A proposal for the study of cementless short-stem hip prostheses / Una propuesta para el estudio de prótesis de cadera de vástago corto

Abstract: Background: With the recent evolution of hip arthroplasty, new models of short stems have emerged. So far, we do not have a clear strategy to analyze their outcomes, since there is confusion around the definition of short stem and there is no consensus for their classification. Purposes: The purpose of this study was to review the current state of the art of cementless short stems considering the main design characteristics; it provides a definition of short stem and proposes a classification, grouping them into families by means of a nomenclature that describes them accurately. Material and methods: We conducted a search in the PubMed and Scopus databases and consulted various implant manufacturers, foundations devoted to research on joint arthroplasty, organizations of independent experts on medical device analysis, and national arthroplasty registries. The stems studied were classified according to a new nomenclature system. Conclusions: We identified 44 different models that share 84 design variables and may be grouped into three types and 16 generic families. The stems were manufactured by 20 different companies. Short stems are those occupying the neck, metaphysis and the proximal aspect of the limit between the metaphysis and diaphysis, regardless of the geometric type of endosteum present. A wide variety of models was identified, with multiple design variables. In order to classify them, it was necessary to design a whole new nomenclature capable of describing them in an unequivocal, unique and distinctive way.

Resumen: Antecedentes: Con la reciente evolución de la artroplastia de cadera han surgido nuevos modelos con componentes femorales cortos. Aún no se tiene una forma clara de analizar sus resultados pues existe confusión en las definiciones y no tenemos una clasificación universal. Objetivos: Revisar el estado del arte de los componentes femorales cortos no cementados, considerar sus características de diseño, tratar de establecer una clasificación y una nomenclatura que permita una mejor definición del implante. Material y métodos: Realizamos una búsqueda en PubMed y Scopus, consultamos a varios fabricantes, fundaciones dedicadas a la investigación en artroplastías, organizaciones dedicadas al análisis de los implantes y algunos registros nacionales de artroplastías. Los componentes femorales estudiados se agruparon en esta clasificación propuesta. Conclusiones: Identificamos 3 tipos y 16 familias genéricas de implantes, se logró establecer una clasificación que generó una nueva nomenclatura que permite la identificación específica de cada uno de los diseños.

Endotoxins in surgical instruments of hip arthroplasty / Endotoxinas en instrumentales quirúrgicos de artroplastia de la cadera / Endotoxinas em instrumentais cirúrgicos de artroplastia do quadril

Abstract OBJECTIVE To investigate endotoxins in sterilized surgical instruments used in hip arthroplasties. METHOD A descriptive exploratory study conducted in a public teaching hospital. Six types of surgical instruments were selected, namely: acetabulum rasp, femoral rasp, femoral head remover, chisel box, flexible bone reamer and femoral head test. The selection was based on the analysis of the difficulty in removing bone and blood residues during cleaning. The sample was made up of 60 surgical instruments, which were tested for endotoxins in three different stages. The EndosafeTM Gel-Clot LAL (Limulus Amebocyte Lysate method) was used. RESULT There was consistent gel formation with positive analysis in eight instruments, corresponding to 13.3%, being four femoral rasps and four bone reamers. CONCLUSION Endotoxins in quantity ≥0.125 UE/mL were detected in 13.3% of the instruments tested.

Resumen OBJETIVO Investigar las endotoxinas en instrumentales quirúrgicos esterilizados empleados en artroplastias de la cadera. MÉTODO Estudio exploratorio, descriptivo, desarrollado en un hospital público de enseñanza. Fueron seleccionados seis tipos de instrumentales, a saber: raspa de acetábulo, raspa femoral, sacacorchos (para extraer la cabeza femoral), gubia quirúrgica, fresa femoral y cabeza femoral de prueba. La selección se hizo desde el análisis de la dificultad para la retirada de residuos de sangre y hueso durante la limpieza. La muestra estuvo constituida de 60 instrumentales quirúrgicos, que fueron puestos a prueba para endotoxinas en tres momentos diferentes. Se utilizó el método de gelificación (Gel-clot) Lisado de Amebocitos de Limulus (LAL) Endosafe(tm). RESULTADO Hubo formación de gel consistente con análisis positivo en ocho instrumentos, lo que corresponde a el 13,3%, siendo cuatro raspas femorales y cuatro fresas femorales. CONCLUSIÓN Fueron detectadas endotoxinas en cantidad ≥0,125 UE/mL en el 13,3% de los instrumentos probados.

Resumo OBJETIVO Investigar endotoxinas em instrumentais cirúrgicos esterilizados empregados em artroplastias do quadril. MÉTODO Estudo exploratório, descritivo, desenvolvido em um hospital público de ensino. Foram selecionados seis tipos de instrumentais, a saber: raspa acetabular, raspa femural, saca-cabeça de fêmur, formão box, fresa de fêmur e cabeça de prova de fêmur. A seleção foi feita a partir da análise da dificuldade para a remoção de resíduos de sangue e osso durante a limpeza. A amostra foi constituída por 60 instrumentais cirúrgicos, que foram testados para endotoxinas em três momentos distintos. Foi utilizado o método de gel-clot pelo Limulus Amebócito Lisado (LAL) Endosafe(tm). RESULTADO Houve formação de gel consistente com análise positiva em oito instrumentais, o que corresponde a 13,3%, sendo quatro raspas de fêmur e quatro fresas de fêmur. CONCLUSÃO Foram detectadas endotoxinas em quantidade ≥0,125 UE/mL em 13,3% dos instrumentais testados.

