ACL knee injury study (ENCORE)

The Enhancing Non-operative Care Of ACL Rupture: Equity and Effectiveness (ENCORE) study

The ENCORE study will test the effect of the Cross-Bracing Protocol for ACL injuries on pain, symptoms, function, work, quality of life, costs, ligament healing, and the need for ACL surgery compared to comprehensive rehabilitation alone.

We will recruit equal numbers of Māori, Pacific, and non-Māori / non-Pacific participants so that results apply to communities currently experiencing the worst outcomes.

ENCORE Study Flier (PDF)

Where to take part

Recruitment of participants is now underway and anticipated to continue until October 2027. If you injure your ACL and are interested in taking part, please contact an ENCORE clinic as soon as you can.

Visit ENCORE clinics to find clinics where you can take part in our study. This page will be continually updated. Recruitment is planned in Northland, Auckland, Waikato, Bay of Plenty, Taranaki, and Wellington. If there is no clinic listed in your region, please email encore.study@otago.ac.nz or ring +64 21 223 9968 to discuss whether a clinic will soon be ready in your region.

Background to the ENCORE study

ACL rupture treatment in New Zealand

Anterior cruciate ligament (ACL) rupture is a serious knee injury that affects thousands of New Zealanders annually with long-term impacts on pain, function, work, and sports participation.

ACL rupture can be managed with rehabilitation first (followed by surgery if needed) or early surgery following by rehabilitation. Most people should complete rehabilitation before considering surgery as many will find that surgery is not necessary and surgical outcomes are better for those who have completed a rehabilitation programme first. In contrast, many New Zealanders receive surgery as first-line care. Two-years following ACL surgery, one-third of people have ongoing unacceptable symptoms and almost half have symptoms consistent with osteoarthritis. These outcomes are worse for Māori and people from Pacific communities.

ACL injuries can heal

New evidence suggests ACL ruptures can heal without surgery. A novel knee bracing protocol that limits knee movement in the first 8 weeks after injury may increase healing rates. The ENCORE trial will investigate whether adding bracing to rehabilitation increases ACL healing and improves outcomes compared comprehensive rehabilitation alone.