In my practice: Ankle and knee imaging

Dr Andrew Rees is a GP who is bucking the trend on ankle ultrasound and knee MRI referrals.

While the number of ultrasound and MRI referrals for acute ankle and knee injuries from each individual GP may be low, the overall number in primary care has been rising since the early 2000s .

Dr Rees, however, has never referred a patient for an ultrasound to help him diagnose an acute ankle injury in his 8-year career  – and he has only ever referred one patient for an MRI to help him diagnose an acute knee injury.

What is happening? Dr Rees sees as an average of 25 to 30 acute ankle and knee injuries each year at his practice in Warwick, in rural Queensland.

But the key reason he has avoided referrals is his confidence in 'making an accurate diagnosis after a proper patient history and physical examination without the need for imaging.'

Dr Rees developed his clinical skills and confidence when he was a medical student, then reinforced them while he was a registrar and subsequently as a practising GP. 

'I had a professor of orthopaedic surgery who really pressed the idea that the job of the doctor is to take a proper history and do a proper examination and when reasonably well done, most of the time it will be as good as, if not better than, imaging,' says Dr Rees.

'Since then, as a GP registrar and now as a GP, I always try to make it my [clinical] practice that every time I examine a joint, I examine it thoroughly, as if I was attending an OSCE [Objective Structured Clinical Exam]. And I’ve never gotten out of the habit ,' he says.

The evidence from studies and guideline recommendations may be summarised as stating that: ‘GPs should only consider referring patients for ankle ultrasound or knee MRI of acute injuries when diagnosis is unclear after a targeted patient history and physical examination, and  if confirming diagnosis will change management.’

The one knee MRI referral made by Dr Rees to help him make a diagnosis during his 8-year career as a GP (he has also referred two other patients, but these were requested by a surgeon) happened earlier this year when he had some doubt about an anterior cruciate ligament tear.

His physical examination found the patient’s uninjured knee had similar laxity to that of the injured knee. Dr Rees wondered if it was a case of unusually lax ligaments. But because the patient wanted to play competitive sport and was open to having surgical reconstruction, an accurate diagnosis was essential.

So Dr Rees ordered an MRI, which confirmed the patient had an ACL tear, and the patient went on to have a surgical reconstruction.

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