Incidencia de chirridos con el uso de cerámica en cerámica Biolox® Delta en artroplastía de cadera / Incidence of squeaking using third-generation Biolox® Delta ceramic-on-ceramic hip bearing surfaces

Introducción: La superficie cerámica-cerámica causa complicaciones, como la fractura y la generación de ruidos articulares (squeaking). Este estudio muestra nuestra experiencia con la utilización del compuesto de matriz alúmina (cerámica Delta). Materiales y Métodos: Se evaluaron, en forma retrospectiva, 109 caderas, 97 pacientes, con edad promedio de 49 años (rango 17-77). Ciento dos de estas caderas fueron cirugías primarias, mientras que 7 fueron revisiones. Todos los componentes acetabulares fueron Pinnacle® (DePuy Orthopaedics, Warsaw, Indiana, EE.UU). La cerámica utilizada en todos los casos fue Biolox® Delta (Ceram Tec AG, Plochingen, Alemania). Resultados: El seguimiento fue de 37 meses (rango 24-50). Se realizó la medición radiográfica de la anteversión, por el método de Ackland (rango 1°-35°), la inclinación (rango 22°-67°), el diámetro acetabular (rango 48-62 mm), el tamaño de la cabeza femoral (88: 36 mm y 21: 28 mm) y la lateralización antes de la cirugía y después de ella. Se evaluó a todos los pacientes con el puntaje de Harris, los resultados fueron, en su mayoría, muy buenos y algunos, buenos. Las complicaciones fueron: una luxación (0,91%), una subluxación protésica (0,91%), una infección aguda (0,91%), una fractura periprotésica (0,91%), una rotura del inserto de cerámica (0,91%). Ningún paciente refirió ruidos o una cadera chirriante. Conclusión: En esta serie, no se reportaron episodios de chirridos, pese a la gran variación en la anteversión y la inclinación del componente acetabular. Creemos que la composición y el diseño de la cerámica de tercera generación determinarían un menor índice de chirridos que las de segunda generación.

Background: Squeaking is the most frequently related complication with ceramic on ceramic total hip arthroplasty. Third generation Delta ceramics present improved mechanical properties and so far squeaking has not been reported with this bearing surface. The aim of this study was to analyze the incidence of squeaking with the use of third-generation ceramics. Methods: This study included 109 hips in 97 patients, with an average age of 49 years (range 17-77 years), an average body mass index of 22.3 (range 19-48). One hundred and two hips were primary total hip arthroplasties, whereas 7 were revisions. Femoral and acetabular components were Pinnacle® (DePuy Orthopaedics, Warsaw, Indiana, USA). The ceramic used was Biolox® Delta (Ceram Tec AG, Plochingen, Germany) in all the cases. Results: Average follow-up was 37 months (range 24-50 months). Radiographic assessment of the anteversion was made with the Ackland method (range 1°-35°). Inclination (range 22°-67°), acetabulum diameter (range 48-62), size of the femoral head (88 = 36 mm and 21 = 28 mm) and pre- and post-operative offset were also evaluated. We observed 2 dislocations, 1 acute superficial infection, 1 periprosthetic fracture and 1 fracture of the ceramic acetabular insert due to incomplete seating of the acetabular liner. No patient referred noise or a squeaking hip. Conclusion: In this series, squeaking was not observed although the range of anteversion and inclination of the cups was widely variable. Due to its composition and design Delta Ceramic components may have a lower rate of squeaking than second-generation ceramics.

Accurate Leg Length Measurement in Total Hip Arthroplasty: A Comparison of Computer Navigation and a Simple Manual Measurement Device

BACKGROUND: Several studies have shown that better placement of the acetabular cup and femoral stem can be achieved in total hip arthroplasty (THA) by using the computer navigation system rather than the free-hand alignment methods. However, there have been no comparisons of the relevant clinical advantages in using the computer navigation as opposed to the manual intraoperative measurement devices. The purpose of this study is to determine whether the use of computer navigation can improve postoperative leg length discrepancy (LLD) compared to the use of the measurement device. METHODS: We performed a retrospective study comparing 30 computer-assisted THAs with 40 THAs performed using a simple manual measurement device. RESULTS: The postoperative LLD was 3.0 mm (range, 0 to 8 mm) in the computer-assisted group and 2.9 mm (range, 0 to 10 mm) in the device group. Statistically significant difference was not seen between the two groups. CONCLUSIONS: The results showed good equalization of the leg lengths using both computed tomography-based navigation and the simple manual measurement device.

