Surgical reconstruction for nonacute ACL injuries has slightly better outcomes than rehabilitation (ACL SNNAP)

Reference

Beard DJ, Davies L, Cook JA, et al, for the ACL SNNAP Study Group. Rehabilitation versus surgical reconstruction for non-acute anterior cruciate ligament injury (ACL SNNAP): a pragmatic randomised controlled trial. Lancet 2022;400(10352):605-615.

Synopsis

In this unmasked pragmatic trial that took place in 29 centers across the United Kingdom, researchers randomized adults with instability consistent with an anterior cruciate ligament (ACL) injury to receive a minimum of 3 months of rehabilitation (n = 160) or reconstructive surgery (n = 156). They excluded patients with meniscal injuries that required surgery (eg, bucket handle tears) or advanced degenerative joint disease. The primary outcome, the Knee Injury and Osteoarthritis Outcome Score (KOOS), was evaluated at baseline and every 6 months until 18 months after enrollment. The KOOS has a few variations, but it is a validated scale with a range from 0 to 100, and it assesses pain, function, and quality of life. Low KOOS scores are bad, and 8 to 10 points is the minimum clinically important difference (MCID). The MCID for the KOOS is a little lower than the generally accepted 10% to 15%. A total of 22% of the original 316 participants either withdrew or were lost to follow-up. (A number greater than 20% creates a worrisome amount of bias). After 18 months, each group improved, and the group treated surgically had a greater degree of improvement (KOOS mean difference 7.9; 95% CI 2.5 - 13.2), although, on average, this does not quite meet the MCID threshold. I would have loved to see the authors report the proportion of participants in each group who experienced clinically meaningful improvements. Among patients treated with rehabilitation, 41% eventually underwent surgery. Of the 156 patients initially randomized to surgery, 43 (28%) didn’t get it: 11 (26% of those not getting surgery) were still on the wait list. Finally, the authors report that no serious adverse events occurred during the study period.