Factors associated to avascular necrosis of the femoral head and non-union in patients younger than 65 years old with displaced femoral neck fractures treated with reduction and internal fixation.

Pocos estudios han evaluado el tratamiento de las fracturas desplazadas de cuello femoral en pacientes menores de 65 años de edad, y no han sido claramente definidos los factores de riesgo para necrosis avascular o no-unión dentro de este rango de edad. Para determinar los factores asociados a la necrosis avascular de la cabeza femoral (AVN) y no-unión en pacientes menores de 65 años de edad con fracturas desplazadas del cuello femoral tratados con reducción y fijación interna, se realizó un estudio retrospectivo de 29 fracturas desplazadas del cuello femoral en 29 pacientes consecutivos tratados en una sola institución. La influencia de la edad, la energía del trauma, tipo de reducción, y el tiempo entre la fractura y el tratamiento en desarrollo de la AVN y no-unión fueron evaluados. Los pacientes que desarrollaron NAV fueron significativamente mayores y sufrieron un trauma de más baja energía que en los casos sin AVN. Ninguna variable fue asociada con la no-unión. La regresión logística determinó que sólo la edad se asoció de forma independiente a NAV. La edad es un buen predictor para el desarrollo de NAV, con un C-estadístico de 0.861, y un mejor corte-determinado en 53,5 años. Conclusión: Los pacientes de entre 53,5 y 65 años presentan un riesgo más alto de NAV. La artroplastia primaria se debe considerar en este subgrupo.

Sub- or intertrochanteric fracture following screw fixation of an intracapsular proximal femoral fracture: true complication or technical error?

PURPOSE: To review, retrospectively, the possible causes of sub- or intertrochanteric fractures after screw fixation of intracapsular fractures of the proximal femur. METHODS: Eighty-four patients with an intracapsular fracture of proximal femur were operated between 1995 and 1998 by using three cannulated 6.25 mm screws. The screws were inserted in a triangular configuration, one screw in the upper part of the femoral neck and two screws in the inferior part. Between 1999 and 2001, we use two screws proximally and one screw distally. RESULTS: In the first series, two patients died within one week after operation. Sixty-four fractures healed without problems. Four patients developed an atrophic non-union; avascular necrosis of the femoral head was found in 11 patients. Three patients (3.6%) suffered a sub- and/or intertrochanteric fracture after a mean postoperative time of 30 days, in one case without obvious trauma. In all three cases surgical revision was necessary. Between 1999 and 2001 we did not observe any fracture after screwing. CONCLUSION: Two screws in the inferior part of the femoral neck create a stress riser in the subtrochanteric region, potentially inducing a fracture in the weakened bone. For internal fixation for proximal intracapsular femoral fracture only one screw must be inserted in the inferior part of neck.

Rigid internal fixation with titanium versus bioresorbable miniplates in the repair of mandibular fractures in rabbits

The purpose of this study was to compare by qualitative histology the efficacy of rigid internal fixation with titanium system and the Lacto Sorb® system in mandibular fractures in rabbits. Thirty male adult rabbits Oryctolagus cuniculus were used. Unilateral mandibular osteotomies were performed between the canine and first premolar. The animals were divided into two groups: for Group I - rigid internal fixation was performed with titanium system 1.5 mm (Synthes, Oberdorf, Switzerland), with two screws of 6 mm (bicortical) on each side of the osteotomy. For Group II-rigid internal fixation was performed with PLLA/PGA system 1.5 mm (Lacto Sorb®, WLorenz, Jacksonville, FL, USA). The histological analysis evaluated the presence of inflammatory reaction, degree of bone healing and degree of resorption of the Lacto Sorb® screws. The results of both fixation systems were similar, only with a small difference after 15 and 30 days. In Group I a faster bony healing was noted. But after 60 days, bony healing was similar in both groups. It is concluded that both PLLA/PGA and titanium plates and screws provide sufficient strength to permit mandibular bone healing. The resorption process of PLLA/PGA osteosynthesis material did not cause acute or chronic inflammatory reaction or foreign body reaction during the studied period. © 2004 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Biomechanical Study in Polyurethane Mandibles of Different Metal Plates and Internal Fixation Techniques, Employed in Mandibular Angle Fractures

