Rehabilitation versus surgical reconstruction for non-acute anterior cruciate ligament injury (ACL SNNAP): a pragmatic randomised controlled trial

Lancet. 2022 Aug 20;400(10352):605-615. doi: 10.1016/S0140-6736(22)01424-6.


Background: Anterior cruciate ligament (ACL) rupture is a common debilitating injury that can cause instability of the knee. We aimed to investigate the best management strategy between reconstructive surgery and non-surgical treatment for patients with a non-acute ACL injury and persistent symptoms of instability.

Methods: We did a pragmatic, multicentre, superiority, randomised controlled trial in 29 secondary care National Health Service orthopaedic units in the UK. Patients with symptomatic knee problems (instability) consistent with an ACL injury were eligible. We excluded patients with meniscal pathology with characteristics that indicate immediate surgery. Patients were randomly assigned (1:1) by computer to either surgery (reconstruction) or rehabilitation (physiotherapy but with subsequent reconstruction permitted if instability persisted after treatment), stratified by site and baseline Knee Injury and Osteoarthritis Outcome Score-4 domain version (KOOS4). This management design represented normal practice. The primary outcome was KOOS4 at 18 months after randomisation. The principal analyses were intention-to-treat based, with KOOS4 results analysed using linear regression. This trial is registered with ISRCTN, ISRCTN10110685, and, NCT02980367.

Findings: Between Feb 1, 2017, and April 12, 2020, we recruited 316 patients. 156 (49%) participants were randomly assigned to the surgical reconstruction group and 160 (51%) to the rehabilitation group. Mean KOOS4 at 18 months was 73·0 (SD 18·3) in the surgical group and 64·6 (21·6) in the rehabilitation group. The adjusted mean difference was 7·9 (95% CI 2·5-13·2; p=0·0053) in favour of surgical management. 65 (41%) of 160 patients allocated to rehabilitation underwent subsequent surgery according to protocol within 18 months. 43 (28%) of 156 patients allocated to surgery did not receive their allocated treatment. We found no differences between groups in the proportion of intervention-related complications.

Interpretation: Surgical reconstruction as a management strategy for patients with non-acute ACL injury with persistent symptoms of instability was clinically superior and more cost-effective in comparison with rehabilitation management.

Funding: The UK National Institute for Health Research Health Technology Assessment Programme.

Publication types

  • Multicenter Study
  • Pragmatic Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Anterior Cruciate Ligament Injuries* / diagnosis
  • Anterior Cruciate Ligament Injuries* / etiology
  • Anterior Cruciate Ligament Injuries* / surgery
  • Anterior Cruciate Ligament Reconstruction* / adverse effects
  • Anterior Cruciate Ligament Reconstruction* / methods
  • Humans
  • Knee Injuries* / etiology
  • Knee Injuries* / rehabilitation
  • Knee Injuries* / surgery
  • Knee Joint / surgery
  • State Medicine
  • Treatment Outcome

Associated data