KNEE Autologous chondrocyte implantation for the treatment of chondral and osteochondral defects of the talus: a meta-analysis of available evidence Philipp Niemeyer • Gian Salzmann • Hagen Schmal • Hermann Mayr • Norbert P. Su ¨ dkamp Received: 5 June 2011 / Accepted: 13 October 2011 / Published online: 30 October 2011 Ó Springer-Verlag 2011 Abstract Purpose While autologous chondrocyte implantation (ACI) has become an established surgical treatment for cartilage defects of the knee, only little is known about the clinical outcome following ACI for chondral or osteo- chondral lesion of the ankle. To evaluate efficiency and effectiveness of ACI for talar lesions was aim of the present meta-analysis. Methods An OVID-based literature search was per- formed to identify any published clinical studies on autologous chondrocyte implantation (ACI) for the treat- ment of pathologies of the ankle including the following databases: MEDLINE, MEDLINE preprints, EMBASE, CINAHL, Life Science Citations, British National Library of Health, and Cochrane Central Register of Controlled Trials (CENTRAL). Literature search period was from the beginning of 1994 to February 2011. Of 54 studies that were identified, a total of 16 studies met the inclusion criteria of the present meta-analysis. Those studies were systematically evaluated. Results All studies identified represented case series (EBM Leven IV). 213 cases with various treatment for osteochondral and chondral defects with a mean size of 2.3 cm 2 (±0.6) have been reported. A total of 9 different scores have been used as outcome parameters. Mean study size was 13 patients (SD 10; range 2–46) with a mean follow-up of 32 ± 27 months (range 6–120). Mean Coleman Methodology Score was 65 (SD 11) points. Overall clinical success rate was 89.9%. Conclusions Evidence concerning the use of ACI for osteochondral and chondral defects of the talus is still elusive. Although clinical outcome as described in the studies available seems promising—with regard to a lack of controlled studies—a superiority or inferiority to other techniques such as osteochondral transplantation or mi- crofracturing cannot be estimated. Keywords Cartilage defect Á Autologous chondrocyte Á Ankle joint Á Meta-analysis Á Cell transplantation Á Chondrocyte Introduction Since the introduction of autologous chondrocyte implan- tation (ACI) by the group of Lars Peterson and Mats Brittberg in 1994 [7], the major focus of this new and innovative therapeutical approach for cartilage repair has always been the treatment of isolated cartilage defects of the knee [8, 15]. For the knee joint, scientific evidence has increased significantly in recent years; there are several prospective randomized trials (RCT) available which proof the effi- ciency of this surgical method. Those are summarized in some recent reviews [5, 49, 50] including three sequential systematic reviews from the Cochrane library [48, 51, 52]. Although some authors still complain about weaknesses of the individual RCTs [6], the methodology of recent ACI studies has significantly increased as indicated by the Coleman Methodology Score [5, 48, 49] compared to earlier analysis of the quality of cartilage repair studies [19]. Additionally, various authors presented long-term P. Niemeyer (&) Á G. Salzmann Á H. Schmal Á H. Mayr Á N. P. Su ¨dkamp Department for Orthopedic Surgery and Traumatology, Freiburg University Hospital, Hugstetter Str. 55, 79095 Freiburg, Germany e-mail: philipp.niemeyer@uniklinik-freiburg.de 123 Knee Surg Sports Traumatol Arthrosc (2012) 20:1696–1703 DOI 10.1007/s00167-011-1729-0