Artroplastia de la articulación interfalángica proximal: comparación entre el abordaje palmar y dorsal / Proximal interphalangeal joint replacement: a comparison between the volar and dorsal approach

Introducción. La artropatía de las articulaciones interfalángicas proximales (AIP) cursa con síntomas muy restrictivos, siendo algunos casos tributarios de artroplastia. En la mayoría de las series de artroplastias de las AIP la técnica utilizada es a través de un abordaje dorsal. El papel del abordaje palmar en la artroplastia de las AIP todavía no se ha valorado suficientemente. Objetivo. Revisar retrospectivamente los pacientes intervenidos de artroplastia de la AIP, y determinar si las realizadas por vía palmar consiguen un rango de extensión mayor que las realizadas por vía dorsal. Pacientes y métodos. Entre 2005-2010 se realizaron 22 artroplastias de AIP. La media de seguimiento fue de 29 meses. El implante que se utilizó en todos los pacientes fue el implante de silicona de AIP modelo Avanta® (Avanta Orthopaedics, San Diego, California, EE. UU.). Se realizó un abordaje dorsal en 14 articulaciones y un abordaje palmar en 8. La valoración clínica preoperatoria incluyó la escala visual analógica (EVA) y el arco de movimiento. El arco de movimiento preoperatorio medio era de -15°/60° en ambos grupos. En la última visita del seguimiento, la EVA y el rango de movimiento se registraron y se compararon con los valores preoperatorios. Resultados. El arco medio de flexo-extensión postoperatorio del grupo del abordaje dorsal era de -15°/60°, y el del abordaje palmar de -2°/62°. Conclusión. En nuestra serie hemos observado que las artroplastias de AIP realizadas por vía palmar consiguen un rango de extensión mayor que aquellas realizadas por vía dorsal. El abordaje palmar ofrece las ventajas de mantener la integridad del mecanismo extensor (AU)

Introduction. Arthropathy of the proximal interphalangeal (PIP) joint symptoms is very restrictive, and in some cases arthroplasty is required. In most of the reported series of PIP silicone arthroplasty, the technique described is the dorsal approach. As far as we know, the role of the volar approach in PIP arthroplasty has still not been adequately assessed. Objectives. To retrospectively review the patients who had PIP joint arthroplasty, and to study the clinical and radiographic outcomes in relation to the approach: volar or dorsal. Methods. A total of 22 PIP joint replacements were performed between 2005 and 2010. The mean age was 56 years and the mean follow-up period was 29 months. The implant used in all patients was the Avanta® PIP Soft-Skeletal Implant (Avanta Orthopaedics, San Diego, USA). The dorsal approach was performed in 14 joints, and a volar approach in 8 joints. The preoperative clinical evaluation included a visual analogue scale (VAS) and the range of motion (ROM). The preoperative ROM mean was -15°/60° in both groups. The VAS and the ROM in the last follow-up visit were recorded and compared with preoperative values. Results. The postoperative ROM of the dorsal approach group had a mean of -15°/60°, and that of the volar approach was -2°/62°. Conclusion. It was found that the volar approach in this series offers the advantages of maintaining the integrity of the extensor mechanism, resulting in a complete restoration of the extension in the range of motion (AU)

[Proximal interphalangeal joint replacement: A comparison between the volar and dorsal approach]. / Artroplastia de la articulación interfalángica proximal: comparación entre el abordaje palmar y dorsal.

