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31 marzo 2014

General: Cómo usar las infiltraciones de PRP en las tendinopatías crónicas

Optimization of ingredients, procedures and rehabilitation for platelet-rich plasma injections for chronic tendinopathy.
Mautner K, Malanga G, Colberg R.
Pain Manag. 2011 Nov;1(6):523-32

Abstract
SUMMARY There is considerable interest amongst clinicians and researchers to create the optimal platelet product to maximize outcomes with platelet-rich plasma (PRP) injections. PRP has been widely introduced as a safe alternative for treating tendinopathies. However, there is still limited clinical evidence describing the components of the platelet product and supporting its use in clinical trials. This article reviews the current literature regarding the role of PRP injections in the treatment of recalcitrant tendinopathies and the different factors in the platelet product that could affect the outcome, including the platelet count, presence of leukocytes, activators used, pH of solution and delivery method, among others. In addition, we address important concepts regarding rehabilitation after PRP procedures, which has little consensus to date and is the subject of much debate. Based on the phases of soft tissue healing, basic science research on platelets, as well as our clinical experience in treating over 500 patients with PRP, we will suggest guidelines regarding the optimal progression of rehabilitation and timing for return to previous activity following the procedure.

General: PRP intratendinoso guiado por ultrasonidos en varias tendinopatías: dicen que funciona

Intratendinous Injection of Platelet-Rich Plasma under US Guidance to Treat Tendinopathy: A Long-Term Pilot Study.
Dallaudière B, Pesquer L, Meyer P, Silvestre A, Perozziello A, Peuchant A, Durieux MH, Loriaut P, Hummel V, Boyer P, Schouman-Claeys E, Serfaty JM
J Vasc Interv Radiol. 2014 Mar 20

Abstract
PURPOSE:
To assess the potential therapeutic effect of intratendinous injection of platelet-rich plasma (PRP) under ultrasound (US) guidance to treat tendon tears and tendinosis in a pilot study with long-term follow-up.

MATERIALS AND METHODS:
The study included 408 consecutive patients referred for treatment by PRP injection of tendinopathy in the upper (medial and lateral epicondylar tendons) and the lower (patellar, Achilles, hamstring and adductor longus, and peroneal tendons) limb who received a single intratendinous injection of PRP under US guidance. Clinical and US data were retrospectively collected for each anatomic compartment for upper and lower limbs before treatment (baseline) and 6 weeks after treatment. Late clinical data without US were collected until 32 months after the procedure (mean, 20.2 months). The McNemar test and regression model were used to compare clinical and US data.

RESULTS:
QuickDASH score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and residual US size of lesions were significantly lower after intratendinous injection of PRP under US guidance at 6 weeks and during long-term follow-up compared with baseline (P < .001 in upper and lower limb) independent of age, gender, and type of tendinopathy (P > .29). No clinical complication was reported during follow-up.

CONCLUSIONS:
Intratendinous injection of PRP under US guidance appears to allow rapid tendon healing and is well tolerated.

Cadera-Rodilla / Hip-Knee: hacer un análisis de orina antes de la artroplastia ¿para qué?

Is there any benefit in pre-operative urinary analysis before elective total joint replacement?
Bouvet, C., Lubbeke, A., Bandi, C., Pagani, L., Stern, R., Hoffmeyer, P., Uckay, I.
Bone Joint J 2014;96-B:390-4

Whether patients with asymptomatic bacteriuria should be investigated and treated before elective hip and knee replacement is controversial, although it is a widespread practice. We conducted a prospective observational cohort study with urine analyses before surgery and three days post-operatively. Patients with symptomatic urinary infections or an indwelling catheter were excluded. Post-discharge surveillance included questionnaires to patients and general practitioners at three months. Among 510 patients (309 women and 201 men), with a median age of 69 years (16 to 97) undergoing lower limb joint replacements (290 hips and 220 knees), 182 (36%) had pre-operative asymptomatic bacteriuria, mostly due to Escherichia coli, and 181 (35%) had white cells in the urine. Most patients (95%) received a single intravenous peri-operative dose (1.5 g) of cefuroxime as prophylaxis. On the third post-operative day urinary analysis identified white cells in 99 samples (19%) and bacteriuria in 208 (41%). Pathogens in the cultures on the third post-operative day were different from those in the pre-operative samples in 260 patients (51%). Only 25 patients (5%) developed a symptomatic urinary infection during their stay or in a subsequent three-month follow-up period, and two thirds of organisms identified were unrelated to those found during the admission. All symptomatic infections were successfully treated with oral antibiotics with no perceived effect on the joint replacement.

We conclude that testing and treating asymptomatic urinary tract colonisation before joint replacement is unnecessary 

30 marzo 2014

Ciencia / Science: asesinato en el scientific express

Cómo acabar con la ciencia: ABC de la ‘ciencidiología’
Bunge M

http://esmateria.com/2014/03/29/abc-de-la-ciencidiologia-mario-bunge/



(Este texto es un adelanto de Ciencia, técnica y desarrollo, que publica la editorial Laetoli en su colección Biblioteca Bunge. El autor del libro, del que publicamos un capítulo, es el reconocido filósofo Mario Bunge, consejero editorial de Materia)

Si queremos saber qué hacer para impulsar el desarrollo de la ciencia, no podemos dejar de averiguar qué puede obstaculizar dicho desarrollo. En general, todo recetario debe contener reglas para hacer bien las cosas así como para evitar cometer los errores más comunes, es decir, debe ser una lista de do’s y don’ts, cosas que hacer y no hacer. Esto no ha ocurrido hasta ahora con la política científica: nos han propuesto recetas, buenas, malas o peores para favorecer la investigación científica, pero no nos han dicho qué basta para obstaculizar o aun impedir el avance de la ciencia. En este apéndice me propongo llenar este vacío o, mejor dicho, colocar la piedra fundamental de la ciencidiología, como propongo llamar a la ciencia para matar a la ciencia (otros, más eruditos, preferirán epistetanatología o quizá Wissenschaftstodeslehre).

