bluuebunny/crossref_metadata_2025 huggingface dataset:
Navel Gazing: Academic Inbreeding and Scientific Productivity
Authors: Horta Hugo , Veloso Francisco M. , Grediaga Rócio
Published: December 2009

The practice of having Ph.D. graduates employed by the university that trained them, commonly called “academic inbreeding,” has long been suspected to be damaging to scholarly practices and achievement. Despite this perception, existing work on academic inbreeding is scarce and mostly exploratory. Using data from Mexico, we find evidence that, first, academic inbreeding is associated with lower scholarly output. Second, the academically inbred faculty is relatively more centered on its own institution and less open to the rest of the scientific world. This navel-gazing tendency is a critical driver of its reduced scientific output when compared with noninbred faculties. Third, we reveal that academic inbreeding could be the result of an institutional practice, such that these faculty members contribute disproportionately more to teaching and outreach activities, which allows noninbred faculty members to dedicate themselves to the research endeavor. Thus, a limited presence of inbreds can benefit the research output of noninbreds and potentially the whole university, but a dominantly inbred environment will stifle productivity, even for noninbreds. Overall, our analysis suggests that administrators and policy makers in developing nations who aim to develop a thriving research environment should consider mechanisms to limit this practice.
Divisor-Based Biproportional Apportionment in Electoral Systems: A Real-Life Benchmark Study
Authors: Maier Sebastian , Zachariassen Petur , Zachariasen Martin
Published: December 2009

Biproportional apportionment methods provide two-way proportionality in electoral systems where the electoral region is subdivided into electoral districts. The problem is to assign integral values to the elements of a matrix that are proportional to a given input matrix, and such that a set of row- and column-sum requirements are fulfilled. In a divisor-based method for biproportional apportionment, the problem is solved by computing appropriate row and column divisors, and by rounding the quotients. We present a comprehensive experimental evaluation of divisor-based biproportional apportionment in an electoral system context. By performing experiments on real-life benchmark instances (election data with multimember districts), we evaluate the general quality of divisor-based apportionments with respect to, e.g., deviation from quota, reversal orderings, and occurrences of ties. For example, we studied the frequency in which a party with a higher vote count in a district ended up with fewer seats in that district.
Timing of RFID Adoption in a Supply Chain
Authors: Whang Seungjin
Published: December 2009

This paper studies the incentives behind the adoption of radio-frequency identification (RFID) in a supply chain. One prominent feature of RFID technology is that once RFID tags are attached on the items at an upstream site, the same tags can be reused at its downstream sites at lower or zero variable cost. This creates an interesting, one-sided “free-rider” problem, where the downstream would wait to free-ride on the upstream's first move, but not vice versa. Using a stylized game-theoretic model, we characterize the equilibrium strategies of the two firms. Compared to the first-best solution, firms in equilibrium tend to adopt too late. We then study the dual benefits of technology coordination between the two firms and find that it would not only save redundant costs of putting tags, but also speed up the downstream's RFID adoption. We also show that the equal-cost-split arrangement shifts the benefit of free-riding to the upstream, thereby mitigating the negative impacts in many cases. But it may distort the market when it operates in the optimal manner. The general message of the model is that technology coordination and cost-split each contribute to the mitigation of the free-rider problem in RFID adoption.
Does Ownership Affect the Variability of the Production Process? Evidence from International Courier Services
Authors: Hsieh Chihmao , Lazzarini Sérgio Giovanetti , Nickerson Jackson A. , Laurini Marcio
Published: December 2009

A firm often must ensure that products or services it produces match customer expectations. We define variability as any deviation in a production process yielding products or services whose attributes differ from the firm's stated target specifications. Firms pursuing products marked by low variability are more subject to maladaptation costs if production processes are not adjusted to avoid nonconformities. Furthermore, such adjustments often require idiosyncratic investments (e.g., dedicated information technology systems), thereby creating contractual hazards and potential underinvestment. We hypothesize that ownership of sequential activities in the value chain helps mitigate problems associated with maladaptation as well as suboptimalities in transaction-specific investment, thereby resulting in lower variability. Using data on delivery times from the Japanese international courier and small package services industry, we assess the variability-reducing role of ownership in two complementary ways. The first approach is parametric, allowing us to assess the impact of ownership on the variance associated with delivery time; here we focus on shipments that frequently fail to arrive precisely within the time period initially expected by customers. The second approach is more consistent with the notion of reliability, or the likelihood that shipments will not arrive later than expected: we nonparametrically estimate the distribution of deviations between actual and expected delivery time, and verify how distinct organizational choices change the distribution. Ownership of multiple segments yields a particularly pronounced effect on both variance and reliability. Ownership bestows variability-reducing benefits of ownership, especially when ownership is observed in multiple stages of the value chain.
Responding to Rivals and Complements: How Market Concentration Shapes Generational Product Innovation Strategy
Authors: Turner Scott F. , Mitchell Will , Bettis Richard A.
Published: December 2009

