Having physiotherapy for an ankle sprain is a waste of time - and no better than managing the injury at home, say scientists.
A study found almost half of patients had not achieved an 'excellent recovery' six months later.
The ankle is held together by bands of elastic fibres called ligaments and a sprain occurs when one or more of these ligaments are stretched beyond their normal range.
In a severe sprain the fibres tear.
Most sprains are mild or moderate and the common injury leads to a high number of A&E visits with the pain lingering for up to seven years.
But clinical standards for the treatments are not well defined and there is a lack of high quality evidence on role of physiotherapy
So in the largest study of its kind researchers lookled at 503 patients aged 16 to 79 who were taken to two hospitals in Kingston, Canada, between 2009 and 2013.
Results showed 43 percent (90/208) of participants in a physiotherapy group and 38% (75/195) in a control group had not reached 'excellent recovery' by six months.
They were randomly assigned to the control group where they received only usual care whereas the others also got up to seven 30 minute sessions of physio.
Dr Brenda Brouwer, of Queen's University in Kingston, said: "While there was not a clinically important effect with the standardised physiotherapy regimen provided to our participants, there is potential for the investigation of alternative interventions that would reduce morbidity in patients with these injuries."
Usual care consisted of medical assessment and a one page written summary of instruction for basic management of the injury at home.
Recommendations focused on ankle protection, rest, ice, application of compression bandage, elevation, use of painkillers, graduated weight bearing activities and information about expected recovery.
Participants were required to complete a questionnaire assessing recovery at one, three and six months.
Questions focused on pain, symptoms, function in activities of daily living, function in sport and recreation, and quality of life.
Dr Chris Bleakley, of Ulster University, reviewed the study for The BMJ and said the randomised controlled study is "an important addition to the evidence base."
He also calls for patients, practitioners and researchers to consider other rehabilitative exercises that can influence treatment success.
Clinical benefit of rehabilitative exercises might depend on the nature, intensity, and duration of treatment, he says.
The maximum of seven lots of 30 minutes of supervised physiotherapy in the latest study might be a "lower dose" when compared to other studies.
He also says there's an "urgent need to diversify the exercise content of treatments beyond the ankle," such as the knee, hip, and in the torso, which can be implicated in long term problems.