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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.

Adults with painful restriction of movement of their hip had greater improvements in their symptoms after arthroscopy (keyhole surgery) than those who had physiotherapy.

This NIHR-funded study included 222 people with hip pain and limited movement due to femoro-acetabular (hip) impingement but without a diagnosis of osteoarthritis. Their average age was 36 years. Half of the people who had surgery had significant benefit compared with a third of those having physiotherapy.

NICE has recommended the surgery as safe and effective, but there has been no evidence to date comparing it with other interventions. This study shows that it may be a good option, although cost-effectiveness wasn’t considered. It provides useful evidence to inform discussions between patients and surgeons to set expectations about the likely success rates of each treatment option.


Why was this study needed?

The hip joint consists of a round head within a socket. Usually, this allows a free range of smooth movement, but an irregularity in the surface can result in pain, limited movement, and degeneration which can lead to osteoarthritis. About a fifth of the population may have some irregularity in the joint but less than 25% of these people develop pain. Those with symptoms are usually treated with physiotherapy.

Keyhole surgery is an alternative treatment. A camera (arthroscope) is inserted into the hip joint through a small incision, and instruments are used to re-shape the joint surface by removing some cartilage or bone.

NICE found enough evidence to say that arthroscopic surgery can safely be offered as a treatment option. But there hasn’t been any high-quality evidence comparing the effectiveness of different treatment options. The aim of this study was to compare arthroscopic hip surgery with physiotherapy.


What did this study do?

This randomised controlled trial recruited 222 adults with femoro-acetabular impingement from seven NHS trusts in England. Half were allocated to receive arthroscopic hip surgery by specialist orthopaedic surgeons. This was followed by the usual postoperative physiotherapy designed to maintain range of movement and help return to activity. The other half were assigned to a physiotherapy and activity modification programme delivered by a specialist physiotherapist. This was tailored to individual patient needs, with a focus on improving core stability and movement control. There was a maximum of eight sessions over five months.

While patients and the clinicians carrying out the interventions could not be blinded, the clinicians performing follow-up assessments were not aware which treatment patients had received, which increases the reliability of the results.


What did it find?

At eight months:

  • Patients in the arthroscopic hip surgery group scored higher on the hip outcome score activities of daily living (HOS ADL) than those in the physiotherapy group, 78.4 versus 69.2 on a scale of 0 to 100 with higher scores indicating better function (adjusted mean difference 10, 95% confidence interval [CI] 6.4 to 13.6). The minimum clinically important difference between groups for this scale is nine points.
  • 51% of patients in the surgery group had an improvement of at least nine points (95% CI 41% to 61%), compared with 32% (95% CI 22% to 42%) of the physiotherapy group.
  • An HOS ADL score higher than 87 points is a “patient acceptable symptomatic state”, or the level that most patients feel they can live with, without further treatment. This was achieved by 48% (95% CI 38% to 58%) of the surgery group at eight months after randomisation, compared with 19% (95% CI 11% to 28%) of the physiotherapy group.
  • No serious adverse events were reported in either group.


What does current guidance say on this issue?

NICE published interventional procedures guidance on arthroscopic femoro-acetabular surgery for hip impingement syndrome in 2011. The evidence available showed that the surgery is effective in the short and medium term. It states that the procedure can be used provided usual arrangements are in place for clinical governance, consent and audit. Only surgeons with specialist expertise in arthroscopic hip surgery should carry out the procedure.

The Royal College of Surgeons published a commissioning guide in 2017 on hip pain in adults. This says that surgery for femoro-acetabular impingement syndrome should be considered when non-operative management (including physiotherapy) has failed.


What are the implications?

This study provides high-quality evidence that arthroscopic hip surgery is better than physiotherapy at improving symptoms in patients who are referred to hospital with hip impingement. However, this doesn’t mean that all patients should automatically be offered surgery. It is a complicated procedure that should only be carried out by specialist surgeons. There has been no evaluation of the cost-effectiveness. Also, not all patients showed improvement following surgery.

The planned three-year follow-up to this study should provide further evidence to guide decision-making, such as whether either strategy changes the risk of osteoarthritis.


Citation and Funding

Palmer AJR, Gupta VA, Fernquest S et al. Arthroscopic hip surgery compared with physiotherapy and activity modification for the treatment of symptomatic femoroacetabular impingement: multicentre randomised controlled trial. BMJ. 2019;364:l185.

This project was funded by the NIHR Biomedical Research Centre at Oxford and Arthritis Research UK.



NHS website. Hip pain in adults. London: Department of Health and Social Care; reviewed 2016.

NICE. Arthroscopic femoro-acetabular surgery for hip impingement syndrome. IPG408. London: National Institute for Health and Care Excellence; 2011.

RCS. Commissioning guide: pain arising from the hip in adults. London: British Hip Society, British Orthopaedic Association and Royal College of Surgeons of England; 2017.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre


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