Summary of evidence of risk factors for structural knee OA (meta-analysis)
| Risk factor | Follow-up (years) and participants (n) | Phase of investigation (number of studies) | ROB* | Inconsistency | Indirectness | Imprecision | Publication bias | Upgrading factors | Modified GRADE | Certainty, direction and magnitude with structural OA |
| Sex38 74 81 89 112 | 2–37 (892) | Phase I (1) Phase II (3) | X | ✓ | X | ✓ | ✓ | X | + | Very low certainty that male sex may† ↑ OA odds up to 1.25 times (95% CI 0.92 to 1.70) |
| Rehabilitation44 61 64 71 83 87 | 5–37 (588) | Phase I (4) Phase II (2) | XX | X | ✓ | X | ✓ | X | + | Very low certainty of no difference in the OA odds between ACL tear management with rehabilitation vs ACLRc or delayed ACLRc |
| ACLRc44 61 71 83 85 87 | 5–37 (612) | Phase I (3) Phase II (3) | X | X | ✓ | X | ✓ | X | + | Very low certainty of no difference in OA odds between ACL tear management with an ACLRc or not |
| Age at ACLRc59 69 75 76 81 89 | 2–23 (1846) | Phase I (4) Phase II (2) | XX | X | X | ✓ | X | X | + | Very low certainty that each 1 year ↑ in age at ACLR may† ↑ OA odds up to 1.36 times (95% CI 0.95 to 1.96) |
| BMI at ACLRc75 81 83 84 | 2–11 (896) | Phase I (2) Phase II (2) | XX | X | X | X | X | X | + | Very low certainty of no difference in OA odds based on BMI at ACLR |
| ACLRc graft source36 38 39 46 53 56 62 66 81 | 2–17 (1166) | Phase I (2) Phase II (7) | XX | ✓ | ✓ | X | ✓ | X | + | Very low certainty of no difference in OA odds between a patellar tendon (autograft) and a semitendinosus tendon (autograft) |
| ACLRc graft augmentation40 42 43 50 | 15–25 (297) | Phase I (1) Phase II (3) | XX | ✓ | X | ✓ | X | ✓ | + | Very low certainty that ACL surgery‡ with graft augmentation may† ↓ OA odds 0.51 (0.24 to 1.05) times vs ACL surgery with no augmentation |
| Cartilage injury at ACLRc29 41 51 70 81 84 | 2–17 (1693) | Phase I (3) Phase II (4) | XX | X | ✓ | ✓ | ✓ | ✓ | + | Very low certainty that cartilage injury at ACLRc ↑ OA odds 2.31 times (1.35 to 3.94) compared with either no or less severe injury at ACLRc |
| ACLRc+partial meniscectomy29 51 75 81 | 2–17 (2007) | Phase I (1) Phase II (3) | XX | ✓ | X | ✓ | X | X | + | Very low certainty that ACLRc+partial meniscectomy ↑ OA odds 1.87 times (1.45 to 2.42) compared with ACLRc alone |
| ACLRc+medial meniscectomy38 59 69 84 | 8–23 (892) | Phase I (3) Phase II (1) | XX | ✓ | ✓ | ✓ | X | ✓ | + | Very low certainty that ACLRc+medial meniscectomy ↑ OA odds 3.14 times (2.20 to 4.48) compared with ACLRc alone |
*Assessed with QUIPS.
†95% CI include the null value and lower CI limit was ≥0.90 or upper CI limit was ≤1.1.
‡ACL surgery refers to ACL reconstruction or ACL repair.
+++, moderate-certainty evidence; +, very low-certainty evidence; ✓, no limitations; ++, low-certainty evidence; ++++, high-certainty evidence; ACL, ACL tear; ACLnoSx, ACL tear with no sx; ACLRc, ACL reconstruction; GRADE, Grading of Recommendations Assessment, Development and Evaluation; n, number; OA, osteoarthritis; PFJ, patellofemoral joint; ROB, risk of bias; SR, self-reported; Sx, surgery; TF, tibiofemoral; X, serious limitations; x, times; XX, very serious limitations.