The aim of this study was to perform a physicochemical and morphological characterization and compare the mechanical behavior of an experimental Ti-Mo alloy to the analogous metallic Ti-based fixation system, for mandibular angle fractures. Twenty-eight polyurethane mandibles were uniformly sectioned on the left angle. These were divided into 4 groups: group Eng 1P, one 2.0-mm plate and 4 screws 6 mm long; group Eng 2P, two 2.0-mm plates, the first fixed with 4 screws 6 mm long and the second with 4 screws 12 mm long. The same groups were created for the Ti-15Mo alloy. Each group was subjected to linear vertical loading at the first molar on the plated side in a mechanical testing unit. Means and standard deviations were compared with respect to statistical significance using ANOVA. The chemical composition of the Ti-15Mo alloy was close to the nominal value. The mapping of Mo and Ti showed a homogeneous distribution. SEM of the screw revealed machining debris. For the plates, only the cpTi plate undergoes a surface treatment. The metallographic analysis reveals granular microstructure, from the thermomechanical trials. A statistically significant difference was found (P < 0.05) when the comparison between both internal fixation techniques was performed. The 2P technique showed better mechanical behavior than 1P.

Development Plates For Stable Internal Fixation: Study Of Mechanical Resistance In Simulated Fractures Of The Mandibular Condyle.

To develop Y-shaped plates with different thicknesses to be used in simulated fractures of the mandibular condyle. Ten plates were developed in Y shape, containing eight holes, and 30 synthetic polyurethane mandible replicas were developed for the study. The load test was performed on an Instron Model 4411 universal testing machine, applying load in the mediolateral and anterior-posterior positions on the head of the condyle. Two-way ANOVA with Tukey testing with a 5% significance level was used. It was observed that when the load was applied in the medial-lateral plate of greater thickness (1.5 mm), it gave the highest strength, while in the anteroposterior direction, the plate with the highest resistance was of the lesser thickness (0.6 mm). A plate with a thickness of 1.5 mm was the one with the highest average value for all displacements. In the anteroposterior direction, the highest values of resistance were seen in the displacement of 15 mm. After comparing the values of the biomechanical testing found in the scientific literature, it is suggested that the use of Y plates are suitable for use in subcondylar fractures within the limitations of the study.

Use of extensible internal device in the femur of young dogs

An extensible internal device (EID) was developed to preserve growth plate during the treatment of fracture complications or segmental bone loss from tumour resection in children. Since this type of extensible, trans-physeal, internal fixation device has only been used in a few paediatric cases; the aim of this study was to evaluate an in vivo canine study, a surgical application of this device, and its interference with longitudinal growth of the non-fractured distal femur. Ton clinically healthy two- to three-month-old poodles weighing 1.5-2.3 kg were used. Following a medial approach to the right distal femur, one extremity of the EID, similar to a T-plate, was fixed in the femoral condyle with two cortical screws placed below the growth plate. The other extremity, consisting of an adaptable brim with two screw holes and a plate guide, was fixed in the third distal of the femoral diaphysis with two cortical screws. The EID was removed 180 days after application. All of the dogs demonstrated full weight-bearing after surgery. The values of thigh and stifle circumferences, and stifle joint motion range did not show any difference between operated and control hindlimbs. The plate slid in the device according to longitudinal bone growth, in all but one dog. In this dog, a 10.5% shortening of the femoral shaft was observed due to a lack of EID sliding. The other dogs had the some longitudinal lengths in both femurs. The EID permits longitudinal bone growth without blocking the distal femur growth plate if appropriately placed.

