Biomechanical study of using patient-specific diaphyseal femoral cone in revision total knee arthroplasty (rTKA).

Background: The primary objective of revision total knee surgery is to achieve solid bone fixation. Generally, this could be accomplished using sleeves and long stems, which require substantial remaining bone stock and may increase the risk of stem tip pain. An alternative approach involves the use of customized diaphyseal cones, which can preserve the integrity of the bone canal. This study evaluates the impact of employing femoral diaphyseal cones with various stem lengths on stress distribution and relative motion. Methods: CT scan data from five patients were used to generate the 3D model of the femur, cement, customized stems, and cones, along with assigning patient-specific material for each candidate's femur. Three different stem lengths, both with and without the customized cone, were assessed under three gait loading conditions to compare the resulting Von Mises stress distribution and relative motion. Results: Analysis indicated that the use of customized femoral cones moderately increases stress distribution values up to 30 % while significantly reducing relative motion at the femoral canal-cone interface by nearly 60 %. The presence of the cone did not significantly alter relative motion with varying stem lengths, although stem length variation without a cone substantially affected these values. Conclusion: Incorporating cones alongside stems enhances metaphyseal fixation, reduces stress shielding, potentially allowing for the use of shorter stems. Furthermore, cones promote osseointegration by minimizing relative motion, ultimately improving prosthetic stability.

Comparison of Novel 3D-printed Stepped Porous Metal Cones and Metaphyseal Sleeves for Reconstruction of Severe Knee Bone Defects: Short-term Clinical Outcomes.

OBJECTIVE: Both porous metal cones and metaphyseal sleeves are excellent implants for reconstructing severe bone defects in the knee joint, but they both exhibit design limitations. The porous metal cone, especially, has significant room for improvement in its shape design. The existing porous metal cones often feature a conical external surface with a relatively small taper, potentially compromising both rotational and axial stability. To improve both axial and rotational stability in porous metal cones, we developed a 3D-printed stepped porous metal cone. This study aimed to assess the short-term clinical outcome of the 3D-printed stepped porous metal cone and to compare it with the clinical outcome of patients who underwent revision total knee arthroplasty (rTKA) with the metaphyseal sleeves during the same period. METHOD: Patients who underwent total knee arthroplasty revision with metaphyseal bone defect reconstruction from 2019 to 2021 were retrospectively analyzed. A total of 61 patients were enrolled in the study, including 15 patients using 3D-printed stepped porous metal cones and 46 patients using metaphyseal metal sleeves. Thirty patients using metaphyseal sleeves were screened by propensity score matching method and compared with those using stepped cones. Analysis included the American Knee Society Score, the Hospital for Special Surgery knee score, the Western Ontario and McMaster Universities Arthritis index, the Short Form 12 (SF-12) health survey, and radiographic assessment with a mean follow-up of 28.5 ± 8.3 months. To conduct comparative analyses, unpaired Student's t-tests were employed for continuous variables, while categorical variables were analyzed using the appropriate Fisher exact or chi-squared test. RESULTS: In this study, the survival rates of both the stepped cone and metaphyseal sleeve were 100%. There was no statistically significant difference in postoperative knee function scores between the two groups (p > 0.05). However, patients in the cone group had significantly higher mental component summary scores on the SF-12 scale (p < 0.05) and higher increases in mean postoperative physical component summary scores than patients in the sleeve group (p < 0.05). In addition, patients in the cone group experienced fewer intraoperative and postoperative complications compared to the sleeve group. CONCLUSION: The 3D-printed stepped porous metal cone can effectively reconstruct bone defects in complex rTKA and provide satisfactory early clinical and radiographic results. The 3D-printed stepped cone provides a more stable structure similar to the sleeve while maintaining the original benefits of the cone making it a promising choice for rTKA.

Porous Tantalum Tibial Metaphyseal Cones in Revision Total Knee Arthroplasty: Excellent 10-Year Survivorship.

