Seudotumor infectado en un paciente con artroplastia de cadera con par de fricción metal-metal / Infected pseudotumour in total hip arthroplasty with metal-on-metal friction couple

La artroplastia total de cadera es el principal tratamiento para la artrosis avanzada de cadera y las complicaciones pueden ser luxación, infección, aflojamiento aséptico y, en menor medida, reacciones adversas al metal. El seudotumor es una complicación poco frecuente con un par de fricción metal-metal. El diagnóstico y el tratamiento correctos son muy importantes para disminuir la morbimortalidad. Presentamos el caso de un hombre de 63 años que había sido sometido a una artroplastia total de cadera con un par de fricción metal-metal, 13 años atrás. Al consultar, tenía una gran masa en el glúteo derecho y parestesias en el territorio ciático homolateral. Se diagnosticó seudotumor asociado a infección periprotésica y el tratamiento definitivo consistió en revisión en un tiempo y la administración de antibióticos. Nivel de Evidencia: IV

Total hip arthroplasty (THA) is the main treatment for advanced hip osteoarthritis and its complications include dislocation, infec-tion, aseptic loosening and, to a lesser extent, adverse reactions to metal. Pseudotumor is a rare complication of THA with a metal-on-metal friction couple; its diagnosis and treatment are extremely important to reduce morbidity and mortality. We present the case of a 63-year-old male patient with a 13-year history of THA with a metal-on-metal friction couple who, at the time of con-sultation, presented a large palpable mass in the right gluteus and paresthesias in the homolateral sciatic nerve. The diagnosis of an infected pseudotumor was reached and treated with hip revision and antibiotic therapy. Level of Evidence: IV

Análisis clínico-radiológico comparativo de tallos femorales no cementados planos de primera vs. segunda generación / Comparative clinical-radiological analysis of first-generation vs. second-generation flat cementless femoral stems

Introducción: El diseño del implante femoral es imprescindible para su adaptación a los distintos tipos de canales. El objetivo del estudio fue comparar la adaptabilidad del implante y el tipo de contacto de los tallos femorales planos de segunda generación. Materiales y Métodos: Se analizó a los pacientes sometidos a un reemplazo total de cadera bilateral en nuestra institución, entre 2007 y 2020, a quienes se les colocó un tallo de primera generación (Accolade TMZF) en una cadera y de segunda generación (Accolade II) en la contralateral. Se estudiaron las variables demográficas, la adaptación y el llenado del canal. Se analizó el Harris Hip Score modificado y el índice WOMAC. Resultados:Se incluyó a 42 pacientes (84 casos).En el grupo 1 (Accolade TMZF), la ocupación del canal fue del 81% y, en el grupo 2 (Accolade II), del 84%. En el grupo 1, el contacto fue tipo 1 (60%), tipo 2 (16%) y tipo 3 (24%). En el grupo 2, fue tipo 1 (88%), tipo 2 (7%) y tipo 3 (5%). El Harris Hip Score modificado para el grupo 1 fue 88 y, para el grupo 2, 87,5. El puntaje WOMAC para el grupo 1 fue 2,5 y, para el grupo 2, de 3. Conclusión: La adaptabilidad del implante es fundamental para la estabilidad primaria y su osteointegración/fijación biológica. En nuestra muestra, es más precisa con tallos de segunda generación debido a las modificaciones del diseño. Nivel de Evidencia: IV

Introduction: The design of the femoral implant is essential for its adaptation to the different types of femoral canals. The objective of this study is to describe the adaptability of the implant and the type of fixation (fill and fit) of second-generation flat femoral stems compared to first-generation femoral stems. Materials and Methods: We described the radiological characteristics of patients who had undergone bilateral total hip replacement between 2007 and 2020 in our institution with both a first-generation Accolade TMZF (Stryker Orthopedics) and a second-generation Accolade II (Stryker Orthopedics) flat cementless femoral implant. Demographic variables, adaptation, and canal filling were studied. The modified Harris Hip Score and the WOMAC index were analyzed. Results: Forty-two patients (84 cases) were included in the sample. In group 1 (Accolade TMZF) we obtained an average canal fill of 81% and in group 2 (Accolade II), we obtained an average of 84%. In group 1, the type of fixation (fit) was type 1 (60%), type 2 (16%) and type 3 (24%). In group 2, it was type 1 (88%), type 2 (7%) and type 3 (5%). The modified Harris Hip Score for group 1 was 88 and, for group 2, 87.5. The WOMAC score for group 1 was 2.5 and for group 2 it was 3. Conclusion: The adaptability of the implant is essential for primary stability and its osseointegration/biological fixation. This adaptability is more precise with second-generation flat femoral stems. Level of Evidence: IV

The immunogenetic diversity of the HLA system in Mexico correlates with underlying population genetic structure.