This study examines how competitive market conditions shape the responsiveness with which businesses release generational product innovations (GPIs) following the introduction of GPIs by either competitors or complementary firms. GPIs are substantial technical advances in the performance of products within technology regimes. Prior studies of innovation timing in the organizational strategy literature emphasize internally driven strategies of GPI. Although internally driven strategies may predominate when businesses face diffuse competition for their product lines, the literature largely overlooks the point that businesses need to be increasingly responsive to external events as market concentration increases. This study, which examines businesses competing in the U.S. packaged software industry in the 1990s, shows that increasing industry concentration raises the stakes surrounding market positions and leads to greater interdependence of innovation strategies in an industry—including interactions both with competitors and with other players in a larger system of complementary products. As concentration increases, therefore, organizations are less driven by historical patterns of innovation and become increasingly responsive to innovations by both types of external actors.
Perspective—Open to Negotiation: Phenomenological Assumptions and Knowledge Dissemination
Authors: Bendersky Corinne , McGinn Kathleen L.
Published: December 2009

Phenomenological assumptions—assumptions about the fundamental qualities of the phenomenon being studied and how it relates to the environment in which it occurs—affect the dissemination of knowledge from subfields to the broader field of study. Micro-process research in organizational studies rests on implicit phenomenological assumptions that vary in the extent to which micro-processes are viewed as parts of larger systems. We suggest that phenomenological assumptions linking micro-processes to organizational contexts highlight the relevance of micro-process research findings to broader organizational questions and therefore increase the likelihood that the findings will disseminate to the larger field of organizational research. We test this assertion by analyzing studies of negotiation published in top peer-reviewed management, psychology, sociology, and industrial relations journals from 1990 to 2005. Our findings reveal a continuum of open systems to closed systems phenomenological assumptions in negotiation research. Analysis of the citation rates of the articles in our data set by non-negotiation organizational research indicates that more open systems assumptions increase the likelihood that a negotiation article will be cited in organizational studies, after controlling for other, previously identified effects on citation rates. Our findings suggest that subfields can increase the impact they have on the broader intellectual discourse by situating their phenomena in rich contexts that illuminate the connections between their findings and questions of interest to the broader field.
Event Attention, Environmental Sensemaking, and Change in Institutional Logics: An Inductive Analysis of the Effects of Public Attention to Clinton's Health Care Reform Initiative
Authors: Nigam Amit , Ocasio William
Published: December 2009

We explore attention to Clinton's health care reform proposal, ongoing debates, and its political demise to develop theory that explains how events create opportunities for cognitive realignment and transformation in institutional logics. Our case analysis illustrates how a bottom-up process of environmental sensemaking led to the emergence and adoption of a logic of managed care, which provided new organizing principles in the hospitals' organizational field. In addition to theorization, highlighted by prior research, we propose a second mechanism of environmental sensemaking: representation of change through exemplars and environmental features. The interplay between theorization, representation, and ongoing event attention can lead to change in institutional logics over an event's life course. We found that the managed care logic did not emerge in a fully formed fashion, but that actors theorized individual dimensions of the logic consistent with changing representations of hospitals' relationships with other actors in the field. As the event unfolded, the individual dimensions came to be theorized as part of an overall managed care logic. The label “managed care,” previously understood as a specific organizational form, took on a new meaning to symbolize the organizing principles for hospitals' relationships with a variety of institutional actors as alternative models not congruent with the changing organizational field were abandoned.
Innovation, Modularity, and Vertical Deintegration: Evidence from the Early U.S. Auto Industry
Authors: Argyres Nicholas , Bigelow Lyda
Published: December 2009

Although vertical integration choices have been found to significantly affect firm performance, there has been little empirical study of how such choices are affected by the stage of industry evolution in which firms find themselves. We empirically investigate two possible impacts of increasing modularity on a firm's vertical integration choices. First, we hypothesize that increasing modularity is associated with vertical deintegration because of the high-level standardization of components that dominant designs tend to promote. Second, we posit that firms selling in higher market segments, because they are attempting to differentiate their products by incorporating unique components with less-modular interfaces with other components, will tend to be more vertically integrated than their lower-price rivals. We find evidence for both of these effects in data from the early U.S. auto industry.
To Share or Not to Share? Professional Norms, Reference Groups, and Information Withholding Among Life Scientists
Authors: Haas Martine R. , Park Sangchan
Published: December 2009

Why do scientists withhold information from colleagues, violating the professional norm of sharing? Norm violations are usually attributed to individual interests that lead scientists to reject professional norms. In contrast, we take the view that norm violations can occur when professional norms are valued but it is difficult to ascertain the appropriate course of professional conduct. This view suggests that scientists may look to cues from their professional reference groups to resolve sociological ambivalence arising from conflicting role expectations. We analyze a data set of 1,251 geneticists and other life scientists from 100 U.S. universities and find that beyond individual-level explanations, information withholding is influenced by the behaviors of peers as well as the attitudes of superiors in the profession. We discuss the implications for the professions literature, theories of organizational learning, and knowledge management initiatives in firms.
Ten-year results of a double-heat-treated metal-on-metal hip resurfacing
Authors: Daniel J. , Ziaee H. , Kamali A. , Pradhan C. , Band T. , McMinn D. J. W.
Published: January 2010

Second-generation metal-on-metal bearings were introduced as a response to the considerable incidence of wear-induced failures associated with conventional replacements, especially in young patients. We present the results at ten years of a consecutive series of patients treated using a metal-on-metal hip resurfacing. A distinct feature of the bearings used in our series was that they had been subjected to double-heat treatments during the post-casting phase of their manufacture. In the past these bearings had not been subjected to thermal treatments, making this a unique metal-on-metal bearing which had not been used before in clinical practice.

