The Direct Superior Approach in Total Hip Arthroplasty: A Systematic Review.

BACKGROUND: Evolution of the surgical approach for total hip arthroplasty (THA) has led to the development of the minimally invasive direct superior approach (DSA). It is hypothesized that the DSA reduces postoperative pain and hospital length of stay (LOS). We aimed to provide an overview of current evidence on clinical, functional, and radiological outcomes with respect to risk of revision, complications, pain scores, physical function, operative time, LOS, blood loss, radiological outcomes, and learning curve. METHODS: A comprehensive search of Medline, Embase, Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar, reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses literature search extension guidelines, was conducted to identify studies evaluating clinical, functional, and radiological outcomes of the DSA. Quality assessment was performed using the Cochrane Risk of Bias tool and Newcastle-Ottawa Scale. The review protocol was prospectively registered in the International Prospective Registry of Systematic Reviews. RESULTS: Seventeen studies were included, generally of moderate quality. Qualitative synthesis evidenced accurate implant positioning, short LOS, and a short learning curve. Conflicting findings were reported for postoperative complications compared with conventional approaches. Better functional outcomes were seen in the early postoperative period than the posterolateral approach (PLA). Outcomes such as blood loss and operative time exhibited conflicting results and considerable heterogeneity. CONCLUSION: Based on moderate-certainty evidence, it is uncertain if the DSA provides short-term advantages over conventional approaches such as PLA. There is limited evidence on long-term outcomes post-THA using the DSA. Further studies and ongoing registry monitoring is crucial for continuous evaluation of its long-term outcomes. LEVEL OF EVIDENCE: Level III. See Instructions for Authors for a complete description of levels of evidence.

Femoral Neck Design Does Not Impact Revision Risk After Primary Total Hip Arthroplasty Using a Dual Mobility Cup.

Background: The use of dual mobility (DM) cups has increased quickly. It is hypothesized that femoral neck taper geometry may be involved in the risk of prosthetic impingement and DM cup revision. We aim to (1) explore the reasons for revision of DM cups or head/liners and (2) explore whether certain femoral neck characteristics are associated with a higher risk of revision of DM cups. Methods: Primary total hip arthroplasties with a DM cup registered in the Dutch Arthroplasty Register between 2007 and 2021 were identified (n = 7603). Competing risk survival analyses were performed, with acetabular component and head/liner revision as the primary endpoint. Reasons for revision were categorized in cup-/liner-related revisions (dislocation, liner wear, acetabular loosening). Femoral neck characteristics were studied to assess whether there is an association between femoral neck design and the risk of DM cup/liner revision. Multivariable Cox proportional hazard analyses were performed. Results: The 5- and 10-year crude cumulative incidence of DM cup or head/liner revision for dislocation, wear, and acetabular loosening was 0.5% (CI 0.4-0.8) and 1.9% (CI 1.3-2.8), respectively. After adjusting for confounders, we found no association between the examined femoral neck characteristics (alloy used, neck geometry, CCD angle, and surface roughness) and the risk for revision for dislocation, wear, and acetabular loosening. Conclusions: The risk of DM cup or head/liner revision for dislocation, wear, and acetabular loosening was low. We found no evidence that there is an association between femoral neck design and the risk of cup or head/liner revision.

No clinically relevant difference in patient-reported outcomes between the direct superior approach and the posterolateral or anterior approach for primary total hip arthroplasty: analysis of 37,976 primary hip arthroplasties in the Dutch Arthroplasty Registry.

