2007 (from 4.21% to 2.14%)11. Dislocation rates have been lowered by increasing the femoral head-neck ratio, decreasing component impingement, increasing the range of hip motion until impingement, and increasing the jump distance when component impingement does occur12,13. Nevertheless, larger femoral heads are not a substitute for proper component placement and precise component orientation; inaccurate component positioning may be associated with alteration in soft-tissue tension and hip biomechanics leading to abnormal gait, trochanteric bursitis, and increased discomfort during walking. All total hip arthroplasty bearing couplings are intolerant of component malpositioning or variation in component positioning; specifically, they are intolerant of excessive lateral opening and anteversion—and implant survivorship and complications are directly related to component positioning8,14. Kurtz et al. forecast that the number of primary and revision hip arthroplasties will significantly increase over the …

Short-Term Dislocation Risk Following Primary Hip Arthroplasty in the Medicare Population

Although larger diameter femoral heads (32 mm and larger) have been used in at least 50% of primary THA since 2004 (Orthopedic Network News, July 2005), recent national data has shown that the most common cause of revision is dislocation. The purpose of this study is to evaluate the risk of short-term dislocations after primary THA and the corresponding patient, hospital, and procedure risk factors.

Potential effects of navigation-induced wave wash on the early life history stages of riverine fish

Navigation alters the ecology of large inland waterways via engineering and more directly by emission of hazardous substances and wave wash. We investigated the potential effects of the latter on the early life history stages of riverine fish, which have their nursery zones generally located in shallow areas with low current and higher water temperatures. Ship induced wave wash causes the following impacts on fish during their early life history stages: i) short-term dislocation of suitable larval and juvenile fish habitats due to wake and splash; ii) water velocities during ship passages frequently exceed maximum swimming performances of 0+fish; and iii) suspended solids concentrations in the inshore habitats increase dramatically and limit the foraging efficiency of young of the year fish (YOY).

The Dilbert Syndrome

The recent popularity of Scott Adams's “Dilbert” cartoon character highlights a phenomenon already palpably evident in business today: Many employees are highly cynical about the effectiveness of management and view large, bureaucratic organizations with disdain and contempt. This article explores the dynamics and implications of this change for how organizations and individuals manage careers. First, the article examines why individuals no longer desire organizationally based careers and why so many organizations are decreasing their number of permanent employees. Next, the chapter identifies the double binds created for individuals and organizations trying to manage careers during this transitional period. Finally, the article suggests how these short-term dislocations might resolve themselves into new models of career management for individuals and organizations alike.

External shocks, adjustment policies and investment in a developing economy: Illustrations from a forward-looking CGE model of the Philippines

The rapid increase in investment and external debt of middle-income countries like the Philippines during the 1970s was perfectly ‘rational’ given existing policies. However, these countries could have done better with an appropriate mix of adjustment policies. Using a dynamic general equilibrium framework, the paper examines the sensitivity of investment and growth to external shocks and adjustment policies. It highlights the intertemporal trade-offs of tariff reform, a policy often recommended in the 1980s, emphasizing the need for complementary measures to ease macro imbalances and short-term dislocations of the protected sector.

Polytechnics: the radical imperative

Uncertainty and gloom hang over the educational world. Fear is rife. Many, particularly in the higher education world, fear not a short term dislocation of activity, but a major discontinuity. Nowhere is this anxiety more widespread than in the Polytechnics. Established in the optimism and white heat of the 60s' technological advance, they appear to be losing their struggle for identity as a different, separate, but equal sector of higher education. The symptoms manifest themselves in a variety of forms such as: