AAOS Now

Published 8/2/2022
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Ariel DeMaio

Delaying ACL Reconstruction by Seven Weeks or More is Associated with Lower Risk of Arthrofibrosis

For patients aged younger than 40 years who planned to undergo reconstruction for a torn anterior cruciate ligament (ACL), delaying the procedure by seven weeks was associated with a lower risk of developing arthrofibrosis, which may ultimately require revision, according to a study from researchers in the department of orthopaedic surgery at George Washington University School of Medicine. Patients aged 40 years or older had a similar benefit if they delayed ACL reconstruction (ACLR) by 11 weeks.

Study coauthor Amil Agarwal, BA, a third-year medical student at George Washington University School of Medicine and Health Sciences, presented the findings at the AAOS 2022 Annual Meeting.

ACLR is a common arthroscopic procedure that can require up to a year of rehabilitation. Despite its frequency, though, the optimal time to perform the procedure—whether immediately after initial onset of injury or later to allow inflammation in the affected area to lessen—has not been established, and most research on the matter involves small patient populations.

“The literature supports delaying reconstruction following ACL tears to increase preoperative range of motion to minimize the risk of arthrofibrosis,” Mr. Agarwal told AAOS Now. “However, there are no guidelines that give specific time cut-offs that tell how long to delay reconstruction, nor any studies observing whether there is a difference with respect to age.”

With this study, Mr. Agarwal and colleagues evaluated postoperative outcomes and the time between diagnosis of ACL tear and eventual surgery while controlling for baseline patient factors. They collected data from a large national insurance database on patients who underwent ACLR from 2010 to 2019. To understand whether age impacted the optimal time interval, the researchers stratified patients into two cohorts: younger (age 10 to 39 years) and older (age 40 to 80 years), according to age during reconstruction. Stratum-specific likelihood ratio (SSLR) analysis was conducted to determine the optimal time intervals from initial ACL injury to reconstruction to minimize arthrofibrosis risk.

Data from 15,645 patients were analyzed—11,554 (73.9 percent) were in the younger cohort, and 4,091 (26.1 percent) were in the older cohort.

In the younger cohort, SSLR analysis defined the intervals of one to six weeks and seven to 26 weeks from injury to reconstruction as the period to optimize differences in arthrofibrosis. Notably, manipulation under anesthesia (MUA) and arthroscopic lysis of adhesions (ALOA) were used as surrogates for arthrofibrosis. The optimal interval was even longer in the older cohort, at one to 10 weeks and 11 to 26 weeks.

For both the younger and older cohorts, multivariate analysis revealed that those with the defined delayed interval had lower odds of combined two-year MUA and ALOA when compared to the defined acute interval, the researchers reported. “Specifically, patients aged younger than 40 years had 0.7 times lower odds of arthrofibrosis if they delayed by seven weeks or more. For those aged 40 years and older, these patients had 0.4 times lower odds of arthrofibrosis if they delayed by 11 weeks or more,” Mr. Agarwal said.

He added that the team did not initially expect that the longer delayed interval of seven weeks would lead to the arthrofibrosis benefit in patients aged younger than 40 years and offered the variation of age in patients who are younger than 40 years as a potential explanation.

Pointing to limitations of the study and areas of future exploration, Mr. Agarwal noted that the researchers were unable to perform a subgroup analysis of patients younger than 40 years due to underpowered cohorts. “Future works can repeat this similar analysis in more age-stratified intervals of 10 to 19 years, 20 to 29 years, and 30 to 39 years. We expect a lower delay needed in younger patients.”

Mr. Agarwal’s coauthors of “Timing of Anterior Cruciate Ligament Reconstruction and Risk of Revision Surgery” are Samrat Choudhury, MD; Sophie Bernstein; Alisa Malyavko; Alex Gu, MD; Savyasachi C. Thakkar, MD; and Teresa Elizabeth Doerre, MD.

Ariel DeMaio is the former managing editor of AAOS Now.