BACKGROUND AND PURPOSE: The direct superior approach (DSA) is a modification of the posterolateral approach (PLA) for total hip arthroplasty (THA). Patient-reported outcome measures (PROMs) of the DSA have not been investigated previously using nationwide data. Our aim was to assess PROMs after THA using the DSA compared with the PLA and, secondarily, with the anterior approach (DAA). PATIENTS AND METHODS: In this population-based cohort study we included 37,976 primary THAs performed between 2014 and 2020 (PLA: n = 22,616; DAA: n = 15,017; DSA: n = 343) using Dutch Arthroplasty Registry data. PROMs (NRS pain, EQ-5D, HOOS-PS, and OHS) were measured preoperatively, and at 3 and 12 months postoperatively. Repeated measurements were analyzed using mixed-effects models, adjusted for confounders, to investigate the association between surgical approach and PROMs over time. RESULTS: From baseline to 3 and 12 months, improvements for NRS pain scores, EQ-5D, and OHS were comparable for the DSA compared with the PLA or DAA. No difference was found in HOOS-PS improvement 3 months postoperatively between DSA and PLA (-0.2, 95% confidence interval [CI] -2.4 to 1.9) and between DSA and DAA (-1.7, CI -3.9 to 0.5). At 12 months postoperatively, patients in the DSA group had improved -2.8 points (CI -4.9 to -0.6) more in HOOS-PS compared with the DAA, but not with the PLA group (-1.0, CI -3.2 to 1.1). CONCLUSION: Our study showed no clinically meaningful differences between the DSA and either PLA or DAA.

Similar revision rate after cemented and cementless femoral revisions for periprosthetic femoral fractures in total hip arthroplasty: analysis of 1,879 revision hip arthroplasties in the Dutch Arthroplasty Register.

BACKGROUND AND PURPOSE: Periprosthetic femoral fracture (PPF) after total hip arthroplasty (THA) is a serious complication, as it often is followed by functional deficits and morbidity. There is no consensus regarding the optimal stem fixation method and whether additional cup replacement is beneficial. The aim of our study was to perform a direct comparison of reasons and risk of re-revision between cemented and uncemented revision THAs following PPF using registry data. PATIENTS AND METHODS: 1,879 patients registered in the Dutch Arthroplasty Registry (LROI) who underwent a first-time revision for PPF between 2007 and 2021 (cemented stem: n = 555; uncemented stem: n = 1,324) were included. Competing risk survival analysis and multivariable Cox proportional hazard analyses were performed. RESULTS: 5- and 10-year crude cumulative incidence of re-revision following revision for PPF was similar between cemented (resp. 13%, 95% CI 10-16 and 18%, CI 13-24) and uncemented (resp. 11%, CI 10-13 and 13%, CI 11-16) revisions. Multivariable Cox regression analysis, adjusting for potential confounders, showed a similar risk of revision for uncemented and cemented revision stems. Finally, we found no difference in risk of re-revision between a total revision (HR 1.2, 0.6-2.1) compared with a stem revision. CONCLUSION: We found no difference in the risk of re-revision between cemented and uncemented revision stems after revision for PPF.

Revision risk by using the direct superior approach (DSA) for total hip arthroplasty compared with postero-lateral approach: early nationwide results from the Dutch Arthroplasty Register (LROI).

BACKGROUND AND PURPOSE: The direct superior approach (DSA) is a modification of the classic posterolateral approach (PLA) for total hip arthroplasty (THA), in which the iliotibial band and short external rotators are spared. The revision rate of the DSA has not been investigated previously using arthroplasty registry data. We examined the reasons and risk of revision of the DSA, compared with the direct anterior approach (DAA) and PLA. PATIENTS AND METHODS: In this population-based cohort study we included 175,543 primary THAs performed between 2014 and 2020 (PLA, n = 117,576; DAA, n = 56,626; DSA, n = 1,341). Competing risk survival analysis and multivariable Cox proportional hazard analyses, adjusted for potential confounders, were performed. RESULTS: After 3 years, crude revision rates due to any reason were 2.1% (95% confidence interval [CI] 1.3-3.3) for DSA, and 2.9% (CI 2.8-3.0) for PLA. Crude dislocation revision rates were 0.3% (CI 0.1-0.8) for DSA, versus 1.0% (CI 0.9-1.0) for PLA. Dislocation revision rate for DSA did not differ from DAA (0.3% [CI 0.2-0.3]). Multivariable Cox regression analysis demonstrated no overall difference in revision rates for the DSA (HR 0.6 [CI 0.4-1.09) compared with the PLA. Lower risk of revision due to dislocation was found in patients operated on through the DSA (HR 0.3 [0.1-0.9]) compared with the PLA. CONCLUSION: Early nationwide results suggest that the DSA for total hip arthroplasty seems to show a tendency towards a lower risk of revision for dislocation but no overall reduced revision risk compared with the PLA.