7-year follow-up after open reduction and internal screw fixation in Bennett fractures

Bennett fractures are unstable, and, with inadequate treatment, lead to osteoarthritis, weakness and loss of function of the first carpometacarpal joint. This study focuses on long-term functional and radiological outcomes after open reduction and internal fixation.

Limited open reduction and internal fixation of displaced intra-articular fractures of the calcaneum

The extended lateral L-shaped approach for the treatment of displaced intra-articular fractures of the calcaneum may be complicated by wound infection, haematoma, dehiscence and injury to the sural nerve. In an effort to reduce the risk of problems with wound healing a technique was developed that combined open reduction and fixation of the joint fragments and of the anterior process with percutaneous reduction and screw fixation of the tuberosity. A group of 24 patients with unilateral isolated closed Sanders type II and III fractures was treated using this technique and compared to a similar group of 26 patients managed by the extended approach and lateral plating. The operation was significantly shorter (p < 0.001) in the first group, but more minor secondary procedures and removal of heel screws were necessary. There were no wound complications in this group, whereas four minor complications occurred in the second group. The accuracy and maintenance of reduction, and ultimate function were equivalent.

High failure rate of trochanteric fracture osteosynthesis with proximal femoral locking compression plate

INTRODUCTION Stable reconstruction of proximal femoral (PF) fractures is especially challenging due to the peculiarity of the injury patterns and the high load-bearing requirement. Since its introduction in 2007, the PF-locking compression plate (LCP) 4.5/5.0 has improved osteosynthesis for intertrochanteric and subtrochanteric fractures of the femur. This study reports our early results with this implant. METHODS Between January 2008 and June 2010, 19 of 52 patients (12 males, 7 females; mean age 59 years, range 19-96 years) presenting with fractures of the trochanteric region were treated at the authors' level 1 trauma centre with open reduction and internal fixation using PF-LCP. Postoperatively, partial weight bearing was allowed for all 19 patients. Follow-up included a thorough clinical and radiological evaluation at 1.5, 3, 6, 12, 24, 36 and 48 months. Failure analysis was based on conventional radiological and clinical assessment regarding the type of fracture, postoperative repositioning, secondary fracture dislocation in relation to the fracture constellation and postoperative clinical function (Merle d'Aubigné score). RESULTS In 18 patients surgery achieved adequate reduction and stable fixation without intra-operative complications. In one patient an ad latus displacement was observed on postoperative X-rays. At the third month follow-up four patients presented with secondary varus collapse and at the sixth month follow-up two patients had 'cut-outs' of the proximal fragment, with one patient having implant failure due to a broken proximal screw. Revision surgeries were performed in eight patients, one patient receiving a change of one screw, three patients undergoing reosteosynthesis with implantation of a condylar plate and one patient undergoing hardware removal with secondary implantation of a total hip prosthesis. Eight patients suffered from persistent trochanteric pain and three patients underwent hardware removal. CONCLUSIONS Early results for PF-LCP osteosynthesis show major complications in 7 of 19 patients requiring reosteosynthesis or prosthesis implantation due to secondary loss of reduction or hardware removal. Further studies are required to evaluate the limitations of this device.

Comparative In vitro Mechanical Evaluation Of Techniques Using A 2.0 mm Locking Fixation System For Simulated Fractures Of The Mandibular Body.

To perform a comparative evaluation of the mechanical resistance of simulated fractures of the mandibular body which were repaired using different fixation techniques with two different brands of 2.0 mm locking fixation systems. Four aluminum hemimandibles with linear sectioning simulating a mandibular body fracture were used as the substrates and were fixed using the two techniques and two different brands of fixation plate. These were divided into four groups: groups I and II were fixed with one four-hole plate, with four 6 mm screws in the tension zone and one four-hole plate, with four 10 mm screws in the compression zone; and groups III and IV were fixed with one four-hole plate with four 6 mm screws in the neutral zone. Fixation plates manufactured by Tóride were used for groups I and III, and by Traumec for groups II and IV. The hemimandibles were submitted to vertical, linear load testing in an Instron 4411 servohydraulic mechanical testing unit, and the load/displacement (3 mm, 5 mm and 7 mm) and the peak loads were measured. Means and standard deviations were evaluated applying variance analysis with a significance level of 5%. The only significant difference between the brands was seen at displacements of 7 mm. Comparing the techniques, groups I and II showed higher mechanical strength than groups III and IV, as expected. For the treatment of mandibular linear body fracture, two locking plates, one in the tension zone and another in the compression zone, have a greater mechanical strength than a single locking plate in the neutral zone.

