A systematic review of Vancouver B2 and B3 periprosthetic femoral fractures

Aims The aim of this study was to investigate the outcomes of Vancouver type B2 and B3 fractures by performing a systematic review of the methods of surgical treatment which have been reported. Materials and Methods A systematic search was performed in Ovid MEDLINE, Embase and the Cochrane Central Register of Controlled Trials. For inclusion, studies required a minimum of ten patients with a Vancouver type B2 and/or ten patients with a Vancouver type B3 fracture, a minimum mean follow-up of two years and outcomes which were matched to the type of fracture. Studies were also required to report the rate of re-operation as an outcome measure. The protocol was registered in the PROSPERO database. Results A total of 22 studies were included based on the eligibility criteria, including 343 B2 fractures and 167 B3 fractures. The mean follow-up ranged from 32 months to 74 months. Of 343 Vancouver B2 fractures, the treatment in 298 (86.8%) involved revision arthroplasty and 45 (12.6%) were treated with internal fixation alone. A total of 37 patients (12.4%) treated with revision arthroplasty and six (13.3%) treated by internal fixation only underwent further re-operation. Of 167 Vancouver B3 fractures, the treatment in 160 (95.8%) involved revision arthroplasty and eight (4.8%) were treated with internal fixation without revision. A total of 23 patients (14.4%) treated with revision arthroplasty and two (28.6%) treated only with internal fixation required re-operation. Conclusion A significant proportion, particularly of B2 fractures, were treated without revision of the stem. These were associated with a higher rate of re-operation. The treatment of B3 fractures without revision of the stem resulted in a high rate of re-operation. This demonstrates the importance of careful evaluation and accurate characterisation of the fracture at the time of presentation to ensure the correct management. There is a need for improvement in the reporting of data in case series recording the outcome of the surgical treatment of periprosthetic fractures. We have suggested a minimum dataset to improve the quality of data in studies dealing with these fractures

Knowledge networks in high-tech clusters: a multilevel perspective on interpersonal and inter-organizational collaboration

This study contributes to research on knowledge networks in high-tech clusters by adding a multilevel perspective. We show that while informal individual-level and formal organizational-level knowledge networks created by nested actors partly follow their own structural logic, they are at the same time logically intertwined. Interpersonal knowledge ties influence the maintenance of formal R&D collaborations and vice versa. To fully understand knowledge exchange in high-tech clusters it is therefore necessary to take a multilevel network perspective. Our study shows how these organizational-level and individual-level knowledge networks are mutually influential. Focusing on knowledge networks emerging in the context of regional clusters, we highlight how R&D collaborations among organizations impact the interpersonal exchange of knowledge among managers and researchers and vice versa. Taking a multilevel network perspective, we extend the existing understanding of knowledge networks by demonstrating that individuals who are willing to share their knowledge with colleagues belong to organizations involved in many R&D collaborations. These managers and their organizations thus benefit from each others’ central positions in the networks by having access to extensive sources of external knowledge. However, the opposite holds true when managers and researchers informally ask for knowledge from many of their colleagues. Our results show that extensive knowledge-seekers belong to organizations with fewer formal R&D collaborations. This can either be a sign of them trying to compensate for the lack of organizational-level collaborations or that they are harming their organizations’ chances to find collaboration partners. Finally, if two organizations collaborate on a joint R&D project there is a good chance that their managers and researchers also informally exchange knowledge with each other. Formal and informal knowledge networks thus overlap and open up the potential to realize synergies. We draw conclusions about whether individuals acquire knowledge independent of the opportunity structures provided by their organizations and thus fully exploit the possibilities provided by clusters

Translating theoretical logics across borders: organizational characteristics, structural mechanisms and contextual factors in international alliances

In this essay, I critically review the 2006 JIBS Decade Award article by Lyles and Salk ‘Knowledge acquisition from foreign parents in international joint ventures (IJVs): An empirical examination in the Hungarian context’. This article develops theoretical arguments and empirically tests a two-stage research question: (1) What are the organizational characteristics and structural mechanisms between IJV parents that influence knowledge acquisition from the foreign parent, and (2) what is the relationship between knowledge acquisition and performance in Hungarian IJVs? The most important contribution is the focus on both the antecedents and the consequences of knowledge acquisition in IJVs. I also discuss subsequent research that draws heavily on the conceptual or empirical findings of the 2006 JIBS Decade Award paper. I conclude by suggesting areas of future research in the field of knowledge transfer, organizational learning and international strategic alliances. Journal of International Business Studies (2007) 38, 38–46. doi:10.1057/palgrave.jibs.8400254