Typical MRI-pattern suggests peak maturation of the ACI graft 2 years after third-generation ACI: a systematic review

Abstract

PurposeThe purpose of the present article was (1) to systematically review the current literature and (2) to collect data regarding the postoperative magnetic resonance imaging (MRI) appearance of third-generation autologous chondrocyte implantation (ACI) grafts and (3) to provide an overview of imaging findings at various postoperative time points. Methods A systematic review of the literature in Medline (Pubmed) and Embase was performed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Articles which reported the post-operative MRI morphological outcomes following the use of third-generation ACI for treatment of knee cartilage lesions were included. All MRI results were allocated to six different time intervals: ≤ 3 months, > 3-6 months, > 6 months-1 year, > 1 year-2 years, > 2-5 years and > 5 years after surgery. Results A total of 22 studies were included and the study populations ranged from 13 to 180 patients adding up to a total of 951 patients. Parameters such as defect fill, border integration, surface contour, graft morphology and integrity of the subchondral lamina all improve gradually with a peak two years following surgery suggesting complete graft maturation at this time point. After this peak, a statistically insignificant decline is noted for most of the parameters. Signal intensity was found to gradually shift from hyperintense to isointense in the first 36 months and to hypointense later on. Contrarily, subchondral bone edema is not only a postoperative feature of the procedure but also can reappear or persist up to ten years after surgery. As graft failures can appear after two years, consequently, the MRI composite score is also affected. Conclusion Recurring patterns in postoperative MRI appearance were observed in certain parameters including defect filling, graft signal intensity and structure, border integration of the graft while parameters like subchondral bone tend to be unpredictable. Given the heterogenous findings in terms of clinical correlation, and relating that aspect to the patterns found in this review, an MRI is justified at three months, one year, two years and five years after surgery, unless the clinical symptomatology and individual patient needs dictate otherwise. Level of evidence IV.

Treatment of cartilage defects in the patellofemoral joint with matrix-associated autologous chondrocyte implantation effectively improves pain, function, and radiological outcomes after 5–7 years

“…None of the patients had an effusion, indicating that the transplanted tissue had successfully integrated into the joint. These findings align well with previously published data [ 8 , 9 , 18 , 24 , 26 , 33 ]. Zak et al [ 8 ] published the findings for a mixed but otherwise very similar cohort consisting of 23 patients with a follow-up period of up to two years after MACI using the Novocart® 3D scaffold.…”

“…For MACI in the PF joint, however, comprehensive prospective mid- and long-term data, especially clinical data with detailed MRI scores, are currently lacking [ 9 – 12 ]. Thus, the aim of the present study was to prospectively evaluate clinical and MRI outcomes over a minimum of 5 years following MACI using the Novocart® 3D matrix for PF cartilage defects.…”

Matrix-assisted autologous chondrocyte transplantation for treatment of focal chondral lesions in the knee: the Hospital Israelita Albert Einstein experience

“…Moreover, the 2-year follow-up is important because it is the time considered necessary for the graft to reach the expected maturity. (26) The main limitations of this study were the small sample size and the lack of a control group, which do not allow conclusions as to the efficacy of the method. A protocol for a new phase 2 study with a larger sample size and control group is already being prepared.…”

Structural and Molecular Changes of Human Chondrocytes Exposed to the Rotating Wall Vessel Bioreactor

“…Tissue engineering of cartilage and restoration of cartilage defects are currently hot topics in translational regenerative medicine. Known techniques are cell-based approaches, such as autologous chondrocyte implantation [5,6], matrix-induced autologous chondrocyte implantation [7], or tissue-engineered cartilage implantation [8,9]. Several bio-printing approaches and bioreactors for tissue engineering of cartilage are currently available and reviewed in [10].…”