Validación de los modelos de impresión 3D paciente-específicos para cirugía ortopédica oncológica pélvica / Validation of patient-specific 3D impression models for pelvic oncological orthopedic surgery

Introducción: Los tumores del anillo pélvico suponen un reto por la dificultad de obtener márgenes quirúrgicos adecuados. Herramientas como la navegación quirúrgica o la impresión 3D para la fabricación de plantillas de posicionamiento quirúrgico paciente-específicas ayudan en la planificación preoperatoria y la ejecución intraoperatoria. Su correcta colocación es fundamental en localizaciones complejas como la pelvis, por lo que es necesario identificar los errores de posicionamiento. El objetivo de este estudio es demostrar la fiabilidad en la colocación de plantillas 3D para la realización de osteotomías en el anillo pélvico. Material y métodos: Estudio experimental en cadáver con 10 hemipelvis. Se realiza TC para la obtención del modelo tridimensional, planificación de osteotomías, diseño de plantillas de posicionamiento en rama isquiopubiana (I), iliopubiana (P), supracetabular (S) y cresta iliaca (C); y un marcador de posicionamiento (rigid-body) sobre las plantillas C y S para la navegación. Las plantillas y el rigid-body son impresos en 3D y se colocan según planificación previa. La navegación permite comprobar la posición final de las plantillas y de las osteotomías. Resultados: El posicionamiento de las plantillas respecto a la planificación preoperatoria varió dependiendo de la localización, siendo mayor el error en las de cresta iliaca. Utilizando la navegación, la media de error de distancia al plano de corte está en 3,5mm, excepto en pubis (5-8mm), estando condicionado por la posición del rigid body. Conclusión: El uso de plantillas paciente-específicas impresas en 3D es una herramienta fiable para la realización de osteotomías en cirugía oncológica pélvica.(AU)

Introduction: Pelvic ring tumors pose a challenge due to the difficulty in obtaining adequate surgical margins. Tools such as surgical navigation or 3D printing for the fabrication of patient-specific surgical positioning templates help in preoperative planning and intraoperative execution. Their correct positioning is essential in complex locations such as the pelvis, so it is necessary to identify positioning errors. The aim of this study is to demonstrate the reliability of 3D template placement for pelvic ring osteotomies. Material and methods: Experimental study in cadaver with 10 hemipelvis. CT was performed to obtain the three-dimensional model, planning of osteotomies, design of positioning templates in ischiopubic (I), iliopubic (P), supracetabular (S) and iliac crest (C) branches; and a positioning marker (rigid-body) on the C and S templates for navigation. The templates and rigid-body are 3D printed and positioned according to pre-planning. Navigation allows the final position of the inserts and osteotomies to be checked. Results: The positioning of the templates with respect to the preoperative planning varied depending on the location, being greater the error in those of the iliac crest. Using navigation the mean error of distance to the cutting plane is 3.5mm, except in pubis 5-8mm), being conditioned by the position of the rigid body. Conclusion: The use of patient-specific templates printed in 3D is a reliable tool for performing osteotomies in pelvic cancer surgery.(AU)

[Translated article] Validation of patient-specific 3D impression models for pelvic oncological orthopedic surgery / Validación de los modelos de impresión 3D paciente-específicos para cirugía ortopédica oncológica pélvica

Introducción: Los tumores del anillo pélvico suponen un reto por la dificultad de obtener márgenes quirúrgicos adecuados. Herramientas como la navegación quirúrgica o la impresión 3D para la fabricación de plantillas de posicionamiento quirúrgico paciente-específicas ayudan en la planificación preoperatoria y la ejecución intraoperatoria. Su correcta colocación es fundamental en localizaciones complejas como la pelvis, por lo que es necesario identificar los errores de posicionamiento. El objetivo de este estudio es demostrar la fiabilidad en la colocación de plantillas 3D para la realización de osteotomías en el anillo pélvico. Material y métodos: Estudio experimental en cadáver con 10 hemipelvis. Se realiza TC para la obtención del modelo tridimensional, planificación de osteotomías, diseño de plantillas de posicionamiento en rama isquiopubiana (I), iliopubiana (P), supracetabular (S) y cresta iliaca (C); y un marcador de posicionamiento (rigid-body) sobre las plantillas C y S para la navegación. Las plantillas y el rigid-body son impresos en 3D y se colocan según planificación previa. La navegación permite comprobar la posición final de las plantillas y de las osteotomías. Resultados: El posicionamiento de las plantillas respecto a la planificación preoperatoria varió dependiendo de la localización, siendo mayor el error en las de cresta iliaca. Utilizando la navegación, la media de error de distancia al plano de corte está en 3,5mm, excepto en pubis (5-8mm), estando condicionado por la posición del rigid body. Conclusión: El uso de plantillas paciente-específicas impresas en 3D es una herramienta fiable para la realización de osteotomías en cirugía oncológica pélvica.(AU)