INTRODUCTION: Arthropathy of the proximal interphalangeal (PIP) joint symptoms is very restrictive, and in some cases arthroplasty is required. In most of the reported series of PIP silicone arthroplasty, the technique described is the dorsal approach. As far as we know, the role of the volar approach in PIP arthroplasty has still not been adequately assessed. OBJECTIVES: To retrospectively review the patients who had PIP joint arthroplasty, and to study the clinical and radiographic outcomes in relation to the approach: volar or dorsal. METHODS: A total of 22 PIP joint replacements were performed between 2005 and 2010. The mean age was 56 years and the mean follow-up period was 29 months. The implant used in all patients was the Avanta® PIP Soft-Skeletal Implant (Avanta Orthopaedics, San Diego, USA). The dorsal approach was performed in 14 joints, and a volar approach in 8 joints. The preoperative clinical evaluation included a visual analogue scale (VAS) and the range of motion (ROM). The preoperative ROM mean was -15°/60° in both groups. The VAS and the ROM in the last follow-up visit were recorded and compared with preoperative values. RESULTS: The postoperative ROM of the dorsal approach group had a mean of -15°/60°, and that of the volar approach was -2°/62°. CONCLUSION: It was found that the volar approach in this series offers the advantages of maintaining the integrity of the extensor mechanism, resulting in a complete restoration of the extension in the range of motion.

Luxación palmar de la articulación metacarpofalángica del pulgar / Palmar dislocation of the metacarpophalangeal joint of the thumb

Presentamos el caso de un hombre de 41 años con una luxación palmar de la articulación metacarpofalángica del pulgar sin semiología de interposición de partes blandas, en el que se realizó reducción cerrada. El resultado fue satisfactorio. Se evidenció bostezo del ligamento colateral radial (AU)

Open reduction is considered almost mandatory, because soft tissue interposition is usually the norm. Soft tissue interposition can be inferred with the physical examination. Methods: We present the case of a 41 year old man with a palmar dislocation of the metacarpophalangeal joint of the thumb in which we achieved a satisfactory closed reduction. Closed reduction was successful. Instability of the radial collateral ligament was identified (AU)

Luxación central bilateral de cadera / Bilateral acetabular fracture dislocation

La luxación central bilateral central de cadera constituye una lesión muy poco frecuente. En este artículo se presenta un caso de un paciente masculino de 95 años que ingresó en nuestro centro presentando la entidad enunciada, no pudiéndose precisar con certeza el motivo de la misma, e indicándose tratamiento conservador dado el contexto patológico y la edad del paciente en cuestión (AU)

The bilateral acetabular fracture dislocation is a rare injury. This article presents the case of a 95 years old male patient who was admitted in our hospital presenting this entity. The reason of it could not be specified; and the treatment indicated was conservative given the pathologic context and age of this patient (AU)

Tratamiento quirúrgico de las fracturas diafisarias y conminutas de la clavícula mediante placa anatómica de bajo perfil / Surgical treatment of diaphyseal and comminuted fractures of the clavicle using a low profile anatomical plate

Objetivo. En este estudio valoramos el tratamiento de las fracturas desplazadas de la clavícula con un tercer fragmento o con conminución mediante la osteosíntesis con una placa anatómica y de bajo perfil colocada en la cara superior. Material y método. Estudio retrospectivo de 34 pacientes intervenidos desde enero de 2006 hasta junio de 2010, con fracturas de tercio medio de la clavícula conminutas o con tercer fragmento. El seguimiento medio ha sido de 25 meses (6-54 meses). Según la clasificación de Robinson 12 casos eran del tipo 2B, 17 del tipo 2B1, y 5 del tipo 2B2. La valoración clínica se realizó mediante la puntuación obtenida en la escala visual analógica (EVA) y en el test de Constant. La valoración radiológica preoperatoria y durante el seguimiento se llevó a cabo mediante proyecciones AP, una neutra y la otra con haz de Rx inclinado caudocranealmente 30°. Resultados. La puntuación media en la escala EVA preoperatoria fue de 6,5 (4-8) y la postoperatoria de 1 (0-2). La puntuación media en el test de Constant fue de 85, con un 30% de casos con buenos resultados y un 70% de excelentes. El tiempo medio en obtener la consolidación fue de 14 semanas. Conclusiones. La fijación interna con placa anatómica de las fracturas conminutas de la clavícula, especialmente si presentan un tercer fragmento vertical, o fracturas tipo 2B, 2B1 y 2B2, constituyen una buena opción de tratamiento dado el buen resultado funcional y la baja incidencia de pseudoartrosis que presentan (AU)

