Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 57
Filtrar
1.
Life (Basel) ; 14(6)2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38929701

RESUMEN

Objective evaluations of transverse tarsometatarsal (TMT) hypermobility/instability are lacking. This study aims to radiographically explore the relationship between transverse TMT instability and metatarsus adductus (MA) in hallux valgus (HV). This study retrospectively analyzed 207 feet with varying degrees of HV, employing the distance between the first and second metatarsals (M1-2 distance) to assess transverse TMT instability of the first ray. Participants were categorized into MA and non-MA groups. It was found that the M1-2 distance significantly increased with the hallux valgus angle (HVA) and metatarsus adductus angle (MAA), demonstrating significant differences between the MA and non-MA groups. The measurement of M1-2 distance showed high reliability, and its cutoff value was determined to be 4.05 mm. Additionally, the results suggest that the widening of the M1-2 distance may be a predisposing factor for MA in HV patients, highlighting its role in the pathogenesis of this foot condition. These findings highlight the need for a comprehensive assessment of TMT instability on both the axial and sagittal planes for the surgical planning of HV, particularly when complicated by a large MAA. Based on these insights, reoriented first-TMT arthrodesis might be recommended for HV with significant MA to address potential multiplanar instability.

2.
Front Bioeng Biotechnol ; 12: 1389127, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38751865

RESUMEN

Introduction: Jones fractures frequently fail to unite, and adequate fixation stability is crucial. This study aimed to elucidate the biomechanical stability of various intramedullary screw fixation constructs. Methods: Jones fracture model over the proximal 5th metatarsal of artificial bone was created in all specimens. Six groups were divided based on varied screw constructs with different screw lengths, either 30 or 40 mm, including cannulated screws-C30 and C40 groups, one high-resistance suture combined with intramedullary cannulated screws (F.E.R.I. technique)-CF30 and CF40 groups, and second-generation headless compression screws (SG-HCS) -HL30 and HL40 groups. Mechanical testing was conducted sequentially, and the maximal force (N) and stiffness (N/mm) of all constructs were recorded. Results: The maximal force (N) at 1.0 mm downward displacement in C30, C40, CF30, CF40, HL30, and HL40 groups were 0.56 ± 0.02, 0.49 ± 0.02, 0.65 ± 0.02, 0.49 ± 0.01, 0.68 ± 0.02, and 0.73 ± 0.02, respectively, and the stiffness (N/mm) in subgroups were 0.49 ± 0.01, 0.43 ± 0.01, 0.67 ± 0.01, 0.42 ± 0.01, 0.61 ± 0.01, and 0.58 ± 0.02, respectively. SG-HCS subgroups exhibited greater maximal force and stiffness than conventional cannulated screws. Screws of 30 mm in length demonstrated better stability than all 40 mm-length screws in each subgroup. In C30 fixation, the stiffness and maximum force endured increased by 1.16 and 1.12 times, respectively, compared with the C40 fixation method. There were no significant differences between CF30 and SG-HCS groups. Only the F.E.R.I technique combined with the 4.5 mm cannulated screw of 30 mm in length increased the biomechanical stability for Jones fractures. Discussion: These biomechanical findings help clinicians decide on better screw fixation options for greater stability in Jones fractures, especially when large-diameter screws are limited in use. However, this biomechanical testing of intramedullary screw fixation on Jones fracture model lacks clinical validation and no comparisons to extramedullary plate fixations. Moving forward, additional clinical and biomechanical research is necessary to validate our findings.

3.
Sci Rep ; 14(1): 5597, 2024 03 07.
Artículo en Inglés | MEDLINE | ID: mdl-38454143

RESUMEN

This study aimed to identify the factors affecting hip-knee-ankle (HKA) angle following Oxford medial unicompartmental knee arthroplasty (MUKA). A retrospective analysis of 200 patients who underwent Oxford MUKA from June 2018 to October 2020 was conducted. Univariate and multivariate analyses were performed to investigate the impact of surgical and radiographic characteristics on the postoperative HKA angle. The mean HKA angle was 9.5 ± 4.3° before surgery and 3.6 ± 3.7° after surgery (p < 0.001). The postoperative HKA angle significantly correlated with the preoperative HKA angle, bearing size, tibial component alignment angle, and BMI (r = 0.71, p < 0.001; r = - 0.24, p = 0.001; r = 0.21, p = 0.004; r = - 0.18, p = 0.011). Multiple linear regression analysis revealed that the preoperative HKA angle (ß = 0.68, p < 0.001), bearing size (ß = - 0.31, p < 0.001), tibial component alignment angle (ß = 0.14, p = 0.003), and BMI (ß = - 0.09, p = 0.047) significantly affected the postoperative HKA angle. In conclusion, larger preoperative varus deformity, smaller bearing size, greater varus alignment of the tibial component, and lower BMI lead to greater postoperative varus alignment of the lower limb in Oxford MUKA. With this concept, surgeons can more accurately predict postoperative lower limb alignment and avoid malalignment in Oxford MUKA.


Asunto(s)
Artroplastia de Reemplazo de Rodilla , Osteoartritis de la Rodilla , Humanos , Estudios Retrospectivos , Osteoartritis de la Rodilla/diagnóstico por imagen , Osteoartritis de la Rodilla/cirugía , Articulación de la Rodilla/diagnóstico por imagen , Articulación de la Rodilla/cirugía , Extremidad Inferior/cirugía , Tibia/diagnóstico por imagen , Tibia/cirugía
4.
BMC Geriatr ; 24(1): 173, 2024 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-38373934

RESUMEN

BACKGROUND: Transient progressive weakness and disability of lower limb during the early stage after TKR will increase the risk of fall, but the superior postoperative strength training mode have not been elucidated for functional restoration. This study aimed to compare whether the isokinetic lower limb training is superior to either isotonic or home isometric exercise during early stage after TKR in older people. METHODS: A total of 43 recruited old participants (mean age, 68.40 years old) receiving TKR were divided randomly based on the different four-week training modes into three groups including isokinetic, isotonic, and home isometric exercise (control group). The primary outcome was set as functional performance in terms of Timed Up and Go (TUG) test and the secondary outcomes include the peak torque of knee at 60 and 120 degree/ second, Short-Form 36 Health Survey (SF-36), and Western Ontario and McMaster Universities Arthritis index (WOMAC). RESULTS: All of the peak torque measurements of the knee improved significantly in both the isokinetic and the isotonic group, but not in the control group. Although isotonic training resulted in more strength gains, a significant enhancement in TUG test was observed in the isokinetic group only (p = 0.003). However, there were no significantly improvement of TUG test after training in other two groups. SF-36 and WOMAC improved after training in all three groups, with no significant difference in the degree of improvement between groups. CONCLUSION: Isokinetic training for 4 weeks following TKR effectively improved all the outcome parameters in this study, including the TUG test, lower limb strength, and functional scores. However, both isokinetic and isotonic training modes could be recommended after TKR because of no significant difference in the degree of improvement between these two groups. TRIAL REGISTRATION: Clinical trial registration number: NCT02938416. LEVEL OF EVIDENCE: I.


Asunto(s)
Artroplastia de Reemplazo de Rodilla , Entrenamiento de Fuerza , Humanos , Anciano , Artroplastia de Reemplazo de Rodilla/efectos adversos , Terapia por Ejercicio/métodos , Entrenamiento de Fuerza/métodos , Rodilla , Ejercicio Físico
6.
Sci Rep ; 13(1): 20475, 2023 11 22.
Artículo en Inglés | MEDLINE | ID: mdl-37993498

RESUMEN

Flexor hallucis longus (FHL) transfer is an effective surgery in treating insertional Achilles tendinopathy (IAT). However, limited data exist regarding the post-surgery changes in the transferred FHL. The study aimed to compare the sequential changes and hypertrophy of FHL after isolated FHL transfer (FHLT). We retrospectively enrolled patients who underwent isolated FHLT for insertional Achilles pathology from 2015 to 2020 and divided them into two groups based on whether reattachment of the residue Achilles stump to the FHL was performed or not. We recorded demographic characteristics, MRI parameters, and functional outcome. We also analyzed the correlation between the collected data and FHL hypertrophy. Results revealed no significant differences in most MRI parameters of FHL and functional outcomes between the groups. However, the fat distribution within the FHL showed significant reduction and notable 20.2% hypertrophy after FHLT. Interestingly, the hypertrophy of the FHL was significantly more pronounced in the non-reattached group. Furthermore, we observed a positive correlation between the follow-up period and FHL hypertrophy. In conclusion, the FHL demonstrated significant enlargement over time following FHLT. The compensatory hypertrophy of the transferred FHL was particularly evident and the cumulative incidences of FHL enlargement over time were higher in the non-reattached groupcompared to reattached group. However, both reattachment and non-reattachment of Achilles stump on FHL transfer for insertional Achilles tendinopathy carried similar postoperative functional outcomes.