Future Bearing Surfaces in Total Hip Arthroplasty

One of the most important issues in the modern total hip arthroplasty (THA) is the bearing surface. Extensive research on bearing surfaces is being conducted to seek an ideal bearing surface for THA. The ideal bearing surface for THA should have superior wear characteristics and should be durable, bio-inert, cost-effective, and easy to implant. However, bearing surfaces that are currently being implemented do not completely fulfill these requirements, especially for young individuals for whom implant longevity is paramount. Even though various new bearing surfaces have been investigated, research is still ongoing, and only short-term results have been reported from clinical trials. Future bearing surfaces can be developed in the following ways: (1) change in design, (2) further improvement of polyethylene, (3) surface modification of the metal, (4) improvement in the ceramic, and (5) use of alternative, new materials. One way to reduce wear and impingement in THA is to make changes in its design by using a large femoral head, a monobloc metal shell with preassembled ceramic liner, dual mobility cups, a combination of different bearing surfaces, etc. Polyethylene has improved over time with the development of highly crosslinked polyethylene. Further improvements can be made by reinforcing it with vitamin E or multiwalled carbon nanotubes and by performing a surface modification with a biomembrane. Surface modifications with titanium nitride or titanium niobium nitride are implemented to try to improve the metal bearings. The advance to the fourth generation ceramics has shown relatively promising results, even in young patients. Nevertheless, further improvement is required to reduce fragility and squeaking. Alternative materials like diamond coatings on surfaces, carbon based composite materials, oxidized zirconium, silicon nitride, and sapphire are being sought. However, long-term studies are necessary to confirm the efficacy of these surfaces after enhancements have been made with regard to fixation technique and implant quality.

Terapia de reposição volêmica durante artroplastia de quadril usando hidroxietilamido (130/0, 4) comparado com Ringer lactato diminui transfusão de sangue alogênico e infecção pós-operatória / Volume replacement therapy during hip arthroplasty using hydroxyethyl starch (130/0. 4) compared to lactated Ringer decreases allogeneic blood transfusion and postoperative infection / Terapia de reposición volémica durante la artroplastia de cadera usando hidroxietilalmidón (130/0, 4): comparado con lactato de Ringer reduce la transfusión de sangre alogénica y la infección posoperatoria

JUSTIFICATIVA E OBJETIVOS: O hidroxietilamido 130/0,4 (HES 130/0,4) é considerado um expansor plasmático efetivo quando comparado com cristaloides. Há controvérsia sobre sua superioridade em relação à otimização hemodinâmica e sobre possíveis efeitos prejudiciais na coagulação. O objetivo deste estudo foi comparar os efeitos do HES 130/0,4 com os da solução de Ringer lactato durante artroplastia de quadril em pacientes adultos sob raquianestesia e levou em consideração sangramento intraoperatório, parâmetros hemodinâmicos, coagulograma, necessidade de transfusão e desfechos clínicos. MÉTODOS: Neste estudo randômico e controlado, 48 pacientes agendados para artroplastia de quadril com raquianestesia foram alocados em dois grupos: 24 receberam uma pré-carga de HES 130/0,4 (15 mL.kg-1) e 24 receberam uma pré-carga de solução de Ringer lactato (30 mL. kg-1) antes da cirurgia. Mensurações hemodinâmicas, concentração de hemoglobina, parâmetros bioquímicos e testes de coagulação foram avaliados em três períodos durante o procedimento cirúrgico. Os pacientes receberam acompanhamento médico durante a internação e até 30 dias no período pós-operatório. O principal fator foi a necessidade de transfusão de hemácias entre os grupos durante a internação. Os fatores secundários foram parâmetros hemodinâmicos, tempo de internação, mortalidade e ocorrência de complicações clínicas. no período pós-operatório. O principal fator foi a necessidade de transfusão de hemácias entre os grupos durante a internação. Os fatores secundários foram parâmetros hemodinâmicos, tempo de internação, mortalidade e ocorrência de complicações clínicas. RESULTADOS: A transfusão de hemácias foi necessária em 17% dos pacientes do grupo HES e em 46% dos pacientes do grupo Ringer lactato (p = 0,029). Infecções pós-operatórias foram observadas com mais frequência no grupo de Ringer lactato (17%) em comparação com o grupo HES (0), p = 0,037. Não houve diferenças significativas entre os grupos em relação à mortalidade, ao tempo de internação e às complicações clínicas, exceto infecção. CONCLUSÕES: Durante a artroplastia de quadril, os pacientes tratados com hemodiluição hipervolêmica normal com hidroxietilamido 130/0,4 precisaram de menos transfusão e apresentaram índice menor de infecção em comparação com os pacientes que receberam Ringer lactato.