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) allele groups and alleles by PCR-SSP based typing in a total of 15,318 mixed ancestry Mexicans from all the states of the country divided into 78 sample sets, providing information regarding allelic and haplotypic frequencies and their linkage disequilibrium, as well as admixture estimates and genetic substructure. We identified the presence of 4268 unique HLA extended haplotypes across Mexico and find that the ten most frequent (HF > 1%) HLA haplotypes with significant linkage disequilibrium (Δ'≥0.1) in Mexico (accounting for 20% of the haplotypic diversity of the country) are of primarily Native American ancestry (A*02~B*39~DRB1*04~DQB1*03:02, A*02~B*35~DRB1*08~DQB1*04, A*68~B*39~DRB1*04~DQB1*03:02, A*02~B*35~DRB1*04~DQB1*03:02, A*24~B*39~DRB1*14~DQB1*03:01, A*24~B*35~DRB1*04~DQB1*03:02, A*24~B*39~DRB1*04~DQB1*03:02, A*02~B*40:02~DRB1*04~DQB1*03:02, A*68~B*35~DRB1*04~DQB1*03:02, A*02~B*15:01~DRB1*04~DQB1*03:02). Admixture estimates obtained by a maximum likelihood method using HLA-A/-B/-DRB1 as genetic estimators revealed that the main genetic components in Mexico as a whole are Native American (ranging from 37.8% in the northern part of the country to 81.5% in the southeastern region) and European (ranging from 11.5% in the southeast to 62.6% in northern Mexico). African admixture ranged from 0.0 to 12.7% not following any specific pattern. We were able to detect three major immunogenetic clusters correlating with genetic diversity and differential admixture within Mexico: North, Central and Southeast, which is in accordance with previous reports using genome-wide data. Our findings provide insights into the population immunogenetic substructure of the whole country and add to the knowledge of mixed ancestry Latin American population genetics, important for disease association studies, detection of demographic signatures on population variation and improved allocation of public health resources.

Genetic diversity of HLA system in two populations from Hidalgo, Mexico: Pachuca and rural Hidalgo.

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) alleles by PCR-SSP based typing in 122 Mexicans from the state of Hidalgo living in the city of Pachuca (N = 41) and rural communities (N = 81), to obtain information regarding allelic and haplotypic frequencies. We find that the most frequent haplotypes in Hidalgo include eight Native American and one European haplotypes. Admixture estimates revealed that the main genetic components in Hidalgo are Native American (58.93 ±â€¯2.16% by ML; 54.51% of Native American haplotypes) and European (32.49 ±â€¯2.88% by ML; 28.69% of European haplotypes), and a relatively high African genetic component (8.58 ±â€¯0.93% by ML; 6.97% of African haplotypes).

Genetic diversity of HLA system in two populations from Morelos, Mexico: Cuernavaca and rural Morelos.

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) alleles by PCR-SSP based typing in 112 Mexicans from the state of Morelos living in the city of Cuernavaca (N = 82) and rural communities (N = 30), to obtain information regarding allelic and haplotypic frequencies. The most frequent haplotypes in Morelos include seven Native American, one European, one African and one Asian haplotype. Admixture estimates revealed that the main genetic components in Morelos are Native American (60.43 ±â€¯2.22% by ML; 53.57% of Native American haplotypes) and European (39.58 ±â€¯3.70% by ML; 27.68% of European haplotypes), and a virtually absent African genetic component (0.00 ±â€¯4.93% by ML; but 11.16% of African haplotypes).

Genetic diversity of HLA system in six populations from Mexico City Metropolitan Area, Mexico: Mexico City North, Mexico City South, Mexico City East, Mexico City West, Mexico City Center and rural Mexico City.