Asunto(s)
Tendón Calcáneo , Tendinopatía , Humanos , Estudios Retrospectivos , Tendón Calcáneo/diagnóstico por imagen , Tendón Calcáneo/cirugía , Transferencia Tendinosa/métodos , Tendinopatía/diagnóstico por imagen , Tendinopatía/cirugía , Imagen por Resonancia Magnética , Hipertrofia
8.
ACS Omega ; 8(19): 17122-17133, 2023 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-37214730

RESUMEN

Nanoparticles (NPs) have attracted great attention in the tertiary oil recovery process due to their unique properties. As an economical and efficient green synthesis method, biosynthesized nanoparticles have the advantages of low toxicity, fast preparation, and high yield. In this study, with the theme of biotechnology, for the first time, the bio-nanoparticles reduced by iron-reducing bacteria were compounded with the biosurfactant produced by Bacillus to form a stable bio-nano flooding system, revealing the oil flooding mechanism and enhanced oil recovery (EOR) potential of the bio-nano flooding system. The interfacial properties of the bio-nano-oil displacement system were studied by interfacial tension and wettability change experiments. The enhanced oil recovery potential of the bio-nano-oil displacement agent was measured by microscopic oil displacement experiments and core flooding experiments. The bio-nano-oil displacement system with different nanoparticle concentrations can form a stable dispersion system. The oil-water interfacial tension and contact angle decreased with the increase in concentration of the bio-nano flooding system, which also has a high salt tolerance. Microscopic oil displacement experiments proved the efficient oil displacement of the bio-nano-oil displacement system and revealed its main oil displacement mechanism. The effects of concentration and temperature on the recovery of the nano-biological flooding system were investigated by core displacement experiments. The results showed that the recovery rate increased from 4.53 to 15.26% with the increase of the concentration of the system. The optimum experimental temperature was 60 °C, and the maximum recovery rate was 15.63%.

9.
Fertil Steril ; 119(6): 942-943, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37054864

Asunto(s)
Hielo , Humanos , Congelación
10.
Int J Mol Sci ; 23(21)2022 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-36361555

RESUMEN

Hydroxygenkwanin, a flavonoid isolated from the leaves of the Daphne genkwa plant, is known to have pharmacological properties; however, its modulatory effect on multidrug resistance, which is (MDR) mediated by ATP-binding cassette (ABC) drug transporters, has not been investigated. In this study, we examine the interaction between hydroxygenkwanin, ABCB1, and ABCG2, which are two of the most well-characterized ABC transporters known to contribute to clinical MDR in cancer patients. Hydroxygenkwanin is not an efflux substrate of either ABCB1 or ABCG2. We discovered that, in a concentration-dependent manner, hydroxygenkwanin significantly reverses ABCG2-mediated resistance to multiple cytotoxic anticancer drugs in ABCG2-overexpressing multidrug-resistant cancer cells. Although it inhibited the drug transport function of ABCG2, it had no significant effect on the protein expression of this transporter in cancer cells. Experimental data showing that hydroxygenkwanin stimulates the ATPase activity of ABCG2, and in silico docking analysis of hydroxygenkwanin binding to the inward-open conformation of human ABCG2, further indicate that hydroxygenkwanin sensitizes ABCG2-overexpressing cancer cells by binding to the substrate-binding pocket of ABCG2 and attenuating the transport function of ABCG2. This study demonstrates the potential use of hydroxygenkwanin as an effective inhibitor of ABCG2 in drug combination therapy trials for patients with tumors expressing higher levels of ABCG2.


