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Treatment for acute anterior cruciate ligament tear: five year outcome of randomised trial

BMJ 2013; 346 doi: (Published 24 January 2013) Cite this as: BMJ 2013;346:f232
  1. Richard B Frobell, associate professor1,
  2. Harald P Roos, associate professor1,
  3. Ewa M Roos, professor2,
  4. Frank W Roemer, associate professor34,
  5. Jonas Ranstam, professor1,
  6. L Stefan Lohmander, professor125
  1. 1Department of Orthopaedics, Clinical Sciences Lund, Lund University, Sweden
  2. 2Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
  3. 3Department of Radiology, University of Erlangen, Erlangen, Germany
  4. 4Quantitative Imaging Center (QIC), Department of Radiology, Boston University School of Medicine, Boston, MA, USA
  5. 5Department of Orthopaedics and Traumatology, University of Southern Denmark, Odense, Denmark
  1. Correspondence to: R B Frobell, Department of Orthopaedics, Lund University Hospital, SE-22185 Lund, Sweden Richard.frobell{at}
  • Accepted 28 December 2012


Objective To compare, in young active adults with an acute anterior cruciate ligament (ACL) tear, the mid-term (five year) patient reported and radiographic outcomes between those treated with rehabilitation plus early ACL reconstruction and those treated with rehabilitation and optional delayed ACL reconstruction.

Design Extended follow-up of prospective randomised controlled trial.

Setting Orthopaedic departments at two hospitals in Sweden.

Participants 121 young, active adults (mean age 26 years) with acute ACL injury to a previously uninjured knee. One patient was lost to five year follow-up.

Intervention All patients received similar structured rehabilitation. In addition to rehabilitation, 62 patients were assigned to early ACL reconstruction and 59 were assigned to the option of having a delayed ACL reconstruction if needed.

Main outcome measure The main outcome was the change from baseline to five years in the mean value of four of the five subscales of the knee injury and osteoarthritis outcome score (KOOS4). Other outcomes included the absolute KOOS4 score, all five KOOS subscale scores, SF-36, Tegner activity scale, meniscal surgery, and radiographic osteoarthritis at five years.

Results Thirty (51%) patients assigned to optional delayed ACL reconstruction had delayed ACL reconstruction (seven between two and five years). The mean change in KOOS4 score from baseline to five years was 42.9 points for those assigned to rehabilitation plus early ACL reconstruction and 44.9 for those assigned to rehabilitation plus optional delayed reconstruction (between group difference 2.0 points, 95% confidence interval −8.5 to 4.5; P=0.54 after adjustment for baseline score). At five years, no significant between group differences were seen in KOOS4 (P=0.45), any of the KOOS subscales (P≥0.12), SF-36 (P≥0.34), Tegner activity scale (P=0.74), or incident radiographic osteoarthritis of the index knee (P=0.17). No between group differences were seen in the number of knees having meniscus surgery (P=0.48) or in a time to event analysis of the proportion of meniscuses operated on (P=0.77). The results were similar when analysed by treatment actually received.

Conclusion In this first high quality randomised controlled trial with minimal loss to follow-up, a strategy of rehabilitation plus early ACL reconstruction did not provide better results at five years than a strategy of initial rehabilitation with the option of having a later ACL reconstruction. Results did not differ between knees surgically reconstructed early or late and those treated with rehabilitation alone. These results should encourage clinicians and young active adult patients to consider rehabilitation as a primary treatment option after an acute ACL tear.

Trial registration Current Controlled Trials ISRCTN84752559.


  • We express our sincere gratitude to all patients who participated in this trial. We also acknowledge the physiotherapists who managed the rehabilitation: Idrottskliniken & Idrottskadecentrum in Helsingborg, Höganäs Fysio and Marianne Roos in Ängelholm, Kupolen in Klippan, Idrottsskademottagningen in Landskrona, Hanspeter Borgman in Eslöv, Idrottshälsan in Lund, Rehab & Friskvårdshuset in Staffanstorp, Mats Gustavsson at Davidshalls rehab, and Tina Magnusson at Fysiocenter in Malmö; and the orthopaedic surgeons: Ola Olsson in Helsingborg, Lars Wahlström in Ängelholm, and Fredrik Nyquist in Malmö who together with HPR performed surgical interventions. Special thanks go to Kerstin Åkesson for study management, Björn Slaug and Ludvig Dahl for database management, Jan-Åke Nilsson for statistical analysis, and Torsten Boegård for radiological advice.

  • Contributors: RBF, HPR, EMR, and LSL were responsible for the study design and protocol. RBF and HPR recruited and followed up patients and collected data. RBF, JR, LSL, and EMR were responsible for the statistical analysis plan. RBF, JR, LSL, FR, and EMR analysed and interpreted data. RBF and LSL wrote the manuscript, and all authors reviewed it and approved the final version. LSL is the guarantor.

  • Funding: The KANON study received funding from the Swedish Research Council (RBF, LSL, EMR), Medical Faculty of Lund University (LSL, EMR), Region Skåne (LSL, RBF, EMR), Thelma Zoegas Fund (RBF, HPR), Stig & Ragna Gorthon Research Foundation (RBF), Swedish National Centre for Research in Sports (LSL, RBF), Crafoord Foundation (RBF), Tore Nilsson Research Fund (RBF), and Pfizer Global Research (LSL).

  • Competing interests: All authors have completed the Unified Competing Interest form at (available on request from the corresponding author) and declare: no support from any organisation for the submitted work other than those listed above under Funding; LSL has received honorariums for lectures from Pfizer; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: This study was approved by the IRB at Lund University, Sweden (LU 535-2001).

  • Data sharing: No additional data available.

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