Following some key principles can help patients get the best outcomes

Shoulder pain affects up to one in five adults annually, with about a third of cases persisting beyond six months, says Dr. Sushil Pant, a Sydney-based orthopaedic shoulder surgeon.

GPs manage approximately 70% of initial presentations, and following a simple framework of classify, investigate, manage, refer can help you make an accurate diagnosis—and reduce the risk of acute issues becoming chronic.

Classifying the acute shoulder

Acute presentations typically fall into one of four categories, which will guide your investigation and management, Dr Pant says.

1. The weak shoulder: acute tear, rupture or avulsion

When a patient presents with acute shoulder pain, the first thing to look for is weakness—which can indicate pathology that may require surgical intervention, Dr Pant says.

This presentation is often seen in younger, working-age patients following a sudden injury or heavy lifting, resulting in pain and functional loss.

Clinically, the patient may exhibit a positive drop arm sign (highly specific for a cuff tear), weakness in external rotation (suggestive of infraspinatus tearing) or a Popeye sign (biceps rupture).

“And a key difference in your examination is they have very minimal active range of motion but quite preserved passive range of motion,” Dr Pant says.

X-ray first to exclude fracture or dislocation, then proceed to ultrasound—which is reasonably sensitive and specific for large rotator cuff tears in young patients, he says.

Management begins with analgesia and brief immobilisation of no more than a week or so.

“But not too much beyond that, because we know that the shoulder muscles—the ones that remain functional—deteriorate if you immobilise patients for too long.”

Tears causing pseudoparalysis require urgent specialist referral, ideally within six to twelve weeks, to prevent tendon retraction, atrophy, and fatty infiltration—which compromise surgical repair.

2. The stiff shoulder: capsulitis

Often seen in menopausal women, the clinical hallmarks of this presentation include night pain (often disrupting sleep) and loss of both active and passive range of motion in all planes.

“That’s usually enough in that sort of age group to diagnose frozen shoulder clinically,” Dr Pant says.

He recommends ordering an X-ray to exclude AVN and investigations to rule out secondary causes such as diabetes and thyroid issues.

If you confirm frozen shoulder, a cortisone injection into the glenohumeral joint is recommended, Dr. Pant says, noting “the earlier you inject, the better they’ll do.”

Physiotherapy can commence once pain starts to settle and should be gentle at first, because aggressive mobilisation can exacerbate pain. Referral is indicated for recalcitrant cases that fail to improve or worsen after several months.

3. Pain flare-up: chronic tears and arthritis

An acute exacerbation of pain in older patients can indicate a chronic (or acute on chronic) cuff tear, cuff tear arthritis, primary glenohumeral joint arthritis, acromioclavicular joint or biceps issues, Dr Pant says.

“So the key in the examination is to work out whether they have weakness of rotator cuff function or is there crepitus in terms of glenohumeral joint movement, or sometimes a bit of both.”

X-ray is the primary investigation, and ultrasound is useful to assess the rotator cuff in more detail, he says, stressing that not all tears require surgery.

“I tell patients that grey hairs equal cuff tears,” he says. “We know the vast majority of patients over the age of 60 or 70, if you scan them, they will have a rotator cuff tear.”

Management depends on the patient’s physiological age, chronological age, overall function, and symptom severity, he explains.

He recommends analgesia, activity modification, and often a subacromial cortisone injection.

Physiotherapy focusing on strengthening the remaining musculature (deltoid and scapular muscles) is essential for these patients, he adds. “If they can strengthen that, they will regain some function.”

Referral is indicated for severe night pain, significant weakness, or lack of response to conservative treatment.

4. The first-time dislocator

Age at first-time dislocation is the number one predictor of recurrent instability and a key factor in management decisions, Dr Pant says.

Patients under about the age of 25 who dislocate for the first time have got a 50% to 90% chance of recurrence of instability, he explains.

They require early specialist referral to manage potential labral tears and plan for stability.

Older patients have a lower risk of recurrence, but a significantly higher chance of a concurrent rotator cuff injury. Along with a plain X-ray, they may need advanced imaging, particularly if you suspect a rotator cuff tear, Dr Pant says. If they have persistent weakness, order an urgent ultrasound of the cuff and refer them on.

“And these patients often will require orthopaedic or physio review before they go back to sport,” he adds.

Sling immobilisation for a few weeks is appropriate after dislocation, and you should advise patients who’ve had an anterior dislocation (about 95% of cases) to avoid the upper outer quadrant. 

Red flags and differentials

While less common, there are some important things to look out for.

• A hot, painful shoulder, particularly in patients who are immunocompromised or have diabetes – which could indicate septic arthritis of the glenohumeral, AC or SC joint, he says.
• Tumours or metastases – “a plain X-ray is very good at screening those patients, particularly those that have a history of malignancy elsewhere in the body.”
• Referred pain – including cervical pain (particularly if it goes down to the hand), and cardiac origin pain.

Key management principles

Keeping a few principles in mind can help you manage any patient with acute shoulder pain.

Investigations

Plain X-ray is first-line and ultrasound is often useful. MRI is generally reserved for specialist or complex cases.

Pain management

Use paracetamol followed by anti-inflammatories (such as Mobic or Celebrex) for approximately 5 to 10 days as required. Slow-release options may be necessary for severe nocturnal pain.

Limit immobilisation

A sling should only be used short-term, ideally less than a week, unless the joint is unstable. Prolonged immobilisation is detrimental, leading to muscle atrophy and symptom worsening.

Cortisone injections

Consider steroid injections (intra-articular, subacromial or elsewhere, depending on the diagnosis) – but usually no more than three in total per year. They should also be avoided for three months before shoulder surgery because they increase the risk of post-operative infection and compromise tendon healing.

When to refer

Refer early to physiotherapy to commence range of motion exercises. Urgently refer cases of suspected septic arthritis (or send them to ED), any patients with a pseudoparalytic shoulder, and younger patients with recurrent dislocation. Patients with recalcitrant capsulitis, and older patients who have significant weakness and loss of function, should be referred semi-urgently.