Risk Factors for Knee Osteoarthritis After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis.

BACKGROUND

The incidence of knee osteoarthritis (KOA) after anterior cruciate ligament (ACL) reconstruction (ACLR) is high, posing significant challenges to long-term joint health and overall quality of life. Identifying and understanding the risk factors associated with postoperative KOA are crucial for improving surgical outcomes and guiding preventive strategies.

PURPOSE: To perform a systematic review and meta-analysis to investigate the risk factors for KOA after ACLR.

STUDY

DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review with meta-analysis was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. There were 3 databases (PubMed, Embase, and Web of Science) searched from inception to September 2024. All prospective and retrospective studies investigating the risk factors for KOA after ACLR were considered. The odds ratio (OR) or weighted mean difference (WMD) was calculated for potential risk factors if ≥2 studies assessed the same risk factor. Variables that could not be subjected to a meta-analysis were qualitatively analyzed.

RESULTS

A total of 39 studies met the inclusion criteria, with a combined sample size of 46,545, and 35 studies were subjected to a meta-analysis. The incidence of KOA after ACLR ranged from 2.34% to 100.00%, with a mean incidence of 8.29%. Overall, 9 factors were associated with an increase in the risk of KOA after ACLR: older age (WMD, 3.30 [95% CI, 2.33-4.28]), male sex (OR, 1.41 [95% CI, 1.14-1.74]), a higher body mass index (WMD, 1.31 [95% CI, 0.34-2.27]), bone-patellar tendon-bone autografts (OR, 1.66 [95% CI, 1.11-2.50]), a longer interval between ACL injury and surgery (WMD, 1.09 [95% CI, 0.55-1.63]), meniscectomy (OR, 2.42 [95% CI, 2.01-2.91]), meniscal injuries (OR, 3.35 [95% CI, 2.06-5.45]), additional injuries (OR, 3.65 [95% CI, 1.74-7.68]), and chondral lesions at the time of ACLR (OR, 2.15 [95% CI, 1.43-3.24]).

CONCLUSION

Older age, male sex, a higher body mass index, bone-patellar tendon-bone autografts, meniscectomy, a longer interval between ACL injury and surgery, and concomitant other injuries (meniscal or chondral) may increase the risk of KOA after ACLR. An increased awareness of relevant risk factors and targeted preventive strategies for modifiable risk factors can effectively reduce the incidence of KOA after ACLR.