Fixation Stability of Uncemented Acetabular Cups With Respect to Different Bone Defect Sizes

BackgroundIn total hip arthroplasty, acetabular press-fit cups require a proper bone stock for sufficient primary implant fixation. The presence of acetabular bone defects compromises the primary fixation stability of acetabular press-fit cups. The aim of the present study is to determine the fixation stability of a cementless acetabular cup regarding standardized bone defects in an experimental setup.MethodsAn acetabular defect model was developed and transferred to a biomechanical cup-block model. The lack of superior cup coverage was divided into 4 stages of superior rim loss (33%, 50%, 67%, and 83%) in the anterior-posterior direction and into 4 stages of mediolateral wall absence (11%, 22%, 33%, and 50%). This resulted in 11 different defect cavities, which were compared to the intact cavity in push-in and lever-out tests of one press-fit cup design (56 mm outer diameter). Thereby, push-in force, lever-out moment, lever-out angle, and interface stiffness were determined.ResultsThe determined lever-out moments range from 15.53 ± 1.38 Nm (intact cavity) to 1.37 ± 0.54 Nm (83%/50% defect). Smaller defects (33%/11%, 33%/22%, and 50%/11%) reduce the lever-out moments by an average of 33.9% ± 2.8%.ConclusionThe lack of mediolateral acetabular coverage of 50% was assessed as critical for cementless cup fixation, whereby the contact zone between implant and bone in the defect is lost. A lack of 20% to 30% mediolateral coverage appears to be acceptable for press-fit cup fixation in the presence of primary stability. A defect of 50%/50% was identified as the threshold for using additional fixation methods.     

Providing Patient Mobilization With a Mobility Technician Improves Staff Efficiency and Constrains Cost in Primary Total Hip Arthroplasty

BackgroundMobility technicians (MTs) demonstrate value in constraining the cost of total joint replacement procedures. MTs are certified medical assistants with specialized ambulation/gait training who work under the direction of the nursing staff to meet patient mobilization demands in hospital wards. This study analyzed their impact on primary total hip arthroplasty (THA).MethodsData were retrospectively reviewed from both the time before and the time after MTs were introduced to the hospital for demographic information (ie, age, gender, race, and payer) and clinical measures (ie, length of stay and discharge disposition). The control group was treated and mobilized according to standard physical therapy and nursing staff protocols. Study group subjects had access to the MTs at the direction of their registered nurse. Included subjects underwent a primary THA procedure for arthritic conditions or hip fractures, or for conversion from a previous hip surgery. Excluded were subjects who underwent procedures for revision, bilateral, or hip resurfacing procedures.ResultsThe study and control groups included 542 and 1297 subjects, respectively. They shared a median length of stay of 2 days (P = .121). More study group subjects were discharged home than were their control group counterparts (91.51%-87.43%, P = .012). Cost analysis revealed an annual savings of $119,794.50 in total first post-acute care (ie, the period spent at a patient’s initial discharge disposition level) costs to the institution. Therefore, MTs would need to successfully treat only 5 patients annually to recoup a savings equivalent to their salary.ConclusionMTs support the recovery of THA patients in the hospital, in turn optimizing their discharge disposition. Institutions may experience a financial benefit in a bundled payment system, in which avoiding costly rehab facilities may result in savings over the episode.     

In the Era of Tranexamic Acid,are Type and Screens for Primary Total Joint Arthroplasty Obsolete?

BackgroundAdvances in technique and perioperative blood management have improved transfusion rates following unilateral primary total joint arthroplasty and led some centers to change their preoperative blood ordering protocols. The purpose of this study is to determine whether deleting type and screens (T&S) from preoperative order sets was safe for patients undergoing primary total knee (TKA) and total hip arthroplasty (THA) and to identify patients who required allogenic blood transfusion.MethodsProspectively collected data were reviewed to identify any patient with a hemoglobin (Hgb) drawn within 30 days of surgery who received a transfusion following a unilateral primary TKA or THA.ResultsA total of 1255 patients met inclusion criteria. Of the total, 682 (54%) were TKAs and 573 (46%) were THAs. The mean preoperative Hgb was 11.5 g/dL with an average delta Hgb of 3.6 g/dL on postoperative day 1. No patient required an intraoperative transfusion. Fourteen patients (mean age and body mass index, 67.9 and 29.0) required a transfusion (1.1%) for postoperative blood loss anemia. Of those transfused, 13 (93%) of the patients underwent THA with the mean estimated blood loss of 378.6 mL. The total cost for a patient obtaining a T&S is $191.27.ConclusionIn our series, the risk of blood transfusion was rare (1.1%) and occurred only secondary to postoperative blood loss anemia. There were no cases of intraoperative complication requiring urgent or emergent blood transfusion. Removing T&S from standard order sets for patients undergoing primary TKA or THA appears to be a safe and cost-effective practice.     