Objectives. In this study we evaluate the treatment of displaced mid-shaft clavicle fractures or comminuted fractures with a third fragment using a superior anatomic plate. Materials and methods. A retrospective study was conducted on 34 patients operated on between January 2006 and June 2010 with this type of fracture. Mean follow up was 25 months (6-54 months). By Robinson Classification, 12 cases were type 2B, 17 type 2B1 and 5 type 2B2. Clinical evaluation was performed with the VAS and Constant test. For the radiological evaluation, we used neutral AP projections, and another with 30 degrees of cranio-caudal inclination. Results. The mean pre-operative VAS was 6.5 (4-8) and the postoperative was 1 (0-2). The mean Constant test score was 85, with 30% good results and 70% excellent results. The mean consolidation time was 14 weeks. Conclusion. Internal fixation of comminuted fractures with an anatomic plate, particularly those with a vertical third fragment and fractures type 2B, 2B1 and 2B2, provides a good treatment option, as it gives good functional results and minimises the incidence of non-union (AU)

[Surgical treatment of diaphyseal and comminuted fractures of the clavicle using a low profile anatomical plate]. / Tratamiento quirúrgico de las fracturas diafisarias y conminutas de la clavícula mediante placa anatómica de bajo perfil.

OBJECTIVES: In this study we evaluate the treatment of displaced mid-shaft clavicle fractures or comminuted fractures with a third fragment using a superior anatomic plate. MATERIALS AND METHODS: A retrospective study was conducted on 34 patients operated on between January 2006 and June 2010 with this type of fracture. Mean follow up was 25 months (6-54 months). By Robinson Classification, 12 cases were type 2B, 17 type 2B1 and 5 type 2B2. Clinical evaluation was performed with the VAS and Constant test. For the radiological evaluation, we used neutral AP projections, and another with 30 degrees of cranio-caudal inclination. RESULTS: The mean pre-operative VAS was 6.5 (4-8) and the postoperative was 1 (0-2). The mean Constant test score was 85, with 30% good results and 70% excellent results. The mean consolidation time was 14 weeks. CONCLUSION: Internal fixation of comminuted fractures with an anatomic plate, particularly those with a vertical third fragment and fractures type 2B, 2B1 and 2B2, provides a good treatment option, as it gives good functional results and minimises the incidence of non-union.

Injerto óseo vascularizado y fijación con mini-acutrak (R) en las pseudoartrosis de escafoides con necrosis del polo proximal / Vascularised bone graft with mini-acutrak (R) fixation in scaphoid pseudoarthrosis with proximal pole necrosis

Objetivo. Evaluar los resultados del injerto óseo vascularizado (IOV) de la arteria 1, 2 suprarretinacular intercompartimental (1,2 SRIC) junto con la fijación, en pseudoartrosis de escafoides y necrosis del polo proximal. Material y método. Realizamos un estudio retrospectivo, entre enero de 2006 y diciembre de 2009. Se trata de 10 pacientes con pseudoartrosis de escafoides con necrosis del polo proximal. Todos eran varones con edad media de 27 años (rango: 18-46). El seguimiento medio fue de 18 meses (rango: 12-43). La evaluación clínica incluye el dolor según la escala visual analógica (EVA), el balance articular y la fuerza de prensión. La evaluación radiológica incluye radiografías, TC y RNM. Se midió el ángulo escafolunar y la altura carpiana de acuerdo con el índice de Nattrass et al. La escala utilizada fue la Mayo Wrist Score. Resultados. La consolidación tuvo lugar en todos en un tiempo medio de 15 semanas (rango: 6-25 semanas). La media de EVA preoperatoria fue de 4,5 (2-8) y postoperatoria de 1 (0-2). El índice de la altura carpiana de Nattrass preoperatorio fue de 1,50 y postoperatorio de 1,58. El ángulo escafolunar medio preoperatorio fue de 52° y postoperatorio de 49°. Los valores preoperatorios de la Mayo Wrist Score fueron de 53 y los valores postoperatorios de 92. Conclusiones. La técnica que combina el IOV y la fijación con un tornillo mini-acutrak®, presenta buenos resultados, en el tratamiento de las pseudoartrosis de escafoides con necrosis del polo proximal. Preferimos el uso de la arteria 1,2 SRIC. En el caso de que esta arteria este ausente se pueden utilizar otros pedículos vasculares (AU)