BACKGROUND AND OBJECTIVES: Hydroxyethyl starch (HES) 130/0.4 is considered an effective plasma expander when compared to crystalloids. There is controversy around its superiority regarding hemodynamic optimization and about possible detrimental effects on coagulation. The aim of this study was to compare the effects of HES 130/0.4 to lactated Ringer solution during hip arthroplasty in adult patients under spinal anesthesia regarding intraoperative bleeding, hemodynamic parameters, coagulation profile, transfusion requirements and clinical outcomes. METHODS: In this randomized, controlled trial, 48 patients scheduled for hip arthroplasty with spinal anesthesia were randomized into two groups: 24 patients were allocated to receive a preload of 15 mL.kg-1 of HES 130/0.4 and 24 patients received a preload of 30 mL.kg-1 lactated Ringer solution before surgery. Hemodynamic measurements, hemoglobin concentrations, biochemical parameters and coagulation tests were evaluated in three periods during surgical procedure. Patients received medical follow-up during their hospital stay and up to postoperative 30 days. Primary outcome was the requirement of red blood cell transfusion between groups during hospital stay. Secondary outcome were hemodynamic parameters, length of hospital stay, mortality and occurrence of clinical postoperative complications. RESULTS: Red blood cell transfusion was required in 17% of patients in the HES group and in 46% in the Ringer group (p = .029). Postoperative infections were more frequently observed in the Ringer group (17%) compared to the HES group (0), p = .037. There were no significant differences between groups in mortality, hospital length of stay and clinical complications other than infection. Conclusions: During hip arthroplasty, patients treated with hypervolemic hemodilution with hydroxyethyl starch 130/0.4 required less transfusion and presented lower infection rate compared to patients who received lactated Ringer.

JUSTIFICATIVA Y OBJETIVOS: El hidroxietilalmidón 130/0,4 (HES 130/0,4) está considerado como un expansivo plasmático efectivo cuando se le compara con los cristaloides. Existen controversias sobre su superioridad con relación a la optimización hemodinámica y sobre posibles efectos perjudiciales en la coagulación. El objetivo de este estudio, fue comparar los efectos del HES 130/0,4 con los de la solución de lactato de Ringer durante la artroplastia de cadera en pacientes adultos bajo raquianestesia, considerando el sangramiento intraoperatorio, los parámetros hemodinámicos, el coagulograma, la necesidad de transfusión y los resultados clínicos. MÉTODOS: En este estudio aleatorio y controlado, 48 pacientes citados para la artroplastia de cadera con raquianestesia fueron aleatoriamente divididos en dos grupos: 24 pacientes fueron ubicados para recibir una pre-carga de HES 130/0,4 (15 mL.kg-1) y 24 pacientes recibieron una pre-carga de solución de lactato de Ringer (30 mL.kg-1) antes de la cirugía. Las medidas hemodinámicas, concentración de hemoglobina, parámetros bioquímicos y los test de coagulación fueron evaluados en tres períodos durante el procedimiento quirúrgico. Los pacientes recibieron un acompañamiento médico durante el ingreso y de 30 días en el período del postoperatorio. El principal factor fue la necesidad de transfusión de hematíes entre los grupos durante el ingreso. Los factores secundarios fueron los parámetros hemodinámicos, tiempo de ingreso, mortalidad y aparecimiento de complicaciones clínicas. RESULTADOS: La transfusión de hematíes fue necesaria en un 17% de los pacientes del grupo HES y en un 46% de los pacientes del grupo lactato de Ringer (p = 0,029). Las infecciones postoperatorias fueron observadas con más frecuencia en el grupo lactato de Ringer (17%) en comparación con el grupo HES (0), p = 0,037. No hubo diferencias significativas entre los grupos con relación a la mortalidad, tiempo de ingreso y complicaciones clínicas, excepto en la infección. Conclusiones: Durante la artroplastia de cadera, los pacientes tratados con hemodilución hipervolémica normal con hidroxietilalmidón 130/0.4 necesitaron menos transfusión y presentaron un índice menor de infección en comparación con los pacientes que recibieron lactato de Ringer.

Cementless Total Hip Arthroplasty for Patients with Crowe Type III or IV Developmental Dysplasia of the Hip: Two-Stage Total Hip Arthroplasty Following Skeletal Traction after Soft Tissue Release for Irreducible Hips

BACKGROUND: Total hip arthroplasty (THA) for severe developmental dysplasia of the hip (DDH) is a technically demanding procedure for arthroplasty surgeons, and it is often difficult to reduce the hip joint without soft tissue release due to severe flexion contracture. We performed two-stage THAs in irreducible hips with expected lengthening of the affected limb after THA of over 2.5 cm or with flexion contractures of greater than 30 degrees in order to place the acetabular cup in the true acetabulum and to prevent neurologic deficits associated with acute elongation of the limb. The purpose of this study is to evaluate the outcomes of cementless THA in patients with severe DDH with a special focus on the results of two-stage THA. METHODS: Retrospective clinical and radiological evaluations were done on 17 patients with Crowe type III or IV developmental DDH treated by THA. There were 14 women and 3 men with a mean age of 52.3 years. Follow-ups averaged 52 months. Six cases were treated with two-stage THA followed by surgical hip liberalization and skeletal traction for 2 weeks. RESULTS: The mean Harris hip score improved from 40.9 to 89.1, and mean leg length discrepancy (LLD) in 13 unilateral cases was reduced from 2.95 to 0.8 cm. In the patients who underwent two-stage surgery, no nerve palsy was observed, and the single one-stage patient with incomplete peroneal nerve palsy recovered fully 4 weeks postoperatively. CONCLUSIONS: The short-term clinical and radiographic outcomes of primary cementless THA for patients with Crowe type III or IV DDH were encouraging. Two-stage THA followed by skeletal traction after soft tissue release could provide alternative solutions to the minimization of limb shortenings or LLD without neurologic deficits in highly selected patients.