Results of Cemented Posterior-Stabilized Total Knee Arthroplasty in Obese Patients With an Average 10-Year Follow-Up

BackgroundObese and morbidly obese patients undergoing primary total knee arthroplasty (TKA) place significant stress at the bone-cement-implant interface over the life of the patient. The purpose of this study is to evaluate results of cemented, posterior-stabilized TKA in obese and morbidly obese patients at an average follow-up of 10 years.MethodsRetrospective study of 181 patients who had a cemented, posterior-stabilized TKA between 2000 and 2013 with body mass index >35 at the time of surgery was conducted. Clinical data and radiographs were evaluated along with survivorship, complications, and revisions. Minimum follow-up was 5 years with an average follow-up of 10 years.ResultsThere were 135 women and 46 men in the study, with mean age of 60.2 years (range 43-80), mean body mass index of 42.0 (range 35.1-66.1), and an average follow-up of 10 years (range 5-18). There were a total of 39 failures (22%) that underwent revision TKA surgery with mean time to revision of 8 years. Failures included 25 (14%) cases of aseptic loosening; 9 (5%) polyethylene wear; 2 (1%) prosthetic joint infection; and 3 additional revisions for instability, pain, and stiffness. There were a total of 11 cases of isolated tibial component loosening and 13 for both tibial and femoral loosening. Survivorship at 15 years with aseptic loosening as the endpoint was 86.7%, and for all causes 79.6% at 15 years.ConclusionAseptic loosening is the leading cause of failure following TKA in obese and morbidly obese patients with decreasing survivorship from 96.1% to 91.2% and 86.7% at 5, 10, and 15 years, respectively.     

The complement system in primary Sjögren’s syndrome: the expression of certain cascade and regulatory proteins in labial salivary glands – observational study

IntroductionThe complement cascade and regulatory proteins are involved in the pathogenesis of the Sjögren’s syndrome and other autoimmune diseases. The complement activation via the alternative pathway was recognized as a major pathogenic mechanism in autoimmune conditions. The aim of this study was to assess expression of complement cascade components and regulatory proteins in minor salivary glands in patients with primary Sjögren’s syndrome (pSS).Materials and methodsThe expression of C1q and C5b-9 – membrane attack complex and regulatory proteins such as: membrane cofactor protein (MCP), decay-accelerating factor (DAF) and protectin were examined using immunochemistry method in specimens from biopsy of minor salivary glands in pSS patients. The biopsy material was obtained from 20 pSS patients, 5 patients with non-specific sialadenitis and from 5 patients with suspicion of dryness syndrome without sialadenitis confirmation.ResultsNone of the examined samples showed the expression of C1q or the effector C5b-9. Membrane cofactor protein expression was lower in pSS group than in both non-specific sialadenitis and noninflamed salivary glands. The inflammatory cells in pSS samples partially expressed MCP. There were differences in the sites and intensity of membrane protectin expression exclusively on the luminal surfaces in pSS; on the luminal and, partially, antiluminal surface in non-specific inflammation, and on the entire cell surface in unaffected salivary glands. There were no DAF expression in salivary gland tissue in biopsy specimens in all studied subjects.ConclusionsThe study demonstrated the absence of complement-cascade proteins (C1q, MAC) in the salivary glands of pSS patients, which may indicated a lack of local complement activation via the classical pathway and the observed gland tissue damage being due to a mechanism other than MAC-induced cytolysis. The differences in the expression of complement regulatory proteins between pSS, non-specific sialadenitis, and normal salivary glands may indicate that alternative functions of these regulatory proteins may be of greater significance in pSS. Low MCP expression in pSS in comparison with non-specific sialadenitis and normal salivary glands, may suggest altered modulation of cell-mediated immunity in pSS. The differences in the location and intensity of protectin (CD59) expression indicates a possibility of reducing the proinflammatory effect of protectin in pSS.     