Introduction: Pelvic ring tumors pose a challenge due to the difficulty in obtaining adequate surgical margins. Tools such as surgical navigation or 3D printing for the fabrication of patient-specific surgical positioning templates help in preoperative planning and intraoperative execution. Their correct positioning is essential in complex locations such as the pelvis, so it is necessary to identify positioning errors. The aim of this study is to demonstrate the reliability of 3D template placement for pelvic ring osteotomies. Material and methods: Experimental study in cadaver with 10 hemipelvis. CT was performed to obtain the three-dimensional model, planning of osteotomies, design of positioning templates in ischiopubic (I), iliopubic (P), supracetabular (S) and iliac crest (C) branches; and a positioning marker (rigid-body) on the C and S templates for navigation. The templates and rigid-body are 3D printed and positioned according to pre-planning. Navigation allows the final position of the inserts and osteotomies to be checked. Results: The positioning of the templates with respect to the preoperative planning varied depending on the location, being greater the error in those of the iliac crest. Using navigation the mean error of distance to the cutting plane is 3.5mm, except in pubis 5-8mm), being conditioned by the position of the rigid body. Conclusion: The use of patient-specific templates printed in 3D is a reliable tool for performing osteotomies in pelvic cancer surgery.(AU)

[Translated article] Validation of patient-specific 3D impression models for pelvic oncological orthopedic surgery.

INTRODUCTION: Pelvic ring tumours pose a challenge due to the difficulty in obtaining adequate surgical margins. Tools such as surgical navigation or 3D printing for the fabrication of patient-specific surgical positioning templates help in preoperative planning and intraoperative execution. Their correct positioning is essential in complex locations such as the pelvis, so it is necessary to identify positioning errors. The aim of this study is to demonstrate the reliability of 3D template placement for pelvic ring osteotomies. MATERIAL AND METHODS: Experimental study in cadaver with 10 hemipelvis. CT was performed to obtain the three-dimensional model, planning of osteotomies, design of positioning templates in ischiopubic (I), iliopubic (P), supracetabular (S) and iliac crest (C) branches; and a positioning marker (rigid-body) on the C and S templates for navigation. The templates and rigid-body are 3D printed and positioned according to pre-planning. Navigation allows the final position of the inserts and osteotomies to be checked. RESULTS: The positioning of the templates with respect to the preoperative planning varied depending on the location, being greater the error in those of the iliac crest. Using navigation the mean error of distance to the cutting plane is 3.5mm, except in pubis (5-8mm), being conditioned by the position of the rigid body. CONCLUSION: The use of patient-specific templates printed in 3D is a reliable tool for performing osteotomies in pelvic cancer surgery.

Validation of patient-specific 3D impression models for pelvic oncological orthopedic surgery. / Validación de los modelos de impresión 3D paciente-específicos para cirugía ortopédica oncológica pélvica.

INTRODUCTION: Pelvic ring tumors pose a challenge due to the difficulty in obtaining adequate surgical margins. Tools such as surgical navigation or 3D printing for the fabrication of patient-specific surgical positioning templates help in preoperative planning and intraoperative execution. Their correct positioning is essential in complex locations such as the pelvis, so it is necessary to identify positioning errors. The aim of this study is to demonstrate the reliability of 3D template placement for pelvic ring osteotomies. MATERIAL AND METHODS: Experimental study in cadaver with 10 hemipelvis. CT was performed to obtain the three-dimensional model, planning of osteotomies, design of positioning templates in ischiopubic (I), iliopubic (P), supracetabular (S) and iliac crest (C) branches; and a positioning marker (rigid-body) on the C and S templates for navigation. The templates and rigid-body are 3D printed and positioned according to pre-planning. Navigation allows the final position of the inserts and osteotomies to be checked. RESULTS: The positioning of the templates with respect to the preoperative planning varied depending on the location, being greater the error in those of the iliac crest. Using navigation the mean error of distance to the cutting plane is 3.5mm, except in pubis (5-8mm), being conditioned by the position of the rigid body. CONCLUSION: The use of patient-specific templates printed in 3D is a reliable tool for performing osteotomies in pelvic cancer surgery.

