Examination of the shoulder joint

The shoulder joint could be described as a trade-off between range and stability. The striking range of movement of this joint is achieved by its shallow articulation and a dynamic cuff of the shoulder muscles and their associated tendons. It is therefore not surprising that ageing has more impact on the soft tissues of the shoulder than on other more stable and less dynamic joints.

An Australian population study1 showed the importance of the history and examination of the shoulder, rather than imaging. In this study, multiple asymptomatic changes in the magnetic resonance imaging (MRI) scan were observed in healthy individuals, and there was a poor correlation between shoulder pain and change in the MRI scan. In many cases, the clinical examination features are mainly diagnostic. Worldwide, there is a well defined, age-dependent increase in the frequency of rotator cuff tears in asymptomatic shoulders.2 In keeping with many joint examination techniques, a series of steps (including look, feel, move and special tests) remains valid with the shoulder.

Physical examination is not a blind or formulaic activity. We need to examine the patient in a sequence to answer specific questions based on diagnoses that may become more or less likely as the examination proceeds (Box 1). The first question should be: is the pain really emanating from the shoulder? If the shoulder is non-tender and moves easily, it is likely that the pain is coming from the neck or other structures, and proceeding with the shoulder examination is unlikely to yield a diagnosis.

If the shoulder joint is established as the source of pain, there are four main shoulder conditions to consider as the examination proceeds:

rotator cuff tendinitis and impingement (Box 2);
rotator cuff tear, in the case of older patients (Box 2);
frozen shoulder, that is, adhesive capsulitis (Box 3); and
arthritis of the glenohumeral joint.

In practice, we can consider shoulder problems to be divided into two main groups, based on whether there is restriction of passive shoulder movement.3 Restricted range of passive movement suggests either adhesive capsulitis (frozen shoulder) or arthritis of the glenohumeral joint. Absence of restriction of passive movement points to impingement syndrome (rotator cuff tendinitis) or a rotator cuff tear. After inspection and palpation, the key step is to examine the shoulder and take it passively through its range of movement.

Passive range of shoulder movement

A relatively unrestricted range of passive movement in all directions suggests that the problem is not emanating from the shoulder, and that it may be referred from the neck or other structures, or that it falls into the category of one of the rotator cuff problems, which include rotator cuff tendinitis, tendonopathy and subacromial bursitis.

If there is a global restriction of passive movement (ie, partial or full restriction in all directions), it may suggest arthritis of the shoulder or frozen shoulder. It is increasingly appreciated that the classic description of a frozen shoulder, in which there is a profound global restriction of movement, does not encompass all cases. For example, much milder global restriction of the shoulder — with a loss of 20–30° of movement in all directions — may be seen in some cases of frozen shoulder.

For these two conditions, which cause restriction of shoulder motion, an x-ray is required to discriminate between frozen shoulder and arthritis of the glenohumeral joint. This may resolve the problem with much greater reliability than any other examination.

Conditions not associated with significant restriction of passive movement include rotator cuff tendinitis or impingement and rotator cuff tear. There are two clues to differentiating between significant rotator cuff tear and tendinitis and impingement syndrome. The first is the age of the patient. Impingement syndrome and rotator cuff tendinitis are more commonly seen in people under the age of 40–50 years. In the population over 50 years, and with increasing frequency with each decade of age after 50 years, the underlying pathology usually involves degenerative change in the tendons of the rotator cuff, particularly supraspinatus, with frank tears.

Active range of shoulder movement and power testing

In a patient with preserved passive range of movement, pain on active and resisted abduction supports the idea of rotator cuff pathology. If there is weakness, particularly in resisted external rotation, this supports a diagnosis of rotator cuff tear.

An examination of power at the shoulder is, therefore, a major discriminator that indicates the presence of a rotator cuff tear of significance. If the rotator cuff is intact, even if inflamed, there will be good preservation of power.

It should be noted that pain on active horizontal adduction of the shoulder (across the body) can also be seen with osteoarthritis at the acromioclavicular joint.

Box 1 –
Shoulder joint examination sequence

Box 2 –
Rotator cuff tendinitis and impingement

Box 3 –
Frozen shoulder

Stating best practice in breast cancer care

Although survival for women with breast cancer in Australia is among the highest in the world, there is evidence that not all patients are receiving the most appropriate care.