We report the outcome of 184 consecutive hips (160 patients) treated using a hybrid-fixed metal-on-metal hip resurfacing during 1996. Patients were invited for a clinicoradiological follow-up at a minimum of ten years. The Oxford hip score and anteroposterior and lateral radiographs were obtained. The mean age at operation was 54 years (21 to 75). A series of 107 consecutive hips (99 patients) who received the same prosthesis, but subjected to a single thermal treatment after being cast, between March 1994 and December 1995, were used as a control group for comparison.

In the 1994 to 1995 group seven patients (seven hips) died from unrelated causes and there were four revisions (4%) for osteolysis and aseptic loosening. In the 1996 group nine patients died at a mean of 6.9 years after operation because of unrelated causes. There were 30 revisions (16%) at a mean of 7.3 years (1.2 to 10.9), one for infection at 1.2 years and 29 for osteolysis and aseptic loosening. Furthermore, in the latter group there were radiological signs of failure in 27 (24%) of the 111 surviving hips.

The magnitude of the problem of osteolysis and aseptic loosening in the 1996 cohort did not become obvious until five years after the operation. Our results indicate that double-heat treatments of metal-on-metal bearings can lead to an increased incidence of wear-induced osteolysis.
Measurement of joint effusion and haematoma formation by ultrasound in assessing the effectiveness of drains after total knee replacement
Authors: Omonbude D. , El Masry M. A. , O’Connor P. J. , Grainger A. J. , Allgar V. L. , Calder S. J.
Published: January 2010

We prospectively randomised 78 patients into two groups, ‘drains’ or ‘no drains’ to assess the effectiveness of suction drains in reducing haematoma and effusion in the joint and its effect on wound healing after total knee replacement. Ultrasound was used to measure the formation of haematoma and effusion on the fourth post-operative day. This was a semi-quantitative assessment of volume estimation. There was no difference in the mean effusion between the groups (5.91 mm in the drain group versus 6.08 mm in the no-drain, p = 0.82). The mean amount of haematoma in the no-drain group was greater (11.07 mm versus 8.41 mm, p = 0.03). However, this was not clinically significant judged by the lack of difference in the mean reduction in the post-operative haemoglobin between the groups (drain group 3.4 g/dl; no-drain group 3.0 g/dl, p = 0.38). There were no cases of wound infection or problems with wound healing at six weeks in any patient.

Our findings indicate that drains do not reduce joint effusion but do reduce haematoma formation. They have no effect on wound healing.
Evaluation and comparison of the antimicrobial efficacy of teicoplanin- and clindamycin-coated titanium implants
Authors: Aykut S. , Öztürk A. , Özkan Y. , Yanik K. , İlman A. A. , Özdemir R. M.
Published: January 2010

We studied the effects of coating titanium implants with teicoplanin and clindamycin in 30 New Zealand White rabbits which were randomly assigned to three groups. The intramedullary canal of the left tibia of each rabbit was inoculated with 500 colony forming units of Staphylococcus aureus. Teicoplanin-coated implants were implanted into rabbits in group 1, clindamycin-coated implants into rabbits in group 2, and uncoated implants into those in group 3. All the rabbits were killed one week later. The implants were removed and cultured together with pieces of tibial bone and wound swabs. The rate of colonisation of the organisms in the three groups was compared.

Organisms were cultured from no rabbits in group 1, one in group 2 but from all in group 3. There was no significant difference between groups 1 and 2 (p = 1.000). There were significant differences between groups 1 and 3 and groups 2 and 3 (p < 0.001). Significant protection against bacterial colonisation and infection was found with teicoplanin- and clindamycin-coated implants in this experimental model.
A double-blind randomised controlled study comparing subacromial injection of tenoxicam or methylprednisolone in patients with subacromial impingement
Authors: Karthikeyan S. , Kwong H. T. , Upadhyay P. K. , Parsons N. , Drew S. J. , Griffin D.
Published: January 2010