Asunto(s)
Antineoplásicos , Neoplasias , Humanos , Resistencia a Múltiples Medicamentos , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/metabolismo , Resistencia a Antineoplásicos , Proteínas de Neoplasias/metabolismo , Línea Celular Tumoral , Antineoplásicos/farmacología , Antineoplásicos/química , Flavonoides/farmacología , Transportadoras de Casetes de Unión a ATP/metabolismo , Neoplasias/tratamiento farmacológico
11.
Biomed Pharmacother ; 154: 113663, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36081287

RESUMEN

The development of multidrug resistance (MDR) is one of the major challenges in the treatment of cancer which is caused by the overexpression of the ATP-binding cassette (ABC) transporters ABCB1 (P-glycoprotein) and/or ABCG2 (BCRP/MXR/ABCP) in cancer cells. These transporters are capable of reducing the efficacy of cytotoxic drugs by actively effluxing them out of cancer cells. Since there is currently no approved treatment for patients with multidrug-resistant tumors, the drug repurposing approach provides an alternative route to identify agents to reverse MDR mediated by ABCB1 and/or ABCG2 in multidrug-resistant cancer cells. WDR5-0103 is a histone H3 lysine 4 (H3K4) methyltransferase inhibitor that disrupts the interaction between the WD repeat-containing protein 5 (WDR5) and mixed-lineage leukemia (MLL) protein. In this study, the effect of WDR5-0103 on MDR mediated by ABCB1 and ABCG2 was determined. We found that in a concentration-dependent manner, WDR5-0103 could sensitize ABCB1- and ABCG2-overexpressing multidrug-resistant cancer cells to conventional cytotoxic drugs. Our results showed that WDR5-0103 reverses MDR and improves drug-induced apoptosis in multidrug-resistant cancer cells by inhibiting the drug-efflux function of ABCB1 and ABCG2, without altering the protein expression of ABCB1 or ABCG2. The potential sites of interactions of WDR5-0103 with the drug-binding pockets of ABCB1 and ABCG2 were predicted by molecular docking. In conclusion, the MDR reversal activity of WDR5-0103 demonstrated here indicates that it could be used in combination therapy to provide benefits to a subset of patients with tumor expressing high levels of ABCB1 or ABCG2.


Asunto(s)
Antineoplásicos , Neoplasias , Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/metabolismo , Transportadoras de Casetes de Unión a ATP , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Resistencia a Múltiples Medicamentos , Resistencia a Antineoplásicos , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Simulación del Acoplamiento Molecular , Proteínas de Neoplasias/metabolismo , Repeticiones WD40
13.
Curr Opin Obstet Gynecol ; 34(4): 159-163, 2022 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-35895955

RESUMEN

PURPOSE OF REVIEW: Artificial Intelligence, a tool that integrates computer science and machine learning to mimic human decision-making processes, is transforming the world and changing the way we live. Recently, the healthcare industry has gradually adopted artificial intelligence in many applications and obtained some degree of success. In this review, we summarize the current applications of artificial intelligence in Reproductive Endocrinology, in both laboratory and clinical settings. RECENT FINDINGS: Artificial Intelligence has been used to select the embryos with high implantation potential, proper ploidy status, to predict later embryo development, and to increase pregnancy and live birth rates. Some studies also suggested that artificial intelligence can help improve infertility diagnosis and patient management. Recently, it has been demonstrated that artificial intelligence also plays a role in effective laboratory quality control and performance. SUMMARY: In this review, we discuss various applications of artificial intelligence in different areas of reproductive medicine. We summarize the current findings with their potentials and limitations, and also discuss the future direction for research and clinical applications.


