Appendix 1. Comparative studies of articular chondrocyte transplantation versus microfracture for articular cartilage lesions of the knee

Study--Level of Evidence / Number of patients / Followup / Defect size / Functional outcome / MRI findings / Histologic outcomes / Comments
Autologous chondrocyte transplantation versus microfracture
Knutsen et al [18]–I / 80–40 ACT, 40Mfx / 2 years / 2-10 cm2 / No difference in Lysholm or VAS-pain, SF-36 PCS higher in Mfx / NA / Trend toward better histology in ACT but not significant / All patients with chronic symptoms before surgery; Mfx results deteriorated in lesions > 4 cm2, whereas ACT did not
Knutsen et al [17]–I / Same / 5 years / Same / No difference in Lysholm, VAS, of SF-36 PCS / NA / NA / Patients with hyaline histology at 2 years showed no failures at 5 years
Saris et al [34]–I / 118–57 ACT, 60 Mfx / 18 months / 1-5 cm2 / No difference in KOOS scores at 12 or 18 months / NA / Better repair tissue in ACT group
Saris et al [33]–I / Same / 36 months / Same / Improved KOOS scores in ACT compared with Mfx; better outcomes in ACT when patient had preoperative symptoms < 2 years / MOCART scores no difference between groups. / NA
Vanlauwe et al [43]–I / 111–51 ACT, 60 Mfx / 5 years / Same / No difference in KOOS scores at 5 years; again better KOOS scores in ACT compared with Mfx in patients with preoperative symptoms < 3 years / NA / NA / Importance of duration of symptoms before treatment; shorter duration does better with ACT
Van Assche et al [42]–I / 67–34 ACT, 33 Mfx / 2 years / 1-5 cm2 / No difference in ROM or objective functional tests at 2 years / NA / NA / Slower recovery at time points less than 1 year for ACT, but no difference at 2 years
Matrix-assisted autologous chondrocyte transplantation versus Microfracture
Kon et al [21]–II
Hyalograft C / 80–40 MACT, 40 Mfx / 5 years / 1-5 cm2 / Greater improvement in IKDC subjective and objective in MACT group; better return to sports at 5 years in the MACT group / NA / NA
Basad et al [4]–I
Chondro-gide / 60–40 MACT, 20 Mfx / 2 years / 4-10 cm2 / Greater improvement in Lysholm, Tegner, ICRS patient score, and ICRS surgeon score in the MACT group / NA / NA
Kon et al [19]–II
Hyalograft C / 41–21 MACT, 20 Mfx / Mean 7.5 years – ACT 5-10 years, Mfx 4-12 years / Greater than 1 cm2 / Better IKDC subjective scores in MACT at final followup; scores decreased in the Mfx group from 2 years to final followup / NA / NA / Professional soccer players; return to competition quicker in Mfx but more durable results in MACT
Crawford et al [6]–I
Neocart / 30–21 MACT, 9 Mfx / 2 years / Linear dimension between 1 and 3 cm / More therapeutic responders in MACT group; greater improvement in KOOS pain, KOOS sports, KOOS quality of life, IKDC and VAS pain in MACT group / NA / NA
Saris et al [32]–I
Chondro-gide / 137–70 MACT, 67 Mfx / 2 years / Greater than 1 cm2 / Greater improvement in KOOS all KOOS subscales, Cincinnati knee score, and SF-12 PCS in MACT group compared with Mfx / No difference in degree of defect fill / No difference in histologic score between groups

ACT -= autologous chondrocyte transplantation; Mfx = microfracture; MACT = matrix-assisted chondrocyte transplantation; KOOS = Knee Injury and Osteoarthritis Outcome Score; IKDC = International Knee Documentation Committee; VAS = visual analog scale; ICRS = International Cartilage Repair Society; MOCART = MR Observation of Cartilage Repair Tissue; PCS = Physical Component Summary; NA = not applicable.