Finite element analysis of mechanical stress in a cementless tapered-wedge short stem in the varus position.

BACKGROUND: In recent years, the use of tapered-wedge short stems has increased due to their ability to preserve bones and tendons. Surgical techniques occasionally result in a varus position of the stem, which is particularly pronounced in short stems. Although the varus position is not clinically problematic, there are reports of an increased incidence of stress shielding and cortical hypertrophy. Thus, we evaluated and examined the acceptable range of varus angles using finite element analysis. METHODS: Patients diagnosed with osteoarthritis of the hip joint who had undergone arthroplasty were selected and classified into three types [champagne-flute (type A), intermediate (type B), and stovepipe (type C)]. Finite element analysis was performed using Mechanical Finder. The model was created using a Taperloc microplasty stem with the varus angle increased by 1° from 0° to 5° from the bone axis and classified into seven zones based on Gruen's zone classification under loading conditions in a one-leg standing position. The volume of interest was set, the mean equivalent stress for each zone was calculated. RESULTS: A significant decrease in stress was observed in zone 2, and increased stress was observed in zones 3 and 4, suggesting the emergence of a distal periosteal reaction, similar to the results of previous studies. In zone 2, there was a significant decrease in stress in all groups at a varus angle ≥ 3°. In zone 3, stress increased from ≥ 3° in type B and ≥ 4° in type C. In zone 4, there was a significant increase in stress at varus angles of ≥ 2° in types A and B and at ≥ 3° in type C. CONCLUSION: In zone 2, the varus angle at which stress shielding above Engh classification grade 3 may appear is expected to be ≥ 3°. Distal cortical hypertrophy may appear in zones 3 and 4; the narrower the medullary cavity shape, the smaller the allowable angle of internal recession, and the wider the medullary cavity shape, the wider the allowable range. Long-term follow-up is required in patients with varus angles > 3°.

Real-World Clinical Performance of a Novolimus-Eluting Stent Versus a Sirolimus-Eluting Stent.

INTRODUCTION: The DESyne novolimus-eluting coronary stent (NES) is a new-generation drug-eluting stent (DES) that is widely used, but clinical data are rarely reported for this stent. We compared the safety and effectiveness of the DESyne NES and the Orsiro bioresorbable polymer sirolimus-eluting stent (SES) in patients undergoing percutaneous coronary intervention (PCI). METHODS: This was a retrospective, single-center, observational study. Between July 2017 and December 2022, patients who presented with chronic or acute coronary syndrome undergoing PCI with DESyne NES or Orsiro SES were consecutively enrolled in the present study. The primary endpoint, major adverse cardiovascular event (MACE), was a composite of cardiovascular death, target-vessel myocardial infarction, or clinically driven target-lesion revascularization. RESULTS: A total of 776 patients (age 68.8 ± 12.2; 75.9% male) undergoing PCI were included. Overall, 231 patients with 313 lesions received NES and 545 patients with 846 lesions received SES. During a follow-up duration of 784 ± 522 days, the primary endpoint occurred in 10 patients (4.3%) in the NES group and in 36 patients (6.6%) in the SES group. After multivariate adjustment, the risk of MACE did not significantly differ between groups (NES vs. SES, hazard ratio 0.74, 95% CI, 0.35-1.55, p = 0.425). The event rate of individual components of the primary endpoint was comparable between the two groups. CONCLUSIONS: Favorable and similar clinical outcomes were observed in patients undergoing PCI with either NES or SES in a medium-term follow-up duration. Future studies with adequately powered clinical endpoints are required for further evaluation.

Long-term effectiveness and safety of XEN45 in open-angle glaucoma patients.