Objectives. We studied the use of vascularized bone graft (VBG) in combination with a fixation with screw in patients with scaphoid nonunion and avascular proximal poles. Materials and methods. Between January 2006 and December 2009, we treated 10 patients with scaphoid nonunion with avascular proximal poles. There were 10 males with nonunion. Their average age was 27years (range: 18-46years). The average follow-up was 18 months (range: 12-43 months). The clinical valuation was the scale of pain (VAS), the range of motion and grip strength. The radiological valuation included radiographies, CT and MRI. We studied the scapholunate angle, the Carpal Height Index by Nattrass et al. and the Mayo Wrist Score. Results. The mean preoperative VAS was 4.5 (2-8) and postoperative VAS 1 (0-2). All patients achieved union in an average time of 15weeks (range: 6-25weeks). X-rays and CT showed a complete osseous union in all patients. Carpal Height Index was a mean of 1.50 preoperative and 1.58 postoperative. The scapholunate angle was a mean of 52° preoperative and 49° postoperative. Mayo Wrist Score was 53 preoperative and 92 postoperative. Conclusions. We have found that the technique which combines VBG with mini acutrak® screw, is successful in treating scaphoid nonunions with avascular poles. We prefer to use the vessel 1, 2 ICSRA. If this vessel is occasionally absent, other pedicles may be used (AU)

Luxación de los tendones extensores de la mano a nivel de la articulación metacarpofalángica / Luxation of the hand extensor tendons around the metacarpophalangeal joint

Objetivo. La luxación de los tendones extensores sobre la cabeza de los metacarpianos, constituye una entidad poco frecuente en pacientes que no presentan una artritis reumatoide. Sin embargo, con el incremento de actividades deportivas, especialmente aquellas que exigen un contacto físico permanente, el número de casos ha ido aumentando. Método. En cuanto al tratamiento se refiere, hay que distinguir los casos agudos (menos de tres semanas de evolución) de los crónicos, pues en los primeros casos suele ser suficiente la inmovilización, mientras que en los segundos es necesario practicar algún tipo de intervención quirúrgica. Resultados. En el presente trabajo se dan a conocer los resultados obtenidos sobre tres pacientes con dicha patología y a los cuales se procedió a la centralización quirúrgica del tendón mediante técnica de Kilgore (AU)

Objectives: Dislocation of the extensors over the head of the metacarpals constitutes a rare condition in patients who do not present rheumatoid arthritis. Nevertheless, with the increase in sport activities and especially those that demand a permanent physical contact, the number of cases has been increasing. Methods: As far as treatment its goes, it is necessary to distinguish the acute cases (less than three weeks evolution) from the chronic ones as immobilization is usually sufficient in the first case. On the other hand, it is necessary to practice some type of operation in the second case. Results: In the present work, the results obtained on three patients with this pathology on whom surgical centralization of the tendon by means of the Kilgore technique is made known (AU)

Reducción abierta y fijación interna de una luxación perilunar inveterada / Open reduction and internal fixation of chronic perilunate dislocation

Presentamos un caso de luxación perilunar inveterada de dos meses de evolución tratada con reducción abierta y fijación interna. Se realizó un abordaje doble, dorsal y palmar. El abordaje palmar permitió abrir el túnel carpiano y reinsertar los ligamentos volares. El abordaje dorsal permitió, con un flap capsular de base radial, reducir la luxación inveterada y reinsertar el ligamento interóseo escafolunar. Estabilizamos la reducción con tres agujas de Kirschner temporales y con una inmovilización durante 6 semanas. La reducción abierta y fijación interna a los dos meses de la luxación perilunar inveterada es el método de elección, en lugar de la carpectomía proximal o la artrodesis parcial (AU)