Ciencia, técnica y desarrollo
Editorial: Laetoli
Páginas: 158
Precio: 16 euros

Los filósofos suelen ignorar, y los investigadores en ciencias básicas suelen tratar de olvidar, que la ciencia no se da en el vacío sino en un contexto biológico, económico, político y cultural. Esto es archisabido, gracias en parte a los historiadores y sociólogos de la ciencia que tratan de averiguar las circunstancias externas en que se hace lo que aquellos no entienden. Con todo, convendrá recordar rápidamente algunas características de ese contexto, porque cada científico social, con excepción del antropólogo, tiende a ver tan sólo un componente o un aspecto del sistema total que es la sociedad.

Toda sociedad, cualquiera sea su nivel de desarrollo, puede considerarse como un sistema caracterizable por su composición, medio y estructura. A su vez, este sistema puede analizarse en cuatro subsistemas principales: el biológico, el económico, el cultural y el político. El primero abarca a todos los miembros de la sociedad; el segundo, a los que producen o distribuyen bienes así como a los que prestan servicios; el tercero, a cuantos crean o difunden bienes culturales; y el cuarto, a todos los que toman decisiones de alcance social o se ocupan de que se cumplan. Cada uno de los cuatro subsistemas condiciona a los otros tres: los cuatro son interdependientes y, si unas veces predomina uno de ellos, otras prevalece algún otro.

La investigación científica, aun cuando es realizada por un individuo por su cuenta, es una actividad social y más precisamente cultural: utiliza medios conceptuales y materiales elaborados por otros, y a su vez ejerce influencia, por modesta que sea, sobre la conducta social de otras personas. Y al igual que las demás actividades sociales, la investigación científica se da en condiciones biológicas, económicas, políticas y culturales. Por ejemplo, un físico teórico, por abstracto que sea el problema que le ocupa, necesita estar sano y disponer de unos ingresos que le permitan pensar en su problema; también necesita poder comunicarse con sus colegas, sea personalmente, sea por intermedio de publicaciones; y necesita libertad académica para escoger su problema y tratarlo como a él se le ocurra, así como para difundir los resultados de su trabajo (sobre todo si éstos contrarían alguna doctrina aceptada).

Estas condiciones, que nos parecen tan obvias, no se dan juntas en la mayoría de las naciones. Lo que suelen darse son condiciones para impedir la investigación o al menos retardarla. Estas condiciones desfavorables se dan espontáneamente, rara vez se crean en forma deliberada para impedir el avance de la ciencia. Es ya hora de terminar con semejante improvisación: si realmente se desea obstaculizar el avance científico, hay que tomar la cosa en serio, es decir, cultivar la ciencidiología. Manos a la obra, pues: pasemos a elaborar recetas biológicas, económicas, políticas y culturales con el objetivo de impedir el avance de la ciencia, a fin de proceder metódicamente y, en lo posible —aunque suene a paradoja—, científicamente.

Las recetas biológicas son las más eficaces, ya que muerto el perro se acabó la rabia. Conviene, pues, empezar por ellas. He aquí algunas:

Si realmente se desea obstaculizar el avance científico, hay que tomar la cosa en serio: elaboremos recetas que impidan el avance de la ciencia

RB1. Manténgase al pueblo en un estado de subdesarrollo biológico. Para esto basta asegurar que la gente de pueblo consuma menos de 70 g de proteínas por día. Uno de los efectos de la subalimentación es un desarrollo subnormal de la corteza cerebral y con ello una disminución acusada de las facultades mentales. En particular, se logra la apatía. En tales condiciones es difícil que surjan jóvenes con inquietudes científicas o de otras, al menos entre el pueblo.
Si, por algún descuido, apareciesen jóvenes con inquietudes científicas entre las clases superiores o medias, será preciso aplicar:

RB2. Elimínese a todos los intelectuales díscolos. Nunca faltará motivo para aplicar esta receta, porque los intelectuales suelen ser individualistas y díscolos. Pero es preciso proceder con moderación, ya que todo Estado moderno necesita intelectuales. No se trata de arrasar con todos ellos sino sólo con los inconformistas. Los demás, los mansos, deberán ser utilizados.
Si fallan las recetas anteriores, será menester recurrir al remedio heroico:

RB3. Declárese una guerra cualquiera con un pretexto cualquiera. Esta receta fue ensayada con gran éxito y repetidamente por diversas potencias europeas, que lograron producir huecos generacionales irreparables. (La indiscutible ventaja científica de EE UU se ha explicado por esta causa: mientras las demás naciones enviaban al exilio o la muerte a sus jóvenes más prometedores, los norteamericanos acogían a los exiliados y se mantenían esencialmente al margen del conflicto). Téngase en cuenta que la guerra no sólo mata a científicos y aprendices de científicos: también interrumpe investigaciones que tal vez no se retomen jamás.

Las recetas biológicas, por eficaces que sean, no son infalibles. Por ejemplo, la persecución de los intelectuales puede causar una rebelión, o bien llevarse al extremo hasta privar al Estado de funcionarios competentes. Y una guerra puede ganarse o perderse antes de haber sido segada la flor y nata de la juventud. Por estos motivos, y porque la ciencia depende también de factores extrabiológicos, es indispensable elaborar recetas para controlarlos. Ocupémonos ahora de éstas.

La receta económica más eficaz salta a la vista:

RE1. Manténgase un régimen económico-social que exija que todo el mundo se ocupe solamente de la subsistencia. La ciencia sólo puede florecer cuando queda tiempo para pensar en problemas que no se refieren a las necesidades inmediatas; por eso no existe en las regiones o los períodos en que dichas necesidades inmediatas no son satisfechas.
Con todo, ocurre a veces, sobre todo en sociedades con una tradición de respeto por el conocimiento, que aparecen investigadores científicos. En tal caso, habrá que recurrir a la:

RE2. Precarícese la remuneración de los investigadores científicos. La aplicación de esta receta limitará las filas de los investigadores a los individuos de medios pecuniarios independientes y a unos pocos desgraciados que prefieren pasar hambre con tal de satisfacer su curiosidad a pasar curiosidad con tal de satisfacer su hambre. Los primeros serán vistos como extravagantes; los segundos, como tontos: ninguno de ellos será tomado como modelo. Y unos y otros serán casi siempre aficionados antes que profesionales.
Aplicada a fondo y sin vacilaciones, basta una sola prescripción política:

RP. Restrínjanse drásticamente las libertades públicas, comenzando por las libertades de investigación, de información, de crítica y de enseñanza. Sin libertad de investigación no hay investigación original sostenida; a lo sumo hay investigación rutinaria, que aplica resultados de investigaciones originales hechas en otros lugares u otros tiempos pero rara vez inaugura rumbos. Sin libertad de información (que incluya la posibilidad de entablar y mantener contactos personales con colegas nacionales y extranjeros), no puede haber información al día, en particular información referente a nuevos enfoques, nuevos problemas y nuevos métodos. Sin libertad de crítica languidece la innovación, que con frecuencia se opone a ideas o métodos establecidos, y florece el dogmatismo. Y sin libertad de enseñanza se les evita a los jóvenes enfrentarse a problemas cuyo tratamiento puede llevar a cuestionar los dogmas establecidos.
Pero, puesto que aun en las sociedades más cerradas aparecen de cuando en cuando cerebros inquisitivos e imprudentes, la regla RP será ineficaz a menos que sea complementada con reglas de política cultural bien específicas. Veamos algunas de ellas.

Puesto que la ciencia no es sino un componente de la cultura, toda política científica debe ser una parte de una política cultural general. A fin de impedir el avance de la ciencia es indispensable, aunque no suficiente, adoptar las recetas que siguen:

RC1. Manténgase o créese una atmósfera ideológica anticientífica. Foméntese la superstición, adóptese una ideología que lo explique todo y celébrese la adhesión fanática a dicha ideología. Si la religión tradicional ya no paraliza los cerebros, combátasela en nombre de una nueva ideología intolerante y propíciense las ciencias ocultas, las seudociencias y las prácticas mágicas. Ensálcense lo misterioso y lo mágico y denígrense la razón y la experiencia controlada. Combátase la tolerancia con el pluralismo y protéjase el monolitismo. Subráyense los límites de la ciencia en oposición al poder ilimitado de la fe ciega.
Es obvio que no basta con proteger el irracionalismo y el inmovilismo, también es preciso combatir activamente sus opuestos. Por esto se recomienda poner en práctica al mismo tiempo la:

RC2. Sométanse las ideas, todas ellas, a un control estricto. La novedad puede explotar donde menos se la espera: en astronomía o en química, en biología o en sociología, e incluso en filosofía. Para evitar que se desarrolle es preciso atraparla en sus comienzos antes de que se difunda. Y para esto es indispensable que se ejerza una vigilancia estricta y permanente. Es aconsejable que con ese fin se cree un cuerpo profesional especializado, la Dirección Nacional de Vigilancia Intelectual, como parte del Consejo Nacional de Seguridad. El director debería gozar de categoría de ministro y disponer de recursos humanos y financieros similares a los que, en sociedades abiertas, manejan los directores de cultura. Pero es un error, cometido muchas veces, encargar la vigilancia intelectual a las fuerzas de represión, sean policiales o armadas. Solamente un intelectual es capaz de discernir la novedad intelectual. Por esto, el director de vigilancia intelectual no debería ser un comisario de policía o un coronel, ni siquiera un general, sino un intelectual, si es posible de prestigio, aunque, por supuesto, manso y enemigo de novedades. Un filósofo o un científico puede servir para este cargo, a condición de que no sea creador.

Una persona optimista, es decir, ingenua y sin experiencia, creerá que la aplicación concienzuda de las reglas expuestas más arriba garantizará que no se desarrolle la ciencia sino como sirvienta de la técnica. Nada más errado. El hombre, como la rata, es perverso y astuto, y se escapará por el menor resquicio que se le deje. Para evitar semejantes fugas es necesario elaborar un reglamento que regule hasta el menor detalle las actividades permitidas a los científicos. Pasemos a bosquejar dicho reglamento.

La primera regla de toda política anticientífica eficaz será ésta:

RPC1. Tolérese alguna investigación aplicada, jamás la básica. La ciencia es, por definición, investigación de problemas cognoscitivos por medios controlables y con el fin de encontrar leyes. Lo demás es ciencia aplicada o tecnología, pero no ciencia propiamente dicha (o básica o pura). Para impedir el desarrollo de la ciencia, basta con privar de recursos a quienes pretenden hacer investigaciones básicas, sea experimentales, sea teóricas: se les dirá que eso que quieren hacer es “irrelevante” para los intereses nacionales (que son, por ejemplo, la producción de goma de mascar y de presos políticos). Se les dirá qué deben hacer en cambio.
Para llevar a cabo esta política habrá que evitar que la Dirección de Ciencia y Tecnología caiga en manos de personas con alguna experiencia científica: confíese el cargo a un gestor público, abogado, político o, a lo sumo, ingeniero o médico.

RPC2. Oblíguese a los investigadores a convertirse en administradores. Si un investigador se ve obligado a llenar una planilla por cada peso (o real o bolívar o quetzal) que recibe en apoyo de sus investigaciones, pronto dejará de investigar. Obligado a llevar cuentas complicadas y detalladas, y a redactar propuestas e informes voluminosos y frecuentes, no le quedará tiempo ni energía para pensar en problemas científicos. Desgraciadamente, este método es costoso y no alcanza a impedir el nacimiento de la ciencia: sólo sirve para acabar con ella. Por este motivo, sólo los países desarrollados pueden darse el lujo de poner en práctica la RPC2. Los demás deberán contentarse con obligar a llenar planillas sin suministrar recursos a cambio.
RPC3. Prémiese a los investigadores mediocres y castíguese a los originales. Es bueno que el público sepa que quienes buscan la verdad, a diferencia de quienes ya la poseen, no deben esperar recompensas externas: que los premios, sillones académicos y demás distinciones se reservarán a los incapaces de descubrir o inventar. Los innovadores, en cambio, serán ignorados o castigados. Si, pese a todas las precauciones tomadas, algunos han logrado alguna notoriedad, se les aplicará la RB2 o se los comprará con cargos burocráticos o decorativos desde los cuales no podrán hacer daño alguno.
RPC4. Destínese todo el presupuesto de investigación a adquirir edificios y aparatos y a mantener una burocracia obstructora, de modo que no quede para pagar sueldos decorosos a los investigadores, técnicos de laboratorio, bibliotecarios y demás personal productivo.
RPC5. Móntense laboratorios sin dotarlos de la infraestructura necesaria: talleres mecánicos, de vidrio, eléctricos, electrónicos, etc. Adquiérase todo el instrumental en el exterior, si es posible por catálogo y sin consultar con los usuarios, a fin de formar un museo de instrumentos ociosos o, mejor, descompuestos.