Cancer Australia has brought together evidence and expertise to support improved and informed practice in breast cancer. The Cancer Australia Statement — influencing best practice in breast cancer is based on the best available evidence and is supported by expert clinical and consumer advice. The statement represents agreed priority areas which, if implemented, will support effective, patient-centred breast cancer care and reduce unwarranted variations in practice.

The statement aims to encourage health professionals to reflect on their clinical practice to ensure that it is aligned with best practice. It also aims to encourage consumers to start conversations with their medical teams to improve their cancer experience and outcomes.

There are 12 practices in the breast cancer statement, from diagnosis across the continuum of care. The practices are identified as either appropriate or not appropriate.

A practice is appropriate if it is beneficial for patients, effective (based on valid evidence, including evidence of benefit), efficient (cost-effective) and equitable.

A practice is not appropriate if it is not consistent with the evidence, may cause potential harm or provides little benefit to patients.

The practices were chosen with the collaboration, participation and engagement of relevant clinical colleges, cancer and consumer organisations. The statement is intended to complement relevant clinical practice guidelines.

Supporting materials have been developed for the statement, including information on the value to patients, evidence base and references for each practice.

More information about the statement and recommended practices is available at canceraustralia.gov.au/statement.

[Correspondence] No health without peace: why SDG 16 is essential for health

We live in an increasingly globalised world in which almost 34 000 people a day are forced to flee their homes because of conflict and persecution.1 Refugees are increasingly moving into more traditionally stable countries, often risking their lives in the process, catalysing public health crises anew. As of 2015, more than 65 million people have been forcibly displaced worldwide; more than 20 million of them since 2011.2 The United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA), established in 1949, provides humanitarian assistance through education, health-care, and relief and social services, to some 5 million Palestine refugees alone in Lebanon, Jordan, Gaza, the West Bank, and Syria.

The medical profession is under attack: WMA

The physical safety and professional autonomy of doctors around the world is under attack from governments, armed groups and individuals, hampering their work and putting the health of patients at serious risk, according to incoming World Medical Association President Dr Ketan Desai.

Speaking following a spate of deadly attacks on hospitals and medical centres in war-torn Syria, Yemen and Afghanistan, Dr Desai told the WMA annual assembly in Taiwan that increasingly the Geneva Convention was being “practised more in breach than observance, invariably ending up in flagrant violation of human rights”.

UN Secretary-General Ban Ki-moon has condemned the sustained bombing of medical facilities in the besieged Syrian city of Aleppo as war crimes, amid claims that 95 per cent of pre-war medical personnel in the city have fled since the conflict began.

In Yemen, Saudi-led forces have been accused of targeting several health facilities, including a strike on a Medicins Sans Frontieres hospital in which 11 died and 19 were injured.

Dr Desai praised the dedication of doctors and health professionals working in these countries, and said they deserved protection: “To a physician, a patient is neither a friend nor an enemy. They legitimately need protection from violence while at work, whether in war or civil conflict situations”.

Doctors also risked physical attack outside war zones.

The WMA President, who was elected to the post after serving as President of the Medical Council of India, said medical practitioners working in many parts of the world, particularly in Asia, were being assaulted, and hospitals and clinics ransacked and damaged, by angry patients and their families.

In addition to these physical threats, Dr Desai said that in countries as diverse as Turkey, India and the United Kingdom, governments were attempting to encroach on the independence and autonomy of the medical professional, to the detriment of patients.

“Regulation of clinical practice, framing evidence-based standard treatment guidelines, defining and checking professional malpractice and medical education all need vital professional independence and a democratic system based on meaningful participative decision-making,” he said. “In many countries there are continued political attempts to undo or marginalise autonomy and self-governance of the medical profession, including mauling and trampling on the trinity of professional autonomy, clinical independence and self-governance.”

Dr Desai said the WMA was alert to these threats and would continue to fight government efforts to make the medical profession subservient.

But he said part of this involved ensuring the medical profession acted with honesty and integrity, something that was at risk in many countries because physicians were prescribing and referring patients based on pecuniary self-interest or kickbacks.