BACKGROUND: To investigate the long-term effectiveness and safety of XEN45 implant, either alone or in combination with phacoemulsification, in eyes with open-angle glaucoma (OAG). METHODS: Retrospective and single center study conducted on consecutive OAG patients who underwent a XEN45 implant between February-2017 and December-2021. The primary endpoint was the mean intraocular pressure (IOP) lowering from preoperative values. Surgical success was defined as an IOP-lowering from preoperative values ≥ 20% and an IOP absolute value between 6 and 13 mm Hg, without (Complete-success) or with (Qualified-success) antiglaucoma medications. RESULTS: A total of 158 eyes (34 (21.5%) eyes XEN-solo and 124 (78.5%) XEN + Phaco) were included. The median follow-up time was 28.5 months. In the overall study population, the mean preoperative IOP was significantly lowered from 19.4 ± 6.5 mm Hg to 12.4 ± 5.0 mm Hg. The mean preoperative (95% confidence interval) IOP was significantly lowered from 21.3 (19.3-23.2) mm Hg and 18.8 (17.7-20.0) mm Hg to 12.0 (10.4-13.6) mm Hg and 12.5 (11.6-13.5) mm Hg in the XEN-Solo and XEN + Phaco groups, respectively (p < 0.0001 each, respectively). The mean number of ocular-hypotensive medications was significantly reduced in the overall study sample (from 3.4 ± 0.9 to 0.9 ± 1.3, p < 0.0001), XEN-Solo (from 3.5 ± 1.1 to 0.6 ± 1.0, p < 0.0001, and XEN + Phaco (from 3.4 ± 1.1 to 0.9 ± 1.3, p < 0.0001) groups. Eighty-four (53.2%) eyes were categorized as success, with 49 (58.3%) classified as complete success. Eighty-one (51.3%) eyes underwent needling and 15 (9.5%) eyes required an additional surgical procedure. One (0.6%) eye had endophthalmitis. CONCLUSION: XEN implant, either alone or in combination with phacoemulsification significantly lowered IOP and reduced the need of ocular-hypotensive medication, while maintaining a good safety profile.

Single center outcomes after temporary mechanical circulatory assist device prior to Heartmate 3 implantation - a retrospective cohort study.

Objectives. Temporary mechanical circulatory support (TMCS) has become a component in the therapeutic strategy for treatment of cardiogenic shock as a bridge-to-decision. TMCS can facilitate recovery of cardiopulmonary function, end-organ function, and potentially reduce the surgical risk of left ventricular assist device (LVAD) implantation. Despite the improvements of hemodynamics and end-organ function, post-LVAD operative morbidity might be increased in these high-risk patients. The aim of the study was to compare outcomes after Heartmate 3 (HM3) implantation in patients with and without TMCS prior to HM3 implant. Methods. In this retrospective cohort study of all HM3 patients in the period between November 2015 and October 2021, patients with and without prior TMCS were compared. Patients' demographics, baseline clinical characteristics, laboratory tests, intraoperative variables, postoperative outcomes, and adverse events were collected from patient records. Results. The TMCS group showed an improvement in hemodynamics prior to LVAD implantation. Median TMCS duration was 19.5 (14-26) days. However, the TMCS group were more coagulopathic, had more wound infections, neurological complications, and more patients were on dialysis compared with patient without TMCS prior to HM3 implantation. Survival four years after HM3 implantation was 80 and 82% in the TMCS (N = 22) and non-TMCS group (N = 41), respectively. Conclusion. Patients on TMCS had an acceptable short and long-term survival and comparable to patients receiving HM3 without prior TMCS. However, they had a more complicated postoperative course.

[First experience of implantation of extended depth of focus intraocular lenses in patients with glaucoma]. / Pervyi opyt implantatsii intraokulyarnykh linz s uvelichennoi glubinoi fokusa u patsientov s glaukomoi.

PURPOSE: This study evaluates the effectiveness of implantation of extended depth of focus (EDOF) intraocular lenses (IOL) in patients with cataract and glaucoma. MATERIAL AND METHODS: The study included 13 patients (16 eyes) who underwent implantation of the Lentis Comfort EDOF IOL (Teleon Surgical BV, Netherlands). Standard phacoemulsification cataract surgery with IOL implantation was performed in a planned manner after the hypotensive surgery stage in two eyes; a combined procedure was performed in 14 cases. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), near visual acuity, and intraocular pressure (IOP) measured with a Maklakov tonometer were assessed preoperatively, on the first day, and 3-6 months after surgery. Computer perimetry using the 30-2 program and spatial contrast sensitivity (SCS) assessment were also performed preoperatively and at the same follow-up time points. RESULTS: On the first day after surgery, UCVA was 0.53±0.65, BCVA was 0.85±0.45. Near UCVA (at 40 cm) was 0.5±0.14 on the first day after surgery and 0.56±0.18 at 3-6 months. According to computer perimetry data, retinal light sensitivity values increased in all patients in the long-term (-3.1±2.9 dB). SCS values increased for objects of all sizes compared to preoperative values. CONCLUSION: Implantation of EDOF IOL contributes to improved vision without reducing contrast sensitivity and retinal light sensitivity in patients with concomitant cataract and glaucoma.

