Evaluación clínico-radiológica de la técnica de aloinjerto compactado y vástago cementado en cirugías de revisión de cadera / Clinical-radiological evaluation of the impaction allografting and cemented rod technique in revision knee surgery

Objetivo. Evaluar a largo plazo, el resultado clínico-radiológico, la supervivencia y las complicaciones intra y postoperatorias de pacientes intervenidos de cirugía de revisión de cadera mediante esta técnica. Material y métodos. Estudio analítico observacional, prospectivo y no aleatorizado de 26 pacientes intervenidos de cirugía de revisión de cadera en nuestro hospital (1997-1998), a los que se les realizó un seguimiento clínico-radiológico y un análisis de la supervivencia del implante. Resultados. Se observan diferencias estadísticamente significativas en los valores pre y postoperatorios de las escalas de Harris y de Merle D'Aubigne. La supervivencia del implante teniendo en cuenta como punto final la cirugía de revisión fue del 84% a los 13 años. Hubo 9 complicaciones intraoperatorias (6 de ellas fueron fracturas) e influyeron de forma significativa en la estancia hospitalaria. El 70% de los pacientes no tuvo ninguna complicación postoperatoria. Ninguna de las variables analizadas influyó en el hundimiento radiográfico de los implantes. Discusión. Diversas técnicas intentan solventar el déficit de stock óseo en las cirugías de revisión de cadera, pero solo una intenta recuperarlo, el injerto compactado. Conclusiones. La técnica de Ling ofrece una mejoría clínica tanto en la escala de Merle D'Aubigne como en la de Harris, a medio-largo plazo. La presentación de complicaciones intraoperatorias incrementa la estancia hospitalaria y los días necesarios para iniciar la sedestación. La técnica de Ling es una buena opción a tener en cuenta en pacientes jóvenes en los que es previsible que haya una nueva cirugía de revisión en el futuro (AU)

Objective. Long term clinical and radiological evaluation of results, survival, and peri- operative and post-operative complications of the patients who have been operated on for revision total hip arthroplasty using the impaction allografting and cemented rod technique. Material and methods. An observational, analytical, prospective and non-random study was conducted on 26 patients who underwent revision total hip arthroplasty in our Hospital (1997-98). They were clinically and radiologically assessed, and a survival analysis of the implant was performed. Results. Statistically significant differences were identified in the pre- and post-operative values, according to Harris and Merle D'Aubigne scores. The femoral components survival was considered as an endpoint of the revision replacement, which was 84% at a mean of 13 years. There were 9 intraoperative complications (6 were fractures) and they significantly affected the length of hospital stay. No post-operative complications were observed in 70% of the patients. None of the analysed variables had any influence on the radiological subsidence of the femoral component. Discussion. Several techniques aim to solve the bone stock deficiency in revision total hip arthroplasty, but only impaction grafting attempts to recover it. Conclusions. The Ling's technique shows an improvement over the Merle D'Aubigne and Harris scores, in the medium-long term. The intraoperative complications are mainly an increase in the length of hospital stay and the number of days needed to be able to sit down. Ling's technique is a good option to consider in young patients where it is foreseeable that there is a new revision surgery in the future (AU)

[Clinical-radiological evaluation of the impaction allografting and cemented rod technique in revision knee surgery]. / Evaluación clínico-radiológica de la técnica de aloinjerto compactado y vástago cementado en cirugías de revisión de cadera.

OBJECTIVE: Long term clinical and radiological evaluation of results, survival, and peri- operative and post-operative complications of the patients who have been operated on for revision total hip arthroplasty using the impaction allografting and cemented rod technique. MATERIAL AND METHODS: An observational, analytical, prospective and non-random study was conducted on 26 patients who underwent revision total hip arthroplasty in our Hospital (1997-98). They were clinically and radiologically assessed, and a survival analysis of the implant was performed. RESULTS: Statistically significant differences were identified in the pre- and post-operative values, according to Harris and Merle D́Aubigne scores. The femoral components survival was considered as an endpoint of the revision replacement, which was 84% at a mean of 13 years. There were 9 intraoperative complications (6 were fractures) and they significantly affected the length of hospital stay. No post-operative complications were observed in 70% of the patients. None of the analysed variables had any influence on the radiological subsidence of the femoral component. DISCUSSION: Several techniques aim to solve the bone stock deficiency in revision total hip arthroplasty, but only impaction grafting attempts to recover it. CONCLUSIONS: The Ling's technique shows an improvement over the Merle D́Aubigne and Harris scores, in the medium-long term. The intraoperative complications are mainly an increase in the length of hospital stay and the number of days needed to be able to sit down. Ling's technique is a good option to consider in young patients where it is foreseeable that there is a new revision surgery in the future.