Computer-Assisted Orthopaedic Surgery and Robotic Surgery in Total Hip Arthroplasty

Various systems of computer-assisted orthopaedic surgery (CAOS) in total hip arthroplasty (THA) were reviewed. The first clinically applied system was an active robotic system (ROBODOC), which performed femoral implant cavity preparation as programmed preoperatively. Several reports on cementless THA with ROBODOC showed better stem alignment and less variance in limb-length inequality on radiographic evaluation, less incidence of pulmonary embolic events on transesophageal cardioechogram, and less stress shielding on the dual energy X-ray absorptiometry analysis than conventional manual methods. On the other hand, some studies raise issues with active systems, including a steep learning curve, muscle and nerve damage, and technical complications, such as a procedure stop due to a bone motion during cutting, requiring re-registration and registration failure. Semi-active robotic systems, such as Acrobot and Rio, were developed for ease of surgeon acceptance. The drill bit at the tip of the robotic arm is moved by a surgeon's hand, but it does not move outside of a milling path boundary, which is defined according to three-dimensional (3D) image-based preoperative planning. However, there are still few reports on THA with these semi-active systems. Thanks to the advancements in 3D sensor technology, navigation systems were developed. Navigation is a passive system, which does not perform any actions on patients. It only provides information and guidance to the surgeon who still uses conventional tools to perform the surgery. There are three types of navigation: computed tomography (CT)-based navigation, imageless navigation, and fluoro-navigation. CT-based navigation is the most accurate, but the preoperative planning on CT images takes time that increases cost and radiation exposure. Imageless navigation does not use CT images, but its accuracy depends on the technique of landmark pointing, and it does not take into account the individual uniqueness of the anatomy. Fluoroscopic navigation is good for trauma and spine surgeries, but its benefits are limited in the hip and knee reconstruction surgeries. Several studies have shown that the cup alignment with navigation is more precise than that of the conventional mechanical instruments, and that it is useful for optimizing limb length, range of motion, and stability. Recently, patient specific templates, based on CT images, have attracted attention and some early reports on cup placement, and resurfacing showed improved accuracy of the procedures. These various CAOS systems have pros and cons. Nonetheless, CAOS is a useful tool to help surgeons perform accurately what surgeons want to do in order to better achieve their clinical objectives. Thus, it is important that the surgeon fully understands what he or she should be trying to achieve in THA for each patient.

Fifteen-year Results of Precoated Femoral Stem in Primary Hybrid Total Hip Arthroplasty

BACKGROUND: There has been controversy whether methylmethacrylate precoating of the cemented femoral stem is a solution for aseptic loosening or rather contributes to increased failure rates in cemented total hip arthroplasties. METHODS: On a retrospective basis, we analyzed 76 primary hybrid total hip arthroplasties from 63 patients with precoated, cemented femoral stems between October 1990 and December 1995. The mean age of the patients was 46.8 years (range, 22 to 77 years) with a minimum follow-up of 14 years (mean, 15.5 years; range, 14 to 19.5 years). Third generation cementing techniques were employed in all cases. RESULTS: Twenty-four out of 76 cases (31.6%) showed aseptic loosening of the femoral stems, of which 23 stems were revised at an average revision time of 8 years (range, 3 to 14.8 years). The main mode of loosening was cement-stem interface failure in 22 hips (91.7%). Twenty-one out of 24 failed hips (87.5%) demonstrated C2 cementing grades (p < 0.001). Kaplan-Meier survivorship analysis using radiographic aseptic loosening of the femoral stem as the endpoint for failure showed survival rates of 76.5% at 10 years (95% confidence interval [CI], 71.4 to 81.6) and 63.2% at 19 years (95% CI, 57.3 to 69.1). CONCLUSIONS: An early failure of the precoated femoral stem in this study was mainly due to an insufficient cementing technique. Achievement of good cement mantle may improve the survival rates.

Long-Term Follow-Up Results of a Second-Generation Cementless Femoral Prosthesis with a Collar and Straight Distal Fixation Channels

PURPOSE: We evaluated the results of more than 10 years of follow-up of total hip arthroplasty using a second-generation cementless femoral prosthesis with a collar and straight distal fixation channels. MATERIALS AND METHODS: One hundred five patients (129 hips) who underwent surgery between 1991 and 1996 for primary total hip arthroplasty using cementless straight distal fluted femoral stems were followed for more than 10 years. Ninety-four hips in 80 patients were available for clinical and radiologic analysis. The mean age at the time of surgery was 47 years, and the mean duration of follow-up was 14.3 years. RESULTS: The mean Harris hip scores had improved from 58 points to 88 points at the time of the 10-year follow-up. Activity-related thigh pain was reported in nine hips (10%). At the last follow-up, 93 stems (99%) were biologically stable and one stem (1%) was revised because of loosening. No hip had distal diaphyseal osteolysis. Proximal femoral stress-shielding was reported in 86 hips (91%). We found no significant relationship between collar-calcar contact and thigh pain, stem fixation status, or stress-shielding. The cumulative survival of the femoral stem was 99% (95% confidence interval, 98-100%) after 10 years. CONCLUSION: The long-term results of total hip arthroplasty using a second-generation cementless femoral prosthesis with a collar and straight distal fixation channels were satisfactory; however, the high rate of proximal stress-shielding and the minimal effect of the collar indicate the need for some changes in the stem design.