BACKGROUND: Highly porous metal tibial metaphyseal cones (TMCs) are commonly utilized in revision total knee arthroplasty (TKA) to address bone loss and obtain biologic fixation. Mid-term (5 to 10 year) studies have previously demonstrated excellent survivorship and high rates of osseointegration, but longer-term studies are lacking. We aimed to assess long-term (≥ 10 year) implant survivorship, complications, and clinical and radiographic outcomes after revision TKA with TMCs. METHODS: Between 2004 and 2011, 228 revision TKAs utilizing porous tantalum TMCs with stemmed tibial components were performed at a single institution and were retrospectively reviewed. The mean age at revision was 65 years, the mean body mass index was 33, and 52% were women. Implant survivorship, complications, and clinical and radiographic outcomes were assessed. The mean follow-up was 6.3 years. RESULTS: The 10-year survivorship free of aseptic loosening leading to TMC removal was 97%, free of any TMC removal was 88%, free of any re-revision was 66%, and free of any reoperation was 58%. The most common indications for re-revision were periprosthetic joint infection, instability, and aseptic femoral component loosening. The 10-year nonoperative complication rate was 24%. The mean Knee Society scores increased from 38 preoperatively to 69 at 10 years. There were 8 knees that had evidence of partial, progressive tibial radiolucencies at 10 years. CONCLUSIONS: Porous tantalum TMCs demonstrated persistently durable longer-term survivorship with a low rate of implant removal. The rare implant removals for component loosening or instability were offset by those required for periprosthetic joint infection, which accounted for 80% of cone removals. Porous tantalum TMCs provide an extremely reliable tool to address tibial bone loss and achieve durable long-term fixation in revision TKA. LEVEL OF EVIDENCE: IV.

Metaphyseal Fixation Using Cones and Sleeves for Severe Proximal Tibial Bone Loss.

BACKGROUND: Tibial bone defects are commonly encountered in revision total knee arthroplasty (rTKA) and can be managed with metaphyseal cones or sleeves. Few studies have directly compared tibial cones and sleeves in rTKA, and none have limited this comparison to the most severe tibial defects. The purpose of this study was to evaluate and compare the outcomes of metaphyseal cones and sleeves for tibial reconstruction in rTKA regarding implant fixation and clinical outcomes. METHODS: A retrospective review was conducted on patients undergoing rTKA in which metaphyseal cones or sleeves were utilized for addressing metaphyseal bone loss (34 cones and 18 sleeves). Tibial bone loss was classified according to the Anderson Orthopaedic Research Institute bone defect classification, with types 2B and 3 being included. Patient-reported outcomes and postoperative complications were collected, and a radiographic evaluation of osseointegration or loosening was performed. RESULTS: There were 52 knees included (34 cones, 18 sleeves), with a median follow-up of 41.0 months. All-cause implant survival was 100% at 2 years and 96% (95% confidence interval: 76 to 99%) at 4 years, with 98% of tibial components demonstrating osseointegration at the final follow-up. During follow-up, there were a total 11 revisions, of which 1 sleeve was revised secondary to implant loosening. Tibial sleeves had a higher risk of revision compared to tibial cones (P < .01), and sleeves fixed with a hybrid technique were more likely to need revision than cones fixed by the same method (P = .01). CONCLUSIONS: Porous metaphyseal tibial cones and tibial metaphyseal sleeves both performed well at a 41-month median follow-up with no difference in aseptic survivorship between the 2 constructs. Both demonstrate high rates of osseointegration, low rates of aseptic failure, and significant improvement in Knee Society Scores in patients with severe tibial defects in rTKA.

Porous Tantalum Metaphyseal Cones for Severe Femoral and Tibial Bone Defects in Revision Total Knee Arthroplasty are Reliable for Fixation at Mean 5-Year Follow-Up.

BACKGROUND: Porous tantalum metaphyseal cones may facilitate reconstructions of severe bone defects during revision total knee arthroplasty (TKA), but there remains a paucity of data on their outcomes at mean 5 years of follow-up. This study reports the component survivorship, patient satisfaction, functional outcomes, radiographic osseointegration, and complications of revision TKA with porous tantalum metaphyseal cones at mid-term (mean 5-year) follow-up. METHODS: This study included 152 patients who had a mean age of 66 years (range, 33 to 86 years) undergoing revision TKA with porous tantalum metaphyseal cones. Indications for surgery included aseptic loosening (n = 87, 57.3%), second-stage reimplantation for infection (n = 42, 27.6%), osteolysis with well-fixed components (n = 20, 13.2%), and periprosthetic fracture (n = 3, 2.0%). Component survivorship, clinical outcomes, radiographic outcomes, and any complications were recorded. The mean follow-up time was 5.6 years (range, 2.2 to 13.7). RESULTS: Survivorship was 100% when the end point was revision of the metaphyseal cone (no cones were revised) and 83.8% (95% confidence interval: 77.9 to 90.2%) when the end point was reoperation for any reason at 5-year follow-up. Reoperations were performed for infection (n = 10), instability (n = 4), periprosthetic fracture (n = 2), and quadriceps rupture/dehiscence (n = 3). The mean patient satisfaction score was 78.8 ± 11.3 and the mean Forgotten Joint Score was 62.2 ± 16.7 at the final follow-up. The preoperative median University of California at Los Angeles score improved from 2 (interquartile range 2 to 3) to 6 points (interquartile range 5 to 6) (P < .001), and the preoperative Oxford knee score improved from 15.2 ± 3.8 to 39.4 ± 5.1 points (P < .001) at the final follow-up. All metaphyseal cones showed radiographic evidence of osteointegration without any subsidence or loosening. CONCLUSIONS: Porous tantalum metaphyseal cones enabled robust reconstructions of severe femoral and tibial bone defects during revision TKA. These reconstructions were associated with excellent survivorship, improvements in functional outcomes, and reproducible radiographic osseointegration at mean 5-year follow-up. The most common reasons for reoperation were infection and instability.