Resultados del cotilo con doble movilidad de última generación en España (135 PTC seguidas durante una media de 32 meses) / Results of the latest generation dual-mobility cup in spain (135 THAs followed-up for a mean of 32 months)

Introducción: En este estudio multicéntrico (Hospital de Cabueñes y Hospital Universitario Santa Lucía) se evalúan los resultados de una serie retrospectiva y continua de 135 PTC realizadas implantando un cotilo doble movilidad de nueva generación. Material y métodos: Se estudiaron 135 PTC intervenidas entre 2005 y 2008. El seguimiento medio fue de 32 meses. Las causas de la cirugía fueron 31.8% coxartrosis y 68.1% fracturas de cadera. La edad media era de 82.1 años. Todos los pacientes eran revisados periódicamente haciendo una valoración clínica y radiográfica. Resultados: El seguimiento pudo ser realizado durante más de 24 meses en 121 PTC (14 pacientes fallecidos). En la última revisión, mayo 2011: 119 cótilos no presentaban aflojamiento. Las complicaciones fueron: 2 luxaciones postquirúrgicas; 4 TVP; 3 infecciones PTH; 5 fracturas peri PTC; 2 aflojamientos cetilo y 1 hundimiento vástago. HHS preoperatorio medio: 45, 83 y postoperatorio medio: 80, 03. De los 135 cotilos revisados sólo dos presentaban modificaciones radiográficas sin signos clínicos. La supervivencia aislada del cótilo a los 12 meses fue 97.03% (87.3-99.2) con un intervalo de confianza del 95% y a los 5 años, un 96.7% (85.4-98.8). Discusión: En nuestro estudio el nuevo cótilo doble movilidad ha mostrado buenos resultados en las siguientes indicaciones: coxartrosis primaria y fracturas de cuello de fémur. Conclusión: Las complicaciones obtenidas en esta serie aparecen en el mismo porcentaje que en otras series de la literatura excepto para la luxación. En ésta, el porcentaje (1.48%) era mucho más pequeño que el de las series clásicas, especialmente en los pacientes con problemas neuromusculares o cognitivos (un tercio de los pacientes).

Introduction: This multi-center study (Cabueñes Hospital and Santa Lucía University Hospital) assessed the results of a retrospective and ongoing series of 135 total hip arthroplasties (THA) in which a latest generation dual-mobility cup was implanted. Material and methods: A total of 135 THAs performed between 2005 and 2008 were analyzed. Mean follow-up was 32 months. The causes of surgery were: coxarthrosis in 31.8% and hip fracture in 68.1%. Mean age was 82.1 years. All patients were seen at regular follow-up visits for clinical and radiological assessments. Results: The follow-up lasted over 24 months in 121 THAs (14 patients died). In the most recent follow-up, in May 2011, 119 cups did not show any loosening. Complications were as follows: 2 postoperative dislocations; 4 DVTs; 3 infections; 5 periprosthetic fractures; 2 loosened cups, and one subsided stem. The mean preoperative Harris Hip Score (HHS) was 45, 83; the mean postoperative HHS was 80, 03. Only two of the 135 cups analyzed had radiographic modifications without clinical signs. Isolated cup survival at 12 months was 97.03% (87.3-99.2) with a 95% confidence interval; survival at 5 years was 96.7% (85.4-98.8). Discussion: In our study, the new dual-mobility cup showed good results for the following indications: primary coxarthrosis and femur neck fractures. Conclusion: The complication rate in our series was similar to the one reported in other series in the literature, except for dislocation. The latter was considerably less frequent (1.48%) in our series compared to the rates reported by the classical series, especially in patients with neuromuscular or cognitive problems (one third of patients).

[Results of the latest generation dual-mobility cup in Spain (135 THAs followed-up for a mean of 32 months)]. / Resultados del cotilo con doble movilidad de última generación en España (135 PTC seguidas durante una media de 32 meses).

