bluuebunny/crossref_metadata_2025 huggingface dataset:
Manhattan-diagonal routing in channels and switchboxes
Authors: Das Sandip , Sur-Kolay Susmita , Bhattacharya Bhargab B.
Published: February 2004

New techniques are presented for routing straight channels, L-channels, switchboxes, and staircase channels in a two-layer Manhattan-diagonal (MD) model with tracks in horizontal, vertical, and ± 45° directions. First, an
O
(
l.d
) time algorithm is presented for routing a straight channel of length
l
and density
d
with
no cyclic vertical constraints
. It is shown that the number of tracks
h
used by the algorithm for routing
multiterminal nets
satisfies
d
≤
h
≤ (
d
+ 1). Second, an output-sensitive algorithm is reported that can route a channel with
cyclic vertical constraints
in
O
(
l.h
) time using
h
tracks, allowing
overlapping
of wire segments in two layers. Next, the routing problem for a multiterminal L-channel of length
l
and height
h
is solved by an
O
(
l.h
) time algorithm. If no cyclic vertical constraints exist, its time complexity reduces to
O
(
l.d
) where
d
is the density of the L-channel. Finally, the switchbox routing problem in the MD model is solved elegantly. These techniques, easily extendible to the routing of staircase channels, yield efficient solutions to detailed routing in general floorplans. Experimental results on benchmarks show significantly low via count and reduced wire length, thus establishing the superiority of MD routing to classical strategies. The proposed algorithms are also potentially useful for general non-Manhattan area routing and multichip modules (MCMs).
A BNF-based automatic test program generator for compatible microprocessor verification
Authors: Wu Lieh-Ming , Wang Kuochen , Chiu Chuang-Yi
Published: February 2004

A novel Backus-Naur-form- (BNF-) based method to automatically generate test programs from simple to complex ones for advanced microprocessors is presented in this paper. We use X86 architecture to illustrate our design method. Our method is equally applicable to other processor architectures by redefining BNF production rules. Design issues for an
automatic program generator
(APG) are first outlined. We have resolved the design issues and implemented the APG by a
top-down recursive descent parsing
method which was originated from compiler design. Our APG can produce not only random test programs but also a sequence of instructions for a specific module to be tested by specifying a user menu-driven file. In addition, test programs generated by our APG have the features of no infinite loop, not entering illegal states, controllable data dependency, flexible program size, and data cache testable. Our method has been shown to be efficient and feasible for the development of an APG compared with other approaches. We have also developed a
coverage tool
to integrate with the APG. Experimental evaluation of the generated test programs indicates that our APG, with the guidance of the coverage tool, only needs to generate a small number of test programs to sustain high coverage.
Telling humans and computers apart automatically
Authors: von Ahn Luis , Blum Manuel , Langford John
Published: February 2004

How lazy cryptographers do AI.
How clean is the future of SOAP?
Authors: Albrecht Conan C.
Published: February 2004

If developers are not wise with its application, SOAP may lose the ability to tunnel through firewalls---an ability that represents one of its primary advantages.
A Helix-Spindle model for ontological engineering
Authors: Kishore Rajiv , Zhang Hong , Ramesh R.
Published: February 2004

Using a forward-lockstep build-test process that combines theoretic and pragmatic approaches to ontology building.
The software customer/supplier relationship
Authors: Brereton Pearl
Published: February 2004

It's a delicate, dynamic relationship that changes with time, demands, and different approaches to procurement.
Assessing data quality with control matrices
Authors: Pierce Elizabeth M.
Published: February 2004

The control matrix, long used by IS auditors to evaluate information integrity, can be modified to assess the reliability of information products.
Technology implementation for telemedicine programs
Authors: Chau Patrick Y. K. , Hu Paul Jen-Hwa
Published: February 2004

Lessons learned in Hong Kong highlight important issues and common pitfalls in telemedicine technology implementation.
Interoperability architecture using RM-ODP
Authors: Egyhazy Csaba , Mukherji Raj
Published: February 2004

RM-ODP gives architects the level of detail necessary to address key integration and interoperability issues.
What's at stake in
MGM v. Grokster
?
Authors: Samuelson Pamela
Published: February 2004

Seeking to balance the needs of copyright holders and technology developers.
Privacy in the global e-village
Authors: Pottie Gregory J.
Published: February 2004

Embed responsibility for privacy into radio-frequency identification tags and other information technology designed to network the physical world.
Introduction
Authors: Sairamesh Jakka , Lee Alison , Anania Loretta
Published: February 2004

With so many of us infohabitants living and working on the Internet, we've now established urban centers there, with dwellings, commerce, social and civic services, government institutions, and lots of social interaction.
Making information cities livable
Authors: Sproull Lee , Patterson John F.
Published: February 2004

Let the most rewarding aspects of our virtual experience and online social interaction also guide participation in our real-world physical communities.
Blending digital and physical spaces for ubiquitous community participation
Authors: Churchill Elizabeth , Girgensohn Andreas , Nelson Les , Lee Alison
Published: February 2004

Blurring the notional boundary between the digital and the physical in social activity spaces helps blend---and motivate---online and face-to-face community participation.
Open frameworks for information cities
Authors: Ferguson Donald , Sairamesh Jakka , Feldman Stuart
Published: February 2004

Helping mimic full-scale urban environments, this middleware promises to help build a vast ecosystem of e-commerce, collaboration, and social computing, along with access to real-world municipal regulations and services.
Using certes to infer client response time at the web server
Authors: Olshefski David , Nieh Jason , Agrawal Dakshi
Published: February 2004

As businesses continue to grow their World Wide Web presence, it is becoming increasingly vital for them to have quantitative measures of the mean client perceived response times of their web services. We present Certes (CliEnt Response Time Estimated by the Server), an online server-based mechanism that allows web servers to estimate mean client perceived response time, as if measured at the client. Certes is based on a model of TCP that quantifies the effect that connection drops have on mean client perceived response time by using three simple server-side measurements: connection drop rate, connection accept rate and connection completion rate. The mechanism does not require modifications to HTTP servers or web pages, does not rely on probing or third party sampling, and does not require client-side modifications or scripting. Certes can be used to estimate response times for any web content, not just HTML. We have implemented Certes and compared its response time estimates with those obtained with detailed client instrumentation. Our results demonstrate that Certes provides accurate server-based estimates of mean client response times in HTTP 1.0/1.1 environments, even with rapidly changing workloads. Certes runs online in constant time with very low overhead. It can be used at websites and server farms to verify compliance with service level objectives.
Parallel program performance prediction using deterministic task graph analysis
Authors: Adve Vikram S. , Vernon Mary K.
Published: February 2004

In this article, we consider analytical techniques for predicting detailed performance characteristics of a single shared memory parallel program for a particular input. Analytical models for parallel programs have been successful at providing simple qualitative insights and bounds on program scalability, but have been less successful in practice for providing detailed insights and metrics for program performance (leaving these to measurement or simulation). We develop a conceptually simple modeling technique called deterministic task graph analysis that provides detailed performance prediction for shared-memory programs with arbitrary task graphs, a wide variety of task scheduling policies, and significant communication and resource contention. Unlike many previous models that are stochastic models, our model assumes deterministic task execution times (while retaining the use of stochastic models for communication and resource contention). This assumption is supported by a previous study of the influence of nondeterministic delays in parallel programs.We evaluate our model in three ways. First, an experimental evaluation shows that our analysis technique is accurate and efficient for a variety of shared-memory programs, including programs with large and/or complex task graphs, sophisticated task scheduling, highly nonuniform task times, and significant communication and resource contention. The results also show that the deterministic assumption is crucial to permit accurate and yet efficient analysis of these programs. Second, we use three example programs to illustrate the predictive capabilities of the model. In two cases, broad insights and detailed metrics from the model are used to suggest improvements in load-balancing and the model quickly and accurately
predicts
the impact of these changes. In the third case, the model provides novel insights into the impact of program design changes that improve communication locality as well as load-balancing, via new (but general-purpose) metrics. Finally, we present results from a comparison of our model and representative stochastic models, and use these to characterize the conditions under which a deterministic model or stochastic models would be appropriate.
Task analysis for groupware usability evaluation
Authors: Pinelle David , Gutwin Carl , Greenberg Saul
Published: February 2004

Researchers in Computer Supported Cooperative Work have recently developed discount evaluation methods for shared-workspace groupware. Most discount methods rely on some understanding of the context in which the groupware systems will be used, which means that evaluators need to model the tasks that groups will perform. However, existing task analysis schemes are not well suited to the needs of groupware evaluation: they either do not deal with collaboration issues, do not use an appropriate level of analysis for concrete assessment of usability in interfaces, or do not adequately represent the variability inherent in group work. To fill this gap, we have developed a new modeling technique called Collaboration Usability Analysis. CUA focuses on the teamwork that goes on in a group task rather than the taskwork. To enable closer links between the task representation and the groupware interface, CUA grounds each collaborative action in a set of group work primitives called the
mechanics of collaboration
. To represent the range of ways that a group task can be carried out, CUA allows variable paths through the execution of a task, and allows alternate paths and optional tasks to be modeled. CUA's main contribution is to provide evaluators with a framework in which they can simulate the realistic use of a groupware system and identify usability problems that are caused by the groupware interface.
A model for notification systems evaluation—assessing user goals for multitasking activity
Authors: McCrickard D. Scott , Chewar C. M. , Somervell Jacob P. , Ndiwalana Ali
Published: February 2004

Addressing the need to tailor usability evaluation methods (UEMs) and promote effective reuse of HCI knowledge for computing activities undertaken in divided-attention situations, we present the foundations of a unifying model that can guide evaluation efforts for notification systems. Often implemented as ubiquitous systems or within a small portion of the traditional desktop, notification systems typically deliver information of interest in a parallel, multitasking approach, extraneous or supplemental to a user's attention priority. Such systems represent a difficult challenge to evaluate meaningfully. We introduce a design model of user goals based on blends of three critical parameters---interruption, reaction, and comprehension. Categorization possibilities form a logical, descriptive design space for notification systems, rooted in human information processing theory. This model allows conceptualization of distinct action models for at least eight classes of notification systems, which we describe and analyze with a human information processing model. System classification regions immediately suggest useful empirical and analytical evaluation metrics from related literature. We present a case study that demonstrates how these techniques can assist an evaluator in adapting traditional UEMs for notification and other multitasking systems. We explain why using the design model categorization scheme enabled us to generate evaluation results that are more relevant for the system redesign than the results of the original exploration done by the system's designers.
Towards modeling individual and collaborative construction of jigsaws using task knowledge structures (TKS)
Authors: Johnson Hilary , Hyde Joanne
Published: February 2004

Recent years have seen an overwhelming interest in how people work together as a group. Both the nature of collaboration and research into how people collaborate is complex and multifaceted, with different research agendas, types of studies, and variations in the behavioral data collected. A better understanding of collaboration is needed in order to be able to make contributions to the design of systems to support collaboration and collaborative tasks. In this article, we combine relevant literature, past research, and a small-scale empirical study of two people individually and collaboratively constructing jigsaws. The objective is to make progress towards the goal of generating extensions to an existing task modeling approach, Task Knowledge Structures. The research described has enabled us to generate requirements for approaches to modeling collaborative tasks and also a set of requirements to be taken into account in the design of a computer-based collaborative virtual jigsaw.
Mechanism of Ischemic Infarct in Spontaneous Carotid Dissection
Authors: Benninger D.H. , Georgiadis D. , Kremer C. , Studer A. , Nedeltchev K. , Baumgartner R.W.
Published: February 2004

Background and Purpose—

It is unclear whether stroke in patients with spontaneous dissection of the cervical internal carotid artery (ICAD) is due to thromboembolism or impaired hemodynamics. This study investigated the mechanism of stroke in ICAD by examining brain imaging and cerebrovascular findings of such patients.

Methods—

We retrospectively evaluated the prospectively collected brain CT, MR, and ultrasound findings of 141 consecutive patients with 143 ICADs causing ischemic stroke. Eleven patients were not included because they had an inappropriate temporal bone window (n=6) or were treated with thrombolysis (n=5). Thus, the data of 130 patients (76 men, 54 women) with 131 ICADs were analyzed.

Results—

All patients had territorial infarcts; 6 patients (5%) also had border-zone infarct patterns. Territorial infarcts affected the middle cerebral artery (MCA) in 130 of 131 cases (99%) and the anterior cerebral artery (ACA) in 1 case (1%). Additional vascular territories were affected in 8 patients with MCA infarcts (ACA, n=5 [4%]; posterior cerebral artery, n=3 [2%]). The pattern (hemodynamic versus thromboembolic) and extent of infarction were not influenced by vascular findings (MCA stenosis or occlusion, ACA occlusion, degree of obstruction in the dissected ICA, pattern of cross-flow in 115 patients with >80% ICA stenosis or occlusion).

Conclusions—

This study suggests that thromboembolism, not hemodynamic infarction, is the essential stroke mechanism in ICAD.
The Consequences of China's WTO Accession for Its Neighbors
Authors: McKibbin Warwick J. , Woo Wing Thye
Published: February 2004

Our simulations of a global macroeconomic model suggest that China's WTO accession could create significant welfare losses in the ASEAN-4 if foreign direct investment (FDI) is significantly redirected away from these countries toward China, and if the ASEAN-4 countries are unable to implement policies to make up for the slower rate of technological diffusion from the reduced FDI inflow. If the ASEAN-4 do not fall behind technologically, then they will be able to find lucrative niches within the lengthened international manufacturing production chains. The ASEAN-4 must therefore strengthen their abilities to absorb new foreign technologies quickly and to engage in indigenous technical innovations.
Chondrocyte Viability in Refrigerated Osteochondral Allografts Used for Transplantation within the Knee
Authors: Pearsall Albert W. , Tucker J. Allan , Hester Raymond B. , Heitman Robert J.
Published: February 2004

Purpose

To evaluate cell viability and matrix characteristics of refrigerated osteochondral allografts implanted up to 44 days after harvest.

Methods

Sixteen refrigerated allografts underwent histologic and ultrastructural examination and fluorescence excitation analysis prior to implantation. The average size of the graft implanted was 6.2 cm2 (± 3.4 cm2). Refrigerated allografts averaged 30 days (range, 17 to 44 days) from donor expiration to implantation. Nine specimens underwent cell viability testing. The percent viability of refrigerated allografts prior to implantation averaged 67%.

Results

No significant correlations were noted between histologic score, electron microscopy score, matrix staining percent (MSP) score, and viability. When time to implantation was assessed, an inverse correlation was noted with MSP score (r= .539) (P< 0.05), indicating less matrix staining in grafts refrigerated longer after harvest.

Conclusion

The current data indicate that refrigerated osteochondral allografts can be maintained for up to 44 days with average chondrocyte viability of 67%.
Ultrasonographic and Power Doppler Evaluation of the Patellar Tendon Ten Years after Harvesting Its Central Third for Reconstruction of the Anterior Cruciate Ligament
Authors: Järvelä Timo , Paakkala Timo , Kannus Pekka , Toivanen Jarmo , Järvinen Markku
Published: February 2004

Background

The long-term morphologic changes in the patellar tendon after harvesting its central third for the reconstruction of the anterior cruciate ligament have not been reported.

Hypothesis

Sonographic morphologic changes in the harvested patellar tendon are common 10 years after the harvesting procedure.

Study Design

Retrospective cohort study.

