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Let’s talk about sex (and gender) after ACL injury: a systematic review and meta-analysis of self-reported activity and knee-related outcomes
  1. Andrea M Bruder1,2,
  2. Adam G Culvenor2,
  3. Matthew G King1,2,
  4. Melissa Haberfield2,
  5. Eliza A Roughead2,
  6. John Mastwyk1,
  7. Joanne L Kemp2,
  8. Marcella Ferraz Pazzinatto2,
  9. Thomas J West2,
  10. Sally L Coburn2,
  11. Sallie M Cowan2,3,
  12. Allison M Ezzat2,4,
  13. Laura To2,3,
  14. Karina Chilman2,
  15. Jamon L Couch1,2,5,
  16. Jackie L Whittaker4,5,
  17. Kay M Crossley2
  1. 1Department of Physiotherapy, Podiatry and Prosthetics and Orthotics, School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, Victoria, Australia
  2. 2La Trobe Sport and Exercise Medicine Research Centre, School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, Victoria, Australia
  3. 3Clifton Hill Physiotherapy, Melbourne, Victoria, Australia
  4. 4Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
  5. 5Arthritis Research Canada, Vancouver, British Columbia, Canada
  1. Correspondence to Dr Andrea M Bruder, Physiotherapy, La Trobe University, Melbourne, VIC 3086, Australia; a.bruder{at}


Objective Investigate sex/gender differences in self-reported activity and knee-related outcomes after anterior cruciate ligament (ACL) injury.

Design Systematic review with meta-analysis.

Data sources Seven databases were searched in December 2021.

Eligibility criteria Observational or interventional studies with self-reported activity (including return to sport) or knee-related outcomes after ACL injury.

Results We included 242 studies (n=123 687, 43% females/women/girls, mean age 26 years at surgery). One hundred and six studies contributed to 1 of 35 meta-analyses (n=59 552). After ACL injury/reconstruction, very low-certainty evidence suggests females/women/girls had inferior self-reported activity (ie, return to sport, Tegner Activity Score, Marx Activity Scale) compared with males/men/boys on most (88%, 7/8) meta-analyses. Females/women/girls had 23%–25% reduced odds of returning to sport within 1-year post-ACL injury/reconstruction (12 studies, OR 0.76 95% CI 0.63 to 0.92), 1–5 years (45 studies, OR 0.75 95% CI 0.69 to 0.82) and 5–10 years (9 studies, OR 0.77 95% CI 0.57 to 1.04). Age-stratified analysis (<19 years) suggests female athletes/girls had 32% reduced odds of returning to sport compared with male athletes/boys (OR 0.68, 95% CI 0.41 to 1.13, I2 0.0%). Very low-certainty evidence suggests females/women/girls experienced inferior knee-related outcomes (eg, function, quality of life) on many (70%, 19/27) meta-analyses: standardised mean difference ranging from −0.02 (Knee injury and Osteoarthritis Outcome Score, KOOS-activities of daily living, 9 studies, 95% CI −0.05 to 0.02) to −0.31 (KOOS-sport and recreation, 7 studies, 95% CI −0.36 to –0.26).

Conclusions Very low-certainty evidence suggests inferior self-reported activity and knee-related outcomes for females/women/girls compared with males/men/boys after an ACL injury. Future studies should explore factors and design targeted interventions to improve outcomes for females/women/girls.

PROSPERO registration number CRD42021205998.

  • Knee injuries
  • Female
  • Physical activity
  • Sport
  • Rehabilitation

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  • Twitter @AndreaBruder, @agculvenor, @MattKing_Physio, @melhabphysio, @eliza_roughead, @JohnMastwyk, @JoanneLKemp, @M_Pazzinatto, @tsewmot, @PhysioHill, @AllisonEzzat, @jamonlevi, @jwhittak_physio, @kaymcrossley

  • Contributors AMB, KMC and AGC designed the study. EAR completed all searches. AMB, EAR, MH, JM, MFP, JLW, LT and MGK completed screening, AGC resolved disagreements. AMB, MK, JLK, MH, SLC, SMC, JM, MFP, AME and TJW assessed risk of bias. AMB and MGK completed certainty of evidence using GRADE approach. AMB, LT, EAR, MK, KMC and JC extracted and/or checked data extraction accuracy. AMB and AGC did the meta-analyses and, in conjunction with KMC and MGK interpreted the data. AMB wrote the initial draft and all authors critically revised the manuscript for important intellectual content and approved the final version of the manuscript.

  • Funding This study was supported by a La Trobe University, Special Strategic Grant (2021). AGC is a recipient of a National Health and Medical Research Council (NHMRC) of Australia Investigator Grant (GNT2008523). JLK is a recipient of a National Health and Medical Research Council (NHMRC) of Australia Investigator Grant (GNT2017844). JLW is supported by a Michael Smith Foundation for Health Research a Scholar Award (SCH-2020-0403) and an Arthritis Society STAR Career Development Award (STAR-19-0493). This research was funded in part by the National Health and Medical Research Council (GNT2008523). For the purposes of open access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission’.

  • Disclaimer The funders had no role in any part of the study or in any decision about publication.

  • Competing interests AGC, MGK and JLW are associate editors of BJSM. KMC is a senior advisor of BJSM. JLK is an editor of BJSM. AGC is an associate editor of Osteoarthritis and Cartilage. JLW is an editor with the Journal of Orthopaedic and Sports Physical Therapy. MGK is an associate editor of BMC Musculoskeletal disorders. MGK, JLK and JLW are international review board members of Journal of Orthopaedic and Sports Physical Therapy. All other authors declare no competing interests.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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