INTRODUCTION: This multi-center study (Cabuenes Hospital and Santa Lucia University Hospital) assessed the results of a retrospective and ongoing series of 135 total hip arthroplasties (THA) in which a latest generation dual-mobility cup was implanted. MATERIAL AND METHODS: A total of 135 THAs performed between 2005 and 2008 were analyzed. Mean follow-up was 32 months. The causes of surgery were: coxarthrosis in 31.8% and hip fracture in 68.1%. Mean age was 82.1 years. All patients were seen at regular follow-up visits for clinical and radiological assessments. RESULTS: The follow-up lasted over 24 months in 121 THAs (14 patients died). In the most recent follow-up, in May 2011, 119 cups did not show any loosening. Complications were as follows: 2 postoperative dislocations; 4 DVTs; 3 infections; 5 periprosthetic fractures; 2 loosened cups, and one subsided stem. The mean preoperative Harris Hip Score (HHS) was 45, 83; the mean postoperative HHS was 80.03. Only two of the 135 cups analyzed had radiographic modifications without clinical signs. Isolated cup survival at 12 months was 97.03% (87.3-99.2) with a 95% confidence interval; survival at 5 years was 96.7% (85.4-98.8). DISCUSSION: In our study, the new dual-mobility cup showed good results for the following indications: primary coxarthrosis and femur neck fractures. CONCLUSION: The complication rate in our series was similar to the one reported in other series in the literature, except for dislocation. The latter was considerably less frequent (1.48%) in our series compared to the rates reported by the classical series, especially in patients with neuromuscular or cognitive problems (one third of patients).

Minimally invasive hip surgery: the approach did not make the difference.

BACKGROUND: We hypothesized that minimally invasive surgery was superior to conventional surgery for total hip arthroplasty procedure. PURPOSE: To compare the results of total hip replacement (THR) made by minimally invasive lateral approach with the results of THR made by conventional lateral approach. MATERIALS AND METHODS: Prospective, randomized trial. Fifty patients were selected and then divided into two groups based on utilized approach. DATA COLLECTED: Perioperative bleeding, postoperative pain, time of recovery, components orientation, complications and functional results. Five-year follow-up. RESULTS: No differences were found in blood loss, postoperative pain, surgical time, components orientation, rate of complications or functional result. Minimally invasive lateral approach produced faster recovery with less hospital stay and earlier walking start. CONCLUSION: Our results suggested that minimally invasive lateral approach has not provided significant benefits over conventional lateral approach for the implantation of a total hip arthroplasty.

Inestabilidad de la artroplastia total de cadera. Una aproximación desde los criterios de la evidencia científica / Instability of total hip arthroplasty: An approach using the scientific evidence

La inestabilidad en las artroplastias de cadera o la luxación en su forma más dramática, es una complicación que altera la evolución de este procedimiento introduciendo una pérdida de bienestar en el paciente y una pérdida de confianza en su relación con el cirujano. Si no consideramos los fracasos por infección, la luxación supone la causa más frecuente de cirugía de revisión a corto y medio plazo y no es desdeñable el número de casos que precisan varias intervenciones para aportar estabilidad a la articulación. A pesar de la frecuencia y gravedad de esta complicación no son frecuentes estudios con alta evidencia científica en este tema. Hemos pretendido recoger la literatura publicada con su grado de evidencia acerca de la etiopatogenia, profilaxis y tratamiento de esta eventualidad. Para ello además de anotar y resumir los hallazgos de cada trabajo, hemos añadido el nivel de evidencia tras la cita bibliográfica correspondiente (AU)

The instability in hip arthroplasty, or joint dislocation in its most dramatic form, is a complication that changes the outcome of this procedure, causing a decrease in the quality of life of the patients, and a loss of confidence in their relationship with the surgeon. If we discount failures due to infection, dislocation is the most frequent cause of a short to medium term revision, and the number of cases that require several operations to provide stability to the joint is not insignificant. Despite the frequency and severity of this complication there are few studies with a high level of scientific evidence on this subject. We have attempted to review the published literature and its level of evidence on the pathogenic origin, prophylaxis and treatment of this eventuality. As well as recording and summarising the findings of each study in this review, we have added the evidence level of the corresponding literature reference (AU)

Abordaje posterior mínimamente invasivo en artroplastia total de cadera. Estudio prospectivo y aleatorizado. Un año de seguimiento / Minimally invasive posterior approach in total hip arthroplasty. Prospective randomised trial