Outcomes of Metaphyseal Cones and Stem Fixation Following Rotating Hinge in Complex Primary and Revision Total Knee Arthroplasty.

BACKGROUND: Although hinged prostheses have been used successfully in complex revision total knee arthroplasty (TKA), concerns exist regarding early failure due to aseptic loosening and other mechanical complications. The use of metaphyseal cones and hybrid cement fixation have been studied in unlinked constrained primary or revision TKA, but their impact on the survivorship of hinged prostheses has yet to be investigated. METHODS: We identified a consecutive series of 164 hinged prostheses and collected data on demographics, indications, complications, and re-revisions in patients who had fully cemented versus hybrid stems, with and without metaphyseal cones. A multivariate analysis was performed to identify independent variables associated with re-revision as the primary end point. RESULTS: In total, 84 patients (51.2%) had fully cemented stems, and 80 patients (48.8%) had hybrid stems. Cones were used in 73 patients (44.5%). At a mean follow-up of 3.4 ± 2.2 years, 42 patients underwent re-revision (25.8%), most commonly for infection (12.2%), followed by loosening (6.7%) and periprosthetic fracture (3.7%). Patients who had fully cemented stems had lower re-revision rates than hybrid fixation constructs (19 versus 26%, P = .043). Using multivariable regression, a construct with hybrid fixation with cones (odds ratio = 2.39; P = .037) was an independent risk factor for failure. Utilization of cones alone did not have an effect on re-revision rates at 3.4-year follow-up. CONCLUSIONS: While we found no difference with the use of cones, patients undergoing revision TKA with a hinge prosthesis and fully cemented stems had better overall survivorship than hybrid stems.

Are Proud Tibial Cone Constructs an Effective Alternative to Those That are Fully Seated in Revision Total Knee Arthroplasty?

BACKGROUND: This study compared the clinical, radiographic, and patient-reported outcomes between patients treated with the traditional fully seated tibial cone construct and those with the novel proud tibial cone construct in revision total knee arthroplasty (rTKA). METHODS: This was a retrospective study of 56 adult patients who had a minimum 2-year follow-up and underwent rTKA with either the fully seated (n = 18 knees) or proud (n = 42 knees) tibial cone construct between 2010 and 2020. The electronic medical record was reviewed for demographic, clinical, and radiographic data. Knee Injury and Osteoarthritis Outcome Scores (KOOS) were collected. RESULTS: All patients had improved mechanical alignment postoperatively regardless of surgical technique. All patients showed good evidence of osseointegration without loss of fixation at the latest follow-up. There were no significant differences in the complication rate or re-revision rate between the groups. KOOS Function in Sport and Recreation (Sport/Rec) scores were significantly higher for patients treated with the fully seated construct (mean 57 [range, 20 to 95] versus 38 [range, 0 to 75], P = .04); however, no significant differences were present for the other KOOS subscales or KOOS Jr. CONCLUSION: The proud tibial cone construct may be an effective alternative to the fully seated construct in the setting of severe bone loss in rTKA. The proud construct avoids a proximal tibial cut, and thus is a bone-preserving technique that provides good fixation, reduces operative time, prevents potential iatrogenic injuries, decreases the need for tibial augments, saves costs, and improves the ease of restoring joint height.

Metaphyseal cones combined with diaphyseal impaction grafting provide good outcomes and survival in a complex revision total knee arthroplasty: a matched comparative analysis.