Asunto(s)
Infertilidad , Medicina Reproductiva , Inteligencia Artificial , Femenino , Humanos , Aprendizaje Automático , Embarazo
14.
Orthop J Sports Med ; 10(6): 23259671221105852, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35757239

RESUMEN

Background: Rebuilding the strength of the quadriceps as soon as possible after total knee replacement (TKR) is important so as to restore gait stability. To date, there are no standard postoperative strength training programs during the early recovery stage after TKR. Purpose: To compare the therapeutic effects between isokinetic and isotonic strengthening in patients after TKR. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: From April 2018 to August 2020, 37 patients met the inclusion criteria and were randomly assigned to perform either 4-week isokinetic or isotonic strength training programs. Other components of the rehabilitation program were kept the same between the 2 groups. All cases were evaluated by the Timed Up and Go (TUG) test, peak torque of knee extension and flexion (60 and 120 deg/s), 36-item Short Form Health Survey (SF-36), and Western Ontario and McMaster Universities Arthritis Index (WOMAC). Results: After undergoing a 4-week strength training regimen, significant improvements in the TUG test were noted in both groups; however, the time improvement in the isotonic group did not reach the minimal detectable change. All peak torque measurements improved in the isokinetic group but not in the isotonic group for knee flexion at 60 deg/s. The pain subdomain, physical domain, mental domain, total SF-36 score, and WOMAC index all improved significantly in both groups after training. Both training groups improved significantly in peak torque of knee strength, TUG test, and functional scores, but the differences between isokinetic and isotonic training were not statistically significant. Conclusion: The study findings showed that a 4-week strengthening exercise program in the early postoperative stage, involving either isokinetic or isotonic training, resulted in significant improvements in patients undergoing TKR. Registration: NCT02938416 (ClinicalTrials.gov identifier).

15.
Bone Jt Open ; 3(3): 211-217, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35274982

RESUMEN

AIMS: The Coronal Plane Alignment of the Knee (CPAK) classification is a simple and comprehensive system for predicting pre-arthritic knee alignment. However, when the CPAK classification is applied in the Asian population, which is characterized by more varus and wider distribution in lower limb alignment, modifications in the boundaries of arithmetic hip-knee-ankle angle (aHKA) and joint line obliquity (JLO) should be considered. The purposes of this study were as follows: first, to propose a modified CPAK classification based on the actual joint line obliquity (aJLO) and wider range of aHKA in the Asian population; second, to test this classification in a cohort of Asians with healthy knees; third, to propose individualized alignment targets for different CPAK types in kinematically aligned (KA) total knee arthroplasty (TKA). METHODS: The CPAK classification was modified by changing the neutral boundaries of aHKA to 0° ± 3° and using aJLO as a new variable. Radiological analysis of 214 healthy knees in 214 Asian individuals was used to assess the distribution and mean value of alignment angles of each phenotype among different classifications based on the coronal plane. Individualized alignment targets were set according to the mean lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) of different knee types. RESULTS: A very high concentration, 191 from 214 individuals (89.3%), were found in knee types with apex distal JLO when the CPAK classification was applied in the Asian population. By using aJLO as a new variable, the high distribution percentage in knee types with apex distal JLO decreased to 125 from 214 individuals (58.4%). The most common types in order were Type II (n = 70; 32.7%), Type V (n = 55; 25.7%), and Type I (n = 46; 21.5%) in the modified CPAK classification. CONCLUSION: The modified CPAK classification corrected the uneven distribution when applying the CPAK classification in the Asian population. Setting individualized TKA alignment targets according to CPAK type may be a practical method to recreate optimal LDFA and MPTA in KA-TKA. Cite this article: Bone Jt Open 2022;3(3):211-217.

16.
Tomography ; 8(1): 284-292, 2022 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-35202188

RESUMEN

BACKGROUND: Haglund's deformity, which is characterized by a bony prominence of the posterosuperior aspect of the calcaneus, causes posterior heel pain. To date, there is no standard radiographic parameter to diagnose symptomatic Haglund's deformity. Herein, we proposed novel radiographic measurements to distinguish between patients with and without symptomatic Haglund's deformity. METHODS: We retrospectively evaluated ankle radiographs of 43 patients who underwent surgery for symptomatic Haglund's deformity (Haglund group) and 41 healthy individuals (control group) free of heel complaints. Fowler-Phillip angle (FPA), Heneghan-Pavlov parallel pitch lines (PPL), Haglund's deformity height, bump height, and bump-calcaneus ratio were measured and compared between the groups. Furthermore, the reliability and cut-off value of each parameter were validated via ICC and ROC curve analysis, respectively. RESULTS: The bump height (p < 0.001) and the bump-calcaneus ratio (p < 0.001) showed significant differences between the control and Haglund groups, unlike FPA, PPL, and Haglund's deformity height. ROC curve analysis revealed that the AUC of bump-calcaneus ratio was larger than that of bump height. The optimal threshold was 4 mm or higher for bump height and 7.5% or higher for bump-calcaneus ratio. The intra- and inter- observer ICCs were, respectively, 0.965 and 0.898 for bump height and 0.930 and 0.889 for bump-calcaneus ratio. CONCLUSIONS: This study proposes two novel radiographic parameters to identify operatively treated Haglund's deformity, namely bump height and bump-calcaneus ratio. They are easy to measure and intuitive. Both of them are effective diagnostic parameters for Haglund's deformity. Furthermore, bump-calcaneus ratio is more reliable diagnostic parameter than bump height.


