Previous Extensor Mechanism Repair Is Associated With Increased Rates of Surgical Complications Following Total Knee Arthroplasty: A Propensity-matched Analysis.

Background: Although extensor mechanism failure following total knee arthroplasty (TKA) is a devastating complication and has been heavily studied in the literature, the impact of extensor mechanism rupture and concomitant repair prior to TKA has not previously been evaluated. The purpose of this investigation was to evaluate how quadriceps and/or patellar tendon repairs prior to TKA would impact medical and surgery-related complications following TKA. Methods: The PearlDiver database was retrospectively reviewed to identify all primary TKA patients from 2010 to 2019. Patients who underwent quadriceps or patellar tendon repair prior to TKA were matched using a propensity score algorithm to a control cohort. We compared medical and surgical complication rates, emergency room visits, readmissions, and 90-day cost of care between the groups. Results: A total of 1197 patients underwent extensor mechanism repair prior to TKA and were matched to 11,970 patients who did not undergo repair prior to TKA. Patients who underwent extensor mechanism repair had higher rates of 90-day medical complications, as well as 1-year surgery-related complications including revision TKA (odds ratio [OR] 6.06; P < .001), lysis of adhesions (OR 2.18; P = .026), aseptic loosening (OR 2.21; P = .018), infection (OR 7.58; P < .001), and fracture (OR 8.53; P < .001). Patients with prior extensor mechanism repair were more likely to return to the emergency department (OR 1.66; P < .001) and become readmitted (OR 4.15; P < .001) within 90 days. Conclusions: Patients with previous extensor mechanism repair exhibited higher medical and surgery-related complications, including lysis of adhesions, following TKA than a control cohort. These findings may suggest that patients may require additional surveillance in the early postoperative period to avoid these disastrous complications following primary TKA.

Scoliosis Without Fusion and Increased Risk of Early Medical and Surgery-Related Complications After Total Hip Arthroplasty: A Propensity-score Analysis.

INTRODUCTION: There is a paucity of literature that examines how the abnormal spinopelvic alignment of scoliosis affects outcomes after total hip arthroplasty (THA) in the absence of a lumbar fusion. METHODS: Patients with a history of scoliosis (idiopathic, adolescent, degenerative, or juvenile) without fusion and those without a history of scoliosis who underwent primary THA were identified using a large national database. Ninety-day incidence of various medical complications, emergency department (ED) visit, and readmission and 1-year incidence of surgery-related complications and cost of care were evaluated in both the scoliosis and control cohorts. Propensity score matching was used to control for patient demographic factors and comorbidities as covariates. RESULTS: After propensity matching, 21,992 and 219,920 patients were identified in the scoliosis and control cohorts, respectively. Patients with scoliosis were at increased risk of several 90-day medical complications, including pulmonary embolism (odds ratio [OR] 1.96; P < 0.001), deep vein thrombosis (1.49; P < 0.001), transfusion (OR, 1.13; P < 0.001), pneumonia (OR, 1.37; P < 0.001), myocardial infarction (OR, 1.38; P = 0.008), sepsis (OR, 1.59; P < 0.001), acute anemia (OR, 1.21; P < 0.001), and urinary tract infection (OR, 1.1; P = 0.001). Patients with a history of scoliosis were at increased 1-year risk of revision (OR, 1.31; P < 0.001), periprosthetic joint infection (OR, 1.16; P = 0.0089), dislocation (OR, 1.581; P < 0.001), and aseptic loosening (OR, 1.39; P < 0.001) after THA. Patients with scoliosis without a history of fusion were more likely to return to the emergency department (OR, 1.26; P < 0.001) and be readmitted (OR, 1.78; P < 0.001) within 90 days of THA. DISCUSSION: Patients with even a remote history of scoliosis without fusion are at increased risk of 90-day medical and surgery-related complications after hip arthroplasty. Hip and spine surgeons should collaborate in future studies to best understand how to optimize these patients for their adult reconstructive procedures.