Role of the orthopaedic surgeon in 3D printing: current applications and legal issues for a personalized medicine. / Papel del cirujano ortopédico y traumatólogo en la impresión 3D: aplicaciones actuales y aspectos legales para una medicina personalizada.

3D printing (I3D) is an additive manufacturing technology with a growing interest in medicine and especially in the specialty of orthopaedic surgery and traumatology. There are numerous applications that add value to the personalised treatment of patients: advanced preoperative planning, surgeries with specific tools for each patient, customised orthotic treatments, personalised implants or prostheses and innovative development in the field of bone and cartilage tissue engineering. This paper provides an update on the role that the orthopaedic surgeon and traumatologist plays as a user and prescriber of this technology and a review of the stages required for the correct integration of I3D into the hospital care flow, from the necessary resources to the current legal recommendations.

3D printing utility for surgical treatment of acetabular fractures. / Utilidad de la impresión 3D para el tratamiento quirúrgico de las fracturas acetabulares. Beca proyecto de investigación SECOT 2014.

INTRODUCTION: Preoperative 3D modelling enables more effective diagnosis and simulates the surgical procedure. MATERIAL AND METHODS: We report twenty cases of acetabular fractures with preoperative planning performed by pre-contouring synthesis plates on a 3D printed mould obtained from a computarized tomography (CT) scan. The mould impression was made with the DaVinci 1.0 printer model (XYZ Printing). After obtaining the printed hemipelvis, we proceeded to select the implant size (pelvic Matta system, Stryker®) that matched the characteristics of the fracture and the approach to be used. RESULTS: Printing the moulds took a mean of 385minutes (322-539), and 238grams of plastic were used to print the model (180-410). In all cases, anatomic reduction was obtained and intra-operative changes were not required in the initial contouring of the plates. The time needed to perform the full osteosynthesis, once the fracture had been reduced was 16.9minutes (10-24). In one case fixed with two plates, a postoperative CT scan showed partial contact of the implant with the surface of the quadrilateral plate. In the remaining cases, the contact was complete. CONCLUSIONS: In conclusion, our results suggest that the use of preoperative planning, by printing 3D mirror imaging models of the opposite hemipelvis and pre-contouring plates over the mould, might effectively achieve a predefined surgical objective and reduce the inherent risks in these difficult procedures.

[Total knee arthroplasty in a patient with meniscal transplantation]. / Artroplastía total de rodilla en paciente con trasplante meniscal.

BACKGROUND: The natural history of a knee subjected to total meniscectomy leads to poor outcomes, so we should be careful with these lesions. Meniscal transplantation may be a proper treatment for these patients as it involves a good medium-term survival. MATERIAL AND METHOD: We report the case of a 52 year-old male who underwent meniscal transplantation and developed left gonarthrosis. The surgical approach consisted of medial longitudinal arthrotomy and implantation of a posterior stabilized prosthesis after releasing the soft tissues, which were very retracted. RESULTS: At the one year follow-up the operated knee had an articular range of 0-110 degrees, with no gap and no pain; no external support was required for walking. CONCLUSIONS: Despite the fact that most case series report good short- and medium-term results, some patients do not have good results and need a total knee prosthesis.

Estudio experimental sobre el patrón de penetración del cemento óseo en la artroplastia de rodilla según la técnica de cementación empleada / An experimental study of bone cement penetration in total knee arthroplasty depending on cementing technique used

Objetivo: Evaluar la distribución y penetración del manto de cemento óseo en la artroplastia de rodilla según la técnica de cementación empleada. Material y método: Se cementaron las piezas en el segundo y quinto minuto según dos técnicas: presurización digital directa sobre el modelo (técnica M) o sobre la prótesis (técnica P). Se analizaron digitalmente las fotografías de los modelos cementados, determinando la longitud del manto de cemento, el porcentaje y la media de penetración. Resultados: La mejor calidad del manto de cemento se obtuvo con la técnica M aplicada en el segundo minuto, que logró una penetración media de 4,44 mm y un porcentaje de penetración del 79,36%; la técnica P en el quinto minuto tuvo el peor resultado (2,12 mm y 45,79%), siendo estas diferencias significativas (p=0,029). Los planos de corte tangencial (anterior y posterior) resultaron ser los peor cementados, con una media de penetración de 2 mm. La técnica M consiguió la mayor longitud de cemento en estos dos planos (35 mm y 17,9 mm), mientras que la técnica P cubrió menos del 50% de la longitud del corte (p=0,01). Conclusión: La cementación con presurización digital sobre la superficie ósea consigue mayor profundidad y porcentaje de penetración que la cementación sobre la prótesis. Los cortes femorales tangenciales (anterior y posterior) se cementan de forma precaria si se aplica sobre el implante (AU)

