Evidence-based status of second- and third-generation autologous chondrocyte implantation over first generation: a systematic review of level I and II studies.
OBJECTIVE
The purpose of this study was to examine the Level I and II evidence for newer generations of autologous chondrocyte implantation (ACI) versus first-generation ACI and to establish whether the newer generations have overcome the limitations associated with first-generation ACI.


METHODS
A literature search was carried out for Level I and II evidence studies on cartilage repair using the PubMed database. All the studies that dealt with ACI were identified. Only Level I and II studies that compared newer generations against earlier generations were selected, whereas studies that compared ACI against other methods of cartilage repair were excluded.


RESULTS
A total of 7 studies matched the selection criteria. Two studies compared periosteum-based autologous chondrocyte implantation (P-ACI) against collagen membrane-based autologous chondrocyte implantation (C-ACI), whereas one study each compared membrane-associated autologous chondrocyte implantation (MACI) against P-ACI and C-ACI. One study on C-ACI compared results related to age, whereas 2 studies evaluated postoperative rehabilitation after MACI. There was weak evidence showing that C-ACI is better than P-ACI and that MACI is comparable with both P-ACI and C-ACI. The weak evidence is because of studies with short durations of follow-up, small numbers of patients, medium-sized defects, and younger age groups. There is good evidence favoring an accelerated weight-bearing regimen after MACI. There is currently no evidence that supports scaffold-based ACI or arthroscopic implantation over first-generation ACI.


CONCLUSIONS
The hypothesis is thus partly proved in favor of C-ACI/MACI against P-ACI with weak evidence, in favor of accelerated weight bearing after MACI with strong evidence, and not in favor of arthroscopic and scaffold-based implantations because of unavailable evidence. LEVEL OF EVIDENCE: Level II, systematic review of Level I and II studies.
Saumya Orthocare: Centre for Advanced Surgeries of the Knee Joint, Ahmedabad, India. Electronic address: deepak@knee.in.
Deepak
D
Goyal
Anjali
A
Goyal
Sohrab
S
Keyhani
Eng Hin
EH
Lee
James H P
JH
Hui
D002358:Cartilage, Articular / Q000601:surgery*; D019902:Chondrocytes / Q000637:transplantation*; D019317:Evidence-Based Medicine / Q000379:methods*; D006801:Humans; D019637:Orthopedic Procedures / Q000379:methods; D014182:Transplantation, Autologous / Q000379:methods