title: Patient-reported knee function, quality of life, and activity level after bilateral anterior cruciate ligament injuries.
abstract: BACKGROUND
  About 12% of patients who have undergone primary anterior cruciate ligament (ACL) reconstruction sustain a contralateral ACL injury within 5 years.
  
  
  OBJECTIVE
  To investigate patient-reported knee function, quality of life, and activity level in patients with bilateral ACL injuries.
  
  
  METHODS
  Cohort study; Level of evidence, 3.
  
  
  METHODS
  A search of hospital records identified 147 patients, aged 18 to 45 years, with bilateral ACL injuries. Of these, 83 met the inclusion criteria, having had their first ACL injury up to 12 years ago with no other major injuries to the knee joint. Sixty-six of these patients (80% of total; 47% female; mean age, 29.1 ± 7.2 years) answered a questionnaire packet. Patients who had undergone unilateral ACL reconstruction (n = 182) were used for comparison.
  
  
  RESULTS
  Patients with bilateral ACL injuries had a median Lysholm knee score of 82 (range, 34-100). The mean EuroQol index (EQ-5D) score of the overall health status was 0.77 ± 0.22, and the mean EQ-5D visual analog scale score was 75.5 ± 17.6. The median Tegner activity level was 9 (range, 1-9) before any injuries, 7 (range, 1-9) before the second ACL injury, and 4 (range, 1-9) at the time of follow-up. The activity level before the second injury was higher compared with the follow-up for patients who had undergone unilateral ACL reconstruction. At follow-up, 23% of the patients with bilateral ACL injuries returned to their previous activity, and 12% of patients returned to the same level as before their injuries compared with 43% (P = .004) and 28% (P = .01) in patients who had undergone unilateral ACL reconstruction, respectively. Patients with bilateral ACL injuries had significantly lower values in the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales for pain, function in sports and recreation, and knee-related quality of life as well as the ACL Deficiency Quality of Life (ACL-QOL) score compared with patients who had undergone unilateral ACL reconstruction.
  
  
  CONCLUSIONS
  Patients with bilateral ACL injuries reported poorer knee function and quality of life compared with those who had undergone unilateral ACL reconstruction. Their activities had changed, and they were dissatisfied with their current activity level. They had a high activity level before their first and second ACL injuries but an impaired activity level after their contralateral injury at follow-up.
authors.affiliation: Anne Fältström, RPT, Department of Physiotherapy, Ryhov County Hospital, Jönköping, 551 85, Sweden. anne.faltstrom@lj.se.
authors.forename: Anne
authors.initials: A
authors.lastname: Fältström
authors.forename: Martin
authors.initials: M
authors.lastname: Hägglund
authors.forename: Joanna
authors.initials: J
authors.lastname: Kvist
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction; D018771:Arthralgia / Q000209:etiology*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007717:Knee / Q000601:surgery; D007718:Knee Injuries / Q000150:complications* / Q000601:surgery; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D020370:Osteoarthritis, Knee / Q000209:etiology; D017060:Patient Satisfaction; D011788:Quality of Life; D013177:Sports; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: ACL; Tegner activity scale; contralateral; knee; ligaments; return to sport; subsequent injury