Skip to content
View commentaries on this research

This is a plain English summary of an original research article

Early weight-bearing in a below-knee rigid boot, a functional brace, following ruptured Achilles tendon can achieve similar results to traditional plaster casting. This NIHR-funded trial included 540 people, and after nine months there appeared to be no difference between the two treatments in terms of how well patients recovered from their injury. The functional brace was preferred by patients.

Functional bracing is an alternative to traditional plaster casting that allows earlier weight-bearing and mobilisation.

The researchers in this trial found that the rate of re-rupture was 5% to 6% and this was lower than that reported in the previous literature.

Clinicians treating Achilles tendon rupture may consider the use of early weight-bearing in a functional brace as a safe and effective alternative to plaster casting.

Why was this study needed?

A new rupture of the Achilles tendon occurs in about 5–10 people per 100,000 each year. Rates depend on age and are increasing. Injures in men are more common than in women. Rupture results from a sporting injury in 80% of cases and affects people in their 40s and 50s, while non-sports related injuries typically peak in the 50s and 60s; however, all adults can be affected. This can result in time away from work and normal activities.

Non-surgical treatment is increasingly preferred for treatment but surgical repair is an alternative.

Traditional non-surgical treatment is by plaster cast. The cast protects the healing tendon, but is heavy and may lead to muscle wasting and increase the risk of blood clots. Functional bracing, where a patient’s calf is placed in a rigid walking boot containing wedges to lift the heel, allows earlier weight-bearing.

To date most trials have been small, single-centre studies, leading to inconclusive results. In the face of the lack of strong evidence, these researchers undertook a larger multicentre trial, with enough participants to find a difference between options if one existed.

What did this study do?

The UKSTAR trial was a randomised controlled superiority trial conducted in 39 UK hospitals between 2016 and 2018. Participants (average age 49 years) all had a primary Achilles tendon rupture.

Those randomised to plaster cast (266 people) had a below-knee cast fitted, with the toes pointing downwards. The cast position was gradually changed, with weight-bearing usually possible at six weeks. The cast was removed at eight weeks.

Those randomised to functional brace (274 people) had a removable, rigid walking boot. Full weight-bearing was possible immediately after fitting. The brace was removed at eight weeks.

All participants received standard physiotherapy advice, although additional rehabilitation support varied. Patients were assessed at eight weeks, and at nine months 93 per cent completed a questionnaire — the Achilles Tendon Total Rupture Score (ATRS). This questionnaire asks about symptoms, physical activity, and pain related to the Achilles tendon and results in a score between 0 and 100 across 10 items, with 100 as the best possible score. The researchers pre-specified the lowest important clinical difference as 8 points.

What did it find?

  • There was no difference in ATRS between the groups at nine months post-injury. Mean score in the cast group was 74.4 and in the functional brace group was 72.8. The adjusted mean difference of -1.38 (95% confidence interval [CI] -4.9 to 2.1) was not clinically important or statistically significant.
  • The rate of re-rupture of the tendon was about 5–6% in the plaster cast group and the functional brace group. None of the re-ruptures occurred more than six months after the injury.
  • Health-related quality of life, measured by EQ-5D-5L, showed a statistically significant benefit for functional brace at eight weeks, but not at later time points.
  • The mean total health and personal social care cost was £1,181 for the plaster cast group and £1,078 for the functional brace group, suggesting there is little difference in these average costs between treatments.

What does current guidance say on this issue?

There are no specific national guidelines on treatments for Achilles tendon rupture in the UK. The American Academy of Orthopaedic Surgeons published a guideline in 2009 which was unable to recommend for or against the use of immediate functional bracing for patients with acute Achilles tendon rupture.

Many UK hospitals offer both plaster and functional brace options for those being treated non-operatively, with the choice being made between the treating clinician and the patient.

What are the implications?

This large, well-conducted trial provides no evidence that traditional plaster casting is superior to early weight-bearing in a functional brace. The use of functional bracing was preferred by patients.

The results can give confidence to treating clinicians and patients that functional bracing is a good option for many patients.

Citation and Funding

Costa ML, Achten J, Marian IR et al. Plaster cast versus functional brace for non-surgical treatment of Achilles tendon rupture (UKSTAR): a multicentre randomised controlled trial and economic evaluation.  Lancet. 2020;395:441–8.

This project was funded by the NIHR Health Technology Assessment Programme (project number 13/115/62).


American Academy of Orthopaedic Surgeons. The diagnosis and treatment of acute Achilles tendon rupture: guideline and evidence report. Rosemont [IL]: American Academy of Orthopaedic Surgeons; 2009; (reviewed 2014).

NICE. Achilles tendinopathy: when should I suspect Achilles tendon rupture? Clinical Knowledge Summary. London: National Institute for Health and Care Excellence; (reviewed 2016).

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

  • Share via:
  • Print article


Template content only


Back to top