DenseUNets with feedback non-local attention for the segmentation of specular microscopy images of the corneal endothelium with guttae.

Corneal guttae, which are the abnormal growth of extracellular matrix in the corneal endothelium, are observed in specular images as black droplets that occlude the endothelial cells. To estimate the corneal parameters (endothelial cell density [ECD], coefficient of variation [CV], and hexagonality [HEX]), we propose a new deep learning method that includes a novel attention mechanism (named fNLA), which helps to infer the cell edges in the occluded areas. The approach first derives the cell edges, then infers the well-detected cells, and finally employs a postprocessing method to fix mistakes. This results in a binary segmentation from which the corneal parameters are estimated. We analyzed 1203 images (500 contained guttae) obtained with a Topcon SP-1P microscope. To generate the ground truth, we performed manual segmentation in all images. Several networks were evaluated (UNet, ResUNeXt, DenseUNets, UNet++, etc.) and we found that DenseUNets with fNLA provided the lowest error: a mean absolute error of 23.16 [cells/mm[Formula: see text]] in ECD, 1.28 [%] in CV, and 3.13 [%] in HEX. Compared with Topcon's built-in software, our error was 3-6 times smaller. Overall, our approach handled notably well the cells affected by guttae, detecting cell edges partially occluded by small guttae and discarding large areas covered by extensive guttae.

A multi-ethnic genome-wide association study implicates collagen matrix integrity and cell differentiation pathways in keratoconus.

Keratoconus is characterised by reduced rigidity of the cornea with distortion and focal thinning that causes blurred vision, however, the pathogenetic mechanisms are unknown. It can lead to severe visual morbidity in children and young adults and is a common indication for corneal transplantation worldwide. Here we report the first large scale genome-wide association study of keratoconus including 4,669 cases and 116,547 controls. We have identified significant association with 36 genomic loci that, for the first time, implicate both dysregulation of corneal collagen matrix integrity and cell differentiation pathways as primary disease-causing mechanisms. The results also suggest pleiotropy, with some disease mechanisms shared with other corneal diseases, such as Fuchs endothelial corneal dystrophy. The common variants associated with keratoconus explain 12.5% of the genetic variance, which shows potential for the future development of a diagnostic test to detect susceptibility to disease.

Eyelid Disorders in Ophthalmology Practice: Results from a Large International Epidemiological Study in Eleven Countries.

PURPOSE: Anecdotal evidence suggests that eyelid disorders are common, although estimates of prevalence vary. The current study determines the prevalence of eyelid disorders, meibomian gland dysfunction (MGD) and related diseases (specifically ocular surface disease) in a population of patients presenting for routine ophthalmologic consultations. METHODS: This cross-sectional epidemiologic survey evaluated patients presenting for routine ophthalmic visits. During the consultation an ophthalmologist completed a questionnaire, and each patient underwent an ophthalmic examination and completed a quality of life questionnaire. RESULTS: Three hundred forty-nine ophthalmologists, recruited from 11 countries, provided data on 6525 patients. Patients were predominantly females (61.6%). The mean age of the study population was 57.0 ± 17.6 years. Eyelid disorders were diagnosed in 5109 (78.3%) patients and were statistically associated with: atopic dermatitis, seborrheic dermatitis, dry eye, age-related macular degeneration, diabetes, cataract, allergy and MGD (P < 0.05, all associations). Eyelid abnormalities were identified in 59.6% of patients; conjunctival or corneal abnormalities were observed in 64.9% and 28.1% of patients, respectively. MGD was diagnosed in 54.3% patients and was statistically significantly associated with the presence of eyelid disorders and eyelid margin abnormalities (P < 0.001, both comparisons). Dry eye was diagnosed in 61.8% of patients. Concurrent dry eye and MGD were present in 67.6% of patients. Most patients reported some degree of impaired vision and daily/work activities related to dry eye. Impact on contact lens usage, emotions and quality of sleep was also reported. The effects on daily life were associated with the presence of MGD. CONCLUSION: In conclusion, eyelid disorders were highly prevalent in this 'real-world' population of patients from ophthalmology clinics. Routine ophthalmologic consultations provide an opportunity to improve patient quality of life and to modify topical therapy in patients who may be predisposed to eyelid disorders.