We present a case of two-month inveterate perilunar luxation treated by open reduction and internal fixation. A dual dorsal and palmar approach was used. The palmar access allowed opening of the carpal tunnel and reinsertion of the volar ligaments. The dorsal approach in turn allowed the use of a radial-base capsular flap to reduce the inveterate luxation and reinsert the scapholunar interbone ligament. The reduction was stabilized with three temporary Kirschner pins and immobilization for 6 weeks. Open reduction and internal fixation two months after inveterate perilunar luxation is the method of choice, in place of proximal carpectomy or partial arthrodesis (AU)

The anatomy and vascularity of the lunate: considerations applied to Kienböck's disease.

PURPOSE: The purpose of this study was to assess the anatomy and vascularity of the lunate. The genesis of lunatomalacia requires some combination of vascular risk and mechanical predisposition. The findings will be correlated with the major existing theories of the cause of Kienböck's disease. METHODS: We studied 27 cadaver upper limbs using latex injection and the Spalteholz technique. We investigated the blood supply to the lunate. In 24 wrists we evaluated the incidence and distribution of anatomic features, arthrosis, and soft tissue lesions. We correlated the lunate morphology and ligaments disruptions with the arthritic changes. RESULTS: The lunate morphology results as classified by Antuña-Zapico were five type I (20.8%), 18 type II (75%) and one type III (4.2%). The lunate was found to have a separate facet for the hamate in 11 cases (45.8%). The most common size of the facet was found to be 3 mm (range, 3-6 mm). Arthrosis was identified with most frequency in the radius (88.2%) and lunate (94.1%). The triangular fibrocartilage complex was found torn in 58.3%, the lunotriquetral interosseous ligament was torn in 20.8% and the scapholunate interosseous ligament (SLIL) was torn in 54.2% of the wrists. There was a correlation between the presence of arthrosis at the hamate and the presence of a lunate facet (P=0.027) and a correlation between the presence of a tear in the SLIL and arthrosis in the scaphoid (P=0.002). The nutrient vessels entered the lunate through the dorsal and volar poles in all the specimens. The dorsal intercarpal and radiocarpal arches supply blood to the lunate from a plexus of vessels located directly over the lunate's dorsal pole. Vessels entered the dorsal aspect of the lunate through one to three foramina. One to five nutrient vessels were observed entering the volar pole through various ligament insertions, including the ligament of Testut-Kuentz (radio-scapho-lunate (RSL) ligament) and the radiolunate triquetrum ligament (or dorsoradial carpal ligament) and ulnar lunate triquetral ligament. CONCLUSIONS: The lunate had consistent dorsal and palmar arteries entering the bone in all the specimens. The blood supply and foramina number is greater in the volar pole of the lunate than the dorsal pole. The lunate blood supply comes from different ligaments. In the etiopathogeny of Kienböck's disease it is possible that an acute or chronic, traumatic or non-traumatic injury of the vessel bearing ligaments, particularly because of their structure and the location of the RSL ligament, may have an important role in the appearance of lunate necrosis.

Principios básicos de la enfermedad de Kienböck: anatomía y vascularización del semilunar / Basic principles of Kienböck´s disease: anatomy and vascularization of the lunate