PURPOSE: To compare clinical and radiological outcomes, implant survivorship at a minimum of 1-year follow-up using metaphyseal trabecular cones with or without impaction grafting in a complex revision TKA. METHODS: A retrospective comparative matched analysis was performed and 15 patients who underwent revision surgery using the combination of porous trabecular metaphyseal cone and diaphyseal impaction grafting (MC-IBG) were matched with a group of 13 patients who also underwent revision surgery using metaphyseal cone (MC) without impaction grafting. All included patients presented severe bone defect (AORI 2,3) and a rotating-hinge prosthesis were implanted. RESULTS: Both groups were comparable regarding the baseline demographic and clinical data. Patients had previously undergone a mean of 4 (range, 2-12) and 3 (range, 2-5) previous procedures in the MC-IBG and MC groups, respectively. The indications for revision were aseptic loosening in 11 (73.3%) and 11 (84.6%) patients; prosthetic joint infection in 4 (26.7%) and 2 (15.4%) in the MC-IBG and MC groups, respectively. There was no significant difference in the mean postoperative Knee Society Score between the study groups (p = 0.806). Overall, 4 patients had further revision. Two patients were revised in the MC-IBG group, one patient for aseptic loosening and the second one after 2 episodes of instability. Two patients in the MC group presented prosthetic joint infection and underwent a two-stage reimplantation. No significant difference was observed between the study groups at comparison (p = 0.92). CONCLUSION: Trabecular metal cones with diaphyseal impaction grafting provide an alternative technique in a complex revision TKA surgery with early clinical and radiographic success.

Powerful antioxidants within Cupressus arizonica Greene female cones and leaves essential oil.

The composition and antioxidant activity of the essential oil obtained from the female cones and leaves of Cupressus arizonica were assessed using the DPPH assay. The total oil yields obtained through hydrodistillation from the female cones and leaves were 1.9% (v/w) and 0.65% (v/w), respectively. The GC-MS chemical analysis of the oils from the female cones and leaves resulted in the identification of 17 and 45 compounds, respectively. Moreover, the essential oils obtained from C. arizonica female cones were predominantly composed of monoterpene hydrocarbons, with α-pinene being the most abundant component at 72.20%. In contrast, the oil extracted from the leaves was rich in oxygenated monoterpenes, particularly umbellulone (17.33%). The oils extracted from the leaves exhibited remarkable DPPH radical scavenging activity, displaying a value of 95.6%. This value was comparable to that of ascorbic acid (99.6%) and BHT (96.9%) when tested at a concentration of 59 mg/mL.

Excellent mid- to long-term survival of tantalum metal cones in a case series of revision knee arthroplasty with severe bony defects.

PURPOSE: Severe metaphyseal bone defects remain a challenge and represent a growing problem in revision total knee arthroplasty (RTKA). The purpose of this study was to examine the survival of first-generation tantalum metal cones (TMC) and to assess clinical and radiographic data obtained from mid- to long-term follow-ups (FU) after RTKA with severe bony defects. METHODS: This retrospective case series included 100 consecutive patients of the same centre, who underwent RTKA surgery with TMC for tibia and/or femur bone defects between January 2011 and December 2015. Fourteen patients had died and six were lost for FU, leaving a total of eighty patients (one hundred and twelve TMC) for final evaluation. Clinical parameters including the Knee Society Score (KSS), visual analogue scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were determined preoperatively based on the patients' medical charts, and assessed again during the final FU after an average of 6.1 (5-9) years postoperative. Standardised postoperative X-rays were analysed during the final FU visit for osseointegration of the cones, and any signs of implant loosening were assessed with the modified Knee Society Radiographic review criteria. Perioperative and postoperative complications, reoperations, as well as implant and cone re-revisions were analysed. Survivorship analysis was performed with (a) cone-related revision for any reason and (b) implant component revision for any reason. RESULTS: Previous RTKA had to be performed due to 64 (80%) aseptic and 16 (20%) septic failures. At the final FU, 75 (94%) tibia and 76 (95%) femur TMCs and implants were clinically stable. One patient experienced loosening of cones and implants at the femur and tibia but denied re-revision surgery. There were eight (10%) reoperations including two early wound healing problems, two inlay changes, two periprosthetic fractures, one debridement, antibiotics and implant retention (DAIR), and one secondary patella replacement. The six (7.5%) re-revisions included two aseptic loosening's of the opposite implant without TMC, one arthrodesis for recurrent instability, and three deep infections managed by two two-stage exchanges, and one amputation for persistent infection. At re-revision, all TMC cones were osteointegrated without signs of loosening. The determined clinical parameters showed significant (p < 0.001) postoperative improvement, and objective KSS was rated as excellent in 51%, and as good in 22% of patients at the final FU. The estimated 8-year Kaplan-Meier survival was 95% for TMC and 92.5% for implant components. CONCLUSION: Tantalum metal cones (TMC) demonstrate a secure fixation for treatment of severe femoral and tibial metaphyseal bone defects during RTKA. This fixation concept showed excellent mid- to long-term clinical and radiographic outcomes with promising 8-year survival rates for cones and implant components. LEVEL OF EVIDENCE: Retrospective cohort study, Level IV.