Juvenile Idiopathic Arthritis is Associated With Early Medical and Surgical Complications Following Primary Total Hip Arthroplasty: A National Database Study.

Background: Juvenile idiopathic arthritis (JIA) is an inflammatory arthropathy that classically affects children but can cause long-term deformity to the femoral head and hip joint, which may require an arthroplasty procedure. There is a paucity of data surrounding the medical and surgical outcomes of total hip arthroplasty (THA) in patients with JIA compared to a control cohort. Methods: Patients with JIA who underwent THA from 2010 to 2019 were identified in a large national insurance database. A propensity score matching algorithm was used to obtain a control cohort who did not have JIA based upon age, sex, and Elixhauser Comorbidity Index in a 1:10 ratio. Seven hundred sixty-three patients with JIA and 7434 patients without JIA were identified who underwent THA. Ninety-day medical outcomes, 1-year surgical outcomes, and 90-day return to the emergency department and readmission were calculated. Results: Patients with JIA were at increased risk of 90-day transfusion (odds ratio [OR] 1.79; P < .001), pneumonia (OR 2.68; P < .001), urinary tract infection (OR 2.64; P < .001), and wound disruption (OR 2.72; P < .001), as well as 1-year risk of revision THA (OR 2.27; P < .001), periprosthetic joint infection (OR 2.98; P < .001), periprosthetic fracture (OR 2.93; P < .001), aseptic loosening (OR 3.92; P < .001), dislocation (OR 2.61; P = .001), and debridement, antibiotics, and implant retention procedure (OR 2.71; P < .001). Patients with JIA were also at increased risk of 90-day emergency department visit (OR 2.54; P < .001) and readmission (OR 2.59; P < .001). Conclusions: Patients with JIA were at increased risk of early medical and surgical complications following THA. These findings are imperative for surgeons to consider and may warrant tailored perioperative decision-making to avoid the aforementioned medical and surgical complications.

Decreased Risk of Periprosthetic Joint Infection with Concurrent Hardware Removal During Conversion Total Hip Arthroplasty Compared to Staged Removal: A Matched Cohort Analysis.

INTRODUCTION: Hardware removal before conversion total hip arthroplasty (cTHA) is a challenging task for the orthopaedic surgeon, although there is little consensus on the timing of hardware removal to mitigate risk of surgery-related complication following cTHA. METHODS: Using a national insurance database, we evaluated patients who underwent hardware removal either on the same day or within 1 year before cTHA, resulting in a total of 7,756 patients. After matching based on demographic factors and comorbidities, both staged and concurrent groups consisted of 2,752 patients. The 90-day and 1-year risk of revision surgery, periprosthetic joint infection (PJI), periprosthetic fracture, and aseptic loosening were calculated and compared. Demographic factors and comorbidities were further evaluated as risk factors for PJI. RESULTS: The rates of infection were 1.85% and 3.05% at 90 days postoperatively and 2.94% and 4.14% at 1 year postoperatively for concurrent versus staged cohorts, respectively (P = 0.004 and P = 0.02). No difference was observed at 90 days or 1 year between the two cohorts in risk of fracture, revision surgery, or aseptic loosening. Diabetes (P = 0.002 and P < 0.001), tobacco use (P < 0.001 and P < 0.001), and obesity (P = 0.026 and P = 0.025) were identified as risk factors for PJI at both 90 days and 1 year postoperatively. DISCUSSION: The timing of hardware removal is associated with an increased risk of PJI, although no difference was observed in revision surgery, fracture, or loosening among staged versus concurrent cohorts. These findings are important to consider when surgeons are evaluating patients with periarticular implants surrounding their hip.

EE-drospirenone-levomefolate calcium versus EE-drospirenone + folic acid: folate status during 24 weeks of treatment and over 20 weeks following treatment cessation.