We have carried out a prospective double-blind randomised controlled trial to compare the efficacy of a single subacromial injection of the non-steroidal anti-inflammatory drug, tenoxicam, with a single injection of methylprednisolone in patients with subacromial impingement. A total of 58 patients were randomly allocated into two groups. Group A received 40 mg of methylprednisolone and group B 20 mg of tenoxicam as a subacromial injection along with lignocaine. The Constant-Murley shoulder score was used as the primary outcome measure and the Disability of Arm, Shoulder and Hand (DASH) and the Oxford Shoulder Score (OSS) as secondary measures. Six weeks after injection the improvement in the Constant-Murley score was significantly greater in the methylprednisolone group (p = 0.003) than in the tenoxicam group. The improvement in the DASH score was greater in the steroid group and the difference was statistically significant and consistent two (p < 0.01), four (p < 0.01) and six weeks (p < 0.020) after the injection. The improvement in the OSS was consistently greater in the steroid group than in the tenoxicam group. Although the difference was statistically significant at two (p < 0.001) and four (p = 0.003) weeks after the injection, it was not at six weeks (p = 0.055). Subacromial injection of tenoxicam does not offer an equivalent outcome to subacromial injection of corticosteroid at six weeks. Corticosteroid is significantly better than tenoxicam for improving shoulder function in tendonitis of the rotator cuff after six weeks.
Treatment of locked chronic posterior dislocation of the shoulder by reconstruction of the defect in the humeral head with an allograft
Authors: Diklic I. D. , Ganic Z. D. , Blagojevic Z. D. , Nho S. J. , Romeo A. A.
Published: January 2010

The treatment of a chronic posterior dislocation of the shoulder is often determined by the size of the associated impression fracture of the humeral head. Our hypothesis was that patients with a chronic unreduced posterior dislocation of the shoulder and a defect in the humeral head involving between 25% to 50% of the articular surface, would do better if reconstructed with an allograft from the femoral head rather than treated by a non-anatomical reconstruction. We reviewed ten men and three women with a mean age of 42 years (36 to 51) at a mean follow-up of 54 months (41 to 64) who had this procedure. At follow-up, nine had no pain or restriction of activities of daily living. Their mean Constant-Murley shoulder score was 86.8 (43 to 98). No patient had symptoms of instability of the shoulder.

Reconstruction of the defect in the humeral head with an allograft provides good pain relief, stability and function for patients with a locked, chronic posterior dislocation where the defect involves between 25% and 50% of the circumference of the articular surface.
Posterior dislocation of the sternoclavicular joint and epiphyseal disruption of the medial clavicle with posterior displacement in sports participants
Authors: Laffosse J.-M. , Espié A. , Bonnevialle N. , Mansat P. , Tricoire J.-L. , Bonnevialle P. , Chiron P. , Puget J.
Published: January 2010

We retrospectively analysed the clinical results of 30 patients with injuries of the sternoclavicular joint at a minimum of 12 months’ follow-up. A closed reduction was attempted in 14 cases. It was successful in only five of ten dislocations, and failed in all four epiphyseal disruptions. A total of 25 patients underwent surgical reduction, in 18 cases in conjunction with a stabilisation procedure.

At a mean follow-up of 60 months, four patients were lost to follow-up. The functional results in the remainder were satisfactory, and 18 patients were able to resume their usual sports activity at the same level. There was no statistically significant difference between epiphyseal disruption and sternoclavicular dislocation (p > 0.05), but the functional scores (Simple Shoulder Test, Disability of Arm, Shoulder, Hand, and Constant scores) were better when an associated stabilisation procedure had been performed rather than reduction alone (p = 0.05, p = 0.04 and p = 0.07, respectively).

We recommend meticulous pre-operative clinical assessment with CT scans. In sternoclavicular dislocation managed within the first 48 hours and with no sign of mediastinal complication, a closed reduction can be attempted, although this was unsuccessful in half of our cases. A control CT scan is mandatory. In all other cases, and particularly if epiphyseal disruption is suspected, we recommend open reduction with a stabilisation procedure by costaclavicular cerclage or tenodesis. The use of a Kirschner wire should be avoided.
Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations
Authors: Vendittoli P.-A. , Roy A. , Mottard S. , Girard J. , Lusignan D. , Lavigne M.
Published: January 2010

We have updated our previous randomised controlled trial comparing release of chromium (Cr) and cobalt (Co) ions and included levels of titanium (Ti) ions. We have compared the findings from 28 mm metal-on-metal total hip replacement, performed using titanium CLS/Spotorno femoral components and titanium AlloFit acetabular components with Metasul bearings, with Durom hip resurfacing using a Metasul articulation or bearing and a titanium plasma-sprayed coating for fixation of the acetabular component.

Although significantly higher blood ion levels of Cr and Co were observed at three months in the resurfaced group than in total hip replacement, no significant difference was found at two years post-operatively for Cr, 1.58 μg/L and 1.62 μg/L respectively (p = 0.819) and for Co, 0.67 μg/L and 0.94 μg/L respectively (p = 0.207). A steady state was reached at one year in the resurfaced group and after three months in the total hip replacement group. Interestingly, Ti, which is not part of the bearing surfaces with its release resulting from metal corrosion, had significantly elevated ion levels after implantation in both groups. The hip resurfacing group had significantly higher Ti levels than the total hip replacement group for all periods of follow-up. At two years the mean blood levels of Ti ions were 1.87 μg/L in hip resurfacing and and 1.30 μg/L in total hip replacement (p = 0.001).