Methods

Thirty-one patients who had undergone an anterior cruciate ligament reconstruction using central-third bone-patellar tendon-bone autograft with a closure of the patellar tendon defect were included in this study. An ultrasonographic and Power Doppler examination was performed at a mean follow-up of 10 years.

Results

Ultrasonography of the harvested patellar tendon showed intratendinous calcification in 9 patients, hypoechoic lesion in 20 patients, hyperechoic lesion in 1 patient, and peritendinous changes in 1 patient. Only 3 (9.7%) of the 31 patients had no changes in the harvested patellar tendon. No abnormality was visible in the contralateral (normal) patellar tendons of the 31 patients. The harvested patellar tendon was significantly thicker than the contralateral patellar tendon (P < 0.05).

Conclusions

Sonographic morphologic changes of the patellar tendon were common 10 years after the harvesting procedure, although no evidence of inflammatory process, as could be seen in Power Doppler flow, was found inside of any patellar tendon.
Augmentation of Femoral Fixation in Hamstring Anterior Cruciate Ligament Reconstruction with a Bioabsorbable Bead
Authors: Arneja Shalinder , Froese Warren , MacDonald Peter
Published: February 2004

Background

The EndoPearl is an adjunct to bioabsorbable interference screw fixation in the femoral tunnel in anterior cruciate ligament (ACL) reconstruction. The purpose of the study was to assess the clinical effectiveness of the EndoPearl using the KT-1000 Knee Arthrometer and the Mohtadi ACL Quality of Life (ACL-QOL) Questionnaire.

Hypothesis

The application of the EndoPearl in hamstring ACL reconstruction has no significant benefit when compared to conventional treatment in KT-1000 and ACL-QOL Questionnaire outcomes.

Study Design

Prospective single-blind randomized clinical trial.

Methods

ACL reconstruction with autogenous semitendinosus and gracilis tendons was performed on 35 patients. Preoperatively, 3 months, 6 months, and 18 months postoperatively, patients’ knees were evaluated using the KT-1000 Knee Arthrometer and the ACL-QOL Questionnaire.

Results

Statistically significant differences were achieved in terms of KT-1000 side-to-side differences between the study group and the control group at 6 months and 18 months postoperatively; the mean side-to-side differences are significantly less in the study group when compared to the control group. Statistically significant differences were not detected when comparing the ACL-QOL Questionnaire between the two groups at all time intervals.

Conclusion

The application of the EndoPearl in conjunction with a bioscrew in the femoral tunnel in autogenous ACL reconstruction using semitendinosus and gracilis tendon grafts provides a significantly decreased laxity up to 18 months postoperatively in terms of KT-1000 side-to-side differences.
Increased Injury Risk among First-Day Skiers, Snowboarders, and Skiboarders
Authors: Langran Mike , Selvaraj Sivasubramaniam
Published: February 2004

Background

Inexperience predisposes skiers, snowboarders, and skiboarders to a higher risk of injury.

Hypothesis

Individuals on their very 1st day's experience of skiing, snowboarding, or skiboarding are at greater risk of injury.

Study Design

Case control study.

Methods

All individuals injured at the three largest ski areas in Scotland during the three winter seasons 1999-2000 through 2001-2002 were included. First-day participants were identified. Individual demographic details and snow sports–related parameters were recorded. Control data were collected from uninjured individuals. Factors associated with injury were explored in univariate and multivariate analyses.

Results

First-day participants were overrepresented in the injured population by a factor of 2.2. Participant age younger than 17 years or older than 26 years, snowboarding, taking professional instruction, and the use of rented or borrowed gear were all independently associated with increased injury risk among 1st-day participants.

Conclusions

First-day participants are at increased risk of injury. Several independent risk factors for injury have been identified.

Clinical Relevance

First-day participants should be targeted in any future educational programs with emphasis on gear selection, use of protective gear, and the risks of exceeding the limits of their ability.
Chondrocyte Survival and Material Properties of Hypothermically Stored Cartilage
Authors: Williams Riley J. , Dreese James C. , Chen Chih-Tung
Published: February 2004

Background

There is little information available on the material properties of hypothermically stored allograft specimens used to repair osteochondral defects.

Purpose

To analyze the effect of hypothermic storage on the material properties of fresh knee specimens over a 60-day interval.

Study Design

Controlled laboratory study.

Methods

Twelve sheep knee condyles were isolated. The femoral and tibial condyles and the patella were stored in a nutritive medium containing Dulbecco's Modified Eagle's Medium for 1, 8, 15, 29, 45, or 60 days. Total chondrocyte density, chondrocyte viability, matrix proteoglycan content, matrix water content, and matrix dynamic modulus of elasticity were determined.

Results

Mean chondrocyte viability decreased significantly over the storage interval: 100% (day 1), 98.2% (day 8), ∗80.2% (day 15), ∗80.6% (day 29), ∗64.6% (day 45), and ∗51.6% (day 60) (∗ P< 0.05). Qualitative analysis demonstrated a preponderance of nonviable chondrocytes in the superficial cartilage layer. Significant decreases in matrix proteoglycan were observed in day 15 through day 60 specimens (P< 0.05). The matrix dynamic modulus significantly decreased from day 1 through day 60 (P< 0.05).

