TABLE 2.

Studies on Smoking and Knee Articular Cartilage^a

A. Basic Science Studies
Author (Year)	Journal	Type of Study	Injury	Pertinent Outcomes
Schmal et al21 (2011)	Am J Sports Med	Descriptive laboratory study	Circumscribed cartilage lesions	Synovial fluid of microfracture and ACI subjects: reduced expression of IGF-1 and bFGF in smokers vs nonsmokers

B. Clinical Studies
Author (Year)	Journal	No. of Patients (mean age, y)	Injury	Surgical Intervention	Pertinent Outcomes
Spahn et al23 (2006)	Arthroscopy	156 (51.6)	Isolated Kellgren-Lawrence grade 2 medial-compartment knee OA	Arthroscopy (debridement or microfracturing of chondral defects)	KOOS determined in all patients; outcome rated poor if score was less than 114 points or if further surgery required Smoking associated with worse outcomes (follow-up, 47–54 mo) as measured by the KOOS (OR, 3.8; 95% CI, 1.6–9.1) Rate of poor results 61.5% in nonsmokers and 83.6% in smokers (P < .001) Complication rate 2.6%; 3 patients had deep vein thromboses; 1 patient had recurrent effusion and underwent revision arthroscopy at 3 wk
Spahn et al22 (2008)	Knee Surg Sports Traumatol Arthrosc	60 (43.3)	Medial meniscus tear and idiopathic ICRS grade II defect of the medial femoral condyle	Partial meniscectomy and either bipolar radiofrequency- based chondroplasty or mechanical shaver debridement	Smokers had significantly worse KOOS outcomes than nonsmokers: debridement, nonsmokers (59.5) vs smokers (46.6; P = .02); radiofrequency chondroplasty: nonsmokers (83.9) vs smokers (73.8; P < .001)
Jaiswal et al13 (2009)	J Bone Joint Surg Br	129 (33.9)	Full-thickness condral defects	ACI with a synthetic type I/III collagen scaffold or matrix-carried procedure	Mean Modified Cincinnati Knee score was significantly lower in smokers (n = 48) than in nonsmokers (n = 66) both before and after surgery (P < .05) Smokers experienced significantly less improvement in the knee score 2 y after surgery (P < .05) Graft failures seen only in smokers (P = .02) Strong negative correlation between the number of cigarettes smoked and the outcome following surgery (Pearson correlation coefficient, 0.65, P = .004) Arthroscopically, higher proportion of excellent and good results according to ICRS scale in nonsmokers versus smokers (P = .01) Smokers were less likely to form hyaline or hyaline-like cartilage than nonsmokers, although not statistically significant owing to the low numbers of biopsies performed (P = .46)
Balain et al3 (2009)	Osteoarthritis Cartilage	53 (42 [median age])	Full-thickness chondral defects	Knee microfracture	Smoking status did not significantly affect the response shift, a change in the internal standards of a patient as determined by patient-reported function and pain scores, following microfracture
Ollat et al19 (2011)	Orthop Traumatol Surg Res	142 (31)	Osteochondral defects	Autologous osteochondral mosaicplasty	Evaluated prognostic factors associated with cartilage defects of the knee in patients treated by mosaicplasty (follow-up, 53–158 mo; mean, 96 mo) Smoking did not have significant effect on the functional results as measured by IKDC score, ICRS score, or Hughston score at final follow-up Complication rate, 13% (n = 19) including hemarthrosis (6 cases), sepsis (1 case), complex regional pain syndrome (1 case)

^aACI, autologous chondrocyte implantation; bFGF, basic fibroblast growth factor; CI, confidence interval; ICRS, International Cartilage Repair Society; IGF-1, insulin-like growth factor-1; IKDC, International Knee Documentation Committee; KOOS, Knee injury and Osteoarthritis Outcome Score; OA, osteoarthritis; OR, odds ratio.