Fundamento. La hipótesis de trabajo fue que la cirugíamínimamente invasiva era superior a la convencionalpara el proceso de artroplastia total de cadera. Paraello se compararon los resultados de la cirugía mínimamenteinvasiva con los de la cirugía convencional enartroplastia total de cadera.Material y métodos. Ensayo clínico prospectivo yaleatorizado. Se seleccionaron 50 pacientes, los cualesfueron divididos en dos grupos en función del abordajequirúrgico: posterior mínimamente invasivo o posteriordirecto convencional. Se evaluaron el sangradoperioperatorio, el dolor postoperatorio, el tiempo de recuperación,la orientación y ajuste de los componentes,la tasa de complicaciones y el resultado funcional y sehan seguido a los pacientes un año mínimo.Resultados. No se han encontrado diferencias significativasentre los grupos en cuanto a sangrado perioperatorio.El dolor postoperatorio fue menor con la cirugíamínimamente invasiva, la velocidad de recuperaciónfue significativamente mayor con el abordaje posteriormínimamente invasivo al detectarse una menor estanciahospitalaria y un inicio más precoz de la deambulación.No se encontraron diferencias en cuanto a tiempoquirúrgico, orientación y ajuste de los componentes,tasa de complicaciones ni resultado funcional. Impactoeconómico favorable a la cirugía mínimamente invasivacon un ahorro del 5% del total de coste del proceso.Conclusiones. El abordaje posterior mínimamente invasivodisminuye el dolor y acelera la recuperación conun impacto económico favorable, sin mostrar diferenciasen ninguna de los demás aspectos estudiados(AU)

Backgrond. Our working hypothesis was that minimallyinvasive surgery was superior to conventionalsurgery for total hip arthroplasty procedure. We comparedTHR results in the minimally invasive posteriorapproach with THR results in the conventional posteriorapproach.Methods. Prospective, randomised trial. Fifty patientswere selected and then divided into two groups basedon treatment (minimally invasive posterior approachor conventional posterior approach). Data collected:Perioperative bleeding, postoperative pain, time ofrecovery, component orientation, complications andfunctional results. One year follow-up.Results. No differences were found in blood loss, surgicaltime, component orientation, rate of complicationsor functional result. The minimally invasive lateralapproach produced less postoperative pain and a fasterrecovery, with a shorter hospital stay and earlierwalking-start, and a positive economic impact with 5%of the total process cost saved.Conclusions. Minimally invasive surgery permits lesspostoperative pain, faster recovery and a positiveeconomic saving, without differences in the rest of theitems studied(AU)

Abordaje lateral mínimamente invasivo en artroplastia total de cadera. Estudio prospectivo y aleatorizado / Minimally invasive lateral approach in total hip replacement: A prospective randomized study

Objetivo: Comparar los resultados de la corrección por vía posterior con una construcción híbrida mediante el empleo de una liberación posterior clásica y la liberación posterior ampliada (LPA). Material y métodos: Efectuamos un estudio de cohortes retrospectivo con 46 pacientes diagnosticados de escoliosis idiopática del adolescente (EIA). Se realizó una corrección por vía posterior mediante el empleo de una instrumentación híbrida. En el primer grupo se realizó una liberación posterior estándar (LPE) y en el segundo se realizó una LPA, y se resecaron todos los ligamentos posteriores y se realizó una facetectomía amplia bilateral. Se compararon los resultados de las mediciones en telerradiografías anteroposteriores y laterales preoperatorias, postoperatorias y a los 2 años. Se valoraron los resultados clínicos mediante el cuestionario SRS 22. Resultados: No hubo diferencias en cuanto al sexo, edad, tipo de curva, niveles instrumentados, tiempo quirúrgico o Cobb preoperatorio (LPE: 60°±10°; LPA: 59°±8°) de la curva principal. En el grupo de LPA la corrección obtenida fue significativamente mayor en el postoperatorio (p<0,001) y a los 2 años (p<0,05). La corrección de la curva proximal y lumbar resultó similar en ambos grupos y no se encontraron diferencias significativas. Las complicaciones menores fueron similares en ambos grupos y no existieron complicaciones graves. Conclusión: La LPA a múltiples niveles mejora la corrección de la curva principal en el plano coronal en los pacientes con EIA, sin aumento de la incidencia de complicaciones, además de aumentar la superficie de artrodesis y facilitar la introducción del alambrado (AU)