Hemos sugerido e intentado justificar los principios fundamentales de la ciencidiología. Estos principios se resumen en reglas prácticas de fácil comprensión: la ciencidiología es una disciplina sencilla al alcance de cualquier subdesarrollado, hasta el punto que muchos gobernantes la han practicado sin saberlo.

¿Cuál de los principios de la ciencidiología deberá escoger el celoso guardián del subdesarrollo? Estimo que solamente una combinación de todos ellos podrá garantizar el éxito ya que, siendo la sociedad un sistema complejo, no puede lograrse un cambio profundo y permanente en uno de sus subsistemas sin alterar también los demás.

Pero la combinación deberá ser juiciosa: no se trata de aplicar los principios de manera mecánica ni, en particular, simultáneamente. Por ejemplo, si se elimina a todos los intelectuales, como ya lo intentó más de una “revolución cultural”, no quedan candidatos para constituir el mandarinato que requiere la buena administración de toda gran empresa y del Estado. Y si se fomenta la investigación aplicada sin reforzar la vigilancia intelectual (RC2), se corre el peligro de que los investigadores pasen al campo básico so pretexto de poder hacer mejor ciencia aplicada.

Puede verse, pues, que aunque los principios de la ciencidiología son sencillos, su aplicación puede ser complicada. Por eso es aconsejable redactar un Código del Investigador que reglamente minuciosamente todas las actividades lícitas del investigador (aplicado). Al mismo tiempo, habrá que incorporar al Código Penal un capítulo íntegro dedicado a definir y sancionar toda investigación básica, posible fuente de subversión y componente necesario del desarrollo global de toda sociedad moderna.

Para terminar, permítaseme una aclaración. Lo que antecede no es una parodia sino un estudio serio, aunque tan sólo preliminar, de un problema serio, a saber: el subdesarrollo científico. Las reglas que he propuesto para asegurar dicho subdesarrollo no son antojadizas: todas ellas han sido ensayadas con éxito por algún gobierno en alguna época, y varias de ellas son puestas en práctica por numerosos gobiernos en nuestros días. Sería, pues, absurdo descartarlas como mera diversión de un bromista. La cosa no es ridícula sino trágica. La ciencidiología no hace más que registrar y codificar las reglas que rigen la conducta de quienes impiden el desarrollo científico. Tan es así que, si se persigue la finalidad contraria, es decir, estimular el desarrollo científico, bastará con invertir los principios de la ciencidiología. Así se obtendrá la epistegenética. Pero, ¡ojo con la Dirección de Vigilancia Intelectual, siempre alerta!

El libro se puede adquirir en www.laetoli.es y ya está a la venta en librerías
— Mario Bunge, Filósofo de la ciencia
 


Ciencia / Science: el diclofenaco mata a los buitres

http://esmateria.com/2014/03/29/un-grupo-de-cientificos-pide-la-prohibicion-del-farmaco-que-mata-los-buitres/


29 marzo 2014

Hombro / Shoulder: No hay que inmovilizar mucho tras reparar el manguito rotador

Effect of Immobilization without Passive Exercise After Rotator Cuff Repair Randomized Clinical Trial Comparing Four and Eight Weeks of Immobilization
Koh K, Lim T, Shon M, et al.
J Bone Joint Surg Am, 2014 Mar 19;96(6):e44 1-9.

Background:
While animal studies have shown better healing with a longer duration of protection without motion exercise after rotator cuff repair, supporting clinical studies are rare. The purpose of this study was to assess the effect of immobilization following rotator cuff repair and to determine whether there was any difference in clinical outcome related to the duration of immobilization.

Methods:
One hundred patients who underwent arthroscopic single-row repair of a posterosuperior rotator cuff tear (mean, 2.3 cm in the coronal-oblique plane and 2.0 cm in the sagittal-oblique plane) were prospectively randomized to be treated with immobilization for four or eight weeks. During the immobilization period, no passive or active range-of-motion exercise, including pendulum exercise, was allowed. According to the intention-to-treat protocol and full analysis set, eighty-eight patients were evaluated clinically and with magnetic resonance imaging postoperatively, after exclusion of twelve patients without postoperative clinical evaluation. Ranges of motion, clinical scores, and retear rates were compared between the four and eight-week groups. Ninety-eight patients were contacted by telephone at a mean of thirty-five months to investigate the clinical outcomes.

Results:
The mean duration of immobilization was 4.1 weeks in the four-week group and 7.3 weeks in the eight-week group. There were nine full-thickness retears (10%), and 89% of the patients rated their result as excellent or good. There were five full-thickness retears in the four-week group and four in the eight-week group (p = 0.726). At the time of final follow-up, the two groups showed no differences in range of motion or clinical scores. However, the proportion showing stiffness was higher in the eight-week group (38% compared with 18%, p = 0.038).

Conclusions:
Eight weeks of immobilization did not yield a higher rate of healing of medium-sized rotator cuff tears compared with four weeks of immobilization.