Commissioning of Aktina SRS cones and dosimetric validation of the RayStation photon Monte Carlo dose calculation algorithm.

Clinical implementation of SRS cones demands particular experimental care and dosimetric considerations in order to deliver precise and safe radiotherapy to patients. The purpose of this work was to present the commissioning data of recent Aktina cones combined with a 6MV flattened beam produced by an Elekta VersaHD linear accelerator. Additionally, the modelling process, and an assessment of dosimetric accuracy of the RayStation Monte Carlo dose calculation algorithm for cone based SRS was performed. There are currently no studies presenting beam data for this equipment and none that outlines the modelling parameters and validation of dose calculation using RayStation's photon Monte Carlo dose engine with cones. Beam data was measured using an SFD and a microDiamond and benchmarked against EBT3 film for cones of diameter 5-39 mm. Modelling was completed and validated within homogeneous and heterogeneous phantoms. End-to-end image-guided validation was performed using a StereoPHAN™ housing, an SRS MapCHECK and EBT3 film, and calculation time was investigated as a function of statistical uncertainty and field diameter. The TPS calculations agreed with measured data within their estimated uncertainties and clinical treatment plans could be calculated in under a minute. The data presented serves as a reference for others commissioning Aktina stereotactic cones and the modelling parameters serve similarly, while providing a starting point for those commissioning the same TPS algorithm for use with cones. It has been shown in this work that RayStation's Monte Carlo photon dose algorithm performs satisfactorily in the presence of SRS cones.

Actin cytoskeletal dynamics do not impose an energy drain on growth cone bioenergetics.

The regulation of the intracellular level of ATP is a fundamental aspect of bioenergetics. Actin cytoskeletal dynamics have been reported to be an energetic drain in developing neurons and platelets. We addressed the role of actin dynamics in primary embryonic chicken neurons using luciferase assays, and by measurement of the ATP/ADP ratio using the ratiometric reporter PercevalHR and the ATP level using the ratiometric reporter mRuby-iATPSnFR. None of the methods revealed an effect of suppressing actin dynamics on the decline in the neuronal ATP level or the ATP/ADP ratio following shutdown of ATP production. Similarly, we find that treatments that elevate or suppress actin dynamics do not alter the ATP/ADP ratio in growth cones, the subcellular domain with the highest actin dynamics in developing neurons. Collectively, the data indicate that actin cytoskeletal dynamics are not a significant energy drain in developing neurons and that the ATP/ADP ratio is maintained when energy utilization varies. Discrepancies between prior work and the current data are discussed with emphasis on methodology and interpretation of the data.

Multi-Residue Method for Pesticides Determination in Dried Hops by Liquid Chromatography Tandem Mass Spectrometry.

In this study a multi-residue determination method for 36 pesticides in dried hops was reported. The sample preparation procedure was based on the acetate buffered QuEChERS method. A few mixtures of dispersive solid phase extraction (dSPE) sorbents consisting PSA, C18, GCB, Z-Sep and Z-Sep+ were investigated to clean-up the supernatant and minimize matrix co-extractives. The degree of clean-up was assessed by gravimetric measurements, which showed the best results for mixtures containing the Z-Sep+ sorbent. This is the first study to apply Z-Sep+ sorbent for hops material and the first to improve the method for pesticide residues determination in hops. Samples were analysed using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and the procedure was validated according to the SANTE/11813/2017 document at four concentration levels: 0.02, 0.05, 0.1 and 1 mg/kg. The limits of quantification (LOQ) were in the range of 0.02-0.1 mg/kg. For all active substances, the trueness (recovery) ranged from 70 to 120% and the precision (RSDr) value was <20%. Specificity, linearity and matrix effect were also evaluated. The validated method was applied to the analysis of 15 real dried hop samples and the relevant data on detected residues were included.