In other developments, the WMA General Assembly:

approved ethical guidelines on the collection and use of identifiable health data (the Declaration of Taipei);
demanded an immediate and impartial inquiry into the bombing of hospitals in Aleppo;
urged national medical associations and other health groups to divest fossil fuel stocks;
called for greater focus on care of the elderly; and
said doctors must be prepared to intervene to protect girls from undergoing female genital mutilation.

Adrian Rollins

[Comment] Magic dolls: no quick fix for teenage pregnancy

Teenage pregnancy is an important adolescent health issue.1 Pregnancy outcomes in teenagers are generally poor with high rates of preterm birth and other complications.2 In the long term, families in which the mother was a teenager at first birth have greater use of public health care and social security than those with older mothers, and the teenagers themselves often fail to fulfil their educational, occupational, and economic potential.1

[Comment] Preventing violent extremism: the role of doctors

Confidentiality and trust are at the heart of the relationship between doctor and patient. Yet, a new Open Society Justice Initiative report, Eroding Trust: the UK’s Prevent Counter-Extremism Strategy in Health and Education,1 published on Oct 19, 2016, shows that this relationship, and its confidentiality and trust, are under threat, particularly for doctors working in parts of the UK with substantial Muslim populations.

Doctor accreditation under review

Health economist Professor Michael Woods will look at ways to encourage collaboration between the health professions as part of a review of accreditation systems.

The Independent Review has been commissioned by the Australian Health Ministers’ Advisory Council to examine the effectiveness of the accreditation system “to ensure that the educational programs provide a sustainable registered health profession workforce that is flexible and responsive to the changing health needs of the Australian community”.

Among his terms of reference, Professor Woods, who is Professor of Health Economics at the University of Technology Sydney, has been asked to report on the cost effectiveness of the accreditation regime, as well as options to streamline the process and “opportunities for increasing consistency and collaboration across professions”.

The review is being conducted at a sensitive time.

The AMA has been in discussion with several professional groups including the Pharmacy Society of Australia about ways to improve coordination and collaboration, and has backed the incorporation of non-prescribing pharmacists as part of a GP-led primary health care team.

But a number of groups, most notably in pharmacy and chiropractic, have earned the AMA’s ire over attempts to encroach on the medical profession’s field of practice and expertise, driven by concerns that it might put patients at risk of harm.

These concerns have been underlined by a direction from the nation’s health ministers, meeting at COAG Health Council last month, for the Chiropractors Board of Australia and Australian Health Practitioner Regulation Agency to provide them with “evidence of any treatments provided by chiropractors that are not appropriately within the chiropractic scope of practice and may be harmful to patients”.

The ministers asked the agencies to advise on “potential regulatory responses”.

Professor Woods is due to complete his review by the end of 2017.

Adrian Rollins

Mental health groups urged to boycott new plan

A prominent mental health advocate has blasted the Government’s draft Fifth National Mental Health Plan as “rubbish”, and called on mental health groups to boycott the consultation process.

The plan was released for consultation on 20 October, with Health Minister Sussan Ley describing it as “an important document” that was “focused on actions that will genuinely make a difference for consumers and carers”.

“The Fifth Plan contains seven priority areas, which have been identified for action in close collaboration with the mental health sector,” Ms Ley said in a statement.

But Professor John Mendoza, the former head of the Mental Health Council of Australia, said the plan would simply continue funding late-term intervention at the expense of prevention and early intervention.

Professor Mendoza called on colleagues at an international mental health conference in Brisbane that the consultation process should be boycotted.

“The plan does not reflect the Prime Minister’s commitment at the election ‘to leave no stone unturned when it comes to mental health’,” Professor Mendoza told The Australian, adding that the plan was “mealy-mouthed rubbish” designed by bureaucrats with no institutional knowledge.

“The plan does not take us one step further in relation to the Government’s announcements last November when it responded to the National Mental Health Commission report and it strongly endorsed the national commission’s recommendations.”

Professor Mendoza said that Prime Minister Malcolm Turnbull had used the words “we need to really embrace innovation, we have to focus on the mental wealth of the nation”.

“And he was stating that because it was clear to him that the economic drag on Australia now, through its focus on acute, late-intervention services rather than early intervention and prevention, means that we have hundreds of thousands of Australians who are unable to participate in work, who are unable to complete education, who are unable to sustain and maintain relationships, because they simply can’t get access to the care they need,” Professor Mendoza said.