Conclusion

The material properties of hypothermically stored knee condyles progressively decline over 60 days.

Clinical Relevance

This observed decline may have significant ramifications on long-term graft survival following storedallograft implantation.
Medial Ankle Instability
Authors: Hintermann Beat , Valderrabano Victor , Boss Andreas , Trouillier Hans Heinrich , Dick Walter
Published: February 2004

Background

Very little objective data are available regarding medial ankle instability.

Hypothesis

Several structures contribute to the stabilization of the medial ankle, and, in the case of injury, they are not involved in a uniform way.

Study Design

Explorative, prospective case series.

Methods

Fifty-one patients (52 ankles; males 27, females 25; age 36.4 [16 to 60] years) were surgically treated because of medial ankle instability. All clinical findings and structural changes, as found by arthroscopy and surgical exploration, were compared with the clinical diagnosis and then addressed for surgical reconstruction.

Results

Pain in the medial gutter was noted in all ankles (100%). Arthroscopy verified a clinically expected additional lateral instability in 40 ankles (77%). At 4.43 years (2 to 6.5 years) after surgical reconstruction, the clinical result was considered to be good/excellent in 46 cases (90%), fair in 4 cases (8%), and poor in 1 case (2%).

Conclusion

The clinical characteristics of medial ankle instability are a feeling of giving way, pain on the medial gutter of the ankle, and a valgus and pronation deformity of the foot that can typically be actively corrected by the posterior tibial muscle. Arthroscopy was shown to be a very helpful diagnostic tool in verifying medial instability.
The Medial Collateral Ligament of the Elbow is not Isometric
Authors: Armstrong April D. , Ferreira Louis M. , Dunning Cynthia E. , Johnson James A. , King Graham J. W.
Published: February 2004

Background

The anterior bundle of the medial collateral ligament (AMCL) of the elbow has been shown to be the most important valgus stabilizer of the elbow. However, the isometry of this band has not been quantified.

Hypothesis

Isometric fibers exist within the AMCL, and these fibers are located within its central region.

Study Design

Controlled laboratory study.

Methods

Twelve cadaveric elbow specimens were mounted in a testing apparatus in a valgus gravity-loaded orientation. Passive supinated flexion was performed and the motion recorded using an electromagnetic tracking device. Hundreds of attachment points for the AMCL of the elbow were recorded on the medial epicondyle and ulna. The overall change in length between each point on the ulna to every humeral point, throughout the arc of motion, was quantified (. L = Lmax – Lmin). The locations of the smallest. L values were determined relative to the attachment site of the AMCL on the medial epicondyle.

Results

True isometry was not found throughout the arc of flexion. The smallest. L values averaged 2.8 ± 1.2 mm (range: 0.7 mm to 5.2 mm). Isometric fibers do not exist within the AMCL; however, “nearly” isometric areas are located on the lateral aspect of the attachment site of the AMCL on the medial epicondyle, near the anatomic axis of rotation.

Conclusions

We postulate that these nearly isometric areas would be the most ideal location for graft attachment during reconstruction of the AMCL.
Sensorimotor Control is Impaired in Dancers with Functional Ankle Instability
Authors: Hiller Claire E. , Refshauge Kathryn M. , Beard David J.
Published: February 2004

Background

Factors potentially causing chronic instability after ankle inversion sprains have rarely been examined during the injuring movement.

Purpose

To compare control of ankle movement during quiet stance and after inversion perturbation in chronically unstable ankles (n = 16) with healthy controls (n = 26).

Methods

Movement control was measured as magnitude of lateral ankle oscillation, using 3SPACE Fastrak during single leg stance (baseline oscillation) in two foot positions, flat and demi-pointe. In both positions, time to resume baseline oscillation after inversion perturbation (perturbation time) of 15 ° for the flat foot and 7.5 ° on demi-pointe was also determined.

Results

Baseline oscillation on demi-pointe was significantly smaller (P < 0.005) for the sprained group (2.5 ± 0.5 mm) than for controls (4.0 ± 2.3 mm). Perturbation time for the flat foot was significantly longer (P < 0.05) for the sprained group (2.2 ± 0.4 seconds) than for controls (1.8 ± 0.5 seconds). However, failure rate was higher (P < 0.05) among the sprained group than controls for perturbation with the foot flat and baseline oscillation on demi-pointe.

Conclusions

Findings demonstrated altered sensorimotor control in chronically unstable ankles. Those sprainers who successfully completed the tasks minimized oscillation. The impairments in the sprained group may reflect deficits in either movement detection, peroneal muscle response, or both.
MR Imaging of the Hip and Knee before and after Marathon Running
Authors: Hohmann Erik , Wörtler Klaus , Imhoff Andreas B.
Published: February 2004

Background

Despite its obvious benefits regarding aerobic fitness, the possible deleterious effects of long-distance running remain controversial. The repetitive loading associated with this activity could potentially predispose to the subsequent development of osteoarthritis. Lower extremity malalignment can also result in abnormal joint loading and is another possible contributing factor for premature articular cartilage degeneration. The purpose of this study is to investigate whether external impact loading in marathon runners creates internal stresses on bone and cartilage that are demonstrable on MR images. Participants were separately assessed for static lower extremity alignment, using standard radiographs.