Purpose: To compare the results of posterior correction using hybrid instrumentation and classical posterior release with those obtained with an extended posterior release. Material and methods: We carried out a retrospective cohort study of 46 patients diagnosed with adolescent idiopathic scoliosis (AIS). A posterior correction was carried out using hybrid instrumentation. In the first group, a standard posterior release (SPR) was performed, whereas in the second an extended release (EPR) was carried out, resecting all posterior ligaments and performing an extended bilateral facetectomy. The results of the measurements were compared using pre-op, post-op and 2-year-follow-up anteroposterior and lateral teleradiographs. Clinical results were evaluated using the SRS 22 questionnaire. Results: There were no differences as regards gender, age, curve type, instrumented levels, OR time or pre-op Cobb's angle (SPR: 60°±10°; EPR: 59°±8°) of the principal curve. In the extended release group the correction obtained was significantly greater at post-op (p<0.001) and at 2 years (p<0.05). Correction of the proximal and lumbar curve was similar in both groups, with no significant differences. Minor complications were similar in both groups, with no serious complications. Conclusion: Multiple-level posterior release improves correction of the principal curve on the coronal plane in patients with AIS, without an increase in the complications rate. The procedure also extends the arthrodesed area and facilitates introduction of the wires (AU)

Minimally invasive osteosynthesis in stable trochanteric fractures: a comparative study between Gotfried percutaneous compression plate and Gamma 3 intramedullary nail.

AIM: Our objective was to compare the results of PCCP (Percutaneous Compression Plate) device and Gamma 3 nail for the treatment of stable trochanteric hip fractures and to demonstrate that PCCP device is a minimally invasive system. METHOD: Prospective, randomized trial. Eighty patients aged 60 and over with stable trochanteric fracture were selected and then randomized using a table of randomized numbers. Length of time of operative procedure, hemoglobin levels at 6 and 48 h after surgery, packed cells units administered, and hospital stay were recorded. In addition, the postoperative complications in the first year after the surgery was collected. RESULTS: No differences were found in hospital stay, surgical time, blood loss, functional outcome at 1-year follow-up, neck-shaft angle, fracture collapse, and mortality. CONCLUSIONS: PCCP and Gamma 3 have not presented significant differences in any measured parameter for treatment of stable trochanteric fractures. Therefore, the PCCP system is shown to be as minimally invasive as the Gamma 3.

Placa de compresión percutánea (PCCP) en el tratamiento de las fracturas intertrocantéreas estables / The percutaneous compression plate (PCCP) in the treatment of stable intertrochanteric fractures

Objetivo. Estudiar los resultados de la placa de compresión percutánea (PCCP) en el tratamiento de las fracturas trocantéreas estables.Material y método. Estudio prospectivo de 42 pacientes con fractura trocantérea estable, según la clasificación de la AO/OTA, intervenidos entre 2003 y 2005 con placa decompresión percutánea (PCCP, percutaneous compressionplate). Fueron 12 varones y 30 mujeres, con una edad media de 82,3 años. Previo a la fractura, 19 pacientes presentaban una deambulación independiente, 16 deambulaban con bastones y 7 precisaban la ayuda de un andador o tercera persona.Resultados. El tiempo quirúrgico medio fue de 87 minutos,15 pacientes precisaron transfusión sanguínea con una media de 0,60 concentrados por paciente, y tuvieron un consumo medio de analgésicos de 3,5 días. La estancia media fue de 16,9 días. Posoperatoriamente el 73% tenían deambulación por sí mismos. Hubo 5 éxitus en el primer año posoperatorio. No hubo complicaciones quirúrgicas. Radiológicamente no hubo complicaciones mecánicas ni fracasos del material.Conclusiones. El sistema de placa de compresión percutánea PCCP nos parece válido y eficaz en el tratamiento de las fracturas trocantéreas estables (AU)