Improved Interchangeability with Different Corneal Specular Microscopes for Quantitative Endothelial Cell Analysis.

INTRODUCTION: During our clinical practice and research, we encountered an interchangeability problem when using the SP-2000P and SP-3000P TopCon corneal specular microscopes (CSMs) (TopCon Medical Systems, Tokyo, Japan) regarding the endothelial cell count (ECC). We describe a method to improve interchangeability between these CSMs. METHODS: Five consecutive good-quality endothelial cell photographs were obtained in 22 eyes of 11 subjects. An ECC comparison between the two CSMs was performed after (I) gauging and calibration by the manufacturer, (II) adjustment of the magnification, (III) correction after external horizontal and vertical calibration. RESULTS: There was a statistically significant difference between the ECC of the SP-2000P and SP-3000P at the start. The SP-2000P counted an average of 500 cells/mm2 more than the SP-3000P (p=0.00). After correction for magnification and determining a correction factor based on external calibration, the difference between the ECC of the SP-2000P and the SP-3000P was then found to be 0.4 cells/mm2 and was not statistically significant (p=0.98). DISCUSSION: We propose a method for improving interchangeability, which involves checking magnification settings, re-checking magnification calibration with external calibration devices, and then calculating correction factors. This method can be applied to various specular or confocal microscopes and their associated endothelial cell analysis software packages to be able to keep performing precise endothelial cell counts and to enable comparison of ECCs when a CSM needs to be replaced or when results from different microscopes need to be compared.

The rising incidence of Acanthamoeba keratitis: A 7-year nationwide survey and clinical assessment of risk factors and functional outcomes.

PURPOSE: To evaluate the incidence of Acanthamoeba keratitis in the Netherlands between 2009 and 2015 and to analyse predicting factors for treatment outcome. METHODS: Patient characteristics, diagnostic methods, diagnostic delay, therapy prior to and after diagnosis, and visual outcome were obtained from medical files of all patients diagnosed with Acanthamoeba keratitis in the Netherlands between 2009 and 2015. A logistic regression analysis on treatment failure, defined as a best corrected visual acuity of less than 20/40 Snellen decimals (i.e. >0.3 logMAR or an approximate loss of three lines of visual acuity) and/or the need for keratoplasty, was performed to determine predicting factors. RESULTS: Two hundred and twenty-four eyes of 224 patients were included. Ninety-five percent of the patients were contact lens wearers, of whom 74% wore soft contact lenses. The number of cases increased from 16 in 2009 to 49 in 2015. This resulted in an estimated incidence of 1 in 21,000 for soft contact lens wearers in 2015. Eighty-seven eyes (39%) met the criteria for treatment failure. In a multivariable regression analysis, higher age at presentation, a higher severity stage and corticosteroid use before diagnosis were positively correlated with treatment failure. Early referral to a cornea specialist was associated with better clinical outcomes. CONCLUSIONS: Although Acanthamoeba keratitis is still a relatively uncommon disease, the incidence in soft contact lens wearers has increased to reach 1 in 21,000 in 2015. Treatment failure occurred in 39% of cases, with age, higher severity stage, corticosteroid use before diagnosis and indirect referral to a cornea specialist as important risks factors.

Toric intraocular lenses for correction of astigmatism in keratoconus and after corneal surgery.