Methods

Six recreational and two semi-professional runners underwent magnetic resonance (MR) imaging of the hip and knee before and after a marathon run using coronal T1-weighted and coronal STIR sequences.

Results

The pre-run and post-run scans failed to demonstrate marrow oedema, periosteal stress reactions, or joint effusions in seven runners. One patient who underwent a reconstruction of his anterior cruciate ligament 18 months ago demonstrated a small effusion in the reconstructed knee before and after the race.

Conclusions

Our results suggest that the high impact forces in long-distance running are well tolerated and subsequently do not demonstrate changes on MR images.
The Effect of Bracing on Patellofemoral Joint Stress during Free and Fast Walking
Authors: Powers Christopher M. , Ward Samuel R. , Chen Yu-jen , Chan Li-der , Terk Michael R.
Published: February 2004

Background

Although several studies have demonstrated decreases in patellofemoral pain (PFP) with the application of bracing, the mechanism by which bracing reduces symptoms has not been elucidated.

Hypothesis

Individuals who responded favorably to bracing will exhibit decreased patellofemoral stress during level walking.

Study Design

Repeated measures, cross-sectional.

Methods

Fifteen subjects with a diagnosis of PFP completed two phases of data collection: 1) MRI assessment of patellofemoral contact area and 2) gait analysis. Data were obtained under braced and nonbraced conditions. Variables obtained from both data collection sessions were used as input variables into a mathematical model to quantify patellofemoral stress.

Results

Subjects reported a 56% reduction in pain following bracing. Bracing significantly reduced peak stress during free and fast walking (17% and 27%, respectively). The decrease in stress was the result of increased contact area as patellofemoral joint reaction forces were increased following bracing.

Conclusion

Bracing resulted in a larger increase in patellofemoral contact area than the increase in joint reaction force, resulting in a decrease in joint stress.

Clinical Relevance

The results of this study suggest a possible mechanism by which bracing may be effective in reducing PFP and provides experimental support for the use of this treatment method.
Wakeboarding Injuries
Authors: Carson William G.
Published: February 2004

Background

Wakeboarding is a popular water sport that has the potential to produce serious injuries. To date, there has been only one article describing an injury caused by wakeboarding.

Hypothesis

Wakeboarding injuries are common.

Study Design

Analysis of data obtained from physician and patient questionnaires.

Methods

Analysis of questionnaire data obtained from 156 orthopaedic surgeons and 86 wakeboarders.

Results

Of 156 orthopaedic surgeons completing a wakeboarding injuries questionnaire, 49% reported no wakeboarding injuries, 36% (57) reported treating at least 1 wakeboarding injury, and 15% had never heard of wakeboarding. Fifty-seven orthopaedic surgeons reported 122 injuries, of which 47% were either anterior cruciate ligament (ACL) tears (31%) or shoulder dislocations (15%). In addition, 21% of all the injuries were some type of fracture. Of 86 wakeboarders completing the injuries survey, 77% reported sustaining an injury. There were 82 reported injuries in this group, of which 34% were either ACL tears (17%) or ankle sprains (17%).

Conclusions

This survey of wakeboarding injuries demonstrates that serious injuries can occur from participation in this sport. The most common injuries reported were ACL tears, shoulder dislocations, and ankle sprains. In addition, 21% of all the injuries were some type of fracture.
Risk Factors for Injuries in Football
Authors: Arnason Arni , Sigurdsson Stefan B. , Gudmundsson Arni , Holme Ingar , Engebretsen Lars , Bahr Roald
Published: February 2004

Background

The injury risk in football is high, but little is known about causes of injury.

Purpose

To identify risk factors for football injuries using a multivariate model.

Study Design

Prospective cohort study.

Methods

Participants were 306 male football players from the two highest divisions in Iceland. Before the 1999 football season started, the following factors were examined: height, weight, body composition, flexibility, leg extension power, jump height, peak O2 uptake, joint stability, and history of previous injury. Injuries and player exposure were recorded throughout the competitive season.

Results

Older players were at higher risk of injury in general (odds ratio [OR] = 1.1 per year, P = 0.05). For hamstring strains, the significant risk factors were age (OR = 1.4 [1 year], P < 0.001) and previous hamstring strains (OR = 11.6, P < 0.001). For groin strains, the predictor risk factors were previous groin strains (OR = 7.3, P = 0.001) and decreased range of motion in hip abduction (OR = 0.9 [1°], P = 0.05). Previous injury was also identified as a risk factor for knee (OR = 4.6) and ankle sprains (OR = 5.3).

Conclusions

Age and previous injury were identified as the main risk factors for injury among elite football players from Iceland.
Calcific Insertional Achilles Tendinopathy
Authors: Maffulli Nicola , Testa Vittorino , Capasso Giovanni , Sullo Alessio
Published: February 2004

Background

Recalcitrant calcific insertional Achilles tendinopathy is difficult to treat.

Hypothesis

Bursectomy, excision of the distal paratenon, disinsertion of the tendon, removal of the calcific deposit, and reinsertion of the Achilles tendon with bone anchors is safe and effective.

Study Design

Longitudinal study.

Methods

Twenty-one patients (six women) (21 feet) (average age 46.9 ± 6.4 years) with recalcitrant calcific insertional Achilles tendinopathy were treated surgically with removal of the calcific deposit; the Achilles tendon was reinserted with bone anchors.

