The corneal endothelium reflected: Studies on surgical damage tot the corneal endothelium and on endothelial specular microscopy

The endothelium is the innermost layer of the cornea. It is a mosaic of hexagonal cells that is only one cell thick. These endothelial cells actively maintain the corneal hydration equilibrium, and hence are very important for its transparency. However, they are vulnerable to trauma, disease, and intra-ocular surgery, because they have a very restricted capacity for cell division. In part II, studies are presented on the reliability of in-vivo examinations of the endothelium with a specific type of specular microscope. We found that after correct calibration and with adequate assessment methods, valid and reproducible measurements of the endothelial cell density (ECD) could be obtained. However, there is a systematic difference between specular microscopic ECDs and donor cornea ECDs that are measured with a different technique. This difference can only in part be explained by optical factors. In part III, in a clinical and an experimental study, no toxic effects on the endothelium of current common applications of the dye trypan blue, in cataract surgery and in eye banks on donor corneas, could be observed. However, caution is warranted, as higher concentrations or longer exposures were found to cause substantial toxicity. In part IV, endothelial cell loss patterns were investigated after selective transplantation of different parts of the cornea (deep anterior and posterior lamellar keratoplasty, DALK and PLK). After DALK, ECD-loss approached normal levels after an initial drop. When however in PLK a posterior lamella including the endothelium was transplanted, ECD-loss continued at an increased level for up to 7 years. The possible consequences of this result for graft survival were discussed

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

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.</p

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.</p

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 arthroplas-ties 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 mea-sured preoperatively, and at 3 and 12 months postoperatively. Repeated measurements were analyzed using mixed-effects models, adjusted for confounders, to investigate the associa-tion between surgical approach and PROMs over time. Results — From baseline to 3 and 12 months, improve-ments for NRS pain scores, EQ-5D, and OHS were com-parable 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 meaning-ful differences between the DSA and either PLA or DAA.</p

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 arthroplas-ties 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 mea-sured preoperatively, and at 3 and 12 months postoperatively. Repeated measurements were analyzed using mixed-effects models, adjusted for confounders, to investigate the associa-tion between surgical approach and PROMs over time. Results — From baseline to 3 and 12 months, improve-ments for NRS pain scores, EQ-5D, and OHS were com-parable 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 meaning-ful differences between the DSA and either PLA or DAA.</p

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