Morphological Assessment of MACI Grafts in Patients with Revision Surgery and Total Joint Arthroplasty

Abstract

Objective To compare the histological and immunohistochemical characteristics of matrix-assisted chondrocyte implantation (MACI) grafts between patients with revision surgery and patients with total joint arthroplasty. Methods Biopsies of MACI grafts from patients with revision and total joint arthroplasty. The graft tissue characteristics and subchondral bone were examined by qualitative histology, ICRS (International Cartilage Repair Society) II scoring and semiquantitative immunohistochemistry using antibodies specific to type I and type II collagen. Results A total of 31 biopsies were available, 10 undergoing total knee arthroplasty (TKA) and 21 patients undergoing revision surgery. Patients in the clinically failed group were significantly older (46.3 years) than patients in the revision group (36.6 years) ( P = 0.007). Histologically, the predominant tissue in both groups was of fibrocartilaginous nature, although a higher percentage of specimens in the revision group contained a hyaline-like repair tissue. The percentages of type I collagen (52.9% and 61.0%) and type II collagen (66.3% and 42.2%) were not significantly different between clinically failed and revised MACI, respectively. The talar dome contained the best and patella the worst repair tissue. Subchondral bone pathology was present in all clinically failed patients and consisted of bone marrow lesions, including edema, necrosis and fibrosis, intralesional osteophyte formation, subchondral bone plate elevation, intralesional osteophyte formation, subchondral bone cyst formation, or combinations thereof. Conclusions MACI grafts in patients with revision and total joint arthroplasty were predominantly fibrocartilage in repair type, did not differ in composition and were histologically dissimilar to healthy cartilage. Clinically failed cases showed evidence of osteochondral unit failure, rather than merely cartilage repair tissue failure. The role of the subchondral bone in relation to pain and failure and the pathogenesis warrants further investigation.

Mesenchymal Stem Cell Therapy Combined with Arthroscopic Abrasion Arthroplasty Regenerates Cartilage in Patients with Severe Knee Osteoarthritis: A Case Series

“…Limited subchondral cyst formation was observed in some participants in zones beneath the area of chondral regeneration or at the interface of regenerative and native cartilage. These cysts were stable between 12 and 36+ months and have been observed in other cartilage graft techniques including Matrix-induced Autologous Chondrocyte Implantation and microfracture [67].…”

Knee articular cartilage injury treatment with matrix-induced autologous chondrocyte implantation (MACI): correlation at 24 and 120 months between clinical and radiological findings using MR arthrography

“…Recently, Beck et al, with the histological evaluation on MACI implants, observed that all failed implants were characterized by fibrous involution independently from patients' clinical conditions [28]. Those results may explain the poor correlation we observed between clinical and radiological scores at long-term FU.…”

Cyst formation in the subchondral bone following cartilage repair

“…McCarthy et al found subchondral bone cysts under the lesion area in 14.7% patients treated with either first-or second-generation ACI at 1 year postoperatively, 25 considerably lower than the data from previous cohorts treated with microfracture (38.5% at 1 year postoperatively) from Cole et al 58 Correspondingly, a recent clinical investigation from biopsies of patients undergoing total knee arthroplasty as a salvage procedure for failed second-generation ACI with an average graft survival period of 26.8 months identified subchondral bone cyst formation within 20% of patients. 61 In a 9-18 years follow-up study, subchondral cysts were reported in 38.8% knee defects treated with firstgeneration ACI. 59 Merkeley et al identified the presence of severe BME (grade IV) as a predictive factor for graft failure (n = 8) among patients (n = 38) receiving a salvage second-generation knee ACI for failed prior marrow stimulation.…”

“…dral bone changes in the context of cartilage repair exposed variable patterns, including the formation of subchondral bone cysts (Figure 1), intralesional osteophytes, generalized upward migration of the subchondral bone plate, and the presence of residual marrow stimulation hole(s), together with peri-hole or generalized bone resorption (Table 1). 51,52 With a view of systematically exploring each of these morphologic changes in both preclinical 46,47,[53][54][55][56][57] and clinical 25, [58][59][60][61][62][63][64][65][66] settings, an adjustable algorithm has been recently proposed to radiographically analyze them ( Figure 2). 52 In this algorithm, the projected tidemark and cement line serve as topographical landmarks.…”

“…Penetrations of the subchondral bone resulting from microfracture 58 or subchondral drilling 116 might serve as their basis. Subchondral cyst formation has also been associated with other cartilage repair procedures, among which ACI 25,59–61 and autologous or allogeneic OCT (Table 2). 62–64 Stem cell therapy, a promising approach for cartilage repair, has not been associated with subchondral bone cyst formation based on the currently available literature and was therefore excluded from the current review.…”