The study confirms even with different bearing diameters and clearances, hip replacement and 28 mm metal-on-metal total hip replacement produced similar Cr and Co metal ion levels in this randomised controlled trial study design, but apart from wear on bearing surfaces, passive corrosion of exposed metallic surfaces is a factor which influences ion concentrations. Ti plasma spray coating the acetabular components for hip resurfacing produces significantly higher release of Ti than Ti grit-blasted surfaces in total hip replacement.
Management of severe extra-articular contracture of the elbow by open arthrolysis and a monolateral hinged external fixator
Authors: Kulkarni G. S. , Kulkarni V. S. , Shyam A. K. , Kulkarni R. M. , Kulkarni M. G. , Nayak P.
Published: January 2010

Arthrolysis and dynamic splinting have been used in the treatment of elbow contractures, but there is no standardised protocol for treatment of severe contractures with an arc of flexion < 30°. We present our results of radical arthrolysis with twin incisions with the use of a monolateral hinged fixator to treat very severe extra-articular contracture of the elbow. This retrospective study included 26 patients (15 males and 11 females) with a mean age of 30 years (12 to 60). The mean duration of stiffness was 9.1 months (5.4 to 18) with mean follow-up of 5.2 years (3.5 to 9.4). The mean pre-operative arc of movement was 15.6° (0° to 30°), with mean pre-operative flexion of 64.1° (30° to 120°) and mean pre-operative extension of 52.1° (10° to 90°). Post-operatively the mean arc improved to 102.4° (60° to 135°), the mean flexion improved to 119.1° (90° to 140°) and mean extension improved to 16.8° (0° to 30°) (p < 0.001). The Mayo elbow score improved from a mean of 45 (30 to 65) to 89 (75 to 100) points, and 13 had excellent, nine had good, three had fair and one had a poor result. We had one case of severe instability and one wound dehiscence which responded well to treatment. One case had deep infection with poor results which responded well to treatment.

Our findings indicate that this method is very effective in the treatment of severe elbow contracture; however, a randomised controlled study is necessary for further evaluation.
A comparison of four systems for calibration when templating for total hip replacement with digital radiography
Authors: Franken M. , Grimm B. , Heyligers I.
Published: January 2010

We have investigated the accuracy of the templating of digital radiographs in planning total hip replacement using two common object-based calibration methods with the ball placed laterally (method 1) or medially (method 2) and compared them with two non-object-based methods. The latter comprised the application of a fixed magnification of 121% (method 3) and calculation of magnification based on the object-film-distance (method 4). We studied the post-operative radiographs of 57 patients (19 men, 38 women, mean age 73 years (53 to 89)) using the measured diameter of the prosthetic femoral head and comparing it with the true value.

Both object-based methods (1 and 2) produced large errors (mean/maximum: 2.55%/17.4% and 2.04%/6.46%, respectively). Method 3 applying a fixed magnification and method 4 (object-film-distance) produced smaller errors (mean/maximum 1.42%/5.22% and 1.57%/4.24%, respectively; p < 0.01). The latter results were clinically relevant and acceptable when planning was allowed to within one implant size. Object-based calibration (methods 1 and 2) has fundamental problems with the correct placement of the calibration ball. The accuracy of the fixed magnification (method 3) matched that of object-film-distance (method 4) and was the most reliable and efficient calibration method in digital templating.
Medial dislocation of the medial meniscus
Authors: Chan S. K. L. , Robb C. A. , Singh T. , Chugh S.
Published: January 2010

We present the first reported case of symptomatic medial dislocation of the medial meniscus in a patient who had no previous history of trauma and who had an otherwise normal knee. The treatment of instability of the medial meniscus is controversial and studies have indicated that certain individuals without a firm meniscal bony insertion may be predisposed to meniscal dislocation. In our patient, the meniscal instability interfered with daily activities. Operative stabilisation by reconstruction of the meniscotibial ligaments cured the symptoms.
Does the anteromedial or anterolateral approach alter the rate of joint puncture in injection of the ankle?
Authors: Heidari N. , Pichler W. , Grechenig S. , Grechenig W. , Weinberg A. M.
Published: January 2010

Injection or aspiration of the ankle may be performed through either an anteromedial or an anterolateral approach for diagnostic or therapeutic reasons. We evaluated the success of an intra-articular puncture in relation to its site in 76 ankles from 38 cadavers. Two orthopaedic surgical trainees each injected methylene blue dye into 18 of 38 ankles through an anterolateral approach and into 20 of 38 through an anteromedial. An arthrotomy was then performed to confirm the placement of the dye within the joint.