Purpose. To assess the results of the PCCP (percutaneouscompression plate) in the treatment of stable intertrochanteric fractures.Materials and methods. Prospective study of 42 patientswith a stable intertrochanteric fracture, classified according to the AO/OTA scale, implanted between 2003 and 2005 with a PCCP percutaneous compression plate. There were 12 males and 30 females, with a mean age of 82.3 years. Prior to the fracture, 19 patients were independent walkers, 16 required a walking-stick and 7 required a walking frame or someone’s assistance.Results. Mean OR time was 87 minutes. Fifteen patients required a blood transfusion with a mean of 0.60 concentrates per patient and a mean analgesic consumption period of 3.5 days. Mean hospital stay was 16.9 days. Postoperatively, 73% could ambulate independently. There were five deaths in the first year post-op. No surgical complications were recorded.Radiologically, there were no mechanical complicationsor material-related failures.Conclusions. The PCCP percutaneous compression platecomes across as a valid and effective system for the treatment of stable intertrochanteric fractures (AU)

Aflojamiento de las artroplastias de cadera / Wearing away of hip arthroplasties

La revisión de una prótesis puede sere debida a diferentes causas que requieren tratamientos específicos. El factor fundamental es el tipo de fijación del implante. El cemento y su forma de utilización influyen en los buenos resultados actuales. Es necesario adoptar una clasificación de los aflojamientos radiográficos femorales, siendo las más conocidas las propuestas por Harris y Johnston para los vástagos cementados y la de Engh para los no cementados. No hay una técnica general que pueda aplicarse a todos los casos con las mismas posibilidades de buenos resultados. La cirugía de reconstrucción acetabular y femoral, la debe indicar el cirujano según la osteolisis periprotésica y los síntomas del enfermo

Revision of a prosthesis may be due to different causes requiring specific treatments. The fundamental factor is the type of implant fixation involved. The cement and its method of use influence the good results presently obtained. A classification is required of femoral radiographic loosening - the best known being the classification proposed by Harris and Johnston for cemented stems, and the Engh classification for non-cemented stems. There is no general technique for application to all cases with the same possibilities of good results. Acetabular and femoral reconstruction surgery should be indicated by the surgeon according to the observed periprosthetic osteolysis and patient symptoms

Utilización de la capacidad de calcificación y osificación de la pared arterial para conseguir regeneración ósea completa en defectos de huesos largos / Use of the calcification and ossification capacity of arterial walls to achieve bone regeneration in complete defects of long bones

Objetivo. Evaluar el uso de aloinjertos arteriales criopreservados como membranas de regeneración ósea guiada en defectos de hueso largo. Material y método. Estudio experimental, prospectivo, aleatorizado y ciego. Se crearon defectos osteoperiósticos de 10 mm de longitud en el tercio medio de la diáfisis del radio de conejos de raza blanca de Nueva Zelanda. En los casos experimentales el defecto se aisló de los tejidos circundantes con un aloinjerto aórtico criopreservado, conforme a las técnicas de regeneración tisular guiada. En los controles no se colocó ningún tipo de membrana. Resultados. No se obtuvo curación del defecto en ningún control. En 9 de los 10 defectos experimentales se observó una regeneración ósea completa, con un patrón similar al del hueso sano en los estudios con técnicas de diagnóstico por imagen, de cuantificación morfodensitométrica y de microscopía óptica y electrónica. Además, los estudios morfológicos y ultraestructurales han mostrado imágenes sugerentes de que los propios aloinjertos aórticos criopreservados pueden haber contribuido a la regeneración ósea en el defecto, por diferenciación osteoblástica de las «células calcificantes vasculares» de la pared arterial (una subpoblación de musculares lisas de la pared arterial que algunos autores consideran células madre adultas) y/o por calcificación u osificación inducida por alteraciones en las proteínas de la matriz extracelular arterial. Conclusiones. Es posible utilizar aloinjertos arteriales criopreservados como membranas de osteopromoción para conseguir regeneración ósea completa en defectos diafisarios de hueso largo, siendo una alternativa al uso de membranas sintéticas