PURPOSE: To describe the results of cataract extraction with toric intraocular lens (IOL) implantation in patients with preexisting astigmatism from three corneal conditions (keratoconus, postkeratoplasty, and postpterygium surgery). METHODS: Cataract patients with topographically stable, fairly regular (although sometimes very high) corneal astigmatism underwent phacoemulsification with implantation of a toric IOL (Zeiss AT TORBI 709, Alcon Acrysof IQ toric SN6AT, AMO Tecnis ZCT). Postoperative astigmatism and refractive outcomes, as well as visual acuities, vector reduction, and complications were recorded for all eyes. RESULTS: This study evaluated 17 eyes of 16 patients with a mean age of 60 years at the time of surgery. Mean follow-up in this study was 12 months. The corrected distance Snellen visual acuity (with spectacles or contact lenses) 12 months postoperatively was 20/32 or better in 82% of eyes. The mean corneal astigmatism was 6.7 diopters (D) preoperatively, and 1.5 D of refractive cylinder at 1-year follow-up. No vision-compromising intra- or postoperative complications occurred and decentration or off-axis alignment of toric IOLs were not observed. CONCLUSION: Phacoemulsification with toric IOL implantation was a safe and effective procedure in the three mentioned corneal conditions. Patient selection, counseling, and IOL placement with optimal astigmatism correction are crucial.

Endothelial cell density after posterior lamellar keratoplasty: five- to seven-year follow-up.

PURPOSE: To report endothelial cell density (ECD) after posterior lamellar keratoplasty (PLK). DESIGN: Prospective, interventional case series. METHODS: In a single institution, PLK was performed in 15 eyes of 15 patients with pseudophakic bullous keratopathy (PPBK), Fuchs endothelial dystrophy (FED), or both. In 11 eyes, the donor tissue was inserted unfolded through a 9.0-mm sclerocorneal incision. In four eyes, the donor was folded and inserted through a 5.0-mm incision. The ECD measurements were performed in each patient at regular intervals until three years after surgery, and then in all patients simultaneously at 54 to 84 months after surgery. RESULTS: Three patients were not available for follow-up. One graft had decompensated. In the remaining 11 eyes, ECDs ranged from 368 to 1576 cells/mm(2). Monophasic and biphasic regression models of ECD against time were fitted for each technique separately. CONCLUSIONS: After PLK, ECD declined at a high rate. Both early- and longer-term loss rates may be related to surgical technique.

Validity of endothelial cell analysis methods and recommendations for calibration in Topcon SP-2000P specular microscopy.

PURPOSE: To report on the calibration of the Topcon SP-2000P specular microscope and the Endothelial Cell Analysis Module of the IMAGEnet 2000 software, and to establish the validity of the different endothelial cell density (ECD) assessment methods available in these instruments. METHODS: Using an external microgrid, we calibrated the magnification of the SP-2000P and the IMAGEnet software. In both eyes of 36 volunteers, we validated 4 ECD assessment methods by comparing these methods to the gold standard manual ECD, manual counting of cells on a video print. These methods were: the estimated ECD, estimation of ECD with a reference grid on the camera screen; the SP-2000P ECD, pointing out whole contiguous cells on the camera screen; the uncorrected IMAGEnet ECD, using automatically drawn cell borders, and the corrected IMAGEnet ECD, with manual correction of incorrectly drawn cell borders in the automated analysis. Validity of each method was evaluated by calculating both the mean difference with the manual ECD and the limits of agreement as described by Bland and Altman. RESULTS: Preset factory values of magnification were incorrect, resulting in errors in ECD of up to 9%. All assessments except 1 of the estimated ECDs differed significantly from manual ECDs, with most differences being similar (< or =6.5%), except for uncorrected IMAGEnet ECD (30.2%). Corrected IMAGEnet ECD showed the narrowest limits of agreement (-4.9 to +19.3%). CONCLUSIONS: We advise checking the calibration of magnification in any specular microscope or endothelial analysis software as it may be erroneous. Corrected IMAGEnet ECD is the most valid of the investigated methods in the Topcon SP-2000P/IMAGEnet 2000 combination.

Endothelial cell density after posterior lamellar keratoplasty (Melles techniques): 3 years follow-up.