Asunto(s)
Tendón Calcáneo , Exostosis , Espolón Calcáneo , Tendón Calcáneo/cirugía , Espolón Calcáneo/diagnóstico , Humanos , Reproducibilidad de los Resultados , Estudios Retrospectivos
17.
Biomed Eng Online ; 21(1): 6, 2022 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-35090461

RESUMEN

BACKGROUND: Menopause-induced decline in estrogen levels in women is a main factor leading to osteoporosis. The objective of this study was to investigate the effect of intermittent parathyroid hormone (PTH) on bone structural parameters of the femoral neck in ovariectomized rats, in addition to correlations of maximum fracture force. METHODS: Fifteen female Wister rats were divided into three groups: (1) control group; (2) ovariectomized (OVX) group; and (3) OVX + PTH group. All rats were then killed and the femurs extracted for microcomputed tomography scanning to measure volumetric bone mineral density (vBMD) and bone structural parameters of the femoral neck. Furthermore, the fracture forces of femoral neck were measured using a material testing system. RESULTS: Compared with the control and OVX + PTH groups, the OVX group had significantly lower aBMD, bone parameter, and mechanical strength values. A comparison between OVX and OVX + PTH groups indicated that PTH treatment increased several bone parameters. However, the OVX + PTH groups did not significantly differ with the control group with respect to the bone structural parameters, except for trabecular bone thickness of cancellous bone, which was greater. In addition, among the bone structural parameters, the CSA and BSI of cortical bone were significantly correlated with the maximum fracture force of the femoral neck, with correlations of, respectively, 0.682 (p = 0.005) and 0.700 (p = 0.004). CONCLUSION: Intermittent PTH helped treat ovariectomy-induced osteoporosis of cancellous bone and cortical bone in the femoral necks of rats. The ability of the femoral neck to resist fracture was highly correlated with the two parameters, namely cross-sectional area (CSA) and bone strength index (= vBMD × CSA), of cortical bone in the femoral neck and was less correlated with aBMD or other bone structural parameters.


Asunto(s)
Cuello Femoral , Osteoporosis , Animales , Femenino , Cuello Femoral/diagnóstico por imagen , Humanos , Osteoporosis/tratamiento farmacológico , Osteoporosis/etiología , Ovariectomía , Hormona Paratiroidea , Ratas , Ratas Sprague-Dawley , Ratas Wistar , Microtomografía por Rayos X
18.
J Chin Med Assoc ; 84(11): 1038-1047, 2021 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-34596083

RESUMEN

BACKGROUND: Medial displacement calcaneal osteotomy (MDCO) is frequently used for the surgical correction of flatfoot. This study aims to investigate the biomechanical effect of the different diagonal screw design on a novel-designed embedded calcaneal plate for MDCO using finite element analysis (FEA), mechanical test and digital image correlation (DIC) measurement. METHODS: Four groups according to the varied implanted plate were set as control group (Group 1), non-diagonal screw (Group 2), one-diagonal screw (Group 3), and two-diagonal screws groups (Group 4). For FEA, A 450 N load was applied to on the anterior process of the calcaneus from top to bottom. Observational indices included the stress on the cortical and cancellous bone of the calcaneus surrounding the implant, the plate itself as well as screws, and the displacement of the overall structure. In addition, this study also used in vitro biomechanics test to investigate the stiffness of the structure after implantation, and used DIC to observe the displacement of the calcaneus structure after external force. RESULTS: Under a simulated load in FEA, there are significant overall instability and high stress concentration on the calcaneal surrounding host bone and the plate/screws system, respectively, in group 2 compared with other groups. Regard to the mechanical testing with DIC system, significant increased rotation stability, maximum force and stiffness with the addition of diagonal screws. In comparison to Group 2, the increase of 112% and 157% in maximum force as well as 104% and 176% in stiffness were found in Group 3 and 4, respectively. CONCLUSION: For reducing stress concentration and enhancing overall stability, more than one-diagonal screw design is recommended and two-diagonal screws design will be superior. This study provided biomechanical references for further calcaneal implants design to prevent clinical failure after MDCO.