BACKGROUND: Adequate folate supplementation in the periconceptional phase is recommended to reduce the risk of neural tube defects. Oral contraceptives may provide a reasonable delivery vehicle for folate supplementation before conception in women of childbearing potential. This study aimed to demonstrate that a fixed-dose combination of an oral contraceptive and levomefolate calcium leads to sustainable improvements in folate status compared with an oral contraceptive + folic acid. METHODS: This was a double-blind, randomized, parallel-group study in which 172 healthy women aged 18-40 years received ethinylestradiol (EE)-drospirenone-levomefolate calcium or EE-drospirenone + folic acid for 24 weeks (invasion phase), and EE-drospirenone for an additional 20 weeks (folate elimination phase). The main objective of the invasion phase was to examine the area under the folate concentration time-curve for plasma and red blood cell (RBC) folate, while the main objective of the elimination phase was to determine the duration of time for which RBC folate concentration remained ≥ 906 nmol/L after cessation of EE-drospirenone-levomefolate calcium. RESULTS: Mean concentration-time curves for plasma folate, RBC folate, and homocysteine were comparable between treatment groups during both study phases. During the invasion phase, plasma and RBC folate concentrations increased and approached steady-state after about 8 weeks (plasma) or 24 weeks (RBC). After cessation of treatment with levomefolate calcium, folate concentrations decreased slowly. The median time to RBC folate concentrations falling below 906 nmol/L was 10 weeks (95% confidence interval 8-12 weeks) after cessation of EE-drospirenone-levomefolate calcium treatment. Plasma and RBC folate levels remained above baseline values in 41.3% and 89.3% of women, respectively, at the end of the 20-week elimination phase. CONCLUSION: Improvements in folate status were comparable between EE-drospirenone-levomefolate calcium and EE-drospirenone + folic acid. Plasma and RBC folate levels remained elevated for several months following cessation of treatment with EE-drospirenone-levomefolate calcium.

Spectrophotometric measurements of human tissues for the detection of subjacent blood vessels in an endonasal endoscopic surgical approach.

Thin slices of human tissues are characterized concerning reflection and transmission in a wavelength range from 400 to 1700 nm. The results are primarily useful to find a wavelength for the detection of subjacent blood vessels during surgical procedures, especially neurological surgery. The measurements have been conducted using a customized measuring station, utilizing two halogen bulb lamps and two spectrometers. This paper focuses on creating a data base with the optical properties of artery, brain, bone, nasal mucosa, and nerve. The spectral distributions are compared among each other, similarities and differences are pointed out. Each tissue has got unique spectral characteristics, whereas typical absorption bands can be found in the overall tissues, especially hemoglobin and water absorption bands. The reflectivity maxima are typically located in the red or near-infrared. All the transmission maxima are located between 1075 nm and 1100 nm. The measurements have been conducted at the Institute of Anatomy at the University of Leipzig.

An Entamoeba cysteine peptidase specifically expressed during encystation.

Protozoan parasites of the genus Entamoeba possess a considerable number of cysteine peptidases (CPs), the function of most of these molecules for amoeba biology needs to be established. In order to determine whether CPs may play a role during Entamoeba stage conversion from trophozoites into cysts and vice versa, expression of cp genes was analysed in the reptilian parasite Entamoeba invadens, a model organism for studying Entamoeba cyst development. By homology search, 28 papain-like cp genes were identified in public E. invadens genome databases. For eight of these genes the expression profiles during stage conversion was determined. By Northern blot analysis, transcripts for eicp-a9, -b7, -b8 and -c2, respectively, were detected neither in trophozoites or cysts nor at any of the point of times analysed during stage conversion. On the other hand, eicp-a5 is constitutively expressed during all developmental stages, whereas eicp-a3 and eicp-a11, respectively, are trophozoite-specific. Only eicp-b9 was found to be cyst-specific as it is expressed exclusively 18 to 28 h after cyst induction. Cyst-specific expression was confirmed by immunofluorescence microscopy of the corresponding protein EiCP-B9. In immature cysts, the molecule is located in structures that accumulate near the cyst wall, but which are uniformly distributed in mature cysts. The precise function of EiCP-B9 during Entamoeba encystation remains to be determined. However, colocalisation studies with an Entamoeba marker for autophagosomes suggest that EiCP-B9 is not associated with Entamoeba autophagy.