Total hip arthroplasty with porous tantalum trabecular metal pads in patients with Crowe IV developmental dysplasia of the hip: a midterm followup study.

PURPOSE: Crowe IV developmental dysplasia of the hip (DDH) is a catastrophic hip disease. Moreover, obtaining ideal clinical efficacy in conventional total hip arthroplasty (THA) is often difficult. In this study, we aimed to assess the mid-term clinical results of THA with porous tantalum trabecular metal (TM) pads for acetabular reconstruction in the treatment of Crowe IV DDH. METHODS: A cohort of 28 patients (32 hips) diagnosed with Crowe type IV DDH who underwent acetabular reconstruction during THA using TM pads with scheduled follow-up between 2011 and 2018, were included in this study. Eight cases were men and 24 were women, with a mean age of 48.4 years (range, 36-72 years) and a mean follow-up was 74.3 months (range, 42-132 months). All patients underwent acetabular reconstruction using TM pads and total hip replacement with subtrochanteric osteotomy. RESULTS: At the final follow-up, 28 hips (87.5%) demonstrated mild or no postoperative limping. The Harris Hip Score improved from 58.4 ± 10.6 preoperatively to 85.6 ± 8.9. The mean pain, stiffness, and function scores on the Western Ontario and McMaster University Osteoarthritis index were 86.5 ± 10.2, 87.3 ± 12.4 and 85.4 ± 11.6 respectively. The mean score of patient satisfaction was 90.4 ± 7.6. Additionally, the SF-12 physical summary score was 41.8 ± 5.6 and the SF-12 mental summary score was 51.6 ± 5.4. TM construct survivorship due to all-cause failure was 90.6% at 5 years with 3 hips at risk, 87.5% at 10 years with 4 hips at risk. The survivorship due to failure from aseptic loosening was 96.9% at 5 years with 1hips at risk and 93.75% at 10 years with 2 hips at risk. CONCLUSION: This study demonstrated satisfactory mid-term clinical and radiological results with the application of TM pads for acetabular reconstruction combined with THA in patients with Crowe IV DDH. TRIAL REGISTRATION NUMBER: ChiCTR1800014526, Date: 18/01/2018.

Cementless Total Knee Arthroplasty: A State-of-the-Art Review.

¼ The demographic profile of candidates for total knee arthroplasty (TKA) is shifting toward younger and more active individuals.¼ While cemented fixation remains the gold standard in TKA, the interest is growing in exploring cementless fixation as a potentially more durable alternative.¼ Advances in manufacturing technologies are enhancing the prospects for superior long-term biological fixation.¼ Current research indicates that intermediate to long-term outcomes of modern cementless TKA designs are comparable with traditional cemented designs.¼ The selection of appropriate patients is critical to the success of cementless fixation techniques in TKA.¼ There is a need for high-quality research to better understand the potential differences and relative benefits of cemented vs. cementless TKA systems.

Rotational stability of two different piggyback toric intraocular lenses for correction of high post-keratoplasty pseudophakic ametropia.