Results

At an average follow-up of 48.4 months, one patient necessitated a further operation. Eleven patients reported an excellent result, and five a good result. The remaining five patients could not return to their normal levels of sporting activity and kept fit by alternative means. The results of the VISA-A questionnaire were markedly improved in all patients, from an average of 62.4% to 88.1%.

Conclusions

We recommend disinsertion of the Achilles tendon to excise the calcific deposit fully and reinsertion of the Achilles tendon in the calcaneus with suture anchors. No patient experienced a traumatic disinsertion of the reattached tendon. However, five patients were not able to return to their original level of physical activity.
Articular Cartilage Lesions in 993 Consecutive Knee Arthroscopies
Authors: Årøen Asbjørn , Løken Sverre , Heir Stig , Alvik Elling , Ekeland Arne , Granlund Odd G. , Engebretsen Lars
Published: February 2004

Background

Traumatic articular cartilage injuries heal poorly and may lead to development of osteoarthritis at a young age. This study estimates the number of patients who may benefit from one of the surgical methods of cartilage repair.

Methods

All patients undergoing knee arthroscopy during a 6-month period at three collaborating hospitals were consecutively evaluated according to the International Cartilage Repair Society (ICRS) knee form. The material consists of 993 consecutive knee arthroscopies in patients with median age of 35 years.

Results

Preoperative radiographs demonstrated degenerative changes in 13% of the knees. Articular cartilage pathology was found in 66% and a localized cartilage defect was found in 20% of the knees. A localized full-thickness cartilage lesion (ICRS grade 3 and 4) was observed in 11% of the knees. Of the localized full-thickness lesions, 55% (6% of all knees) had a size above 2 cm2.

Conclusion

Eleven percent of all knee arthroscopies show cartilage defects that may be suitable for cartilage repair procedures. However, the natural history of these lesions and the number of patients that will benefit from a cartilage repair procedure are so far unknown.
Patellar Tendon-to-Bone Healing Using High-Density Collagen Bone Anchor at 4 Years in a Sheep Model
Authors: Walsh W. R. , Harrison John A. , Van Sickle David , Alvis Mark , Gillies R. Mark
Published: February 2004

Background

This study reports the long-term histologic and mechanical properties of the healing patellar tendon–bone interface reconstructed using a high-density type I collagen bone anchor (HDC) compared to a metal anchor in sheep.

Hypothesis

To determine the long-term histology and mechanical properties of extra-articular tendon-bone healing and in vivo response to a HDC anchor.

Study Design

Controlled laboratory study.

Methods

The structural properties, tendon-bone histology, and device histology in the bone were examined out to 208 weeks in a sheep model.

Results

The patellar tendon–proximal tibia bone interface continued to remodel with time but, by 4 years, had yet to develop the well-defined zones of tendon, fibrocartilage, calcified cartilage, and bone of the native patellar tendon to bone insertion. The insertion repair strength did not vary between the repaired tendons and the nonoperated controls at any time.

Conclusion

The healing tendon-bone interface undergoes a gradual remodeling process, which had yet to reconstitute back to the control interface by 208 weeks. The HDC device remained essentially intact at 208 weeks showing little signs of degradation.

Clinical Relevance

Tendon-bone healing is mechanically equivalent to the contralateral side by 26 weeks whereas histologic structure requires much longer to remodel back to the native insertion.
Prevalence of the Bennett Lesion of the Shoulder in Major League Pitchers
Authors: Wright Rick W. , Paletta George A.
Published: February 2004

Background

The Bennett lesion is a mineralization of the posterior inferior glenoid noted in overhead throwing athletes. Although previous studies have debated appropriate treatment of the lesion, no studies have indicated the lesion prevalence in throwing athletes.

Hypothesis

The Bennett lesion is more common than previously believed and may represent an asymptomatic finding.

Study Design

Uncontrolled retrospective review.

Methods

Fifty-five asymptomatic major league pitchers underwent routine preseason radiographic screening. Radiographs were reviewed for the presence of a Bennett's lesion. Player demographics, pitching, and baseball records were reviewed to obtain the patient's dominant arm, age, years and innings pitched, and time on the disabled list or surgery.

Results

Twelve pitchers (22%) were noted to have a radiographic Bennett lesion. No statistically significant difference was noted in age, years pitched, or innings pitched between pitchers with and without a Bennett lesion. No player who demonstrated a Bennett lesion required surgical treatment for shoulder pain during his time with the club. Two players required time on the disabled list, but neither player had complaints of posterior shoulder pain.

Conclusions

This lesion is a relatively common finding in major league pitchers. Concomitant pathology should be suspected when evaluating throwers with posterior shoulder pain and this lesion.
Bilateral Anterior Cruciate Ligament Reconstruction as a Single Procedure
Authors: Larson Christopher M. , Fischer David A. , Smith J. Patrick , Boyd Joel L.
Published: February 2004

Background

The ideal treatment for patients presenting with bilateral anterior cruciate ligament (ACL) deficiency remains controversial.

Purpose

To evaluate cost and early functional results after bilateral ACL reconstruction at a single setting.

Study Design

Retrospective review.