Of the anteromedial injections 31 of 40 (77.5%, 95% confidence interval (CI) 64.6 to 90.4) were successful as were 31 of 36 (86.1%, 95% CI 74.8 to 97.4) anterolateral injections. In total 62 of 76 (81.6%, 95% CI 72.9 to 90.3) of the injections were intra-articular with a trend towards greater accuracy with the anterolateral approach, but this difference was not statistically significant (p = 0.25). In the case of trainee A, 16 of 20 anteromedial injections and 14 of 18 anterolateral punctures were intra-articular. Trainee B made successful intra-articular punctures in 15 of 20 anteromedial and 17 of 18 anterolateral approaches. There was no significant difference between them (p = 0.5 and p = 0.16 for the anteromedial and anterolateral approaches, respectively). These results were similar to those of other reported studies. Unintended peri-articular injection can cause complications and an unsuccessful aspiration can delay diagnosis. Placement of the needle may be aided by the use of ultrasonographic scanning or fluoroscopy which may be required in certain instances.
Is the frog lateral plain radiograph a reliable predictor of the alpha angle in femoroacetabular impingement?
Authors: Konan S. , Rayan F. , Haddad F. S.
Published: January 2010

The radiological evaluation of the anterolateral femoral head is an essential tool for the assessment of the cam type of femoroacetabular impingement. CT, MRI and frog lateral plain radiographs have all been suggested as imaging options for this type of lesion. The alpha angle is accepted as a reliable indicator of the cam type of impingement and may also be used as an assessment for the successful operative correction of the cam lesion.

We studied the alpha angles of 32 consecutive patients with femoroacetabular impingement. The angle measured on frog lateral radiographs using templating tools was compared with that measured on CT scans in order to assess the reliability of the frog lateral view in analysing the alpha angle in cam impingement.

A high interobserver reliability was noted for the assessment of the alpha angle on the frog lateral view with an intraclass correlation coefficient of 0.83. The mean alpha angle measured on the frog lateral view was 58.71° (32° to 83.3°) and that by CT was 65.11° (30° to 102°). A poor intraclass correlation coefficient (0.08) was noted between the measurements using the two systems.

The frog lateral plain radiograph is not reliable for measuring the alpha angle. Various factors may be responsible for this such as the projection of the radiograph, the positioning of the patient and the quality of the image. CT may be necessary for accurate measurement of the alpha angle.
Total ankle replacement by the Ankle Evolution System
Authors: Morgan S. S. , Brooke B. , Harris N. J.
Published: January 2010

We present the outcomes in 38 consecutive patients who had total ankle replacement using the Ankle Evolution System with a minimum follow-up of four years. Pain and function were assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) score and regular standardised anteroposterior and lateral weight-bearing radiographs were obtained. Patient satisfaction and complications were recorded and the survival of the implants was demonstrated by the Kaplan-Meier method.

The mean follow-up was for 57.8 months (48 to 80). The cumulative survival rate at six years was 94.7% (95% confidence interval 80.3 to 98.7). The mean total AOFAS score was 88.1 (53 to 100). The mean score for pain was 35.8 (20 to 40). Ten patients presented with edge-loading of whom nine had corrective surgery. Two ankles were revised, one to an arthrodesis and the other to replace the tibial component. Nine patients showed radiological evidence of osteolysis. They had minimal non-progressive symptoms and further surgery was not undertaken. Nevertheless, the concerns about osteolysis led to the implant being withdrawn by the manufacturer.

The medium-term results of the ankle evolution system ankle replacement are satisfactory with high patient satisfaction, but the rate of osteolysis is of some concern. The long-term benefit of this procedure has yet to be determined.
Locked intramedullary nailing of symptomatic metastases in the humerus
Authors: Spencer S. J. , Holt G. , Clarke J. V. , Mohammed A. , Leach W. J. , Roberts J. L. B.
Published: January 2010

The humerus is a common site for skeletal metastases in the adult. Surgical stabilisation of such lesions is often necessary to relieve pain and restore function. These procedures are essentially palliative and should therefore provide effective relief from pain for the remainder of the patient’s life without the need for further surgical intervention.

We report a retrospective analysis of 35 patients (37 nails) with symptomatic metastases in the shaft of the humerus which were treated by locked, antegrade nailing. There were 27 true fractures (73.0%) and ten painful deposits (27.0%). Relief from pain was excellent in four (11.4%), good in 29 (82.9%) and fair in two (5.7%) on discharge. Function was improved in all but one patient. One case of palsy of the radial nerve was noted. The mean postoperative survival was 7.1 months (0.2 to 45.5) which emphasises the poor prognosis in this group of patients. There were no failures of fixation and no case in which further surgery was required.

Antegrade intramedullary nailing is an effective means of stabilising the humerus for the palliative treatment of metastases. It relieves pain and restores function to the upper limb with low attendant morbidity.
Treatment of malunited fractures of the ankle
Authors: Reidsma I. I. , Nolte P. A. , Marti R. K. , Raaymakers E. L. F. B.
Published: January 2010

In this retrospective study, using the prospectively collected database of the AO-Documentation Centre, we analysed the outcome of 57 malunited fractures of the ankle treated by reconstructive osteotomy. In all cases the position of the malunited fibula had been corrected, in several cases it was combined with other osteotomies and the fixation of any non-united fragments. Patients were seen on a regular basis, with a minimum follow-up of ten years. The aim of the study was to establish whether reconstruction improves ankle function and prevents the progression of arthritic changes.