Efficacy of fitting HydroCone (Toris K) contact lenses for the visual rehabilitation of patients with posterior microphthalmos / Eficácia da adaptação de lentes de contato HydroCone (Toris K) para reabilitação visual de pacientes com microftalmia posterior

ABSTRACT Purpose: To evaluate the efficacy of soft HydroCone silicone hydrogel contact lenses in patients with posterior microphthalmos. Methods: The charts of 13 patients with posterior microphthalmos (26 eyes) who were fitted with soft HydroCone silicone hydrogel contact lenses were reviewed retrospectively. All the patients underwent assessments of uncorrected and best spectacle-corrected visual acuity and cycloplegic refraction. They were fitted with contact lenses according to the parameter values obtained from the topographical analysis and best contact lens-corrected visual acuity measurement. Results: The spherical equivalents of the right and left eyes ranged from 10.00 to 19.25 diopters and from 11.00 to 21.5 diopters, respectively. The mean axial and posterior chamber lengths were shorter than those of the age-matched population. However, the mean values of the anterior segment parameters such as horizontal visible iris diameter, central anterior chamber depth, lens thickness, and central corneal thickness were in the normal range. The mean keratometric measurements revealed increased corneal curvature compared with that in the normal population. The mean best contact lens-corrected visual acuity was significantly higher than the mean best spectacle-corrected visual acuity for both eyes (p=0.045). Conclusion: HydroCone silicon soft contact lenses provided better visual acuity than spectacles in the patients with posterior microphthalmos in this study.

RESUMO Objetivo: Avaliar a eficácia das lentes de contato gelatinosas HydroCone, de hidrogel com silicone, em pacientes com microftalmia posterior. Métodos: Foram revisados retrospectivamente 26 olhos com microftalmia posterior, a partir dos prontuários de 13 pacientes que receberam lentes de contato gelatinosas HydroCone, de hidrogel com silicone. Todos os pacientes foram submetidos ao exame de acuidade visual não corrigida e com melhor correção por óculos e com refração cicloplégica. Todos os pacientes receberam lentes de contato de acordo com os parâmetros obtidos na análise topográfica e foi obtida a melhor acuidade visual corrigida com lentes de contato. Resultados: O equivalente esférico do olho direito variou de 10,00 a 19,25 dioptrias, e o do olho esquerdo de 11,00 a 21,5 dioptrias. Os comprimentos médios axiais e das câmaras posteriores foram menores do que para a população de mesma idade. No entanto, os valores médios dos parâmetros do segmento anterior, como o diâmetro horizontal visível da íris, a profundidade da câmara anterior central, a espessura da lente e a espessura central da córnea estavam dentro da faixa normal. Os valores médios da ceratometria revelaram curvatura corneana aumentada em relação à população normal. A média da melhor acuidade visual corrigida com lentes de contato foi significativamente maior que a média da melhor acuidade visual corrigida com óculos em ambos os olhos (p=0,045). Conclusão: As lentes de contato gelatinosas de silicone HydroCone proporcionam melhor acuidade visual que óculos em pacientes com microftalmia posterior.

Is hybrid fixation in revision TKA using LCCK prostheses reliable?

