A framework for the etiology of running-related injuries

The etiology of running-related injury is important to consider as the effectiveness of a given running-related injury prevention intervention is dependent on whether etiologic factors are readily modifiable and consistent with a biologically plausible causal mechanism. Therefore, the purpose of the present article was to present an evidence-informed conceptual framework outlining the multifactorial nature of running-related injury etiology. In the framework, four mutually exclusive parts are presented: (a) Structure-specific capacity when entering a running session; (b) structure-specific cumulative load per running session; (c) reduction in the structure-specific capacity during a running session; and (d) exceeding the structure-specific capacity. The framework can then be used to inform the design of future running-related injury prevention studies, including the formation of research questions and hypotheses, as well as the monitoring of participation-related and non-participation-related exposures. In addition, future research applications should focus on addressing how changes in one or more exposures influence the risk of running-related injury. This necessitates the investigation of how different factors affect the structure-specific load and/or the load capacity, and the dose-response relationship between running participation and injury risk. Ultimately, this direction allows researchers to move beyond traditional risk factor identification to produce research findings that are not only reliably reported in terms of the observed cause-effect association, but also translatable in practice.

MRI features of posterior ankle impingement syndrome in ballet dancers: a review of 25 cases

AIM

To describe the magnetic resonance imaging (MRI) features of posterior ankle impingement syndrome (PAIS) in classical ballet dancers.

MATERIALS AND METHODS

A retrospective review was undertaken of 25 MRI examinations of the ankle performed on 23 ballet dancers over a 26-month period. Images were examined for the presence of osseous and soft-tissue anatomical variants at the posterior ankle and imaging signs of PAIS. All patients presented with symptoms and signs suggestive of PAIS including posterior ankle pain, swelling and stiffness during plantar flexion.

RESULTS

Anatomical variants predisposing to PAIS including as os trigonum and tuberosity arising from the superior calcaneum were clearly depicted. The most common imaging feature of PAIS in our series was high T2 signal posterior to the talocalcaneal joint indicating synovitis (n = 25). Thickening of the posterior capsule (n = 13) and tenosynovitis of flexor hallucis longus (n = 17) were also common. An os trigonum was an infrequent finding (n = 7). Bone marrow oedema, commonly in the posterior talus (n = 10) or in a patchy distribution (n = 10) was often noted.

CONCLUSION

MRI is a useful diagnostic tool in PAIS, and in the present series, clearly demonstrates the anatomical variants and range of osseous and soft-tissue abnormalities associated with this condition. Prospective studies are needed to understand the significance and importance of individual MRI findings in producing the symptoms of PAIS.

Intracranial pressure in patients with dementia and communicating hydrocephalus

✓ Intracranial pressure (ICP) was monitored continuously for 48 to 72 hours in 12 patients with dementia and communicating hydrocephalus, to see if this would help determine which patients might benefit from surgical shunting of CSF, since not all such patients respond to treatment. Patients who showed variability of ICP improved following surgery, while patients with consistently flat ICP tracings did not. It is suggested that continuous monitoring of ICP may help identify cases suitable for surgery.

Expression of Escherichia coli B nitroreductase in established human tumor xenografts in mice results in potent antitumoral and bystander effects upon systemic administration of the prodrug CB1954

Expression of the Escherichia coli enzyme nitroreductase (NTR) in mammalian cells enables them to activate the prodrug 5-(aziridin-1-yl)-2,4-dinitrobenzamide (CB1954), leading to interstrand DNA cross-linking and apoptosis in both proliferating and quiescent cells. In the work reported here, we used human hepatocellular carcinoma and squamous carcinoma cell lines constitutively expressing NTR to demonstrate that the ntr/CB1954 system results in potent, long-lasting antitumoral effects in mice. We also demonstrate that this enzyme/prodrug combination results in antitumoral effects in vivo when only a minority of tumor cells express the enzyme, using either cells constitutively expressing NTR or ntr gene delivery in situ.

Baclofen in the elderly stroke patient its side-effects and pharmacokinetics

A double blind crossover trial of baclofen against placebo in elderly stroke patients was discontinued because the drug produced an unacceptably high level of drowsiness. In a subsequent study baclofen 10 mg was given orally to 12 elderly stroke patients, and drug concentrations measured from a series of plasma samples. A group of healthy subjects given the same dose in a previous study were used as controls. Elderly patients took longer to achieve peak plasma baclofen concentrations, but healthy controls had higher peak values and eliminated the drug more rapidly; areas under the curve were similar in the two groups. Simulations based on mean data suggest that increased drowsiness in the elderly was probably not due to changes in the drug's pharmacokinetic behaviour.

Pictorial review: MRI features of foot and ankle injuries in ballet dancers

Foot and ankle pain is common in ballet dancers. Although clinical examination often points to the underlying cause, imaging is often necessary to confirm the diagnosis and thus ensure appropriate future management. Factors predisposing to the increased incidence of injuries in this population include the classical position in which ballet dancers stand, which is on the tips of the toes in the en pointe position or on the balls of the feet in the demi-pointe position. Furthermore, the repetitious nature of ballet and the long hours spent rehearsing cause over-use injuries. The causes of foot and ankle pain can be thought of in four different groups: the impingement syndromes; tendon abnormalities; osseous pathology; and ligament abnormalities. These will be discussed and illustrated.