PURPOSE: To report the midterm endothelial cell density measurements after posterior lamellar keratoplasty (Melles techniques). DESIGN: Cohort study. METHODS: Fifteen consecutive eyes of 15 patients in whom a posterior lamellar keratoplasty procedure was performed for pseudophakic bullous keratopathy or Fuchs' endothelial dystrophy were evaluated. In 11 corneas the donor tissue was inserted through a 9.0-mm sclerocorneal pocket incision (technique A); in four cases the donor was folded and inserted through a 5.0-mm incision (technique B). Specular microscopy was performed at 6, 12, 24, and 36 months after surgery, to measure the endothelial cell density. RESULTS: Mean postoperative endothelial cell density averaged 2,126 cells/mm(2) (+/-548) at 6 months, 1,859 cells/mm(2) (+/-477) at 12 months, 1,385 cells/mm(2) (+/-451) at 24 months, and 1,047 cells/mm(2) (+/-425) at 36 months. CONCLUSION: In posterior lamellar keratoplasty, the donor corneal endothelium showed a decrease in cell density similar to that after conventional full-thickness penetrating keratoplasty.

Biocompatibility of trypan blue with human corneal cells.

OBJECTIVE: To quantify the toxicity of trypan blue on human corneal cells according to exposure time and concentration. METHODS: Three in vitro experiments were performed. (1) We exposed cultured human corneal fibroblasts to trypan blue (0.0001% to 0.1%) in Eagle modified minimum essential medium (EMEM) or phosphate-buffered saline (PBS) for 15 minutes to 24 hours. Cytotoxicity was evaluated by Mosmann's colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MMT) assay. (2) We exposed human corneas in EMEM for 24 hours to trypan blue (0.001% to 0.1%). Fellow donor corneas served as controls. Endothelial survival was evaluated morphologically and by cell density assessment. (3) We morphologically compared the endothelial viability of human donor corneas after exposure to 0.1% trypan blue for 5 to 30 minutes with control corneas. RESULTS: In experiment 1, trypan blue in EMEM was not significantly toxic at concentrations of 0.005% or lower. Higher concentrations were toxic only after exposure to trypan blue for at least 6 hours. In PBS, significant toxicity was found after exposure to 0.1% trypan blue for 30 minutes or longer. Lower concentrations were toxic after longer exposures. In experiment 2, exposure to 0.01% and 0.1% trypan blue for 24 hours resulted in significant loss in cell density. At lower concentrations, the endothelium was affected only morphologically. In experiment 3, endothelial morphology changed in control corneas and after exposure to 0.1% trypan blue for as little as 5 minutes. After 30-minute exposure, morphologic deterioration was more pronounced. CONCLUSIONS: Trypan blue was toxic in vitro to corneal endothelium and corneal fibroblasts at higher concentrations and notably longer exposure times. Toxicity was less in EMEM than in PBS. Clinical Relevance At commonly used concentrations, both during cataract surgery and in the cornea bank, trypan blue is safe for corneal cells. At higher concentrations or longer exposures, however, caution is warranted.

Endothelial cell density after deep anterior lamellar keratoplasty (Melles technique).

PURPOSE: To measure the recipient endothelial cell loss after the Melles technique for deep anterior lamellar keratoplasty. METHODS: In 21 eyes of 21 patients, a deep anterior lamellar keratoplasty procedure was performed. Before surgery and at 6, 12, and 24 months after surgery, specular microscopy was performed to evaluate the endothelial cell density. For each postoperative time interval, the mean endothelial cell loss relative to the preoperative value was calculated. RESULTS: Mean postoperative endothelial cell loss averaged 283 cells/mm(2) (+/- 293) at 6 months, 335 cells/mm(2) (+/- 309) at 12 months, and 421 cells/mm(2) (+/- 316) at 24 months. Estimate relative endothelial cell density losses obtained by mixed model analysis of variance were 11.1%, 2.0%, and 1.2%, respectively, each time compared with its previous measurement point. Second order comparisons showed that the loss within the first 6 months was significantly higher than after 6 months. CONCLUSION: In deep anterior lamellar keratoplasty, the recipient corneal endothelium showed a small initial drop in endothelial cell density followed by a physiologic rate of cell loss. Cell survival after lamellar keratoplasty may be expected to be better when compared with that following penetrating keratoplasty.