Objective: To assess the distribution and penetration of the cement mantle in knee arthroplasty depending on technique used. Material and method: Parts were cemented in the second and fifth minute using two techniques: digital pressurization (fingerpacking) directly over the model (technique M) or over the implant (technique P). We analyze digitally the photographs of the cemented models determining length of the cement mantle, percentage penetration and mean penetration. Results: The best quality of cement mantle was obtained with the technique M applied in the second minute, which achieved a mean penetration of 4.44 mm and a percentage penetration of 79.36%; technique P in the fifth minute obtained poorer result (2.12 mm and 45.79%), these differences being significant (p = 0.029). The tangential planes (anterior and posterior) proved to be poorer cemented, with a mean penetration of 2 mm. The technique M obtained the longest cement mantle in these two planes (35 mm and 17.9 mm), while tehnique P covered < 50% of the length of the plane (p = 0.01). Conclusions: Fingerpacking pressurization over the bone surface achieves a greater depth and percentage penetration of the cement mantle than cementing over the prosthetic implant. Tangential femoral cuts (anterior and posterior) are fixed unstably if it is cemented over the implant (AU)

Influencia de la técnica de cementación sobre la calidad del manto de cemento en la artroplastia de rodilla. Estudio experimental sobre un modelo sintético / Influence of the fixing technique on the quality of the cement mantle in knee arthroplasty. Experimental study on a synthetic model

Objetivo. Evaluar la calidad del manto de cemento obtenido con diferentes técnicas de cementación en la artroplastia de rodilla. Material y método. Estudio experimental con modelos óseos sintéticos (16 tibias y 16 fémures), empleando instrumental protésico PROFIX(R) y cemento de alta viscosidad (Palacos R(R)), aplicado en el segundo y quinto minuto tras la mezcla de componentes mediante dos técnicas de cementación: directamente sobre la superficie ósea por presurización digital (técnica M), o sobre el implante protésico (técnica P). Realizamos análisis digital de las fotografías de los modelos determinando para cada plano de corte: penetración media, porcentaje de penetración y longitud del manto de cemento. Resultados. La técnica M empleada en el minuto dos consiguió una mejor calidad del manto, con una penetración media de 4,44mm y un porcentaje de penetración del 79,36%; la técnica P en el minuto cinco obtuvo los peores resultados (2,12mm y 45,79%), siendo estas diferencias significativas (p=0,029). La cementación de los planos tangenciales femorales (anterior y posterior) resultó precaria, con una penetración media de 2mm. La longitud media del manto de cemento en estos dos planos con la técnica M fue de 35mm y 17,9mm, en contraste con la técnica P (12,5mm y 7,2mm), que consiguió una cobertura<50% (p=0,01). Conclusiones. La cementación sobre la superficie ósea con presurización digital consigue mayor profundidad y porcentaje de penetración que con la cementación directa sobre los implantes protésicos, con mayores diferencias cuanto mayor es la viscosidad del cemento. La cementación tangencial de los cortes femorales anterior y posterior resulta muy precaria si se cementa sobre el implante (AU)

Objective. To assess the quality of the cement mantle obtained with different fixation techniques in knee arthroplasty. Material and method. An experimental study with synthetic bone models (16 tibias and 16 femurs), employing a PROFIX(R) prosthetic tool and high viscosity cement (Palacos R(R)), applied on the second and fifth minute after mixing the components using two fixation techniques: directly over the bone surface by digital pressure (technique M), or over the prosthetic implant (technique P). We performed a digital analysis on the photographs of the models, determining for each cut plane: mean penetration, percentage penetration and length of the cement mantle. Results. Technique M applied in minute 2 achieved a better quality mantle, with a mean penetration of 4.44mm and a percentage penetration of 79.36%; technique P in minute five obtained poorer results (2.12mm and 45.79%), these differences being significant (p=0.029). The femur tangential fixation (anterior and posterior) was unstable, with a mean penetration of 2mm. The mean length of the mantle in these two planes with technique M was 35mm and 17.9mm, compared with technique P (12.5mm and 7.2mm), which achieve a coverage of <50% (p=0.01). Conclusions. Cementing over the bone surface with digital pressure achieves a greater depth and percentage penetration than that with direct cementing over the prosthetic implant, with greater differences when the cement viscosity is higher. Tangential fixation of the anterior and posterior cuts is very unstable if it is cemented over the implant (AU)

The patellar thinning osteotomy in patellofemoral arthritis: four to 18 years' follow-up.