We present the case of a 65-year-old man with bilateral keratoconus and history of bilateral penetrating keratoplasty (PK) who developed gradual visual decline in the left eye due to cataract formation. Following successful left eye cataract surgery and monofocal, non-toric intraocular lens (IOL) in-the-bag implantation, the patient experienced persistently low uncorrected distance visual acuity (UDVA) due to high residual refractive error and intolerance to contact lenses. A supplementary toric IOL was placed in the ciliary sulcus, but subsequent rotational instability of the lens required repeated realignment. Despite two attempts at IOL repositioning, the rotational instability persisted, necessitating the replacement of the original Sulcoflex IOL with a toric, implantable Collamer lens. Following the implantation of the toric ICL, the patient achieved excellent UDVA with no adverse events over a 4-year follow-up period. This case highlights the potential rotational instability associated with toric piggyback IOLs in keratoconic, post-PK, pseudophakic eyes and the special considerations on choosing the type of piggyback lens in these eyes.

A retrospective analysis of surgical outcome in sutureless glueless scleral fixation of foldable intraocular lens.

INTRODUCTION: Cataract surgery constitutes one of the highest volume surgeries performed worldwide approximating 10 million annually, varying from 100 to 6000 per million population. Implantation of scleral fixated intra-ocular lens (SFIOL) is getting popular in managing difficult situations like aphakia, subluxated lens, and dislocated cataracts. OBJECTIVE: This retrospective series evaluated our experience with foldable 3-piece acrylic SFIOL implantation for various challenging surgical scenarios in a tertiary care ophthalmic institute in the southern part of India. RESULTS: The data from the first 150 patients, those operated in our hospital in the aforementioned technique, have been reviewed and analyzed. The mean age of the population was 46.43 years. The most common indication was found to be surgical aphakia (34.66%) followed by traumatic subluxated lens (8.33%). Postoperative BCVA at 3 months improved to 0.255 on the LogMAR scale from preoperative BCVA of 0.795 (P < 0.01). Intraocular pressure was found to stabilize over 3 months follow-up (P = 0.002). The various intraoperative and postoperative complications have been recorded. Ten patients required resurgery out of which eight had postoperative haptic dislocation. A detailed comparison of the role of a surgeon's experience in influencing outcomes has been evaluated. CONCLUSION: The technique offers physiological IOL placement using minimal surgical maneuvers. We strongly recommend this as a technique of choice for the surgical management of complicated scenarios with inadequate capsular bag support.

Copenhagen Mesenteric stent study (COMESS)-a randomized trial of stent versus covered stent treatment for chronic mesenteric ischemia.

BACKGROUND: Current management of mesenteric ischemia is primarily endovascular stent treatment. Typical CMI symptoms are postprandial abdominal pain, food fear, weight loss, and diarrhea. Revascularization is often necessary, as mesenteric ischemia may progress to bowel necrosis and death if left untreated. This study aims to compare the outcome using bare metal stent (BMS) or covered stent (CS) in the endovascular treatment of chronic and acute on chronic mesenteric ischemia. METHODS: This is an investigator-driven, prospective, randomized, single-blinded, and single-center, national cohort study at the Copenhagen University Hospital, Denmark. A total of 98 patients with chronic mesenteric ischemia (CMI) and acute-on-chronic mesenteric ischemia (AoCMI) will be randomized to treatment with either BeSmooth BMS (Bentley Innomed GmbH) or BeGraft CS (Bentley Innomed GmbH). Randomization occurs intraoperatively after lesion crossing. DISCUSSION: There is currently no published data from prospective controlled trials regarding the preferred type of stent used for the treatment of chronic and acute-on-chronic mesenteric ischemia. This trial will evaluate the short- and long-term outcome of BMS versus CS when treating CMI and AoCMI, as well as the benefit of a more intense postoperative surveillance program. TRIAL REGISTRATION: ClinicalTrials.gov NCT05244629. Registered on February 8, 2022.

Long-term efficacy and safety of XEN-45 gel stent implantation in patients with normal-tension glaucoma.