Good or excellent results were obtained in 85% (41) of patients indicating that reconstructive surgery is effective in most and that the beneficial effects can last for up to 27 years after the procedure. Minor post-traumatic arthritis is not a contraindication but rather an indication for reconstructive surgery. We also found that prolonged time to reconstruction is associated negatively with outcome.
Comparison between surgery and physiotherapy in the treatment of small and medium-sized tears of the rotator cuff
Authors: Moosmayer S. , Lund G. , Seljom U. , Svege I. , Hennig T. , Tariq R. , Smith H.-J.
Published: January 2010

In order to compare the outcome from surgical repair and physiotherapy, 103 patients with symptomatic small and medium-sized tears of the rotator cuff were randomly allocated to one of the two approaches. The primary outcome measure was the Constant score, and secondary outcome measures included the self-report section of the American Shoulder and Elbow Surgeons score, the Short Form 36 Health Survey and subscores for shoulder movement, pain, strength and patient satisfaction. Scores were taken at baseline and after six and 12 months by a blinded assessor. Nine patients (18%) with insufficient benefit from physiotherapy after at least 15 treatment sessions underwent secondary surgical treatment.

Analysis of between-group differences showed better results for the surgery group on the Constant scale (difference 13.0 points, p − 0.002), on the American Shoulder and Elbow surgeons scale (difference 16.1 points, p < 0.0005), for pain-free abduction (difference 28.8°, p = 0.003) and for reduction in pain (difference on a visual analogue scale −1.7 cm, p < 0.0005).
Enhancement of meniscal repair in the avascular zone using mesenchymal stem cells in a porcine model
Authors: Dutton A. Q. , Choong P. F. , Goh J. C-H. , Lee E. H. , Hui J. H. P.
Published: January 2010

We hypothesised that meniscal tears treated with mesenchymal stem cells (MSCs) together with a conventional suturing technique would show improved healing compared with those treated by a conventional suturing technique alone. In a controlled laboratory study 28 adult pigs (56 knees) underwent meniscal procedures after the creation of a radial incision to represent a tear. Group 1 (n = 9) had a radial meniscal tear which was left untreated. In group 2 (n = 19) the incision was repaired with sutures and fibrin glue and in group 3, the experimental group (n = 28), treatment was by MSCs, suturing and fibrin glue.

At eight weeks, macroscopic examination of group 1 showed no healing in any specimens. In group 2 no healing was found in 12 specimens and incomplete healing in seven. The experimental group 3 had 21 specimens with complete healing, five with incomplete healing and two with no healing. Between the experimental group and each of the control groups this difference was significant (p < 0.001).

The histological and macroscopic findings showed that the repair of meniscal tears in the avascular zone was significantly improved with MSCs, but that the mechanical properties of the healed menisci remained reduced.
Fixator-assisted nailing and consecutive lengthening over an intramedullary nail for the correction of tibial deformity
Authors: Bilen F. E. , Kocaoglu M. , Eralp L. , Balci H. I.
Published: January 2010

We report the results of using a combination of fixator-assisted nailing with lengthening over an intramedullary nail in patients with tibial deformity and shortening. Between 1997 and 2007, 13 tibiae in nine patients with a mean age of 25.4 years (17 to 34) were treated with a unilateral external fixator for acute correction of deformity, followed by lengthening over an intramedullary nail with a circular external fixator applied at the same operating session. At the end of the distraction period locking screws were inserted through the intramedullary nail and the external fixator was removed.

The mean amount of lengthening was 5.9 cm (2 to 8). The mean time of external fixation was 90 days (38 to 265). The mean external fixation index was 15.8 days/cm (8.9 to 33.1) and the mean bone healing index was 38 days/cm (30 to 60).

One patient developed an equinus deformity which responded to stretching and bracing. Another developed a drop foot due to a compartment syndrome, which was treated by fasciotomy. It recovered in three months. Two patients required bone grafting for poor callus formation.

We conclude that the combination of fixator-assisted nailing with lengthening over an intramedullary nail can reduce the overall external fixation time and prevent fractures and deformity of the regenerated bone.
Temporal trends in hip and knee replacement in the United Kingdom
Authors: Culliford D. J. , Maskell J. , Beard D. J. , Murray D. W. , Price A. J. , Arden N. K.
Published: January 2010

Using the General Practice Research Database, we examined the temporal changes in the rates of primary total hip (THR) and total knee (TKR) replacement, the age at operation and the female-to-male ratio between 1991 and 2006 in the United Kingdom.

We identified 27 113 patients with THR and 23 843 with TKR. The rate of performance of THR and TKR had increased significantly (p < 0.0001 for both) during the 16-year period and was greater for TKR, especially in the last five years. The mean age at operation was greater for women than for men and had remained stable throughout the period of study. The female-to-male ratio was higher for THR and TKR and had remained stable.