Isolated patellofemoral osteoarthritis can be a disabling disease. When conservative treatment fails, surgical options can be unpredictable and may be considered too aggressive for middle-aged and active people. We analysed the clinical and radiological results of a new coronal osteotomy involving thinning of the patella in a selected group of patients with isolated patellofemoral osteoarthritis. Since 1991, 31 patients (35 knees) have been treated, of whom 34 were available for follow-up at a mean of 9.1 years. The Knee Society Score, the Patellar score and the Short-form-36 questionnaire were used for clinical evaluation. We also examined the radiological features to confirm bone consolidation and assess the progression of osteoarthritis. A significant improvement in the functional scores and radiological parameters was noted. All patients except one were satisfied with the operation. Radiological progression of the patellofemoral osteoarthritis was slowed but radiological femorotibial osteoarthritis progressed in 23 (65%) cases, with a total knee replacement becoming necessary in four cases without technical problems in resurfacing the patella. We compared the results with other forms of surgical treatment reported in the literature. This treatment offers good clinical and radiological results, presenting an alternative method of managing patellofemoral osteoarthritis.

Artroplastia patelar secundaria en el tratamiento de la prótesis total de rodilla dolorosa / Secondary patellar resurfacing in painful total knee arthroplasty

Objetivo. Analizar los resultados de las artroplastias patelares secundarias (APS) realizadas en nuestro centro sobre pacientes con artroplastia total de rodilla (ATR) dolorosa.Material y método. Se estudiaron retrospectivamente 20 pacientes sobre los que se había realizado una APS por presentar una ATR con dolor de origen patelar. El intervalo medio de tiempo desde la ATR fue de 24,8 meses (8,5-67) y el seguimiento posoperatorio medio de los casos fue de 13,5 meses (2-44). Se realizó un análisis radiológico y una evaluación clínica mediante las variaciones del rango articular y el alivio del dolor.Resultados. El 60% de los pacientes tuvo un alivio del dolor, el 30% de forma permanente y el 30% de forma temporal con un tiempo medio libre de dolor de 8,2 meses (1,5- 18). Los parámetros radiológicos de alineación rotuliana mejoraron en todos los casos y se observó un acortamiento del tendón rotuliano. El grosor patelar medio posoperatorio fue mayor que el preoperatorio. Se observaron complicaciones en el 10% de los pacientes.Conclusiones. La reproducibilidad de la técnica con losnuevos implantes, la baja tasa de complicaciones y las aceptables cifras de resultados satisfactorios la convierten en una técnica valorable para determinados casos. El carácter multifactorial de la ATR dolorosa con rótula nativa y la complejidad diagnóstica que esto implica debe plantear cautela a la hora de indicar una APS de forma rutinaria

Purpose. To analyze the results of the secondary patellar resurfacing (SPR) procedures carried out in our department for the treatment of patients with painful total knee arthroplasty (TKA).Materials and methods. We retrospectively reviewed 20 patients who had undergone SPR due to persistent anteriorknee pain following TKA. The mean time interval to secondary resurfacing was 24.8 months (8.5-67) and the mean follow- up was 13.5 months (2-44). Patients were evaluated radiologically and clinically through an analysis of variations in ROM and pain relief.Results. Pain relief was reported for 60% of patients, 30% permanently and 30% temporaly with a pain-free time interval of 8.2 months (1.5-18). The radiological parameters for patellofemoral congruency improved in all patients and there was a shortening of the mean length of the patellar tendon. The mean patellar thickness increased after the secondary procedure. There were complications in 10% of patients.Conclusions. The reproducibility of the technique with new implants, the low rate of complications and the percentage of satisfactory results make this technique suitable for selected cases. The diverse origin of painful TKA and the complexities of diagnosis should make the surgeon weigh the situation carefully before embarking on an SPRc