Objetivo: El propósito del estudio es investigar la vascularización y lasrelaciones anatómicas del semilunar. Se correlacionan los patronesde vascularización con la morfología del semilunar, la ruptura de losligamentos y el grado de artrosis. Los hallazgos obtenidos ayudan aapoyar o descartar algunas de las teorías etiopatogénicas.Material y Métodos: Estudiamos 24 extremidades superiores decadáver mediante la técnica de Spalteholtz e investigamos la circulaciónextra e intraósea en el semilunar. Evaluamos la incidencia ydistribución de distintas características anatómicas, artrosis y lesionesde partes blandas.Resultados: La morfología del semilunar fue de 5 casos tipo I(20.8%), 18 casos tipo II (75%) y 1 caso tipo III (4.2%). El semilunarpresentaba una faceta articular para ganchoso en 11 casos (48.8%).El tamaño de esta faceta fue de 3 mm (rango, 3-6 mm). La artrosisse identificó con más frecuencia en el radio (88.2%) y en el semilunar(94.1%). El complejo fibrocartílago triangular (CFCT) estaba roto en el58.3%, el ligamento interóseo lunopiramidal (LILP) en el 20.8%, y elligamento interóseo escafolunar (LIEL) en el 54.2% de los carpos.Existe una correlación entre la artrosis del ganchoso y la faceta lunarpara el ganchoso (p= 0.027), así como, una correlación entre la rupturadel LIEL y la artrosis del escafoides (p= 0.002). Los vasosnutrientes entran en el semilunar por su polo dorsal y volar en todoslos especímenes. El arco radiocarpiano e intercarpiano dorsal nutre elsemilunar por un plexo que entra en éste por 1-3 foráminas. Las arteriolaspalmares entran en el semilunar a través de 2-6 foráminas yvan acompañadas de tres inserciones ligamentosas: ligamento radioescafolunarprofundo de Testut-Kuentz, ligamento radio-semilunarpiramidaly del ligamento cúbito-semilunar.Conclusiones: El semilunar tiene entradas vasculares dorsales yvolares en todos los especímenes. La suplencia vascular llega pordistintos ligamentos. El aporte vascular entra en el hueso a travésde foráminas que se encuentran en mayor número en la carillavolar que en la dorsal. En la etiopatogenia de la enfermedad deKienböck es posible que una lesión aguda o crónica, traumática ono-traumática pueda dañar los vasos que tienen estos ligamentos,en particular el ligamento radioescafolunar profundo de Testut-Kuentz, que debido a su estructura y localización, pueda tener unpapel relevante en la aparición de la necrosis del semilunar

Purpose: The purpose of this study was to assess the anatomyand vascularization of the lunate. We correlated vascularizationpatterns with lunate morphology, ligament tears andthe degree of arthrosis. The findings will be correlated with themajor existing theories of the cause of Kienböck´s disease.Material and Methods: We studied 24 cadaver upper limbsusing latex injection and the Spalteholz technique. We investigatedthe extra and intraosseous blood supply to the lunate.We evaluated the incidence and distribution of anatomic features,arthrosis, and soft tissue lesions.Results: The lunate morphology was 5 type I (20.8%), 18 type II(75%) and 1 type III (4.2%). The lunate was found to have aseparate facet for the hamate in 11 cases (45.8%). The mostcommon size of the facet was found to be 3 mm (range, 3-6mm). Arthrosis was identified most frequently in radius (88.2%)and lunate (94.1%). The triangular fibrocartilage complex (TFCC)was found torn in 58.3%, the lunotriquetral interosseous ligament(LTIL) was torn in 20.8% and the scapholunate interosseous ligament(SLIL) was torn in 54.2% of the wrists. There was a correlationbetween the presence of arthrosis at the proximal pole of thehamate and the presence of a lunate facet (p= 0.027) and acorrelation between the presence of a tear in the SLIL and arthrosisin the scaphoid (p= 0.002). The nutrient vessels entered thelunate through the dorsal and volar poles in all the specimens.The dorsal intercarpal and radiocarpal arches supply blood to thelunate from a plexus of vessels located directly over the lunate´sdorsal pole. Vessels entered the dorsal aspect of the lunatethrough one to three foramina. Two to five nutrient vessels wereobserved entering the volar pole through various ligament insertions,including the ligament of Testut-Kuentz (radioscapholunateligament) and the radiolunate triquetrum ligament (or dorsoradialcarpal ligament) and ulnar lunate triquetral ligament.Conclusions: The lunate had consistent dorsal and palmararteries entering the bone in all the specimens. The bloodsupply and foramina number is greater in the volar pole of thelunate than the dorsal pole. The lunate blood supply comesfrom different ligaments. In the aetiopathogeny ofKienböck’disease it is possible that an acute or chronic, traumaticor non-traumatic lesion of the vessel bearing ligaments,particularly because of their structure and the location of theradioscapholunate ligament of Testut-Kuentz, may have animportant role in the appearance of lunate necrosis

Management of metallic mercury injection in the hand.