BACKGROUND: Minimally invasive bleb surgery using the XEN-45 gel stent has not been established for the treatment of normal-tension glaucoma (NTG). The main objective of this study was to evaluate the long-term treatment efficacy and safety of XEN-45 in eyes with uncontrolled NTG. METHODS: A retrospective analysis of patients with NTG who underwent XEN-45 gel stent implantation at university hospital Tuebingen between 2016 and 2021. The primary outcome measure was surgical success after three years defined as lowering of intraocular pressure (IOP) of ≥ 20%, with target IOP between 6 and 15 mmHg. Success was complete without and qualified irrespective of topical antiglaucoma medication use. The need for further glaucoma surgery, except for needling, was regarded as a failure. The secondary outcome measures included changes in mean IOP, number of antiglaucoma medications, and needling and complication rates. RESULTS: Twenty-eight eyes from 23 patients were included in the final analysis. Complete and qualified success rates were 56.5% and 75% after three years, respectively. Mean postoperative IOP ± standard deviation decreased significantly after three years from 19.3 ± 2.0 mmHg at baseline to 13.7 ± 4.2 mmHg (n = 22; p < 0.0001). The median number of antiglaucoma medications decreased from 2 (range 0-4) to 0 after three years (range 0-3; p < 0.0001). Sixteen eyes (57%) required a median of 1 (range 1-3) needling procedures. One eye required further glaucoma surgery. No sight-threatening complications were observed. CONCLUSION: The XEN-45 stent is effective and safe for the long-term treatment of NTG. However, needling was frequently required to improve outcomes.

Clinical results with a multifocal intraocular lens with a novel optical design.

BACKGROUND: To evaluate the optical performance and safety of a new multifocal lens with a novel optical design featuring two additional foci (or intensifiers) in patients with cataract and presbyopia. METHODS: In this single-center, non-randomized prospective observational study, 31 patients underwent implantation of the new multifocal IOL between March 2020 and November 2021 at a tertiary clinical center in Buenos Aires and Ramos Mejia, Argentina. Postoperative examinations with emphasis on uncorrected and corrected visual acuity at distance and near and at two different intermediate distances (80 cm and 60 cm) were performed during the 3 postoperative months. RESULTS: Of the 31 patients who underwent implantation of the new IOL, 30 underwent bilateral surgery (61 eyes in total). At 3 months, all 61 eyes had an uncorrected distance visual acuity (UCDVA) of at least 0.15 logMAR; 57 eyes (93%) had an uncorrected distance visual acuity (UCDVA) of 0.1 logMAR and 27 eyes (44%) had an UCDVA of 0.0 logMAR. At 80 cm, 60 eyes (98%) had an uncorrected intermediate visual acuity (UCIVA) of at least 0.1 log MAR and 48 eyes (79%) had an UCIVA of 0.0 logMAR. CONCLUSION: The new multifocal IOL with a novel optical concept (5 foci) showed a wide range of visual acuity especially at intermediate and near distances in patients undergoing cataract surgery. Uncorrected visual acuity was excellent at all tested distances, monocularly and binocularly, spectacle independence and patient satisfaction were high.

Aphakia treatment with sutureless scleral fixation or retropupillary iris-claw intraocular lens implantation: visual acuity, anterior segment and keratometry outcomes.

PURPOSE: Evaluation of anterior segment parameters using the Scheimpflug corneal topography 1 year after surgery in patients who underwent sutureless scleral fixation intraocular lens (SFIOL) implantation using the modified Yamane technique and retropupillary iris-claw intraocular lens (RPIOL) implantation. METHODS: A total of 60 eyes from 57 patients who underwent sutureless SFIOL implantation and 57 eyes from 52 patients who underwent RPIOL implantation were included. Anterior chamber depth (ACD), anterior chamber angle (ACA), anterior chamber volume (ACV), anterior-posterior corneal astigmatism, and keratometric values were assessed using the Scheimpflug corneal topography (Pentacam HR, Germany). RESULTS: There was no statistically significant difference in postoperative UCVA and BCVA between the sutureless SFIOL and the RPIOL group (p = 0.236, p = 0.293, respectively). While there was no statistically significant difference in postoperative IOP between the two groups (p = 0.223), a statistically significant decrease in IOP was observed in both groups (p < 0.001). While there was no statistical difference between the sutureless SFIOL group and the RPIOL group in terms of spherical value (p = 0.441) and spherical equivalence (p = 0.237), there was a statistically significant difference in cylindrical value (p < 0.001). While there was a statistical difference in anterior astigmatism (p < 0.001), there was no statistical difference in posterior astigmatism (p = 0.405). There was no statistical difference in terms of ACV, ACD, and ACA between the sutureless SFIOL and the RPIOL group (p = 0.812, p = 0.770, p = 0.401, respectively). CONCLUSION: In this study, although there was a statistical difference in cylindrical value and anterior corneal astigmatism between the sutureless SFIOL and RPIOL groups, vision was not affected. According to this study, sutureless SFIOL and RPIOL are two successful methods in terms of visual acuity, anterior segment, and keratometry outcomes in aphakic patients after phacoemulsification.