Cirugía de revisión acetabular utilizando un cotilo modular con superficie de metal trabecular de tantalio: resultados a corto plazo / Acetabular revision surgery using a modular acetabular cup coated with trabecular metal of tantalum: short term results

Objectives: To evaluate short-term clinical results of patients performed acetabular revision surgery using a Trabecular Tantalum coated modular acetabular cups. Materials and Methods: This is a retrospective and descriptive analysis of a serie of 32 consecutive patients (34 hips) with acetabular revision surgery (23 women, 9 men, mean age 70.7 years), mean follow-up 32 month (12-60). The Paprosky and the AAOS acetabular defects classifications were assessed. According to Paprosky acetabular defects classification, there were eleven type I, two IIA, three IIB, nine IIC, seven IIIA and two IIIB. According to AAOS acetabular defects classification there were thirteen patients with type 1, nine patients with type 2, ten type 3 and two type 4. The percentage of own acetabular bone in contact with the new cup was recorded for each patient at the time of surgery and was 45 percent (range from 20 to 80 percent), with 23 patients presenting less than 50 percent of bone contact (mean 35 percent). Postoperatively, osseous integration was radiographically assessed. Functional results were evaluated according to the Harris Hip Score (HSS). The complications related to the implant were also recorded. Results: In all radiographic assessments performed at 3, 6 and 12 month postoperatively an integrated cup without signs of migration or osteolysis was observed. Four patients (11.8 percent) presented recurrent hip dislocation that required a revision surgery without further cup revision. The final clinical assessment was performed at a mean of 26 month after surgery (12-60) with a mean HHS of 91.8 points. Conclusion: Trabecular tantalum coated modular acetabular cups in acetabular revision surgery shows good short term clinical results even with acetabular defects greater than 50 percent. No cup loosening was observed in these series.

Objetivo: Evaluar los resultados clínicos a corto plazo de pacientes sometidos a cirugía de revisión acetabular utilizando cotilos modulares con superficie de metal trabecular de tantalio. Material y Métodos: Estudio retrospectivo-descriptivo de una serie consecutiva de 32 pacientes (34 caderas) sometidos a cirugía de revisión acetabular (23 mujeres, 9 hombres, edad promedio 70,7 años), seguimiento promedio 32 meses (12-60). Se clasifican los defectos acetabulares de acuerdo ala clasificación de Paprosky y de la AAOS. Según la clasificación de Paprosky de los defectos acetabulares, 11 pacientes tenían categoría I, 2 categoría IIA, 3 categoría IIB, 9 categoría IIC, 7 categoría IIIA y 2 categoría IIIB. Según la clasificación de la AAOS, 13 pacientes correspondieron a nivel 1, 9 pacientes a nivel 2, 10 a nivel 3 y 2 a nivel 4. Se registra el porcentaje de hueso propio acetabular en contacto con el nuevo cotilo de cada paciente que fue en promedio 45 por ciento (20-80 por ciento), presentándose en 23 caderas un porcentaje < 50 por ciento, el cual fue en promedio 35 por ciento. En el postoperatorio se evalúa la integración ósea mediante radiografías de pelvis. Se evalúan los resultados funcionales mediante el HHS (Harris Hip Score) y las complicaciones postoperatorias relacionadas con el implante. Resultados: En todas las radiografías postoperatorias realizadas a los 3, 6 y 12 meses se evidenciaba el cotilo integrado, sin signos de migración ni osteolisis. Cuatro pacientes (11,8 por ciento) presentaron luxaciones recidivantes de cadera, las cuales requirieron de una cirugía de revisión sin recambio del cotilo. La última evaluación clínica fue en promedio 26 meses tras la cirugía (12-60 meses) constatándose un HHS promedio de 91,8 puntos. Conclusión: El uso de cotilos modulares con revestimiento de metal trabecular de tantalio en cirugías de revisión acetabular presenta buenos resultados clínicos a corto plazo incluso en defectos óseos acetabulares superiores...

