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Incidence of Anterior Cruciate Ligament Tears and Reconstruction: a 21-Year Population-Based Study.

·Am J Sports Med·2016·1,285 citations·Sports Medicine
DOI·PubMed
SummaryAbstract on PubMed →

This 21-year population-based cohort used the Rochester Epidemiology Project to define the general-population incidence of isolated ACL tears. It asks how often ACL tears occur, how incidence varies by age and sex, and how reconstruction rates changed over two decades.

Study Snapshot

Design
Population-based cohort
Setting: Olmsted County, Minnesota (REP)
Funding: NIH (NIA)
Objective
Whether ACL injury incidence and subsequent reconstruction rates increase over time in the general population.
Outcome(s)
Age- and sex-adjusted annual incidence of isolated ACL tears
Subjects
1841 isolated ACL tears
Inclusion
  • New-onset complete isolated ACL tear
  • Olmsted County resident at injury
  • Diagnosed 1990-2010
Exclusion
  • Partial ACL tear or concurrent PCL tear
  • Femur/tibia fracture or knee dislocation
  • Chronic tear (>1 year before diagnosis)
Follow-up
21-year observation period (1990-2010)
Statistics
Poisson regressionSmoothing splinesAge/sex adjustment

Key Findings

  • The overall age- and sex-adjusted annual incidence of isolated ACL tears was 68.6 per 100,000 person-years (95% CI, 65.4-71.8) across 1841 cases, anchoring the scope of this injury in the general population, not just athletes.
  • Incidence was higher in males than females at 81.7 vs 55.3 per 100,000 (P < .001). This sex difference is a high-yield board fact.
  • Age peaks differed by sex: females peaked at 14-18 years (227.6 per 100,000) while males peaked at 19-25 years (241.0 per 100,000). The authors attribute this to females being concentrated in high school competitive sports and males continuing in college, intramural, and club sports.
  • ACL injury incidence actually declined in males (96.0 to 70.9 per 100,000, P < .001) and stayed stable in females over 21 years. Counterintuitively, fewer injuries were occurring even as more surgery was performed.
  • Reconstruction within 1 year of injury rose sharply in every age group (P < .001), reaching about 75% by 2005-2010 and 98.3% in patients under 18. The authors conclude rising surgery reflects treatment trends, not more injuries.
  • Nearly 60% of acute ACL tears had a concurrent meniscal tear at presentation (medial 30%, lateral 20.5%, both 9.2%), reinforcing that the ACL injury rarely occurs in isolation.
  • MRI confirmed the tear in 94.6% of clinically diagnosed cases, supporting MRI as the confirmatory study.
Board PearlIsolated ACL tears occur in about 69 per 100,000 person-years, with males peaking at 19-25 years and females at 14-18 years.

Clinical Relevance

Memorize the headline number: isolated ACL tears occur at roughly 69 per 100,000 person-years in the general population. This is the population-based denominator, distinct from the higher rates reported in select athletic cohorts.

The sex-specific age peaks are testable and clinically useful. Expect ACL injury in females during the high school window (14-18) and in males a few years later (19-25), tracking with sports participation.

The paper's central teaching point: rising ACL reconstruction volume does not mean rising injury rates. Injury incidence declined in males and was stable in females, yet surgery rates climbed across all ages. Use this to separate epidemiology from treatment-pattern shifts.

The near-universal reconstruction rate in patients under 18 (98.3%) reflects a strong bias toward surgery in skeletally immature and young patients, consistent with concern for meniscal and chondral protection. Finally, the 60% concurrent meniscal injury rate is a reminder to scrutinize the menisci on MRI and at arthroscopy in every acute ACL tear.

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|

Incidence of Anterior Cruciate Ligament Tears and Reconstruction: a 21-Year Population-Based Study.

·Am J Sports Med·2016·1,285 citations·Sports Medicine
DOI·PubMed
SummaryAbstract on PubMed →

This 21-year population-based cohort used the Rochester Epidemiology Project to define the general-population incidence of isolated ACL tears. It asks how often ACL tears occur, how incidence varies by age and sex, and how reconstruction rates changed over two decades.

Study Snapshot

Design
Population-based cohort
Setting: Olmsted County, Minnesota (REP)
Funding: NIH (NIA)
Objective
Whether ACL injury incidence and subsequent reconstruction rates increase over time in the general population.
Outcome(s)
Age- and sex-adjusted annual incidence of isolated ACL tears
Subjects
1841 isolated ACL tears
Inclusion
  • New-onset complete isolated ACL tear
  • Olmsted County resident at injury
  • Diagnosed 1990-2010
Exclusion
  • Partial ACL tear or concurrent PCL tear
  • Femur/tibia fracture or knee dislocation
  • Chronic tear (>1 year before diagnosis)
Follow-up
21-year observation period (1990-2010)
Statistics
Poisson regressionSmoothing splinesAge/sex adjustment

Key Findings

  • The overall age- and sex-adjusted annual incidence of isolated ACL tears was 68.6 per 100,000 person-years (95% CI, 65.4-71.8) across 1841 cases, anchoring the scope of this injury in the general population, not just athletes.
  • Incidence was higher in males than females at 81.7 vs 55.3 per 100,000 (P < .001). This sex difference is a high-yield board fact.
  • Age peaks differed by sex: females peaked at 14-18 years (227.6 per 100,000) while males peaked at 19-25 years (241.0 per 100,000). The authors attribute this to females being concentrated in high school competitive sports and males continuing in college, intramural, and club sports.
  • ACL injury incidence actually declined in males (96.0 to 70.9 per 100,000, P < .001) and stayed stable in females over 21 years. Counterintuitively, fewer injuries were occurring even as more surgery was performed.
  • Reconstruction within 1 year of injury rose sharply in every age group (P < .001), reaching about 75% by 2005-2010 and 98.3% in patients under 18. The authors conclude rising surgery reflects treatment trends, not more injuries.
  • Nearly 60% of acute ACL tears had a concurrent meniscal tear at presentation (medial 30%, lateral 20.5%, both 9.2%), reinforcing that the ACL injury rarely occurs in isolation.
  • MRI confirmed the tear in 94.6% of clinically diagnosed cases, supporting MRI as the confirmatory study.
Board PearlIsolated ACL tears occur in about 69 per 100,000 person-years, with males peaking at 19-25 years and females at 14-18 years.

Clinical Relevance

Memorize the headline number: isolated ACL tears occur at roughly 69 per 100,000 person-years in the general population. This is the population-based denominator, distinct from the higher rates reported in select athletic cohorts.

The sex-specific age peaks are testable and clinically useful. Expect ACL injury in females during the high school window (14-18) and in males a few years later (19-25), tracking with sports participation.

The paper's central teaching point: rising ACL reconstruction volume does not mean rising injury rates. Injury incidence declined in males and was stable in females, yet surgery rates climbed across all ages. Use this to separate epidemiology from treatment-pattern shifts.

The near-universal reconstruction rate in patients under 18 (98.3%) reflects a strong bias toward surgery in skeletally immature and young patients, consistent with concern for meniscal and chondral protection. Finally, the 60% concurrent meniscal injury rate is a reminder to scrutinize the menisci on MRI and at arthroscopy in every acute ACL tear.

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