Cumulative incidence of ACL reconstruction after ACL injury in adults: role of age, sex, and race

Abstract

Background: Anterior cruciate ligament (ACL) injuries are common and potentially disabling and frequently prompt surgical reconstruction. The utilization of ACL reconstruction among ACL-injured patients has not been examined rigorously.

Purpose: This study reports the 3-year cumulative incidence of ACL reconstruction among adults with ACL injury and compares demographic and clinical characteristics of ACL-injured patients who do and do not go on to undergo ACL reconstruction.

Study design: Cohort study; Level of evidence, 3.

Methods: A tertiary health care system patient data repository was used to identify patients diagnosed with an ACL injury between January 1, 2001, and December 31, 2007. Follow-up data were obtained to determine how many patients with ACL injury underwent ACL reconstruction within 3 years of ACL injury diagnosis. Stratified analyses were used to examine incidence rates separately by sex, age, race, primary language, socioeconomic status (SES), and health insurance status. Multivariable logistic regression models were built to examine the association of patient characteristics with utilization of ACL reconstruction.

Results: There were 2304 patients, with a mean age of 47 years, diagnosed with an ACL injury between 2001 and 2007. The 3-year cumulative incidence of ACL reconstruction after ACL injury diagnosis was 22.6% (95% CI, 20.9%-24.3%). Eighty-six percent of patients undergoing reconstruction did so within 6 months of injury diagnosis, while 94% underwent reconstruction within 1 year. In multivariable models, several patient features were independently associated with a higher adjusted odds of undergoing ACL reconstruction, including male sex (adjusted odds ratio [aOR], 1.4; 95% CI, 1.1-1.7), younger age (aOR per decade, 1.8; 95% CI, 1.7-2.0), white race (aOR, 1.4; 95% CI, 0.94-1.9), higher SES (aOR, 1.4; 95% CI, 1.04-1.8 for high vs low SES; aOR, 1.3; 95% CI, 1.02-1.8 for medium vs low SES), and private health insurance versus self-pay (aOR, 1.9; 95% CI, 1.04-3.5).

Conclusion: Less than a quarter of patients with a diagnosed ACL injury underwent ACL reconstruction in the 3 years after diagnosis. The odds of having surgery were higher for men, whites, younger patients, patients with higher SES, and patients with private health insurance.

Figure 1. Proportion with ACL Reconstruction Among those with Injury by Sex and Age Group

Each bar represents the proportion of the cohort, stratified by sex (dark bars for females, light bars for males) and age group (increasing from left to right) that underwent ACL reconstruction. The p-value for the interaction effect is 0.62.

Figure 2. Kaplan-Meier Curves Depicting Probability of ACL Reconstruction for Patients with ACL Injury Stratified by Sex

Each line represents the probability of undergoing reconstruction by time since first documentation of ACL Injury stratified by sex (dark line for females, light line for males). The log-rank p-value for a difference in the survival curves is < 0.001.