Recurrence of primary sclerosing cholangitis after liver transplantation is associated with specific changes in the gut microbiome pretransplant – a pilot study

Primary sclerosing cholangitis (PSC) is a common indication for liver transplantation (LT). Up to 25% of patients experience recurrence of PSC (rPSC) after LT, which is associated with significant morbidity and mortality. To date, it is not possible to predict which patients are at risk for rPSC. The aetiology of PSC is complex and is speculated to involve translocation of intestinal bacteria to the liver, because of its frequent co-occurrence with inflammatory bowel diseases (IBD). Here, we investigate whether the mucosal intestinal microbiome of PSC patients (n = 97) at time of first LT can identify those patients who will develop rPSC. 16S gene sequencing of bacterial DNA isolated from formalin-fixed paraffin-embedded biopsies showed that PSC patients with Crohn’s disease (n = 15) have a reduced microbial diversity and that inflammation of the mucosa is associated with beta-diversity changes and feature differences. No differences in alpha- or beta diversity were observed between patients with rPSC (n = 14) and without rPSC (n = 83). However, many over-represented bacterial features were detected in patients with rPSC, while surprisingly, those without recurrence of disease were characterized by an increased presence of the Gammaproteobacteria Shigella. This pilot study warrants further investigation into bacterial differences between rPSC and non-rPSC patients.     

Prevalence of primary aldosteronism in hypertensive kidney transplant recipients: A cross-sectional study

Due to high prevalence of primary aldosteronism (PA) in the general hypertensive population, and its association with worse cardiovascular and renal outcomes, the 2016 Endocrine Society Guidelines explicitly recognize PA as a major public health issue requiring urgent attention. Its prevalence in hypertensive kidney transplant recipients (KTRs) is unknown. In this cross-sectional study, we screened KTRs with hypertension who were on ≥4 antihypertensive medications, on 3 antihypertensive medications with BP ≥ 140/90, and on potassium supplements, or were hypokalemic. 172 of 280 eligible patients successfully completed the testing. A positive screen for PA defined by an aldosterone-to-renin ratio of ≥20 and a plasma aldosterone concentration of >15 ng/dL yielded a prevalence of 15.7%. Potassium supplement requirement (52% vs 27%, P = .01) and hypokalemia (25.9% vs 4.8%, P < .01) were more common in patients who screened positive compared with those who screened negative. 67% of patients who screened positive were on potassium supplements and/or were hypokalemic. Our study is the first to systematically explore the prevalence of PA among the hypertensive KTR population, which has inherently high cardiovascular risk. Further studies are needed to determine the cardiovascular and renal risk attributable to PA, and define optimal therapy for KTRs with PA.     

唑来膦酸与阿仑膦酸钠治疗原发性骨质疏松疗效及安全性的Meta分析

目的系统评价唑来膦酸与阿仑膦酸钠治疗原发性骨质疏松的有效性与安全性。方法计算机检索PubMed、Embase、Cochrane Library、CNKI、CBM、万方数据库,检索时间均为建库至2018年12月,采用改良Jadad量表及Cochrane风险偏倚评估工具评价纳入研究的方法学质量。使用Rev Man5.3及Stata15.0软件进行Meta分析。结果共纳入12篇文献,1 344例患者。Meta分析结果表明:在疗效方面,腰椎骨密度(bone mineral density,BMD)在治疗12个月后[SMD=0.96,95%CI(0.03,1.90),P=0.04]、24个月后[SMD=1.70,95%CI(0.30,3.11),P=0.02],股骨颈BMD在治疗12个月后[SMD=0.34,95%CI(0.19,0.50),P0.000 1],VAS评分[MD=-0.76,95%CI(-0.93,-0.58),P0.000 01],Oswestry功能障碍指数(ODI)[MD=-10.48,95%CI(-11.38,-9.58),P0.000 01],差异具有统计学意义(P0.05),唑来膦酸治疗效果优于阿仑膦酸钠。在安全性方面,不良反应[RR=1.79,95%CI(1.41,2.28),P0.000 01]差异具有统计学意义,唑来膦酸安全性小于阿仑膦酸钠。结论与阿仑膦酸钠相比,唑来膦酸在治疗后期能明显提高患者腰椎、股骨颈BMD,有效降低VAS评分、Oswestry功能障碍指数,进而显著提升患者的生活质量,但不良反应相对较多。