Prosthesis usability experience is associated with extent of upper limb prosthesis adoption: A Structural Equation Modeling (SEM) analysis.

Factors associated with upper limb prosthesis adoption are not well understood. In this study, we explored how prosthesis usability experience relates to the extent of prosthesis adoption through the development of a structural equation model (SEM). First, items related to prosthesis usability were developed and refined using cognitive testing and pilot testing and employed in a survey of 402 prosthesis users (mean age 61.7 (sd 14.4), 77.1% Veterans). The SEM examined two unidimensional latent constructs: Prosthesis Usability Experience and Prosthesis Adoption-and each had multiple measured indicators. SEMs tested direct as well as moderating and mediating effects between the latent constructs and covariates related to demographics and prosthesis type. SEM found a significant positive association between Prosthesis Usability Experience and Extent of Prosthesis Adoption. Several covariates had direct effects on prosthesis adoption: 1) Extent of Prosthesis Adoption was lower for those with transhumeral and shoulder amputation, and higher for those with bilateral amputation, compared to the reference group with unilateral transradial amputation and 2) Myoelectric multiple degree of freedom (multi-DOF) prosthesis use was associated with lower Extent of Prosthesis Adoption, compared to body-powered prosthesis use. Myoelectric multi-DOF use also modified the effect of Prosthesis Usability Experience on Extent of Prosthesis Adoption. For those with bilateral ULA, the strength of the relationship between Prosthesis Usability Experience and Extent of Prosthesis Adoption was reduced. Findings suggest that in order to increase prosthesis adoption, prosthetics developers and rehabilitation providers should focus on implementing strategies to improve prosthesis usability experience. New Prosthesis Usability Experience measures could be used to identify persons at greater risk for poor prosthesis adoption and target interventions to increase prosthesis use.

Effects of shape and structure of a new 3D-printed personalized bioresorbable tracheal stent on fit and biocompatibility in a rabbit model.

To date, several types of airway stents are available to treat central airway obstructions. However, the ideal stent that can overcome anatomical, mechanical and microbiological issues is still awaited. In addition, therapeutic effect and self-elimination of these stents are desirable properties, which pose an additional challenge for development and manufacturing. We aimed to create a prototype bioresorbable tracheal stent with acceptable clinical tolerance, fit and biocompatibility, that could be tested in a rabbit model and in the future be further optimized to enable drug-elution and ensure local therapeutic effect. Twenty-one New Zealand White Rabbits received five different types of bioresorbable tracheal stents, 3D-printed from poly(D,L-lactide-co-ε-caprolactone) metacrylates. Various configurations were tested for their functionality and improved until the best performing prototype could undergo detailed in vivo assessment, regarding clinical tolerance, migration and biocompatibility. Previously tested types of 3D printed stents in our preliminary study required improvement due to several problems, mainly related to breakage, unreliable stability and/or migration within the trachea. Abandoned or refined pre-prototypes were not analyzed in a comparative way. The final best performing prototype stent (GSP2 (Group Stent Prototype 2), n = 8) allowed a transoral application mode and showed good clinical tolerance, minimal migration and acceptable biocompatibility. The good performance of stent type GSP2 was attributed to the helix-shaped surface structure, which was therefore regarded as a key-feature. This prototype stent offers the possibility for further research in a large animal model to confirm the promising data and assess other properties such as bioresorption.

Robot-Assisted Correction of a Supra-Long Tracheal Stenosis Using C-Type Nickel-Titanium Alloy Exterior Stenting and Suspension Fixation Technique: A Case Report.