Aim. To assess the use of cryopreserved arterial allograft membranes in guided bone regeneration (GBR) in bone defects of long bones. Materials and methods. Prospective randomized blind study using white New Zealand rabbits as an animal model. Bone and periosteum defects 10 mm in length were created in the middle third of the shaft of the radius of white New Zealand rabbits. In the rabbits in the study group the bone defect was isolated from surrounding tissues with a membrane of cryopreserved aortic allograft according to guided tissue regeneration (GTR) techniques. In the rabbits in the control group no membrane was used. Results. The defect did not heal in any of the rabbits in the control group. In 9 out of 10 of the rabbits in the study group there was complete bone regeneration. The regenerated bone had a similar pattern to that of healthy bone in diagnostic images, in morpho-densitometric quantification studies and when seen using light and electron microscopes. Morphological and microscopic images suggest that cryopreserved aortic allografts may have contributed to bone regeneration in the defect area by osteoblastic differentiation of calcifying vascular cells (CVC) of the arterial walls and/or by calcification or ossification induced by alterations of proteins of the arterial extracellular matrix. Calcifying vascular cells are a sub-population of smooth muscle cells of the arterial walls that are considered to be adult stem cells by some authors. Conclusions. It is possible to use cryopreserved arterial allografts as membranes to promote bone growth and achieve complete bone regeneration in long bone shaft defects. These membranes can be used as an alternative to synthetic membranes

A simple method for bone-graft handling during spine surgery.

Morsellized bone-graft handling during spine surgery to get vertebral fusion can be a slow, laborious and time-consuming procedure. It is not absolutely exempt from complication risk. An easy, quick and inexpensive alternative technique is described.

Complicaciones del enclavado elástico de Ender en las fracturas del macizo trocantéreo / Ender's nailing complications in the trochanteric fractures

Se revisaron 101 pacientes diagnosticados de fractura de la extremidad proximal del fémur, ocurridas entre los años 1986-1996. Se escogieron aleatoriamente, a partir de un listado de todos 108 Pacientes intervenidos mediante osteosíntesis con clavos de Ender (748), aquellos pacientes que llevasen un postoperatorio mayor de un año y sus historias clínicas fueron solicitadas del archivo central del hospital sin ninguna instrucción al personal administrativo. Se tuvo en cuenta: edad, sexo, lado, estado previo del paciente (autonomía) en la valoración de los resultados. Todos los pacientes recuperaron su estado previo a la fractura al final del periodo de observación, salvo cuatro casos de exitus en el postoperatorio inmediato por complicaciones de su patología previa. (AU)

Behavior of the femoral stem in the Bihapro hip prosthesis.

This study evaluated the hydroxyapatite-coated femoral stem of the Bihapro hip prosthesis (Biomet Ltd, Bridgend, United Kingdom) using radiography, TC-99 scintigraphy, and bone densitometry. Thirty stems with >2 years of follow-up (mean: 31 months) were evaluated. No loosening or changes in the position of the implant were seen, and the mean subsidence was 2.2 mm. Radiography revealed a densification in the metaphyseal zone with reconstruction of the trabecular lines in 21 cases, while in 22 patients, radiolucent lines in the distal area of the femoral component were observed. Scintigraphy showed a diaphyseal normo-captation in 19 cases and a hypercaptation <1.4 with a mean index of 1.1 in 10 patients. Metaphyseal hypercaptation >1.4 was seen in 24 patients. Bone densitometry revealed increased density in the metaphyseal zones in 29 patients with a periprosthetic/normal bone quotient of 1.4.

A simple technique for handling morcellized bone-graft during impaction grafting.

Handling morcellized bone-graft during impaction grafting can be a slow and laborious procedure. An alternative quick technique is described.

Hydroxyapatite-coated hip prostheses. Early results from an international study.

A hydroxyapatite-coated hip prosthesis designed to stimulate proximal femoral stress transfer was studied in 222 patients undergoing primary total hip arthroplasty with a minimum followup of 2 years. The femoral component was a roughened titanium alloy with a 50-mu coating of hydroxyapatite applied to the proximal third. A proximal press-fit technique was applied with distal femoral over-reaming as standard procedure. The hydroxyapatite-coated acetabulum was of hemispherical design. Analysis of the clinical results showed a mean Merle D'Aubigné score of 16.7 points at 6 months and 17.4 points at 2 years. Mild residual thigh pain of unknown origin was reported in 3.6% of patients at 2 years. Radiographic evaluation showed complete acetabular and proximal femoral osseointegration without any loosening. No radiolucency or reactive line formation was observed around the hydroxyapatite-coated areas of the prostheses. Femoral bone densification occurred at the coated-uncoated transition zone (54%); 4% to 6% of cases showed cortical hypertrophy at the uncoated area of the stem. Reactive lines were seen around the distal stem in 52% of patients after 2 years. The clinical outcome was excellent, and the radiographic data pointed mainly to proximal femoral stress transfer.