The data support the notion that the rate of joint replacement is increasing in the United Kingdom with the rate of TKR rising at the highest rate. The perception that the mean age for TKR has decreased over time is not supported.
Operative treatment of patients with pertrochanteric femoral fractures outside working hours is not associated with a higher incidence of complications or higher mortality
Authors: Bosma E. , de Jongh M. A. C. , Verhofstad M. H. J.
Published: January 2010

This retrospective cohort study was conducted to investigate whether operative treatment of patients with a pertrochanteric femoral fracture outside working hours is associated with an increased risk of complications and higher mortality. During the study period 165 patients were operated on outside working hours and 123 were operated on during working hours (08.00 to 17.00). There was no difference in the rate of early complications (outside working hours 33% versus working hours 33%, p = 0.91) or total complications during follow-up (outside working hours 40% versus working hours 41%, p = 0.91). Both in-hospital mortality (outside working hours 12% versus working hours 11%, p = 0.97) and mortality after one year (outside working hours 29% versus working hours 27%, p = 0.67) were comparable. Adjustment for possible confounders by multivariate logistic regression analysis revealed no increased risk of complications when patients were operated on outside working hours.

On the basis of these data, there is no medical reason to postpone operative reduction and fixation in patients with a proximal femoral fracture until working hours.
Fracture of the clavicle does not affect arthritis of the ipsilateral acromioclavicular joint compared with the contralateral side
Authors: Chen M. R. , Huang J. I. , Victoroff B. N. , Cooperman D. R.
Published: January 2010

In an osteological collection of 3100 specimens, 70 were found with unilateral clavicular fractures which were matched with 70 randomly selected normal specimens. This formed the basis of a study of the incidence of arthritis of the acromioclavicular joint and the effect of clavicular fracture on the development of arthritis in the ipsilateral acromioclavicular joint. This was graded visually on a severity scale of 0 to 3. The incidence of moderate to severe arthritis of the acromioclavicular joint in normal specimens was 77% (100 specimens). In those with a clavicular fracture, 66 of 70 (94%) had arthritis of the acromioclavicular joint, compared to 63 of 70 (90%) on the non-injured contralateral side (p = 0.35).

Clavicles with shortening of 15 mm or less had no difference in the incidence of arthritis compared to those with shortening greater than 15 mm (p = 0.25). The location of the fracture had no effect on the development of arthritis.
The impact of national guidelines for the prophylaxis of venous thromboembolism on the complications of arthroplasty of the lower limb
Authors: Jameson S. S. , Bottle A. , Malviya A. , Muller S. D. , Reed M. R.
Published: January 2010

The National Institute for Clinical Excellence (NICE) produces recommendations on appropriate treatment within the National Health Service (NHS) in England and Wales. The NICE guidelines on prophylaxis for venous thromboembolism in orthopaedic surgery recommend that all patients be offered a low molecular weight heparin (LMWH). The linked hospital episode statistics of 219 602 patients were examined to determine the rates of complications following lower limb arthroplasty for the 12-month periods prior to and following the publication of these guidelines. These were compared with data from the National Joint Registry (England and Wales) regarding the use of LMWH during the same periods. There was a significant increase in the reported use of LMWH (59.5% to 67.6%, p < 0.001) following the publication of the guidelines. However, the 90-day venous thromboembolism events actually increased slightly following total hip replacement (THR, 1.69% to 1.84%, p = 0.06) and remained unchanged following total knee replacement (TKR, 1.99% to 2.04%). Return to theatre in the first 30 days for infection did not show significant changes. There was an increase in the number of patients diagnosed with thrombocytopenia, which was significant following THR (0.11% to 0.16%, p = 0.04). The recommendations from NICE are based on predicted reductions in venous thromboembolism events, reducing morbidity, mortality and costs to the NHS.

The early results in orthopaedic patients do not support these predictions, but do show an increase in complications.
Cemented versus uncemented hemiarthroplasty for intracapsular hip fractures
Authors: Parker M. I. , Pryor G. , Gurusamy K.
Published: January 2010

We undertook a prospective randomised controlled trial involving 400 patients with a displaced intracapsular fracture of the hip to determine whether there was any difference in outcome between treatment with a cemented Thompson hemiarthroplasty and an uncemented Austin-Moore prosthesis. The surviving patients were followed up for between two and five years by a nurse blinded to the type of prosthesis used.

The mean age of the patients was 83 years (61 to 104) and 308 (77%) were women. The degree of residual pain was less in those treated with a cemented prosthesis (p < 0.0001) three months after surgery. Regaining mobility was better in those treated with a cemented implant (p = 0.005) at six months after operation. No statistically significant difference was found between the two groups with regard to mortality, implant-related complications, re-operations or post-operative medical complications.

The use of a cemented Thompson hemiarthroplasty resulted in less pain and less deterioration in mobility than an uncemented Austin-Moore prosthesis with no increase in complications.