Asunto(s)
Placas Óseas , Tornillos Óseos , Fijación Interna de Fracturas/métodos , Espolón Calcáneo/cirugía , Fenómenos Biomecánicos , Análisis de Elementos Finitos , Humanos , Osteotomía/métodos , Soporte de Peso
19.
J Clin Med ; 10(18)2021 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-34575339

RESUMEN

PURPOSE: Maintaining gap balance is critical for total knee arthroplasty (TKA). This study aimed to elucidate if the extension-flexion gaps would be changed with posterior cruciate ligament (PCL) intact (PI) and PCL resection (PR) during TKA. The flexion gaps were measured using two methods, open-(Fo) and closed-chain position (Fc), based on the definition of kinetic chain position, respectively. METHODS: This retrospective study enrolled a total of 33 patients who underwent posterior-stabilized (PS) TKA for symptomatic advanced osteoarthritis of knees. After bone cuts were completed, the extension-flexion gaps before and after PCL resection during TKA were measured using a calibrated tensioning device set at a 100 Nm distraction force. To further differentiate the effect of thigh weight on the 90° flexion gap, two varied methods of examination, either in closed chain (Fc) or open chain (Fo) were performed. RESULTS: The increases in the 90° knee flexion gap after PCL resection were measured by both methods, i.e., ΔFc (PR-Fc-PI-Fc): 2.04 ± 2.06 mm, p < 0.001; and mean ΔFo (PR-Fo-PI-Fo): 1.64 ± 1.36 mm, p < 0.001. However, there were no differences between ΔFc and ΔFo before and after PCL resection. A greater amount of flexion gap was identified in open chain than in closed chain after PCL resection, and the PR-Fo and PR-Fc were 14.36 ± 3.13 and 11.40 ± 3.47 (p < 0.001), respectively. CONCLUSIONS: The resection of PCL during TKA distinctly increased the flexion gap, but not the extension gap. This disproportionate increase of the gap will cause a gap balance mismatch. The tensioning maneuver in open-chain was more effective to detect the gap differences than in closed-chain before and after PCL resection during TKA.

20.
J Clin Med ; 10(16)2021 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-34441920

RESUMEN

This study investigated the differences in ankle alignment changes after TKA in patients with varying preexisting ankle deformities. We retrospectively examined 90 knees with osteoarthritis and varus deformity in 78 patients who underwent TKA. Preoperative and postoperative radiographic parameters were analyzed. According to their preexisting ankle deformity, patients were assigned to the valgus or varus group. Overall, 14 (15.6%) cases were of preoperative valgus ankle deformity; the remainder were of preoperative varus ankle deformity. Hip-knee-ankle angle (HKA), tibial plafond-ground angle (PGA), and talus-ground angle (TGA) all exhibited significant correction in both groups; however, tibial plafond-talus angle (PTA) and superior space of ankle joint (SS) only changed in the varus group. The median PTA and SS significantly decreased from 1.2° to 0.3° (p < 0.001) and increased from 2.5 to 2.6 mm (p = 0.013), respectively. Notably, ∆PTA positively correlated with ∆HKA in the varus group (r = 0.247, p = 0.032) but not in the valgus group. Between-group differences in postoperative PTA (p < 0.001) and ∆PTA (p < 0.001) were significant. The degree of ankle alignment correction after TKA differed between patients with preexisting varus and valgus ankle deformities. TKA could not effectively correct the preexisting ankle valgus malalignment.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...