“The Commission said this isn’t good enough, we need fundamental reform. And the Government said that was what it was going to do.

“Now, the Fifth Plan that’s been released for consultation does nothing of the sort.

“It pays no attention to the Government’s reform agenda, and it certainly doesn’t marry up with what either the Queensland and NSW Governments [are doing] – two different sides of politics, both of them have articulated clear plans.

“This national plan is completely devoid of any specific actions, any measures, any targets.”

The seven priority areas are:

Integrated regional planning and service delivery;
Coordinated treatment and support for people with severe and complex mental illness;
Suicide prevention;
Aboriginal and Torres Strait Islander mental health and suicide prevention;
Physical health of people living with mental health issues;
Stigma and discrimination reduction; and
Safety and quality in mental health care.

The Department of Health and Mental Health Australia will hold consultation meetings in all capital cities, as well as Townsville and Alice Springs, in November and December.

The final plan will be considered by the Australian Health Ministers’ Advisory Council and the COAG Health Ministers’ Council early next year.

Maria Hawthorne

[Comment] Available at a flash: a new way to check glucose

Type 1 diabetes accounts for 5–10% of diabetes cases diagnosed worldwide.1 Hypoglycaemia is common and can limit efforts to tighten glucose control, lower quality of life,2 and increase mortality.3 Insulin analogues, structured education, insulin pump therapy, and continuous glucose monitoring have helped to decrease the burden of hypoglycaemia,4,5 but it remains considerable.

Aiming for the truth: understanding the difference between validity and precision

In teaching generations of registrars, a recurring theme is the conflation of the concepts of validity and precision, resulting in an erroneous understanding of the role of statistics. In this article, we clarify the definition of these two concepts, looking at what drives these measures and how they can be maximised.

Understanding error

Clinical epidemiology is the science of distinguishing the signal from the noise in health and medical research. The signal is the true causal effect of a factor on an outcome; for example, a risk factor on a disease outcome or a medication on disease progression. The noise is the variation in the data, which has traditionally been referred to as error.

There are two types of errors: random error, also called chance or non-differential error, and systematic error, also known as differential error or bias (Box 1). Random error is the scatter in the data, which statistics uses to estimate the central or most representative point, along with some plausible range, known as the confidence interval. Increasing the sample size shrinks the confidence interval so that we have greater precision in our estimate. However, no statistical test can tell us how close that estimate is to the truth, which is a matter of validity — also known as study validity, to distinguish it from measurement validity or accuracy. Study validity can only be judged by critical appraisal of the design.

In the widely used Robin Hood analogy of precision and validity (Box 2), Robin Hood represents the researcher, and aiming the bow and arrow at the target represents the study that seeks to find the truth about some cause and effect in medicine. Each arrow fired at the target is the study results and is launched by a bow, which represents the study design. The scatter where the arrows hit the target represents the random error. Statistics can be used to analyse the random error and estimate the most representative point (ie, the effect size of the association under investigation) with its confidence interval. However, statistics do not tell us how far that estimate is from the truth (the bullseye). Systematic error (bias) in the design can be visualised as a warp in the bow (the study design), which causes the arrows to systematically hit off target, missing the bullseye. No matter how many arrows are fired (ie, large sample size) and how precise the estimate is, the estimate is still no closer to the truth.

Validity also has two components: internal validity, which is how accurate or close to the truth the result is; and external validity or generalisability, which is how applicable the result is to the population that the study is investigating.

These concepts, when understood correctly, are very powerful and can lead to some revelations:

large sample sizes do not ensure validity;
P values do not provide information about the design of a study or the validity of the result;
complex statistical models will not necessarily remove bias;
critical appraisal skills are the only way to judge validity;
small studies can be closer to the truth than large studies if designed better; and
study results may be internally valid but not generalisable.

Understanding bias

Epidemiology provides a framework to understand how a design can be biased. Since Sackett1 published his classic article naming 35 different kinds of bias, various authors have updated the list and one recent review listed 74 individual biases.2 All these biases can be classified into three main categories,2 although their use is not always consistent:3

selection bias, which is a warp in the way participants are identified or recruited;
measurement bias, which is a warp in how information is measured or collected; and
confounding, which is a warp in the measure of association or conclusion about causation, due to improper or incomplete analysis.