New insights into the phylogeny of Entamoeba species provided by analysis of four new small-subunit rRNA genes.

Sequences of small-subunit rRNA genes have been obtained for four new isolates of Entamoeba. Phylogenetic analyses give new insights into the evolution of these organisms. A novel Entamoeba from pigs in Vietnam that produces uninucleate cysts proved to be unrelated to other uninucleated cyst-producing species. Revival of the name Entamoeba suis for this organism is proposed. Instead of being related to Entamoeba polecki, it shares a recent common ancestor with the non-encysting Entamoeba gingivalis in a lineage that is basal to the tetranucleate cyst-producing clade. This suggests that species producing cysts with four nuclei are descended from an ancestor that produced cysts with a single nucleus. An Entamoeba from a horse was isolated in culture. No cysts were observed in the original stool sample but the sequence is placed unequivocally within the clade of tetranucleate cyst-producing species with no other sequences being specifically related. Revival of the name Entamoeba equi for this organism is proposed. The Entamoeba ecuadoriensis sequence was found to be the most closely related to Entamoeba histolytica and Entamoeba dispar, as predicted, despite the organism having been an environmental isolate originally assigned to Entamoeba moshkovskii. Finally, a partial E. polecki gene sequence from a pig proved to be virtually identical to that of Entamoeba struthionis from an ostrich, suggesting that the latter name is a synonym.

Characterization of chitin synthases from Entamoeba.

A major component of the Entamoeba cyst wall is chitin, a homopolymer of beta-(1,4)-linked N-acetyl-D-glucosamine. Polymerization of chitin requires the presence of active chitin synthases (CHS), a group of enzymes belonging to the family of beta-glycosyl transferases. CHS have been described for fungi, insects, and nematodes; however, information is lacking about the structure and expression of this class of enzymes in protozoons such as Entamoeba. In this study, the primary structures of two putative E. histolytica CHS (EhCHS-1 and EhCHS-2) were determined by gene cloning and homologous proteins were identified in databases from E. dispar and the reptilian parasite E. invadens. The latter constitutes the widely used model organism for the study of Entamoeba cyst development. The two ameba enzymes revealed between 23% and 33% sequence similarity to CHS from other organisms with full conservation of all residues critically important for CHS activity. Interestingly, EhCHS-1 and EhCHS-2 differed substantially in their predicted molecular weights (73 kD vs. 114 kD) as well as in their isoelectric points (5.04 vs. 8.05), and homology was restricted to a central stretch of about 400 amino acid residues containing the catalytic domain. Outside the catalytic domain, EhCHS-1 was predicted to have seven transmembrane helices (TMH) of which the majority is located within the C-terminal part, resembling the situation found in yeast; whereas, EhCHS-2 is structurally related to nematode or insect chitin synthases, as it contained 17 predicted TMHs of which the majority is located within the N-terminal part of the molecule. Northern blot analysis revealed that genes corresponding to CHS-1 and CHS-2 are not expressed in Entamoeba trophozoites, but substantial amounts of CHS-1 and CHS-2 RNA were present 4 to 8 hours after induction of cyst formation by glucose deprivation of E. invadens. The time-courses of expression differed slightly between the two ameba CHS genes, as in contrast to CHS-1 RNA, expression of CHS-2 RNA was more transient and no plateau was observed between 8 and 16 hours of encystation. However, both CHS RNAs were no longer detectable after 48 hours when most of the cells had been transformed into mature cysts.