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) alleles by PCR-SSP based typing in 1217 Mexicans from the Mexico City Metropolitan Area living in the northern (N = 751), southern (N = 52), eastern (N = 79), western (N = 33), and central (N = 152) Mexico City, and rural communities (N = 150), to obtain information regarding allelic and haplotypic frequencies. We found that the most frequent haplotypes include 11 Native American haplotypes. Admixture estimates revealed that the main genetic components are Native American (63.85 ±â€¯1.55% by ML; 57.19% of Native American haplotypes) and European (28.53 ±â€¯3.13% by ML; 28.40% of European haplotypes), and a less apparent African genetic component (7.61 ±â€¯1.96% by ML; 7.17% of African haplotypes).

HLA concordance between hematopoietic stem cell transplantation patients and umbilical cord blood units: Implications for cord blood banking in admixed populations.

Umbilical cord blood stem cell transplantation is an important choice for treating a variety of hematopoietic, neoplastic, and genetic disorders. The optimal size for a cord blood bank to provide matching units for 80% of patients requiring a stem cell transplantation procedure depends on the particular characteristics of each population. In this study, we analyzed the immunogenetic diversity of a sample set of Mexican patients suffering from blood, hematopoietic, and immunological diseases, to assess the best strategy for cord blood banking. For achieving that, we analyzed HLA-A, HLA-B, HLA-DRB1, and HLA-DQB1 genotype and allele frequencies of both units from the bioarchive of the Umbilical Cord Blood Bank from La Raza and patients requiring a stem cell transplant and compared these variables with data from the same geographic and genetic context. We were able to detect significant differences for at least half of the alleles were observed for HLA class I and class II genes between units and patients. Five Native American haplotypes had lower frequencies in patients sample than in the cord blood units. Genetic admixture estimations for both groups showed a higher contribution of Native American component in the cord blood units. Differences in ancestral components in the Umbilical Cord Blood Bank from La Raza and six virtual banks modeled from a pool of Mexican mixed ancestry individuals show that genetic background is important in cord blood collection. In conclusion, increasing diversity over quantity of new cord blood units will improve the cost effectiveness of cord blood banking and health policies regarding hematopoietic stem cell transplantation in admixed populations such as those present in Latin American countries.

Genetic Differentiation in a Sample from Northern Mexico City Detected by HLA System Analysis: Impact in the Study of Population Immunogenetics.

The major histocompatibility complex is directly involved in the immune response, and thus the genes coding for its proteins are useful markers for the study of genetic diversity, susceptibility to disease (autoimmunity and infections), transplant medicine, and pharmacogenetics, among others. The polymorphism of the system also allows researchers to use it as a proxy for population genetics analysis, such as genetic admixture and genetic structure. In order to determine the immunogenetic characteristics of a sample from the northern part of Mexico City and to use them to analyze the genetic differentiation from other admixed populations, including those from previous studies of Mexico City population, we analyzed molecular typing results of donors and patients from the Histocompatibility Laboratory of the Central Blood Bank of the Centro Médico Nacional La Raza selected according to their geographic origin. HLA-A, -B, -DRB1, and -DQB1 alleles were typed by polymerase chain reaction with sequence-specific primers. Allelic and haplotype frequencies, as well as population genetics parameters, were obtained by maximum likelihood methods. The most frequent haplotypes found were HLA-A*02/-B*39/-DRB1*04/-DQB1*03:02P, HLA-A*02/-B*35/-DRB1*04/-DQB1*03:02P, HLA-A*68/-B*39/-DRB1*04/-DQB1*03:02P, and HLA-A*02/-B*35/-DRB1*08/-DQB1*04. Importantly, the second most frequent haplotype found in our sample (HLA-A*02/-B*35/-DRB1*04/-DQB1*03:02P) has not been previously reported in any mixedancestry populations from Mexico but is commonly encountered in Native American human groups, which can reflect the impact of migration dynamics in the genetic conformation of the northern part of Mexico City, and the limitations of previous studies with regard to the genetic diversity of the analyzed groups. Differences found in haplotype frequencies demonstrated that large urban conglomerates cannot be analyzed as one homogeneous entity but, rather, should be understood as a set of structures in which social, political, and economical factors influence their genesis and dynamics.