Selection bias

In general, the process by which study participants are identified or recruited will affect the external validity (generalisability) of the study, but not the internal validity. For example, a study that targets people with dementia by advertising through local media will attract those with less severe dementia (spectrum bias) or with an interest in their health and who are therefore healthier (volunteer bias). Although the results of the study may be true (internally valid) for this group of people with dementia, they may not be applicable to the wider population with more severe dementia (externally invalid).

In some cases, however, selection bias may severely affect the internal validity of the trial. Recruitment via advertising through local media excludes those who have died (survivor bias). If we are exploring the link between smoking and dementia, those who participate in the study may be selectively depleted of smokers, who are likely to die of many other causes before recruitment (eg, heart attack, stroke, chronic obstructive pulmonary disease, cancer). This may then lead to a situation where smokers are under-represented in the dementia group compared with the control population. The study would then erroneously indicate that smoking is protective for dementia, as was published in a 1991 article.4 A prospective study, which avoided survivor bias, subsequently showed the correct result: that smoking increases the risk of dementia.5

Berkson’s bias6 is another example of how selection bias can influence internal validity. In a study of the association between obesity and dementia, one might choose to identify people with dementia from hospital records. Apart from selecting those with more severe dementia, this might also create a spurious association with obesity, given that those with obesity are more likely to end up in hospital because of other health problems compared with those with dementia and no obesity.

Measurement bias

A warp may occur in how the measurements are made, whether these are measurements of the exposure of interest, the outcome of interest or another variable that could be adjusted in the analysis. This source of error will always affect internal validity and hence external validity. In the study investigating the association of smoking and dementia, we can contemplate how we measure smoking (exposure) and dementia (outcome). It is possible that participants with dementia systematically under-report their smoking due to their memory problems (recall bias), which will lead to an underestimate of the true effect or even a reversal. Alternately, a systematic bias that overcalls vascular dementia in smokers (eg, making smoking or vascular disease part of the definition of the outcome) may overstate an association with smoking where there is none in reality.

Analytical bias or confounding

Confounding is a warp in the measure of association or conclusion about causation due to improper or incomplete analysis. A confounder is a variable (or set of related variables) associated with the exposure of interest and the outcome of interest, which causes a spurious or distorted estimate of this association, without being an intermediate between the two. Whereas selection and measurement bias are handled by good design and choice of measures, confounding differs in that, if it is measured accurately, it can be handled in the analysis. As an example, in the study of the association between smoking and dementia, we can postulate a third variable, drinking alcohol, that goes hand in hand with smoking and which may actually be responsible for causing dementia. If this variable (alcohol) is not measured and included in the analysis, the effect of alcohol and smoking on dementia will be inseparable and the effect size will be falsely attributed entirely to smoking. It is in fact possible that smoking does not contribute at all to the risk of dementia but that confounding makes it appear to have an effect, or that smoking has an effect but this is overestimated or underestimated by alcohol. A future article in this series will be devoted to confounding, including relevant information on study design, measuring potentially confounding variables and adjusting for them in the analysis.

Handling selection and measurement bias

The possibilities of selection bias and measurement bias must be anticipated during the planning phase of a study. A good study design will minimise these biases to the point where they are tolerable, that is, unlikely to alter our findings to a clinically meaningful extent. When reading a study, one must make a judgement about the magnitude and direction of the bias. If the bias is likely to be towards the null, meaning that the effect size is smaller in magnitude than it is in reality, then this should be taken into account when interpreting the results. If the study shows an effect despite this bias, then the real effect must be larger and robust. If the bias is likely to be away from the null — meaning that the study will overstate the effect size — then one must be wary of the result.

Conclusion

Differentiating the concepts of validity and precision will help clinicians understand the role of statistics and the importance of critical appraisal when reading articles.

Box 1 –
Random error (chance) is a matter of precision and it is best handled with statistics. Systematic error (bias) is a matter of validity and it is best handled by critical appraisal and good design

Box 2 –
The Robin Hood analogy of precision and validity

Adapted from: Barry C. Accuracy vs precision: what’s the difference? State College: The Minitab Blog; 2012. http://blog.minitab.com/blog/real-world-quality-improvement/accuracy-vs-precision-whats-the-difference (accessed Sept 2016).