This case report discusses a patient who injected 20 mL of metallic mercury subcutaneously in his left hand during an attempted suicide. The blood mercury level was 118 microg/L and the urinary mercury level was 43 microg/L, which confirmed the diagnosis of metallic mercury poisoning. A good result was obtained in this patient and the local and systemic toxicity and its management are discussed. A chelation therapy with dimercaprol and early surgical excision of injected material are recommended because this treatment effectively lowers mercury blood levels and controls the local inflammatory reaction. Intraoperative fluoroscopy is useful to confirm the extent of removal.

Intramedullary nails vs osteosynthesis plates for femoral fracture stabilization: A finite element analysis.

In diaphyseal femoral fractures, an accurate quantification of the biomechanical differences between implants can help the surgeon make his choice. This study uses the finite element (FE) method to characterize the differences between intramedullary nails and osteosynthesis plates at different stages of femoral fracture healing, and assesses how these differences are affected by the size and consolidation of the fracture. Simulations were performed using a femur model with a 1 and 3 mm diaphyseal fracture at two stages of consolidation. The fracture was stabilized with an osteosynthesis plate or an intramedullary nail made of stainless steel (SS), titanium (Ti) or a composite material. The Ti implants bore lower von Mises stresses ( ó vM ) than the SS implants, and ó vM in the implants decreased with fracture consolidation. Nails tended to bear higher stresses than plates, though these differences were reduced in unstable fractures. This change in trend proves that fixation choice is critical for weak fractures. Both the dilatational stress ó dil and the octahedral shear strain å oct of the fractures varied significantly with the type of fracture and fixation device. In accordance with the literature, our results suggest that plates induce fracture healing through intramembranous ossification without fracture callus formation. Nails, on the other hand, induce endochondral ossification with fibrous tissue formation. The composite implants have mechanical limitations, but increasing their yield stress could overcome these drawbacks.

Yield point in prediction of compressive behavior of lumbar vertebral body by dual-energy x-ray absorptiometry.

The aims of the present study were to evaluate the influence of bone mineral content (BMC) and density on the behavior of the lumbar vertebra during compression and to determine critical points during compression. Dual-energy X-ray absorptiometry (DXA) and compression tests were performed on 44 vertebral bodies obtained from 22 cadavers. The results of the study indicate that bone mineral content measured by DXA were strongly correlated with ultimate failure load (r = 0.53, p < 0.001), ultimate failure stress (r = 0.581, p < 0.001), and toughness (r = 0.632, p < 0.001). Correlation with the yield point (r = 0.543, p < 0.001) was also significant. Bone mineral density showed similar results with ultimate failure load (r = 0.742, p < 0.001), ultimate failure stress (r = 0.742, p = 0.001), toughness (r = 0.673, p < 0.001), and yield point (r = 0.693, p < 0.001). The correlation between elastic parameters and DXA were suggestive but not quite significant. BMC was not related significantly with stiffness or Young's modulus. There was no correlation between bone mass and vertebral deformation parameters. In conclusion, bone mass and bone density appear to have a clear relationship to ultimate parameters and yield point. The relation with the yield point might be critical because it marks the beginning of the plastic region and signals the appearance of the first trabecular fractures.

Midshaft clavicular non-unions treated with the Herbert cannulated bone screw.

PURPOSE: To assess an alternative technique for the treatment of midshaft non-unions of the clavicle. METHODS: Five patients with symptomatic non-unions of the clavicle were treated with open reduction and intramedullary fixation by using a Herbert cannulated bone screw. Autogenous bone grafting was applied in one case and decortication in the other 4 cases. RESULTS: Review of the clinical and radiological documentation at a mean time of 13 months (range, 9-26 months) postoperatively shows that union was achieved in all 5 cases. There were no complications related to the operation, and no patient needed removal of the implant for protrusion, loosening, or any other cause. CONCLUSION: Midshaft non-unions of the clavicle can be treated successfully using the Herbert cannulated bone screw, which avoids the need for a second operation to remove the implant after bone union.

