TABLE 1.
Studies on Smoking and Knee Ligamentsa
| A. Basic Science Studies
| ||||
|---|---|---|---|---|
| Author (Year) | Journal | Type of Study | Injury | Outcomes |
| Gill et al11 (2006) | J Orthop Res | Animal model (mouse) | MCL | Smoking decreased cellular density and type I collagen expression in injured MCL of mice exposed to cigarette smoke versus control mice not exposed to cigarette smoke |
| Wright et al27 (2010) | J Knee Surg | Animal model (mouse) | MCL | MCL of mice exposed to cigarette smoke were biomechanically weaker and less stiff than the ligaments of control mice |
| B. Clinical Studies
| |||||
|---|---|---|---|---|---|
| Author (Year) | Journal | No. of Patients (mean age, y) | Injury | Surgical Intervention | Pertinent Outcomes |
| Dunn et al8 (2003) | J Bone Joint Surg Am | 2192 (28) | ACL | Diagnostic arthroscopy or ACLR | The outcome of interest was development of disability following the initial hospitalization related to an ACL injury Cigarette smoking was significantly correlated (P =.01) to a significantly higher rate of disability discharge from active duty following an ACL injury (10% of all ACL injuries) |
| Karim et al15 (2006) | J Bone Joint Surg Br | 304 (32.8) | ACL | ACLR | Smokers had worse outcomes for the mean subjective IKDC score (P < .001), the frequency (P = .005), and intensity (P = .005) of pain Smokers were also less likely to return to their original level of pre-injury sport (P = .003) and had an overall worse IKDC grade score (P = .007), a calculation based on effusion, deficit in passive movement, ligament examination, compartment findings, pathology of the harvest site, radiological findings, and functional knee tests Smokers had more objective laxity as measured by Westminster cruciometry recordings (P = .001) |
| Kowalchuk et al16 (2009) | Arthroscopy | 402 (27.3) | ACL | ACLR | Subjective IKDC scores were used to measure patient-reported outcomes following ACL reconstruction Lower patient-reported outcomes were associated with smoking, as smokers had 0.36 times the odds of having a successful outcome as subjects who did not smoke (P = .02) |
| Dunn et al9 (2010) | Am J Sports Med | 390 (27) | ACL | ACLR | Smoking within 6 mo prior to an ACL reconstruction was associated with lower postoperative activity levels at a follow-up of 2 y as measured by the Marx activity level (OR, 0.55; 95% CI, 0.33–0.92; P = .02) |
| Spindler et al24 (2011) | Am J Sports Med | 378 (27) | ACL | ACLR | Six years after ACL reconstruction, smoking was correlated with worse outcomes across several measures, including a longer return to sports function and knee-quality of life (as measured by IKDC and KOOS) |
| Li et al17 (2011) | Am J Sports Med | 249 (26.4) | ACL | ACLR | Attempted to determine the overall prevalence of and risk factors for the development of radiographic knee OA using the Kellgren-Lawrence scale after single-bundle ACL reconstruction Reported that smoking was not a statistically significant risk factor (P = .18) for the development of knee OA |
a
ACL, anterior cruciate ligament; ACLR, anterior cruciate ligament reconstruction; CI, confidence interval; IKDC, International Knee Documentation Committee; KOOS, Knee injury and Osteoarthritis Outcome Score; MCL, medial collateral ligament; OA, osteoarthritis; OR, odds ratio.