Smallest worthwhile effect of anterior cruciate ligament reconstruction compared with non-surgical management: a benefit-harm trade-off study.

QUESTIONS: What is the estimated smallest worthwhile effect of anterior cruciate ligament (ACL) reconstruction followed by rehabilitation for improving knee function and return to sport compared with rehabilitation only? What are the associations between participant characteristics (age, gender, health insurance status, sports participation level, preference for surgery versus non-surgical management, previous ACL rupture) and these smallest worthwhile effect estimates?

DESIGN

Benefit-harm trade-off study conducted via an online survey.

PARTICIPANTS

A total of 92 people engaged in recreational or competitive sport.

DATA COLLECTION: Participants provided demographic information and answered two benefit-harm trade-off scenarios: a knee function scenario and a return to sport scenario. Participants indicated the minimum additional percentage improvement they would require for ACL reconstruction to be worthwhile compared with the anticipated percentage improvement with rehabilitation only. The expected benefits of rehabilitation only were based on published trial data. Associations between these smallest worthwhile effect estimates and participant characteristics were investigated using univariable regression models.

RESULTS

The median smallest worthwhile effect was 12% (IQR 8 to 16) for knee function and 41% (IQR 35 to 47) for return to sport. Smallest worthwhile effects were slightly higher for those participating in competitive sport. Age was associated with smallest worthwhile effect for the knee function scenario (0.3% increase per year older, 95% CI 0.1 to 0.4), although the size of this effect may not be clinically relevant. None of the tested predictors were associated with the smallest worthwhile effect for the return to sport scenario.

CONCLUSION

This study is the first to estimate the smallest worthwhile effect of ACL reconstruction. Participants require an additional 12% improvement in knee function or a 41% increase in the likelihood of returning to sport to justify undergoing ACL reconstruction. Therefore, the effects of surgery reported in many studies fall below what patients consider to be worthwhile.

REGISTRATION: OSF; https://osf.io/2kn97/.