Gait analysis of patients with metal-on-metal resurfacing hip arthroplasty compared with big-femoral-head total hip arthroplasty

To evaluate gait patterns in patients with metal-on-metal resurfacing hip arthroplasty [RHA] compared with big-femoral-head total hip arthroplasty [BHA] at one year postoperatively. In this retrospective comparative observational study, 2 groups of 30 resurfacing hip arthroplasty [RHA] and big-femoral-head total hip arthroplasty [BHA] patients participated between June 2006 and March 2009 in the Sixth Affiliated People's Hospital, Shanghai Jiaotong University, Shanghai, China. Gait parameters and range of motion [ROM] in gait cycles were measured by Vicon gait analysis system and were used to calculate operated/contralateral ratios. No significant difference was found between gait parameter ratios, Hospital for Special Surgery Score [HSS], and University of California at Los Angeles Score [UCLA] of the 2 groups. However, there was significant difference between ROM ratios in gait cycles. Range of motions of operated hip joint were more similar to that of contra-lateral side in RHA group [hip flexion/extension p=0.007, hip abduction/adductionp=0.005, hip rotation p=0.006, knee flexion/extension p=0.037]. Gait parameters of patients who underwent RHA and BHA are approaching to normal values at one year postoperatively. At the time point, ROMs of RHA patients are larger than that of BHA patients during walking

Vástago no cementado sportono. Resultado a largo plazo / Cementless spotorno stem. Long term results

El vástago Spotorno es un vástago cónico recto no cementado; inicialmente la estabilidad se consigue por el diseño el implante con una amplia zona metafisiaria provista de cuatro aletas y sección rectangular que permite una excelente estabilidad primaria axial y rotacional. Su composición Ti-6AI-7Nb (Protasul 1000) permite el crecimiento “on-growth” del tejido óseo en la superficie de titanio, proporcionando la estabilidad secundaria. Se presenta un estudio retrospectivo de 26 vástagos Spotorno, con un seguimiento medio de 134 meses. Clínicamente los resultados fueron excelentes o buenos en el 96 % de los casos. Radiológicamente todos los vástagos han sido considerados estables sin ningún caso de aflojamiento aséptico.

Spotorno stem is a tapered straight cementless stem. Spotorno Stem achieved initial stability by wedging a proximal fluted, straight stem into a retained bed a femoral trabecular and cortical bone, rectangular cross section provides excellent rotational stability distally. The titanium-aluminium-niobium alloy enables the fast on growth of newly formed osseous tissue to act as secondary stabilization. This retrospective study review 26 Spotorno stem, the mean follow-up was 134 months. Clinical result were graded excellent and good in 93 per cent of hips. At follow-up, none patient presents radiological evidence of aseptic stem loosening and 100 per cent of stems showed stable fixation.

Total hip arthroplasty in 40 years old patients or younger in comparison with the old ones

The results of total hip arthroplasty in young adults indicate a high complication rate and questionable durability. We set up this study to evaluate our experience in the mentioned topic. In a retrospective study, we evaluate 239 hips which have been undergone THA since 1983 in our hospital. We invite them for current set of clinical and radiological evaluation. Ninety Six of them responded and came for follow up. Then the Harris hip score and status of implant were compared. The mean age at the time of follow-up was 33.1 +/- 7.6 in younger group and 67 +/- 13.6 in older group. The mean Harris score, survival of cup and survival of stem was 79.8 +/- 14.6, 4 +/- 2.6 and 4.26 +/- 3 in young patients and 77.5 +/- 16.2, 5.2 +/- 3.7 and 5.3 +/- 3.6 in older patients respectively [P<0.55, P<0.06, and P<0.10 respectively]. Multivariable analysis shows significant effect of age and duration of follow up [P<0.039] on overall implant loosening which indicate the confounder role of follow up period. We match the following up period between the groups. Analysis of cemented THA shows: mean Harris score of 88 +/- 4 in younger and 8.12 +/- 11.7 in older group [P<0.27], 0% cup loosening of younger and 9.5% of older group [P<0.52] and 25% stem loosening of younger and 9.5% of the older group [P<0.38]. Analysis of cement less THA showed: mean Harris score of 76.5 +/- 15.9 in younger and 80.2 +/- 14.5 in older group [P<0.05, r-0.295] and 0% stem loosening of younger and 4% of older group [P<0.46]. The major draw back of our study was lower cementless cup survival in younger patients. Anyway, the new implant design and technique seems to improve durability of implant in younger adult but not enough to reject the concept of poor survival of THA in younger patients

Acetabular position setting in total hip arthoplasty by using V-inclinometer.

The abduction angle of the acetabular implant position is important in the process of total hip arthroplasty. The authors evaluated the potential benefit of a V-inclinometer in the prediction of the abduction angle. To evaluate the accuracy of the V-inclinometer, acetabular cups were inserted in 50 cadaveric pelvises. The abduction angle from V-inclinometer and digital photograph were compared and analyzed using paired t-test. There was no statistical difference of the acetabular abduction angle between digital photograph and V-inclinometer (P > 0.05). The V-inclinometer can be used to predict the abduction angle on a cadaveric pelvis, suggesting that it could be a useful adjunct in clinical practice.