Level of Evidence:
Therapeutic Level I

Hombro / Shoulder: cómo evitar la deformidad de Popeye con imaginación

The "anchor shape" technique for long head of the biceps tenotomy to avoid the popeye deformity.
Narvani AA, Atoun E, Van Tongel A, Sforza G, Levy O

Arthrosc Tech 2013 May; 2(2):e167-70.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3716228/pdf/

Abstract
Surgical options for symptomatic pathologies of the long head of the biceps (LHB) include tenotomy and tenodesis. Tenotomy is surgically simple and quick, does not require immobilization, and avoids implant complications. However, it is associated with residual "Popeye" muscle deformity and biceps muscle cramps. Tenodesis avoids Popeye deformity, but it is technically a more difficult operation with a longer rehabilitation period and possible implant complications. The purpose of this report is to describe a novel technique for LHB tenotomy that avoids the Popeye muscle deformity. Before releasing the LHB from its anchor over the superior labrum, this technique consists of making an oblique incision, involving 50% of the tendon, distal to its attachment at the superior labrum. A second standard complete tenotomy incision is made about 1.5 cm medial to the oblique incision. The remaining stump of the LHB at the tendon-labrum junction is resected. The first incision, an oblique incomplete incision, allows the remnant of the LHB to open up and form an "anchor shape" that anchors the LHB at the articular entrance of the bicipital groove, thus decreasing the risk of Popeye deformity.


28 marzo 2014

Rodilla / Knee: en la PTR infectada, pronto lavado artroscopico y a veces quitar el plástico

Arthroscopic Debridement for Acutely Infected Prosthetic Knee: Any Role for Infection Control and Prosthesis Salvage?
Arthroscopy: The Journal of Arthroscopic & Related Surgery
Available online 18 March 2014
Jun Young Chung , Chul-Won Ha , Yong-Beom Park , Young-Joon Song , Kun-Sik Yu

Purpose
The purpose of this study was to assess the success rate of arthroscopic debridement guided by C-reactive protein (CRP) levels for acutely infected total knee prostheses.

Methods
From January 2002 to December 2009, 16 consecutive eligible patients met the following inclusion criteria: duration of symptoms less than 72 hours, previously well-functioning prostheses, and no radiographic signs of loosening. Each patient underwent arthroscopy with thorough debridement and synovectomy and copious irrigation. In addition to the standard anterior portals, a posterior portal was used, and a drain was placed through this portal. The need for subsequent open debridement was determined by the postarthroscopy trends of CRP levels. Treatment success was defined as continuing freedom from infection based on clinical and laboratory results, salvage of the prosthesis, and no evidence of infection for at least 2 years.

Results
Arthroscopic debridement eradicated the infection in 10 (62.5%) of the 16 cases. The other 6 knees (37.5%) underwent subsequent open debridement with polyethylene insert exchange, which resulted in successful infection control with prosthetic salvage.

Conclusions
Patients who had undergone total knee arthroplasty (TKA) and had acute joint infection for less than 72 hours with no evidence of a loosening prosthesis were treated by arthroscopic debridement guided by the CRP level and had a 62.5% success rate with arthroscopic treatment alone but a 100% success rate when initial failures were treated with open debridement and polyethylene exchange.

Level of Evidence
Level IV, case series.

 

27 marzo 2014

Prótesis total articular / Total Joint Arthroplasty: ver las bacterias ocultas en el biofilm

Imaging bacteria and biofilms on hardware and periprosthetic tissue in orthopedic infections.
Nistico L, Hall-Stoodley L, Stoodley P
Methods Mol Biol. 2014;1147:105-26

Abstract
Infection is a major complication of total joint arthroplasty (TJA) surgery, and even though it is now as low as 1 % in some hospitals, the increasing number of primary surgeries translates to tens of thousands of revisions due to prosthetic joint infection (PJI). In many cases the only solution is revision surgery in which the hardware is removed. This process is extremely long and painful for patients and is a considerable financial burden for the health-care system. A significant proportion of the difficulties in diagnosis and treatment of PJI are associated with biofilm formation where bacteria attach to the surface of the prosthesis and periprosthetic tissue and build a 3-D biofilm community encased in an extracellular polymeric slime (EPS) matrix. Bacteria in biofilms have a low metabolic rate which is thought to be a major contributor to their recalcitrance to antibiotic treatment. The diagnosis of biofilm infections is difficult due to the fact that bacteria in biofilms are not readily cultured with standard clinical microbiology techniques. To identify and visualize in situ biofilm bacteria in orthopedic samples, we have developed protocols for the collection of samples in the operating room, for molecular fluorescent staining with 16S rRNA fluorescence in situ hybridization (FISH), and for imaging of samples using confocal laser scanning microscopy (CLSM). Direct imaging is the only method which can definitively identify biofilms on implants and complements both culture and culture-independent diagnostic methods.


25 marzo 2014

Trauma: Menisco dañado al introducir un clavo de tibia

Anterior meniscus root avulsion following intramedullary nailing for a tibial shaft fracture.
Ellman MB, James EW, Laprade CM, Laprade RF.
Knee Surg Sports Traumatol Arthrosc. 2014 Mar 19. [Epub ahead of print]


Abstract
This paper presents the first reported case of iatrogenic injury to the anterior medial meniscal root attachment following intramedullary nailing for a tibial shaft fracture. The patient experienced a closed right tibia-fibula fracture 7 years prior to presentation, which was treated with a reamed intramedullary nail. The nail was removed 3 years after the index surgery due to chronic anterior knee pain, which persisted following hardware removal. At presentation, the patient was diagnosed with an anterior horn medial meniscal root tear likely secondary to insertion of the intramedullary nail through the anatomic footprint of the anterior medial root. After undergoing a medial meniscus anterior horn root repair, the patient was asymptomatic and resumed normal activities.

LEVEL OF EVIDENCE:
Case report, Level IV.

Hombro / Shoulder: Menos luxaciones si se inclina hacia abajo la glenosfera

Optimal glenoid component inclination in reverse shoulder arthroplasty. How to improve implant stability.
Randelli P, Randelli F, Arrigoni P, Ragone V, D'Ambrosi R, Masuzzo P, Cabitza P, Banfi G
Musculoskelet Surg 2014 Mar 23.

Abstract
PURPOSE
The purpose of this study is to demonstrate that inferior inclination of the glenosphere is a protecting factor from joint dislocation in reverse total shoulder replacement. The hypothesis is that an average of 10° of inferior inclination of the glenoid component would determine a significant inferior rate of dislocation as compared to neutral inclination.