Minimally invasive fixation versus conservative treatment of undisplaced scaphoid fractures: a cost-effectiveness study.

This study compares the direct and indirect costs of conservative and minimally invasive treatment for undisplaced scaphoid fractures. Costs data concerning groups of non-operated and operated patients were analysed. Direct costs were higher in operated patients. Although highly variable, indirect costs were significantly smaller in operated patients and the total costs were higher in non-operated patients. In conclusion, operative treatment of scaphoid fractures is initially more expensive than conservative treatment but markedly decreases the work compensation costs.

Finite element evaluation of three methods of stable fixation of condyle base fractures

The surgical treatment of mandibular condyle fractures currently offers several possibilities for stable internal fixation. In this study, a finite element model evaluation was performed of three different methods for osteosynthesis of low subcondylar fractures: (1) two four-hole straight plates, (2) one seven-hole lambda plate, and (3) one four-hole trapezoidal plate. The finite element model evaluation considered a load applied to the first molar on the contralateral side to the fracture. Results showed that, although the three methods are capable of withstanding functional loading, the lambda plate displayed a more homogeneous stress distribution for both osteosynthesis material and bone and may be a better method when single-plate fixation is the option.

Comparison of compressive strength between three different plates for mandibular angle fractures fixation

The present study aims to compare three types of internal fixation for fractures of the mandibular angle. Mechanical testing was performed on replicas of polyurethane hemimandibles sectioned at the angle region to simulate a fracture and fixed with three different hardwares. Fixation devices enrolled on this survey included the grid plates with and without an intermediate bar and the method described by Champy and colleagues in 1978 and the sample consisted of 10 hemimandibles for each group. Vertical loadings were applied on each hemimandible and recorded after a vertical displacement of 3 and 5 mm. Statistical analysis was made by means of the variance analysis (ANOVA) and the Duncan test with a significance level of 5%. The Champy technique showed a statistically significant increased resistance when compared to the grid plates after vertical displacements of 3 and 5 mm. The results of this survey suggest that the Champy technique, when compared to the grid plate positioned at the middle of the mandibular bone (placement site selected for this study), is more resistant than the grid plate and that the inclusion or not of an intermediate bar to the grid plates does not improve its resistance after linear vertical loadings.

Comparative study of bone repair in mandibular body osteotomy between metallic and absorbable 2.0 mm internal fixation systems. Histological and histometric analysis in dogs: a pilot study

The objective of this study was to compare the bone repair along a mandibular body osteotomy stabilized with 2.0 mm absorbable and metallic systems. 12 male, adult mongrel dogs were divided into two groups (metallic and absorbable) and subjected to unilateral osteotomy between the mandibular third and fourth premolars, which was stabilized by applying two 4-hole plates. At 2 and 18 weeks, three dogs from each group were killed and the osteotomy sites were removed and divided equally into three parts: the upper part was labelled the tension third (TT), the lower part the compression third (CT), and the part between the TT and CT the intermediary third (IT). Regardless of the treatment system, union between the fragments was observed at 18 weeks and the CT showed more advanced stages of bone repair than the TT. Histometric analysis did not reveal any significant differences among the 3 parts or systems in the distance between bone fragments at 2 weeks. Although at 18 weeks the proportions of newly formed bone did not differ among TT, IT and CT, significantly enhanced bone formation was observed in all sections for the metallic group. The patterns of repair were distinct between treatments.