Rupture of all the flexor tendons in the hand due to malunion of a distal radius fracture.

We report the case of a patient in whom the flexor digitorum superficialis and flexor digitorum profundus tendons to the index, middle, ring and little fingers ruptured 6 years following malunion of a distal radius fracture. There was no history of rheumatoid disease. The distal ulna was displaced volarly and perforated the volar wrist capsule. There was a cumulative biological effect from chronic synovitis and mechanical compression due to the ulnar head impinging upon the normal anatomic course of the flexor tendons to the ring and little fingers. We discuss the physiopathology of this rare lesion and postulate that flexor tendon rupture to the index and middle fingers will occur on the volar surface of the radius when there is a malunion with dorsal tilt.

Estudio biomecánico del tornillo canulado de Herbert en el tratamiento de la pseudoartrosis de clavícula* / Biomechanical study of the Herbert cannulated screw in the treatment of clavicular nonunion

Objetivo. Valorar biomecánica y clínicamente una técnica alternativa quirúrgica para el tratamiento de la pseudoartrosis del tercio medio de la clavícula. Material y método. Estudio mecánico: diecinueve especímenes de clavículas humanas fueron divididos en tres grupos: grupo A, 5 clavículas intactas, grupo B, 5 clavículas osteotomizadas perpendicularmente al eje longitudinal del hueso, en su parte media, y tratadas con placas DCP de 3,5 mm y 6 orificios, y grupo C, 9 clavículas osteotomizadas y tratadas con clavo canulado de Herbert, de 4,5 mm. Todas las clavículas fueron sometidas a ensayos mecánicos en una máquina de ensayos servohidraúlica obteniendo la resistencia máxima (N), la rigidez (N/Mm) y la tensión máxima (Mpa). Resultados. Estudio mecánico: tanto la placa recta DCP como el tornillo canulado de Herbert se comportaron mecánicamente de forma similar. Conclusiones. La ventaja de la síntesis intramedular con tornillo canulado de Herbert es que no requiere una segunda operación para retirar el implante una vez conseguida su consolidación (AU)

Distal interphalangeal joint arthrodesis: treatment with Herbert screw.

From 1996 to 2000, 20 patients with a mean age of 53 underwent 20 arthrodeses with Herbert screws. There were 16 (80%) distal interphalangeal joint (DIP) and 4 (20%) thumb interphalangeal (IP) joint arthrodeses. Average follow-up was 25 months (range, 6-39 months). The diagnoses included rheumatoid arthritis in 10 patients, degenerative arthritis in 4, and post-traumatic arthritis in 6. Arthrodesis relieved pain and restored stability in all patients. Solid osseous union occurred in 19 patients (95%). The average interval to fusion was 8 weeks for DIP and 12 weeks for IP joint arthrodesis. Solid osseous union occurred in 19 patients (95%). The average interval to fusion was 8 weeks for distal interphalangeal joint arthrodesis and 12 weeks for interphalangeal joint of the thumb. There were three complications: one delayed union, one nonunion because of a short screw, and one dorsal skin necrosis with amputation. It was shown that distal interphalangeal joint arthrodesis with a Herbert screw is a technique with several advantages: good clinical results, high rates of fusion, early mobilization, and the screw does not need to be removed after the fusion heals. Potential complications may be avoided by using the Herbert mini-screw.

Osteoid osteoma of the coracoid process.

Osteoid osteoma is a small, benign, and painful tumor most commonly affecting the extra-articular portions of the long bones, especially the femur or tibia. Osteoid osteoma of the coracoid process is so rare that we have found only three previously reported cases in the international literature. We describe our experience in managing a case of osteoid osteoma in this unusual location.