Methods

Eleven patients (22 knees) who underwent bilateral ACL reconstruction at a single setting were compared with 33 patients (35 knees) who underwent unilateral ACL reconstruction during the same time period.

Results

The mean time to full unrestricted activity between groups was 6.5 months for both groups (P= 0.92). There were no significant differences between groups at latest follow-up for complication rates or laxity as judged by Lachman test, pivot shift test, and KT 1000 arthrometry. The mean International Knee Documentation Committee subjective score at a mean 3.1-year follow-up was 91.9 for the bilateral ACL group compared to 92.0 for the unilateral ACL group (P= 0.95). There was a total cost savings per knee (based on 2001 dollars) of $3751.59 when performing bilateral ACL reconstruction at a single setting (P= 0.0001).

Conclusions

For patients presenting with bilateral ACL deficient knees, reconstruction of both knees at a single setting is safe, cost effective, and does not appear to compromise early functional results.
Grade 1 or “Ding” Concussions in High School Athletes
Authors: Lovell Mark R. , Collins Michael W. , Iverson Grant L. , Johnston Karen M. , Bradley James P.
Published: February 2004

Background

Recent concussion management guidelines have suggested that athletes with mild (grade 1) concussions may be returned to play if asymptomatic for 15 minutes. The purpose of this study was to assess the utility of a current concussion management guideline in classifying and managing mild concussion.

Hypothesis

High school athletes diagnosed with a grade 1 concussion will demonstrate measurable decline in neuropsychological functioning that persists during the 1st week of recovery.

Study Design

Prospective study designed to evaluate neuropsychological functioning both prior to and following concussion.

Methods

Forty-three high school athletes completed neuropsychological test performance and symptom ratings prior to the season and at two times during the 1st week following mild concussion.

Results

Thirty-six hours after injury, mildly concussed high school athletes demonstrated a decline in memory (P < 0.003) and a dramatic increase in self-reported symptoms (P < 0.00001) compared to baseline performance.

Conclusions

Athletes with grade 1 concussion demonstrated memory deficits and symptoms that persisted beyond the context in which they were injured. These data suggest that current grade 1 return-to-play recommendations that allow for immediate return to play may be too liberal.

Clinical Relevance

A reconsideration of current concussion grading systems appears to be warranted.
Infraspinatus Muscle Atrophy in Professional Baseball Players
Authors: Cummins Craig Anthony , Messer Terry M. , Schafer Michael F.
Published: February 2004

Background

Infraspinatus muscle atrophy has been observed in athletes who stress their upper extremities in an overhead fashion. The majority of such case reports have been in volleyball players, with far fewer cases reported in baseball players.

Hypothesis

Infraspinatus muscle atrophy occurs to a notable degree in professional baseball players.

Study Design

Retrospective cohort study.

Methods

At the end of the 1999 baseball season, data were collected from all Major League Baseball teams in regards to players affected with infraspinatus muscle atrophy.

Results

Twelve of the 1491 major league professional baseball players were identified as having appreciable infraspinatus muscle atrophy. There was an increased prevalence of the muscle atrophy in professional pitchers (10 of 494, 4%) compared to position players (2 of 997, 0.2%) (P< 0.001). Among affected pitchers, the atrophy was identified more frequently in starting pitchers (8 of 10) compared to relief pitchers (2 of 10) (P= 0.036), pitchers who had played for more years at the major league level (8.7 ± 4.9 versus 5.2 ± 4.0) (P= 0.017), and pitchers who had thrown for more innings at the major league level (971.4 ± 784.4 versus 485.0 ± 594.6) (P< 0.001).

Conclusion

Infraspinatus atrophy was identified in 4.4% of major league starting pitchers and occurred in those pitchers who pitched for more years and innings during their major league career.
Recovery of Articular Cartilage Metabolism following Thermal Stress is Facilitated by IGF-1 and JNK Inhibitor
Authors: Chu Constance R. , Kaplan Lee D. , Fu Freddie H. , Crossett Lawrence S. , Studer Rebecca K.
Published: February 2004

Background

The safety of intra-articular use of thermal probes is related to whether chondrocytes can tolerate exposure to high temperatures and whether cytoprotective agents may improve chondrocyte survival after thermal injury.

Purpose

This study was conducted to characterize the metabolic responses of articular cartilage after short-term exposure to temperatures between 50 ° C and 60 ° C with and without addition of insulin-like growth factor 1 (IGF-1) and c-Jun N-terminal kinase (JNK) inhibitor.

Methods

Human articular cartilage from osteoarthritic knees was subjected to defined thermal stress.

Results

Although significant reduction of proteoglycan synthesis was observed after 5 seconds of exposure to 55 ° C and 60 ° C and after 10- to 30-second exposures to 53 ° C, recovery of metabolic activity levels was observed after 7 days.

Conclusion

Addition of IGF-1 and JNK inhibitor Sp600125 enabled the cartilage to maintain significantly higher levels of proteoglycan synthesis immediately after thermal stress. IGF-1 also enhanced recovery of metabolic activity after 7 days.

Clinical Significance

Results from this study indicate that there may be time and temperature parameters within which thermal chondroplasty can be safely performed. The data additionally suggest that inadvertent chondrocyte injury may be minimized through potential addition of substances like IGF-1 or JNK inhibitor.