SEATTLE—Identification and patient education regarding modifiable risk factors may minimize the chance of a future anterior cruciate ligament (ACL) tear, according to research presented at the 2014 Annual Meeting of the American Orthopaedic Society for Sports Medicine. “Our research suggests that a few risk factors such as, age, activity level and type of graft utilized may point to the possibility of re-injury,” said lead author, Christopher C. Kaeding, MD, of the Ohio State University in Columbus, and his research colleagues.
The researchers analyzed data from 2,695 patients through the MOON ACL database from 2002 to 2008. Subjects who had a primary ACL reconstruction with no history of contralateral knee surgery and had 2-year follow-up data were included. Subjects who had multi-ligament surgery were excluded.
Graft type, age, Marx score at time of index surgery, sport played post–ACL reconstruction, sex, smoking status, lateral meniscus tear at the time of ACL reconstruction, medial meniscus tear at the time of ACL reconstruction, body mass index (BMI), and MOON site were evaluated to determine their contribution to both ipsilateral retear and contralateral ACL tear.
The analysis was repeated using the 2002 to 2003 and 2007 to 2008 cohort and included age, graft, sex, and Marx. An analysis of variance with post-hoc analysis was performed to detect significant differences in age and Marx score by graft type over time.
Study findings also indicate:
• There were 165/2801 (5.89%) ipsilateral and 177/2801 (6.32%) contralateral ACL tears identified in the cohort at the two-year follow-up.
• The odds of ipsilateral retear are 1.68 times greater for hamstring autograft (P = 0.04) and 4.67 times greater for an allograft (P < 0.001) compared to auto-BTB.
• The odds of ipsilateral retear decrease by 8% for every yearly increase in age (P < 0.001) and increases by 6% for every increased point on the Marx score (P = 0.017).
• The odds of contralateral ACL tear increase by 7% for every increased point on the Marx score (P = 0.004) and decreases by 5% for every one-point increase in BMI (P = 0.03).
• In 2002 to 2003, there were 61 out of 815 (7.5%) retears compared to 37 out of 1056 (3.5%) in 2007 and 2008.
“The study highlights that younger age, higher activity levels at time of injury, and what type of graft used (allograft) may increase risk of same side ACL injury within two years. With individuals having higher activity levels and lower age, retears on the opposite leg were more prominent,” said Dr. Kaeding. “Physicians and physical therapists need to better educate their patients about continued neuromuscular training even after the immediate rehabilitation process has ended to help prevent future tears.”