METHODS
A retrospective case (dislocation)-control (stability of the implant) study was performed. Inclusion criteria were the homogeneity of the prosthetic model and availability of pre- and postoperative imaging of the shoulder, including antero-posterior and axillary X-ray views. Glenoid and glenosphere inclination were calculated according to standardized methods. Difference in between the angles determined the inferior tilt.

RESULTS
Thirty-three cases fit the inclusion criteria. Glenoid and glenosphere inclination measured, respectively, 74.1° and 83.5°. The average tilt of the glenosphere measured 9.4°. The average tilt in stable patients was 10.2°. Tilt in patients with atraumatic dislocation measured, respectively, -6.9° (superior tilt) and 2.4°, while it was 8.3° for the patient with traumatic instability. The association between the tilt of glenosphere and atraumatic dislocation was significant.

CONCLUSIONS
A 10° inferior tilt of the glenoid component in reverse shoulder arthroplasty is associated with a reduced risk of dislocation when compared to neutral tilt.

General: células madre mesenquimales al alcance de la mano

Recent insights into the identity of mesenchymal stem cells: Implications for orthopaedic applications
Murray, I. R., Corselli, M., Petrigliano, F. A., Soo, C., Peault, B.
Bone Joint J 2014;96-B:291–8.

The ability of mesenchymal stem cells (MSCs) to differentiate in vitro into chondrocytes, osteocytes and myocytes holds great promise for tissue engineering. Skeletal defects are emerging as key targets for treatment using MSCs due to the high responsiveness of bone to interventions in animal models. Interest in MSCs has further expanded in recognition of their ability to release growth factors and to adjust immune responses.

Despite their increasing application in clinical trials, the origin and role of MSCs in the development, repair and regeneration of organs have remained unclear. Until recently, MSCs could only be isolated in a process that requires culture in a laboratory; these cells were being used for tissue engineering without understanding their native location and function. MSCs isolated in this indirect way have been used in clinical trials and remain the reference standard cellular substrate for musculoskeletal engineering. The therapeutic use of autologous MSCs is currently limited by the need for ex vivo expansion and by heterogeneity within MSC preparations. The recent discovery that the walls of blood vessels harbour native precursors of MSCs has led to their prospective identification and isolation. MSCs may therefore now be purified from dispensable tissues such as lipo-aspirate and returned for clinical use in sufficient quantity, negating the requirement for ex vivo expansion and a second surgical procedure.

In this annotation we provide an update on the recent developments in the understanding of the identity of MSCs within tissues and outline how this may affect their use in orthopaedic surgery in the future.
 

Trauma: peor si la cadera se rompe el fin de semana

The weekend effect: short-term mortality following admission with a hip fracture
Thomas, C. J., Smith, R. P., Uzoigwe, C. E., Braybrooke, J. R.
Bone Joint J 2014;96-B:373–8

We retrospectively reviewed 2989 consecutive patients with a mean age of 81 (21 to 105) and a female to male ratio of 5:2 who were admitted to our hip fracture unit between July 2009 and February 2013. We compared weekday and weekend admission and weekday and weekend surgery 30-day mortality rates for hip fractures treated both surgically and conservatively. After adjusting for confounders, weekend admission was independently and significantly associated with a rise in 30-day mortality (odds ratio (OR) 1.4, 95% confidence interval (CI) 1.02 to 1.9; p = 0.039) for patients undergoing hip fracture surgery. There was no increase in mortality associated with weekend surgery (OR 1.2, 95% CI 0.8 to 1.7; p = 0.39). All hip fracture patients, whether managed surgically or conservatively, were more likely to die as an inpatient when admitted at the weekend (OR 1.4, 95% CI 1.02 to 1.80; p = 0.032), despite our unit having a comparatively low overall inpatient mortality (8.7%). Hip fracture patients admitted over the weekend appear to have a greater risk of death despite having a consultant-led service.


 

24 marzo 2014

Trauma: cada hora de retraso en tratar fracturas abiertas graves, un 3% más probable que se infecten

Delayed debridement of severe open fractures is associated with a higher rate of deep infection
Hull, P. D., Johnson, S. C., Stephen, D. J. G., Kreder, H. J., Jenkinson, R. J.
Bone Joint J 2014;96-B:379–84

This study explores the relationship between delay to surgical debridement and deep infection in a series of 364 consecutive patients with 459 open fractures treated at an academic level one trauma hospital in North America.

The mean delay to debridement for all fractures was 10.6 hours (0.6 to 111.5). There were 46 deep infections (10%). There were no infections among the 55 Gustilo-Anderson grade I open fractures. Among the grade II and III injuries, a statistically significant increase in the rate of deep infection was found for each hour of delay (OR = 1.033: 95% CI 1.01 to 1.057). This relationship shows a linear increase of 3% per hour of delay. No distinct time cut-off points were identified. Deep infection was also associated with tibial fractures (OR = 2.44: 95% CI 1.26 to 4.73), a higher Gustilo-Anderson grade (OR = 1.99: 95% CI 1.004 to 3.954), and contamination of the fracture (OR = 3.12: 95% CI 1.36 to 7.36). These individual effects are additive, which suggests that delayed debridement will have a clinically significant detrimental effect on more severe open fractures.

Delayed treatment appeared safe for grade 1 open fractures. However, when the negative prognostic factors of tibial site, high grade of fracture and/or contamination are present we recommend more urgent operative debridement.

22 marzo 2014

Hombro / Shoulder: es poco frecuente reintervenir pronto tras una prótesis humeral

Thirty and ninety-day reoperation rates after shoulder arthroplasty
Streubel PN, Simone JP, Sperling JW, Cofield R
J Bone Joint Surg Am 2014 Feb 5; 96(3):e17.

Abstract
BACKGROUND
The purpose of the present study was to assess thirty and ninety-day reoperation rates after shoulder arthroplasty from 2000 to 2010.

