Early results in the treatment of proximal humeral fractures with a polyaxial locking plate

Objectives: We report early results using a second generation locking plate, non-contact bridging plate (NCB PH®, Zimmer Inc. Warsaw, IN, USA), for the treatment of proximal humeral fractures. The NCB PH® combines conventional plating technique with polyaxial screw placement and angular stability. Design: Prospective case series. Setting: A single level-1 trauma center. Patients: A total of 50 patients with proximal humeral fractures were treated from May 2004 to December 2005. Intervention: Surgery was performed in open technique in all cases. Main outcome measures: Implant-related complications, clinical parameters (duration of surgery, range of motion, Constant-Murley Score, subjective patient satisfaction, complications) and radiographic evaluation [union, implant loosening, implant-related complications and avascular necrosis (AVN) of the humeral head] at 6, 12 and 24weeks. Results: All fractures available to follow-up (48 of 50) went to union within the follow-up period of 6months. One patient was lost to follow-up, one patient died of a cause unrelated to the trauma, four patients developed AVN with cutout, one patient had implant loosening, three patients experienced cutout and one patient had an axillary nerve lesion (onset unknown). The average age- and gender-related Constant Score (n=35) was 76. Conclusions: The NCB PH® combines conventional plating technique with polyaxial screw placement and angular stability. Although the complication rate was 19%, with a reoperation rate of 12%, the early results show that the NCB PH® is a safe implant for the treatment of proximal humeral fracture

Initial Results of the S3-Humerus Plate

Fractures of the humeral head account for 5% of all fractures and incidence increases with age. Depending on fracture form and patients age a wide variety of therapeutical options exist. Stable fractures can be treated conservatively, while the majority of unstable and displaced fractures require surgical treatment. Many different surgical options are available; open reduction and internal fixation are widely preferred. The S3 Proximal Humerus Plate is a contoured plate to match the complex shape of the proximal humerus. It is designed to be positioned distal to the greater tuberosity preventing subacromial impingement

Biomechanical comparison of screw-based zoning of PHILOS and Fx proximal humerus plates

Background Treatment of proximal humerus fractures with locking plates is associated with complications. We aimed to compare the biomechanical effects of removing screws and blade of a fixed angle locking plate and hybrid blade plate, on a two-part fracture model. Methods Forty-five synthetic humeri were divided into nine groups where four were implanted with a hybrid blade plate and the remaining with locking plate, to treat a two-part surgical neck fracture. Plates’ head screws and blades were divided into zones based on their distance from fracture site. Two groups acted as a control for each plate and the remaining seven had either a vacant zone or blade swapped with screws. For elastic cantilever bending, humeral head was fixed and the shaft was displaced 5 mm in extension, flexion, valgus and varus direction. Specimens were further loaded in varus direction to investigate their plastic behaviour. Results In both plates, removal of inferomedial screws or blade led to a significantly larger drop in varus construct stiffness than other zones. In blade plate, insertion of screws in place of blade significantly increased the mean extension, flexion valgus and varus bending stiffness (24.458%/16.623%/19.493%/14.137%). In locking plate, removal of screw zones proximal to the inferomedial screws reduced extension and flexion bending stiffness by 26–33%. Conclusions Although medial support improved varus stability, two inferomedial screws were more effective than blade. Proximal screws are important for extension and flexion. Mechanical consequences of screw removal should be considered when deciding the number and choice of screws and blade in clinic

The development of metacognitive ability in adolescence

Introspection, or metacognition, is the capacity to reflect on our own thoughts and behaviours. Here, we investigated how one specific metacognitive ability (the relationship between task performance and confidence) develops in adolescence, a period of life associated with the emergence of self-concept and enhanced self-awareness. We employed a task that dissociates objective performance on a visual task from metacognitive ability in a group of 56 participants aged between 11 and 41 years. Metacognitive ability improved significantly with age during adolescence, was highest in late adolescence and plateaued going into adulthood. Our results suggest that awareness of one’s own perceptual decisions shows a prolonged developmental trajectory during adolescence

Efficient preparation of Arabidopsis pollen tubes for ultrastructural analysis using chemical and cryo-fixation

The pollen tube (PT) serves as a model system for investigating plant cell growth and morphogenesis. Ultrastructural studies are indispensable to complement data from physiological and genetic analyses, yet an effective method is lacking for PTs of the model plant Arabidopsis thaliana. Methods: Here, we present reliable approaches for ultrastructural studies of Arabidopsis PTs, as well as an efficient technique for immunogold detection of cell wall epitopes. Using different fixation and embedding strategies, we show the amount of PT ultrastructural details that can be obtained by the different methods. Results: Dozens of cross-sections can be obtained simultaneously by the approach, which facilitates and shortens the time for evaluation. In addition to in vitro-grown PTs, our study follows the route of PTs from germination, growth along the pistil, to the penetration of the dense stylar tissue, which requires considerable mechanical forces. To this end, PTs have different strategies from growing between cells but also between the protoplast and the cell wall and even within each other, where they share a partly common cell wall. The separation of PT cell walls in an outer and an inner layer reported for many plant species is less clear in Arabidopsis PTs, where these cell wall substructures are connected by a distinct transition zone. Conclusions: The major advancement of this method is the effective production of a large number of longitudinal and cross-sections that permits obtaining a detailed and representative picture of pollen tube structures in an unprecedented way. This is particularly important when comparing PTs of wild type and mutants to identify even subtle alterations in cytoarchitecture. Arabidopsis is an excellent plant for genetic manipulation, yet the PTs, several-times smaller compared to tobacco or lily, represent a technical challenge. This study reveals a method to overcome this problem and make Arabidopsis PTs more amenable to a combination of genetic and ultrastructural analyses

Treatment of periprosthetic femur fractures with the non-contact bridging plate : a new angular stable implant

OBJECTIVES: We report the application of a new fixed angle plate (NCB DF, Zimmer inc. USA, Warsaw, IN) in the treatment of periprosthetic femur fractures. The NCB DF combines conventional plating technique with polyaxial screw placement and angular stability. DESIGN: Prospective cohort study. SETTING: A single level-1 trauma center. PATIENTS: From May 2003 to December 2005, a total of 24 patients with periprosthetic femur fractures were treated. The NCB DF femur plate was used in all cases. The average follow-up period was 12 months (3-31 months). Twelve patients had a periprosthetic fracture after total knee replacement (TKA) and 12 patients after total hip replacement (THA). The mean period from primary joint replacement to periprosthetic fracture was 8.2 years for the THA group and 7.2 years for the TKA group. INTERVENTION: A combined conventional/locking surgical technique was performed in all the cases. MAIN OUTCOME MEASURES: Union, non-union, mal-union, duration of surgery, range of motion, postoperative mobility, subjective patient satisfaction and complications. RESULTS: The union rate was 90%, the mal-union rate 5% and the re-operation rate 15%. Postoperative mobility reached the preoperative level in all but for two patients. Three complications occurred relating to the implant or the procedure: one fatigue failure of the plate (non-union), one screw breakage, and one wound infection. CONCLUSIONS: The NCB DF combines conventional plating technique with polyaxial screw placement and angular stability. This combination technique shows promising results regarding union and mal-union rates in periprosthetic fractures in elderly and osteoporotic patients