Menstrual Irregularity, Hormonal Contraceptive Use, and Bone Stress Injuries in Collegiate Female Athletes in the United States

BACKGROUND

Menstrual irregularity (MI) is common in female athletes and is a component of the Female Athlete Triad (Triad). Many athletes with the Triad are started on hormonal contraceptives (HC) for MI, but this interferes with the ability to monitor menstrual cycle regularity and can mask other causes of MI. There are limited studies investigating the relationship between MI, HC use, and injury in female collegiate athletes.

OBJECTIVE

To examine the prevalence of and relationship between HC use, MI, and bone stress injuries in female collegiate athletes in the United States.

DESIGN

Cross-sectional study.

SETTING

Online survey.

PARTICIPANTS

1020 U.S. female collegiate athletes (age ≥ 18 years).

METHODS OR INTERVENTIONS

Assessment of risk factors for menstrual irregularity and bone stress injuries was conducted via a one-time survey.

MAIN OUTCOME MEASURES

HC use, MI, history of stress fractures.

RESULTS

Current HC use prevalence was 65% (95% confidence interval [CI], 61.9%, 67.8%). Of all athletes, 47% reported past MI. Of the athletes who were not currently using HCs, 32% had current MI. Compared with athletes without past MI, more athletes with past MI reported current HC use (73% vs. 57%) and indicated menstrual cycle consistency as the primary reason for use (24% vs. 4%) (P < .001). Additionally, 25% of athletes reported a history of stress fractures, which was associated with lean/aesthetic sports participation (odds ratio [95% CI]: 1.9 [1.4, 2.5]; P < .001) and less oral contraceptive pill (OCP) use (0.7 [0.5, 1.0]; P = .043). Compared with OCPs, injectable HCs were associated with greater odds of a history of stress fractures (4.5[1.6, 12.3]; P = .004).

CONCLUSIONS

HC use was prevalent among this cohort of female collegiate athletes, and almost half of the athletes reported past MI. A goal of menstrual cycle regularity was cited by 24% of athletes as a primary reason to use HCs, which shows that more athlete education is needed to avoid masking MI and the Triad with HCs. Further studies elucidating the relationship between HC use, MI, and sports-related injury are warranted.

From control to causation: Validating a 'complex systems model' of running-related injury development and prevention

INTRODUCTION

There is a need for an ecological and complex systems approach for better understanding the development and prevention of running-related injury (RRI). In a previous article, we proposed a prototype model of the Australian recreational distance running system which was based on the Systems Theoretic Accident Mapping and Processes (STAMP) method. That model included the influence of political, organisational, managerial, and sociocultural determinants alongside individual-level factors in relation to RRI development. The purpose of this study was to validate that prototype model by drawing on the expertise of both systems thinking and distance running experts.

MATERIALS AND METHODS

This study used a modified Delphi technique involving a series of online surveys (December 2016- March 2017). The initial survey was divided into four sections containing a total of seven questions pertaining to different features associated with the prototype model. Consensus in opinion about the validity of the prototype model was reached when the number of experts who agreed or disagreed with survey statement was ≥75% of the total number of respondents.

RESULTS

A total of two Delphi rounds was needed to validate the prototype model. Out of a total of 51 experts who were initially contacted, 50.9% (n = 26) completed the first round of the Delphi, and 92.3% (n = 24) of those in the first round participated in the second. Most of the 24 full participants considered themselves to be a running expert (66.7%), and approximately a third indicated their expertise as a systems thinker (33.3%). After the second round, 91.7% of the experts agreed that the prototype model was a valid description of the Australian distance running system.

CONCLUSION

This is the first study to formally examine the development and prevention of RRI from an ecological and complex systems perspective. The validated model of the Australian distance running system facilitates theoretical advancement in terms of identifying practical system-wide opportunities for the implementation of sustainable RRI prevention interventions. This 'big picture' perspective represents the first step required when thinking about the range of contributory causal factors that affect other system elements, as well as runners' behaviours in relation to RRI risk.

Intestinal ischaemia associated with phaeochromocytoma

The present case report describes a patient with an adrenal phaeochromocytoma who presented with infarction of the small intestine. The clinical features, diagnosis and treatment of this case are described. Despite excision of the tumour and necrotic intestine, this patient died in the postoperative period from overwhelming sepsis and multi-organ failure. Special reference is made to the delayed effects of established intestinal ischaemia on immune function and it is suggested that this was major contributory factor to the fatal outcome in the present case. The onset of gastro-intestinal symptoms in patients with phaeochromocytoma should suggest the possibility of imminent gut ischaemia and indicate the necessity for prompt excision of the tumour.

The value of MRI undertaken immediately after reduction of the hip as a predictor of long-term acetabular dysplasia

Our aim was to determine whether abnormalities noted on MRI immediately after reduction for developmental dysplasia of the hip could predict the persistance of dysplasia and aid surgical planning. Scans of 13 hips in which acetabular dysplasia had resolved by the age of four years were compared with those of five which had required pelvic osteotomy for persisting dysplasia. The scans were analysed by two consultant musculoskeletal radiologists who were blinded to the outcome in each child. The postreduction scans highlighted a number of anatomical abnormalities secondary to developmental dysplasia of the hip, but statistical analysis showed that none were predictive of persisting acetabular dysplasia in the older child, suggesting that the factors which determine the long-term outcome were not visible on these images.