title: Does ACL reconstruction alter natural history?: A systematic literature review of long-term outcomes.
abstract: BACKGROUND
  Anterior cruciate ligament (ACL) injury can lead to tibiofemoral instability, decreased functional outcomes, and degenerative joint disease. It is unknown whether ACL reconstruction alters this progression at long-term follow-up.
  
  
  METHODS
  A systematic literature review of the long-term results (minimum follow-up, more than ten years) after operative intra-articular reconstruction of ACL injuries and after nonoperative management was performed to compare (1) knee stability on physical examination, (2) functional and patient-based outcomes, (3) the need for further surgical intervention, and (4) radiographic outcomes. After application of selection criteria, forty patient cohorts with a mean of 13.9 ± 3.1 years of postoperative follow-up were identified. Twenty-seven cohorts containing 1585 patients had undergone reconstruction, and thirteen containing 685 patients had been treated nonoperatively.
  
  
  RESULTS
  Comparison of operative and nonoperative cohorts revealed no significant differences in age, sex, body mass index, or rate of initial meniscal injury (p > 0.05 for all). Operative cohorts had significantly less need for further surgery (12.4% compared with 24.9% for nonoperative, p = 0.0176), less need for subsequent meniscal surgery (13.9% compared with 29.4%, p = 0.0017), and less decline in the Tegner score (-1.9 compared with -3.1, p = 0.0215). A difference in pivot-shift test results was observed (25.5% pivot-positive compared with 46.6% for nonoperative) but did not reach significance (p = 0.09). No significant differences were seen in outcome scores (Lysholm, International Knee Documentation Committee [IKDC], or final Tegner scores) or the rate of radiographically evident degenerative joint disease (p > 0.05 for all).
  
  
  CONCLUSIONS
  At a mean of 13.9 ± 3.1 years after injury, the patients who underwent ACL reconstruction had fewer subsequent meniscal injuries, less need for further surgery, and significantly greater improvement in activity level as measured with the Tegner score. There were no significant differences in the Lysholm score, IKDC score, or development of radiographically evident osteoarthritis.
authors.affiliation: Department of Orthopaedic Surgery, Rush University Medical Center, 1611 West Harrison Street, Suite 200, Chicago, IL 60612.
authors.forename: Peter N
authors.initials: PN
authors.lastname: Chalmers
authors.affiliation: St. Louis Center for Cartilage Restoration and Repair, Regeneration Orthopedics, 6 McBride and Sons Center Drive, Suite 204, St. Louis, MO 63005. E-mail address: nathanmall@yahoo.com.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Mall
authors.affiliation: Department of Anesthesiology, Rush University Medical Center, 1653 West Congress Parkway, Jelke 7, Chicago, IL 60612.
authors.forename: Mario
authors.initials: M
authors.lastname: Moric
authors.affiliation: Department of Orthopaedic Surgery, University of Missouri, 1100 Virginia Avenue, Columbia, MO 65212.
authors.forename: Seth L
authors.initials: SL
authors.lastname: Sherman
authors.affiliation: Department of Orthopaedic Surgery, University of Missouri, 1100 Virginia Avenue, Columbia, MO 65212.
authors.forename: George P
authors.initials: GP
authors.lastname: Paletta
authors.affiliation: Department of Orthopaedic Surgery, Rush University Medical Center, 1611 West Harrison Street, Suite 200, Chicago, IL 60612.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Cole
authors.affiliation: Department of Orthopaedic Surgery, Rush University Medical Center, 1611 West Harrison Street, Suite 200, Chicago, IL 60612.
authors.forename: Bernard R
authors.initials: BR
authors.lastname: Bach
mesh_terms: D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000503:physiopathology; D007718:Knee Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000503:physiopathology; D011859:Radiography; D012086:Reoperation; D016896:Treatment Outcome