T-tubes and airway stents are commonly used but have limited effectiveness and frequent complications. A 50-year-old male patient presented with severe tracheal stenosis, affecting an 8.7 cm length of the airway. We employed an innovative approach known as external suspension fixation of tracheal stent using robotic assistance. This method involves surgically attaching the stent to the exterior of the trachea to provide support and stabilize the softened or collapsed tracheal segments. We designed a C-shaped nickel-titanium alloy exterior stent and successfully fixed it using robotic assistance. This intervention effectively restored tracheal function and led to a favorable postoperative recovery. The technique does not affect tracheal membrane function or airway mucociliary clearance. It could potentially be considered as a new option for treating long-segment benign tracheal softening or collapse.

Limited Revision with a Newly Designed Hinge Device for the Treatment of Mega-Prosthesis Hinge Failure: Two Case Reports.

BACKGROUND: Surgical treatment for hinge failure in mega-prosthesis continues to be a challenge. This study introduces a new method for treating hinge failure by using a unilateral prosthesis and hinge revision. CASE PRESENTATION: We here present two patients who underwent mega-prosthesis reconstruction after resection of osteosarcoma in the distal femur. To address the issue of knee hyperextension after mega-prosthesis reconstruction, one patient underwent three revision surgeries, two surgeries were performed using the original hinge, and one surgery involved a newly designed hinge. To resolve the problem of dislocation, one patient underwent three revisions, with the first two revisions not involving hinge replacement and the third revision involving a newly designed hinge. Two replacements of unilateral prosthesis and hinge renovations were successful. CONCLUSIONS: Unilateral prosthesis and newly designed hinge device revision are effective in treating the failure of old-fashioned mega-prosthesis hinges.

[Tribology in arthroplasty : Friction and wear, a key to a long lifetime]. / Tribologie in der Endoprothetik : Reibung und Verschleiß, ein Schlüssel zu langen Standzeiten.

This article is intended to highlight one of the key roles in endoprosthetic treatment with artificial implants and the extension of service life. Like every joint, artificial joints are subject to the physical laws of friction and wear-in short, tribology. Material pairings, surfaces and mechanisms of action in particular play a decisive role here. The special features and current findings relating to the three largest synovial joints (hip, knee and shoulder) will be discussed in detail and suggestions will be made for future developments. Continuous developments in the field of the tribology of artificial joints can massively improve care for patients. The revision figures and reasons already show the success of individual improvements in recent years.

3D-printed Personalized Porous Acetabular Component to Reconstruct Extensive Acetabular Bone Defects in Primary Hip Arthroplasty.

OBJECTIVE: Management of extensive acetabular bone defects in total hip arthroplasty (THA) remains challenging. This study aims to investigate the feasibility and preliminary outcomes of 3D-printed personalized porous acetabular components for the reconstruction of acetabular defects in primary THA. METHODS: This retrospective study involved seven patients who received 3D-printed acetabular components in primary THA between July 2018 and March 2021. Preoperatively, acetabular bone defects were evaluated by referencing the Paprosky classification. There were two "Paprosky type IIIA" defects and five "Paprosky type IIIB" defects. The acetabular components were custom-made for each patient to reconstruct the extensive acetabular defects. The hip function was assessed according to the Harris hip score (HHS). Clinical and radiographic outcomes were assessed. RESULTS: The average follow-up period was 40 months, ranging from 26 to 57 months. There were no patients lost to follow-up. The HHS improved from 44 (range: 33-53) before the operation to 88 (range: 79-93) at the final follow-up. Postoperative X-rays showed that the 3D-printed personalized components were properly fitted with the acetabulum. The average center of rotation (COR) discrepancy was 2.3 mm horizontally and 2.1 mm vertically, respectively. Tomosynthesis-Shimadzu metal artifact reduction technology images showed that the implant was in close contact with the host bone. Moreover, no complications were observed during the follow-up period, including loosening, dislocation, or component protrusion. CONCLUSION: The implantation of 3D-printed personalized acetabular components showed accurate reconstruction, stable mechanical support, and favorable function at short-term follow-up. This may be a viable alternative method for reconstructing extensive acetabular defects in THA.