INTRODUCTION: The optimal technique for component fixation in revision total knee arthroplasty (rTKA) remains controversial: full cementation (FC) versus hybrid fixation (HF), which involves press-fit stem with cement fixation in the metaphyseal and epiphyseal zones. Previous series have either demonstrated the superiority of one or the other of these techniques or their equivalence. However, few studies have compared these 2 methods for rTKA using the Legacy® Constrained Condylar Knee (LCCK) prosthesis (Zimmer, Warsaw, Indiana, USA). HYPOTHESIS: Our hypothesis was that HF of LCCK components is associated with a higher rate of aseptic loosening (AL) than FC. MATERIALS AND METHODS: This was a single-center, multi-surgeon, retrospective study. Primary revisions between January 2010 and December 2014 were included for all indications. The only exclusion criterion was death without revision before the 5-year follow-up. The primary objective of this study was to compare the survivorship of 2 groups of LCCK components (femoral or tibial), depending on whether their stems had been cemented (HF versus FC), taking AL, revised or not, as the endpoint. The secondary objective was to look for other predictive factors of AL. RESULTS: A total of 75 rTKAs (150 components) were included. The FC group (51 components) had more Anderson Orthopedic Research Institute (AORI) type 2B and type 3 bone defects (BDs) (p<0.001), more reconstructions using trabecular metal (TM) cones (19 FCs and 5 HFs; p<0.001), and bone allografts (p<0.001). At more than 5 years, none of the FC components were loose compared to 10 HF components (9.4%), with 4 of these stems revised. The only significant difference was survivorship without radiographic AL at 9 years (FC=100%; HF=78.6%; p=0.04). The only predictive factor of AL in the HF group was the filling of the diaphyseal canal (p<0.01). The detrimental effect of BD severity (p=0.78) and the protective effect of TM cones were not demonstrated (p=0.21). DISCUSSION: Other series studying revisions using the same type of prosthesis also concluded the superiority of FC, not found for other revision prostheses. Despite this study's limitations (retrospective, multi-surgeon, limited sample size, and limited follow-up), all patient outcomes were known, and the difference in survivorship between the groups was very significant. CONCLUSION: HF has not been proven effective for the LCCK prosthesis. Better diaphyseal filling, wider metaphyseal bone tunnels enabling better cement injections, and stem designs more appropriate for press-fit fixation could improve these results. TM cones are an interesting avenue for further research. LEVEL OF EVIDENCE: III; retrospective comparative study.

C-subfamily ATP binding cassette transporters extrude the calcium fluorescent probe fluo-4 from a cone photoreceptor cell line.

Whole transcriptome sequencing has revealed the existence of mRNAs for multiple membrane transporters in photoreceptors. Except for ATP binding cassette (ABC) member A4, involved in the retinoid cycle, an understanding of the function of most transport proteins in photoreceptors is lacking. In this research paper, extrusion of fluo-4, a Ca2+ fluorescent probe, from 661W cells, a cone photoreceptor murine cell line was studied with online fluorometry and immunocytochemistry. Fluo-4 efflux was temperature dependent, required ATP but not extracellular Na+, was not affected by pH in the range 5.4-8.4, and followed saturating kinetics with a Km of nearly 4 µM, suggesting it was effected by ABC type transporters. A panel of antagonists showed an inhibitory profile typical of the C subfamily of ABC transporters. Immunofluorescence staining was positive for ABCC3, ABCC4 and ABCC5. These experimental results are compatible with fluo-4 being extruded from 661W cones by one or a combination of C-type ABC transporters. Examination of physicochemical descriptors related to drug membrane permeability and ABC substrate binding region further suggested efflux of fluo-4 by C-type ABC transporters. Possible functions of this transport mechanism in photoreceptors are discussed.

Effect of using Austrian pine cones powder as an additive on oil well cement properties.

There have been many investigations to improve both the physical and mechanical properties of oil well cement using a wide range of materials. Most of these additives are expensive and practically ineffective. In this article, a comprehensive evaluation was conducted for using Austrian pinecones powder (APCP) as an inexpensive supplementary cementing material (SCM) for well cement. Firstly, Portland cement class G was characterized based on X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD). In this paper, the properties of the cement systems include rheological parameters, density, slurry stability (free water test, and sedimentation test), water absorption, porosity, permeability, the volume of fluid loss, pH value, thermogravimetric analysis, and the mechanical characteristics (in terms of compressive strength, tensile strength, flexural strength, and shear strength bond) were investigated in details. The cement sample containing the APCP was also examined using scanning electron microscopy (SEM). According to the experimental results, adding APCP led to increasing in rheological parameters. Also, led to decreasing in fluid loss, free water, sedimentation effect, and density which positively affects the preservation of the original properties of cement slurry. The results also showed a decrease in the permeability of cement samples and an increase in the porosity and the ability to absorb water. The addition of APCP did not significantly affect the pH values. The addition of APCP also deteriorated the mechanical properties of the cement samples. The addition of the APCP has contributed to an increase in total weight loss at high temperatures. So, the APCP can be considered as a new filler for well cement due to its ability to fill the pores in the cement matrix and at the same time improve some properties of the well cement such as density, free water, sedimentation, and fluid loss.

Chemical composition of essential oil from female cones of Cupressus arizonica Greene.

