Skip to content
View commentaries on this research

This is a plain English summary of an original research article

Keyhole surgery to reshape the joint surfaces in people with hip impingement improves hip-related quality of life more than physiotherapy.

In hip impingement, there is a painful restriction of the smooth movement of the ball of the femur inside the cup (acetabulum) of the pelvis. It mainly affects younger, active people. Observational studies have supported the use of keyhole surgery (arthroscopy), but there was a lack of high-quality evidence. This NIHR-funded study is the first trial to compare arthroscopy with optimal conservative care.

Both arthroscopy and physiotherapy led to improvements on a 100-point hip score by 12 months. However, arthroscopy caused an additional 6.8 points improvement, which is a clinically meaningful difference.

Further follow-up is needed to show that the effect is sustained. Nevertheless, this is the first good evidence for the effectiveness of arthroscopy, although it was more costly than physiotherapy.

Why was this study needed?

Hip impingement is common, with one NHS trust estimating it affects 30% of people in the UK with higher prevalence among athletes. Different types are recognised, according to whether the shape of the head of the femur (cam impingement), the hip socket (pincer impingement) or both (mixed), are shaped slightly differently from normal. Over time this damages cartilage in the joint which causes pain and can lead to osteoarthritis.

Surgery to reshape the socket and repair damaged tissues has become an established treatment with around 2,000 procedures performed in the UK each year, mostly keyhole (arthroscopic). However, a 2014 Cochrane review identified no randomised controlled trials investigating arthroscopy for femoroacetabular impingement. The lack of good evidence prompted this randomised controlled trial comparing arthroscopy with the best available conservative care.

What did this study do?

The UK FASHIoN study was conducted in 23 UK hospitals. It allocated 348 people with femoroacetabular impingement (average 35 years) to either arthroscopy or a personalised physiotherapy programme. Randomisation was balanced according to the treatment centre and type of bone abnormality. If participants had impingement affecting both hips, the most affected side was treated. Patients with established osteoarthritis, prior hip fracture or other hip disease were excluded.

The physiotherapy programme involved personalised assessment, education, supervised physiotherapy and pain-relief when needed. It involved 6 to 10, face-to-face sessions over 12-24 weeks. Patients having arthroscopy received physiotherapy rehabilitation after surgery but delivered by separate physiotherapists.

Retention was high, 86% of patients received the allocated interventions and 92% completed quality-of-life questionnaires at 12 months. Assessors were unaware of the intervention received, which increases reliability in the results.

What did it find?

  • Arthroscopy gave greater improvement in hip-related quality of life at 12 months. This was measured using the international Hip Outcome Tool (iHOT-33) which measures pain, function and psychological effects on a 100-point score where lower scores indicate greater impairment. Physiotherapy improved from scores from 35.6 to 49.7 while arthroscopy improved them from 39.2 to 58.8. This gave a 6.8 difference in favour of arthroscopy (95% confidence interval [CI] 1.7 to 12.0) after adjusting for baseline score, gender, type of impingement and treatment centre. This exceeded the 6.1 point threshold for a clinically meaningful difference.
  • Planned subgroup analyses according to type of abnormality found a benefit of arthroscopy for cam impingement only (difference of 8.3, 95% CI 2.5 to 14.2) and not for pincer or mixed impingement. However, 75% of patients had cam impingement with smaller numbers in other groups limiting the reliability of this analysis.
  • Adverse effects were reported by 72% of the arthroscopy group and 60% of the physiotherapy group, with muscle soreness most common in both groups. Seven serious adverse effects were reported. Five of six in the arthroscopy group were related to treatment, mostly infections. The other two events, including one in the physiotherapy group, were not treatment-related.
  • There was no difference between groups in overall quality of life at 12 months, as measured using the EQ-5D or Short-Form Health survey (SF-12).
  • Average per person treatment costs were £3,042 for arthroscopy compared with £155 for physiotherapy. Despite 12 month benefits for hip-related quality of life, arthroscopy was not estimated to be a cost-effective use of NHS resources.

What does current guidance say on this issue?

NICE’s 2011 interventional procedures guidance advised that there is adequate evidence from non-randomised trial and case studies that arthroscopy for femoroacetabular impingement gives symptom relief in the short- to medium-term. However, they advised that there are well-recognised complications. NICE recommended that the procedure is carried out with normal arrangements for clinical governance, consent and audit with local review of outcomes.

Details of patients having these procedures should be added to the Non-Arthroplasty Hip Register (NAHR) run by the British Hip Society.

What are the implications?

This study provides the first good evidence for arthroscopy for femoroacetabular impingement. Without a placebo or sham procedure, it's difficult to rule out the possibility that receiving an intervention could have biased patient-reported improvements, and surgery was more costly than physiotherapy. Follow-up is needed to see whether improvements are sustained in the long-term to support the high cost of this treatment.

Citation and Funding

Griffin DR, Dickenson EJ, Wall PDH, et al; FASHIoN Study Group. Hip arthroscopy versus best conservative care for the treatment of femoroacetabular impingement syndrome (UK FASHIoN): a multicentre randomised controlled trial. Lancet. 2018;391(10136):2225-35.

This project was funded by the National Institute for Health Research Health Technology Assessment Programme (project number 13/103/02).


British Hip Society. NAHR. London: British Hip Society; Accessed 22 July 2018.

Griffin D, Wall P, Realpe A, et al. UK FASHIoN: feasibility study of a randomised controlled trial of arthroscopic surgery for hip impingement compared with best conservative care. Health Technol Assess 2016;20(32).

NHS Oxford University Hospitals. Hip impingement. Oxford: NHS Oxford University Hospitals.

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

Wall PDH, Brown JS, Parsons N, et al. Surgery for treating hip impingement (femoroacetabular impingement). Cochrane Database Syst Rev. 2014;(9): CD010796.

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

  • Share via:
  • Print article
Back to top