Wear of Retrieved UHMWPE Hip Liners

After the gamma-irradiation sterilization, the most widely used orthopaedic grade polymer bearing liner material for the total joint replacement, ultra-high molecular weight polyethylene (UHMWPE), degrades through the progressive in vivo oxidation. The oxidative degradation makes UHMWPE brittle and leads to reduction of its mechanical properties. In this study, the effect of the in vivo post-irradiation ageing time on the wear of UHMWPE was investigated. Twelve retrieved polyethylene hip liners implanted for 3-16 years and then stored in the air for 1.5-8 years were used. Two types of the pin-on-disk wear testing were conducted. The uni-directional repeat pass rotating and the linear reciprocating wear testing were done with stainless steel disks against stationary polyethylene pins under 4MPa at 1Hz with bovine serum lubrication. Wear of the retrieved polyethylene hip liners does not have significant correlation with the in vivo or total ageing time. The linear reciprocal sliding motion generated a more pronounced wear than the uni-directional repeat pass sliding motion. This indicates that the kinematic motion significantly affects the wear of aged UHMWPE, having a brittle, white band region.

Metalosis por titanio. diagnostico diferencial de masa de compartimiento iliopssoas: caso clínico / Titanium metalosis. differential diagnosis of iliopssoas compartment mass: clinical case

An 52 year-old female patient with right hip joint Tuberculosis, received a Titanium total joint arthroplasty in 1991. Eleven years later, she presented low extremity swelling and inguinal mass, which was studied with ultrasound and computed tomography. The main differential diagnosis was an iliopsoas sarcoma, so an ultrasound-guided biopsy was performed. The result was Titanium particle debris. The lesion was removed, but it recurred, so that joint replacement was required. Joint Titanium particle wear debris a condition due to particle releaseis as an arthroplasty complication. When its clinical manifestation is a pelvic mass, the main differential diagnoses include tumors and granulomatous disease. Both clinical manifestations and the radiology are variable. This pathology in patient with hip joint Titanium arthroplasty must be consided.

Se presenta el caso clínico de una paciente de 52 años con diagnóstico de tuberculosis de cadera derecha a quien en 1991 se le instala prótesis de Titanio. Once años después presenta aumento de volumen de la extremidad inferior y masa palpable en zona inguinal. Fue estudiada con ultrasonografía y tomografía computada cuyos hallazgos se describen. Se planteó como diagnóstico diferencial principal un sarcoma en compartimiento iliopsoas por lo cual se realiza biopsia bajo ultrasonografía que demostró metalosis por Titanio diagnóstico que debe ser considerado en pacientes con masa inguinal y prótesis de cadera. Se reseca la lesión, la cual recidiva, requiriendo recambio articular.

Artoplastias totais do quadril com prótese PCA (Porous Coated Anatomic) / Total HIP arthroplasty with PCA (Porous Coated Anatomic) prosthesis

Foram realizadas 27 artroplastias totais do quadril nos anos de 1988 e 1993, com próteses do quadril PCA (Anatômica com revestimento poroso) em 26 pacientes. O tempo médio de seguimento foi de nove anos. Foram excluídos desta avaliação sete quadris: um devido a infecção profunda precoce, dois referentes a pacientes falecidos de causa não relacionada a operação e quatro em que os pacientes não foram localizados para a presente avaliação. A idade média no tempo da operação foi de 53 anos. O diagnóstico pré-operatório foi de osteoartrite primária em nove pacientes, osteoartrite secundária em sete pacientes e artrite inflamatória em quatro pacientes. Os pacientes foram avaliados do ponto de vista clínico, radiográfico e subjetivo. As radiografias foram estudadas em relação a ocorrência de osteólise, migração ou afrouxamento da taça, desgaste do polietileno, desprendimento de contas, afundamento ou afrouxamento da hasta femoral, reabsorção proximal do fêmur, reação periosteal, hipertrofia cortical e pedestal. Os resultados clínicos foram bons em 17 quadris (85 por cento). Três quadris apresentaram maus resultados (15 por cento) devido a migração e soltura da taça em dois casos e desgaste do polietileno em um caso. Houve concordância entre os resultados clínicos e subjetivos. Entretanto algumas alterações radiográficas observadas não se relacionaram com maus resultados.

Uso del acetabulo expansivo de spotorno en secuela e fractura acetabular / Use of spotorno expansive acetabulum in sequel of acetabular fracture

El presente trabajo es un estudio retrospectivo de 14 pacientes de cadera con artrosis secundaria a fractura del acetábulo, sometidos a artroplastia total de cadera con el uso del acetábulo no segmentado expansivo de Spotorno. La edad media de los pacientes en el momento de la artroplastia era de 47 años (28-77). El período de estudio fue de 11 años (1989- 1999), y el tiempo de seguimiento medio fue de 4 años y 9 meses. Fueron utilizados los criterios propuestos por Merle dï Aubigné y Postel para evaluación clínica, que revelaron 78,50 por ciento de los pacientes con resultados buenos y muy buenos. La evaluación radiológica, que se basó en los criterios de DeLee y Charnley, mostró líneas de radiolucencia en 3 pacientes. Basados en los resultados obtenidos en esta serie, los autores concluyen que la artrosis post traumática de acetábulo puede ser adecuadamente manejada, si hubiera indicación de artroplastia, con el uso del acetábulo expansivo de Spotorno