METHODS
Our institution's joint registry was queried to identify shoulder arthroplasties performed from January 2000 to December 2010. Data regarding patient demographics and the type of procedure were reviewed. Reoperations within thirty and ninety days after the index procedure were analyzed. During the eleven-year study period, 2305 primary arthroplasties (502 hemiarthroplasties, 1440 anatomic total shoulder arthroplasties, and 363 reverse total shoulder arthroplasties) and 518 revision arthroplasties (twenty-one hemiarthroplasties, 356 anatomic total arthroplasties, and 141 reverse arthroplasties) were performed. Fifty-four percent of patients were female; mean age was sixty-eight years (range, eighteen to ninety-seven years) and body mass index was 30.3 kg/m2 (range, 14.7 to 65.9 kg/m2).

RESULTS
Reoperation was required within thirty days after fourteen primary arthroplasties (0.6%) and eight revision arthroplasties (1.5%); it was required within ninety days after thirty-two primary arthroplasties (1.4%) and thirteen revision arthroplasties (2.5%). The most frequent causes for reoperation after primary and revision arthroplasty were instability (n = 14 and 6) and infection (n = 13 and 3). The mean number of additional procedures required was 1.3 (range, one to four) for primary arthroplasties and 1.8 (range, one to three) for revision arthroplasties; 20% of patients undergoing reoperation required two or more additional procedures. Reoperations led to readmission in 82% of cases.

CONCLUSIONS
Short-term reoperation after shoulder arthroplasty was infrequent. Wound complications and shoulder instability were the most frequent causes for reoperation. Reoperation was twice as frequent after revision surgery as after primary shoulder arthroplasty.

Hombro / Shoulder: Mejores resultados si pones muchas prótesis de hombro ¡claro!

The effect of surgeon and hospital volume on shoulder arthroplasty perioperative quality metrics.
Singh A, Yian EH, Dillon MT, Takayanagi M, Burke MF, Navarro RA
J Shoulder Elbow Surg 2014 Feb 3

Abstract
BACKGROUND
There has been a significant increase in both the incidence of shoulder arthroplasty and the number of surgeons performing these procedures. Literature regarding the relationship between surgeon or hospital volume and the performance of modern shoulder arthroplasty is limited. This study examines the effect of surgeon or hospital shoulder arthroplasty volume on perioperative metrics related to shoulder hemiarthroplasty, total shoulder arthroplasty, and reverse shoulder arthroplasty. Blood loss, length of stay, and operative time were the main endpoints analyzed.

METHODS
Prospective data were analyzed from a multicenter shoulder arthroplasty registry; 1176 primary shoulder arthroplasty cases were analyzed. Correlation and analysis of covariance were used to examine the association between surgeon and hospital volume and perioperative metrics adjusting for age, sex, and body mass index.

RESULTS
Surgeon volume is inversely correlated with length of stay for hemiarthroplasty and total shoulder arthroplasty and with blood loss and operative time for all 3 procedures. Hospital volume is inversely correlated with length of stay for hemiarthroplasty, with blood loss for total and reverse shoulder arthroplasty, and with operative time for all 3 procedures. High-volume surgeons performed shoulder arthroplasty 30 to 50 minutes faster than low-volume surgeons did.

CONCLUSIONS
Higher surgeon and hospital case volumes led to improved perioperative metrics with all shoulder arthroplasty procedures, including reverse total shoulder arthroplasty, which has not been previously described in the literature. Surgeon volume had a larger effect on metrics than hospital volume did. This study supports the concept that complex shoulder procedures are, on average, performed more efficiently by higher volume surgeons in higher volume centers.

General: al usar PRP, la carga de leucocitos y glóbulos rojos empeora la viabilidad de los sinoviocitos

The Effect of Platelet-Rich Plasma Formulations and Blood Products on Human Synoviocytes: Implications for Intra-articular Injury and Therapy.
Braun HJ, Kim HJ, Chu CR, Dragoo JL.
Am J Sports Med. 2014 Mar 14

Abstract
BACKGROUND: The effect of platelet-rich plasma (PRP) on chondrocytes has been studied in cell and tissue culture, but considerably less attention has been given to the effect of PRP on synoviocytes. Fibroblast-like synoviocytes (FLS) compose 80% of the normal human synovium and produce cytokines and matrix metalloproteinases that can mediate cartilage catabolism. 

PURPOSE: To compare the effects of leukocyte-rich PRP (LR-PRP), leukocyte-poor PRP (LP-PRP), red blood cell (RBC) concentrate, and platelet-poor plasma (PPP) on human FLS to determine whether leukocyte and erythrocyte concentrations of PRP formulations differentially affect the production of inflammatory mediators.

STUDY DESIGN: Controlled laboratory study. 

METHODS: Peripheral blood was obtained from 4 donors and processed to create LR-PRP, LP-PRP, RBCs, and PPP. Human synoviocytes were cultured for 96 hours with the respective experimental conditions using standard laboratory conditions. Cell viability and inflammatory mediator production were then evaluated. 

RESULTS: Treatment with LR-PRP resulted in significantly greater synoviocyte death (4.9% ± 3.1%) compared with LP-PRP (0.72% ± 0.70%; P = .035), phosphate-buffered saline (PBS) (0.39% ± 0.27%; P = .018), and PPP (0.26% ± 0.30%; P = .013). Synoviocytes treated with RBC concentrate demonstrated significantly greater cell death (12.5% ± 6.9%) compared with PBS (P < .001), PPP (P < .001), LP-PRP (P < .001), and LR-PRP (4.9% ± 3.1%; P < .001). Interleukin (IL)-1β content was significantly higher in cultures treated with LR-PRP (1.53 ± 0.86 pg/mL) compared with those treated with PBS (0.22 ± 0.295 pg/mL; P < .001), PPP (0.11 ± 0.179 pg/mL; P < .001), and RBCs (0.64 ± 0.58 pg/mL; P = .001). IL-6 content was also higher with LR-PRP (32,097.82 ± 22,844.300 pg/mL) treatment in all other groups (P < .001). Tumor necrosis factor-α levels were greatest in LP-PRP (9.97 ± 3.110 pg/mL), and this was significantly greater compared with all other culture conditions (P < .001). Interferon-γ levels were greatest in RBCs (64.34 ± 22.987 pg/mL) and significantly greater than all other culture conditions (P < .001). 