The hydrodistilled volatile essential oils extracted from the female cones of Cupressus arizonica Greene that harvested in winter and spring seasons were analysed for their chemical composition by using gas chromatography-mass spectrometry (GC/MS). Twenty-four and seventeen components were identified, accounting for winter (95.5%) and spring (96.9%) of the total oils volume, respectively. Monoterpenoids (winter 93.7% and spring 95.0%) dominated the identified components in the essential oils, followed by a small portion of sesquiterpenoids (winter 1.8% and spring 1.9%). Monoterpene hydrocarbons (MH) (winter 90.9% and spring 94.9%) were the principal subclasses of components with α-pinene (winter 42% and spring 72%), ß-myrcene (winter 18.5% and spring 7.7%), δ-3-carene (winter 11.3% and spring 5.1%), limonene (9.4% for winter), and ß-pinene (5.3% for spring) as main constituents. Limonene (9.4%), camphor (0.2%), exo-methylcamphenilol (0.2%), terpinene-4-ol (0.6%), ß-citronellol (0.9%), and bornyl acetate (0.3%) were representative of the monoterpene hydrocarbon and oxygen-containing monoterpenoids (OM) in winter essential oil.

Tantalum Cones for Severe Bone Defects in Revision Knee Arthroplasty: A Minimum 10-Year Follow-Up.

BACKGROUND: Two-to 6-year results of reconstruction of severe bone defects in revision total knee arthroplasty (TKA) with highly porous tantalum cones have been encouraging, but 10-year follow-up is lacking. The purpose of this study was to determine the minimum 10-year results of tantalum cones in revision TKA. METHODS: From 2005 to 2010, 30 consecutive patients (30 knees) underwent revision TKA with the use of cones. All patients were followed clinically and radiographically for a minimum of 10 years. A total of 42 cones (25 tibial and 17 femoral) were used to reconstruct massive bone defects classified as Anderson Orthopaedic Research Institute Types 2A (10), 2B (12), and 3 (19). The mean age of the patients was 73 years (range, 55 to 84) at the time of revision. The indication for the revision included aseptic loosening (15 patients) and second-stage reimplantation for deep infection (15 patients). Six patients were lost to follow-up. RESULTS: In total, 6 cones had to be revised. Minimum 10-year cone survivorship for any reason was 81% (25 of 31 cones). With cone revision for aseptic loosening as the end point, survivorship was 96% (30 of 31). No evidence of loosening or migration of any implant was noted on the most recent radiographs. CONCLUSION: Metaphyseal fixation with tantalum cones in revision TKA demonstrated excellent survivorship and fixation at a minimum follow-up of 10 years. This type of metaphyseal reconstruction can be a durable option for revision TKA in patients who have massive bone defects.

Metaphyseal cones and sleeves are similar in improving short- and mid-term outcomes in Total Knee Arthroplasty revisions.

PURPOSE: The purpose of this systematic review and metanalysis was to assess clinical and radiological outcomes of metaphyseal sleeves and cones and to identify their possible advantages and disadvantages. METHODS: A comprehensive search from the inception of the databases to March 2021 was performed on Medline, Scopus, CINAHL, Cochrane, Embase, Ovid, and Google scholar databases. Coleman Methodology Score was used for quality assessment. Author, year of publication, type of study, level of evidence, sample size, number of patients, number of knees treated, mean age, gender, mean follow-up, clinical outcomes, complications, the reason for revision and, type of prosthesis were extracted for analysis. Clinical studies providing data about patient's outcomes after the primary and Total Knee Arthroplasty revision with the usage of sleeves or cones and a minimum of 2 years of follow-up were included. RESULTS: The literature search and cross-referencing resulted in a total of 93 articles, but only 30 articles were appropriate for the systematic review. Comparable clinical results were reported between cones and sleeves. The meta-analysis showed a greater incidence of intraoperative fractures in patients treated with sleeves (1.6%, [95% CI 0.7; 3.4] in cones and 4.6%, [95% CI 3.3; 6.4] in sleeves, p = 0.01), while the risk of postoperative fractures (4.3%, [95% CI 2.7; 7] in cones and 2.1%, [95% CI 1.2; 3.5] in sleeves, p = 0.04) and infections (8.5%, [95% CI 6; 12] in cones and 3.7%, [95% CI 2.1; 7.3] in sleeves, p = 0.03) was higher with cones. CONCLUSION: A higher incidence of intraoperative fracture was reported in patients treated with sleeves, while a higher rate of postoperative fractures and infections was described in patients treated with cones. Nonetheless, complications were reported in both groups. LEVEL OF EVIDENCE: III.