title: The Fate of Meniscus Tears Left In Situ at the Time of Anterior Cruciate Ligament Reconstruction: A 6-Year Follow-up Study From the MOON Cohort.
abstract: BACKGROUND
  The management of meniscus tears identified at the time of primary anterior cruciate ligament (ACL) reconstruction is highly variable and includes repair, meniscectomy, and nontreatment.
  
  
  OBJECTIVE
  The purpose of this study was to determine the reoperation rate for meniscus tears left untreated at the time of ACL reconstruction with a minimum follow-up of 6 years. The hypothesis was that small peripheral tears identified at the time of ACL reconstruction managed with "no treatment" would have successful clinical outcomes.
  
  
  METHODS
  Cohort study; Level of evidence, 3.
  
  
  METHODS
  Patients with meniscus tears left untreated at the time of primary ACL reconstruction were identified from a multicenter study group with a minimum 6-year follow-up. Patient, tear, and reoperation data were obtained for analysis. The need for reoperation was used as the primary endpoint, with analysis performed to determine patient and tear characteristics associated with reoperation.
  
  
  RESULTS
  There were 194 patients with 208 meniscus tears (71 medial, 137 lateral) left in situ without treatment with a complete follow-up for analysis. Of these, 97.8% of lateral and 94.4% of medial untreated tears required no reoperation. Sixteen tears (7.7%) left in situ without treatment underwent subsequent reoperation: 9 tears (4.3%) underwent reoperation in the setting of revision ACL reconstruction, and 7 tears (3.4%) underwent reoperation for an isolated meniscus injury. The patient age was significantly lower in patients requiring reoperation, while tears measuring ≥10 mm more frequently required reoperation.
  
  
  CONCLUSIONS
  Lateral and medial meniscus tears left in situ at the time of ACL reconstruction did not require reoperation at a minimum 6-year follow-up for 97.8% and 94.4% of tears, respectively. These findings re-emphasize the low reoperation rate after the nontreatment of small, peripheral lateral meniscus tears while noting less predictable results for medial meniscus tears left without treatment.
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA.
authors.forename: Kyle R
authors.initials: KR
authors.lastname: Duchman
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Westermann
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors.forename: Kurt P
authors.initials: KP
authors.lastname: Spindler
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors.forename: Emily K
authors.initials: EK
authors.lastname: Reinke
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Huston
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA.
authors.forename: Annunziato
authors.initials: A
authors.lastname: Amendola
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA brian-wolf@uiowa.edu.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Wolf
mesh_terms: D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007718:Knee Injuries / Q000601:surgery*; D007719:Knee Joint / Q000601:surgery; D008297:Male; D011446:Prospective Studies; D012086:Reoperation; D012421:Rupture / Q000601:surgery; D000070600:Tibial Meniscus Injuries; D055815:Young Adult
keywords: anterior cruciate ligament (ACL) reconstruction; in situ; meniscus; nontreatment