CONCLUSION: Treatment of synovial cells with LR-PRP and RBCs resulted in significant cell death and proinflammatory mediator production. 

CLINICAL RELEVANCE: Clinicians should consider using leukocyte-poor, RBC-free formulations of PRP when administering intra-articularly.

21 marzo 2014

Rodilla / Knee: La tunelización del injerto de isquitibiales grande hasta cierto punto

Intraoperative Hoffa Fracture During Primary ACL Reconstruction: Can Hamstring Graft and Tunnel Diameter Be Too Large?
Werner BC, Miller MD
Arthroscopy 2014 Mar 15.

Abstract

Intraoperative fracture during tunnel placement in primary anterior cruciate ligament (ACL) reconstruction is rarely reported. To our knowledge, this is the first case report of an intraoperative distal femoral coronal plane (Hoffa) fracture that occurred during independent femoral tunnel drilling and dilation in a primary ACL reconstruction. The patient was treated with open reduction and internal fixation, without compromise of graft stability and with good recovery of function. We discuss the potential ramifications of suche a complication in the context of the current emphasis placed on large graft and femoral tunnel sizes.

Rodilla / Knee: ligamentoplastia y meniscectomía acaban en artrosis

Increased Risk of Osteoarthritis After Anterior Cruciate Ligament Reconstruction: A 14-Year Follow-up Study of a Randomized Controlled Trial.
Barenius B, Ponzer S, Shalabi A, Bujak R, Norlén L, Eriksson K
Am J Sports Med 2014 Mar 18

Abstract
BACKGROUND: The reported prevalence of radiological osteoarthritis (OA) after anterior cruciate ligament (ACL) reconstruction varies from 10% to 90%.

Purpose/ HYPOTHESIS: To report the prevalence of OA after ACL reconstruction and to compare the OA prevalence between quadrupled semitendinosus tendon (ST) and bone-patellar tendon-bone (BPTB) grafts. The hypothesis was that there would be no difference in OA prevalence between the graft types. The secondary aim was to study whether patient characteristics and additional injuries were associated with long-term outcomes. 

STUDY DESIGN: Randomized controlled trial; 

Level of evidence, 1. 

METHODS: Radiological examination results, Tegner activity levels, and Knee injury and Osteoarthritis Outcome Score (KOOS) values were determined in 135 (82%) of 164 patients at a mean of 14 years after ACL reconstruction randomized to an ST or a BPTB graft. Osteoarthritis was defined according to a consensus by at least 2 of 3 radiologists of Kellgren-Lawrence grade ≥2. Using regression analysis, graft type, sex, age, overweight, time between injury and reconstruction, additional meniscus injury, and a number of other variables were assessed as risk factors for OA 14 years after ACL reconstruction.   

RESULTS: Osteoarthritis of the medial compartment was most frequent, with 57% of OA cases in the ACL-reconstructed knee and 18% of OA cases in the contralateral knee (P < .001). There was no difference between the graft types: 49% of OA of the medial compartment for BPTB grafts and 65% for ST grafts (P = .073). The KOOS results were lower for patients with OA in all subscales, indicating that OA was symptomatic. No difference in the KOOS between the graft types was found. Meniscus resection was a strong risk factor for OA of the medial compartment (odds ratio, 3.6; 95% CI, 1.4-9.3) in the multivariable logistic regression analysis. 

CONCLUSION: A 3-fold increased prevalence of OA was found after an ACL injury treated with reconstruction compared with the contralateral healthy knee. No differences in the prevalence of OA between the BPTB and quadrupled ST reconstructions were found. An initial meniscus resection was a strong risk factor for OA; the time between injury and reconstruction was not.


19 marzo 2014

Rodilla / Knee: El injerto autólogo de tendón cuadricipital mejor que el de tendón rotuliano

Is Quadriceps Tendon a Better Graft Choice than Patellar Tendon? A Prospective Randomized Study.
Lund B, Nielsen T, Faunø P, Christiansen SE, Lind M
Arthroscopy 2014 Mar 14.

Abstract
PURPOSE
The purpose of this randomized controlled study was to compare knee stability, kneeling pain, harvest site pain, sensitivity loss, and subjective clinical outcome after primary anterior cruciate ligament (ACL) reconstruction with either bone-patellar tendon-bone (BPTB) or quadriceps tendon-bone (QTB) autografts in a noninferiority study design.

METHODS
From 2005 to 2009, a total of 51 patients were included in the present study. Inclusion criteria were isolated ACL injuries in adults. Twenty-five patients were randomized to BPTB grafts and 26 to QTB grafts. An independent examiner performed follow-up evaluations 1 and 2 years postoperatively. Anteroposterior knee laxity was measured with a KT-1000 arthrometer (MEDmetric, San Diego, CA). Anterior knee pain was assessed clinically and by knee-walking ability. Knee Injury and Osteoarthritis Outcome Score (KOOS) and subjective International Knee Documentation Committee (IKDC) score were used for patient-evaluated outcome.

RESULTS
Anterior knee laxity was equal between the 2 groups with KT-1000 values of 1.1 ± 1.4 mm and 0.8 ± 1.7 mm standard deviation (SD) at follow-up in QTB and BPTB groups, respectively (P = .65), whereas positive pivot shift test results were seen less frequently (14% compared with 38%, respectively; P = .03). Anterior kneeling pain, evaluated by the knee walking ability test, was significantly less in the QTB group, with only 7% of patients grading knee walking as difficult or impossible compared with 34% in the BPTB group. At 1 and 2 years' follow-up, there was no difference between the 2 groups in subjective patient-evaluated outcome. The IKDC score was 75 ± 13 patients and 76 ± 16 SD at 1-year follow-up in QTB and BPTB groups, respectively (P = .78). At 2 years, 12 patients were lost to follow-up, resulting in 18 in the BPTB group and 21 in the QTB group.

CONCLUSIONS
The use of the QTB graft results in less kneeling pain, graft site pain, and sensitivity loss than seen with BPTB grafts; however, similar anterior knee stability and subjective outcomes are seen. The results of this study show that QTB is a viable option for ACL reconstruction.

LEVEL OF EVIDENCE
Level II, randomized controlled clinical trial.