Matrix-induced autologous chondrocyte implantation for the treatment of chondral defects of the knees in Chinese patients

Abstract

Articular cartilage injury is the most common type of damage seen in clinical orthopedic practice. The matrix-induced autologous chondrocyte implant (MACI) was developed to repair articular cartilage with an advance on the autologous chondrocyte implant procedure. This study aimed to evaluate whether MACI is a safe and efficacious cartilage repair treatment for patients with knee cartilage lesions. The primary outcomes were the Knee Injury and Osteoarthritis Outcome Score (KOOS) domains and magnetic resonance imaging (MRI) results, compared between baseline and postoperative months 3, 6, 12, and 24. A total of 15 patients (20 knees), with an average age of 33.9 years, had a mean defect size of 4.01 cm(2). By 6-month follow-up, KOOS results demonstrated significant improvements in symptoms and knee-related quality of life. MRI showed significant improvements in four individual graft scoring parameters at 24 months postoperatively. At 24 months, 90% of MACI grafts had filled completely and 10% had good-to-excellent filling of the chondral defect. Most (95%) of the MACI grafts were isointense and 5% were slightly hyperintense. Histologic evaluation at 15 and 24 months showed predominantly hyaline cartilage in newly generated tissue. There were no postoperative complications in any patients and no adverse events related to the MACI operation. This 2-year study has confirmed that MACI is safe and effective with the advantages of a simple technique and significant clinical improvements. Further functional and mechanistic studies with longer follow-up are needed to validate the efficacy and safety of MACI in patients with articular cartilage injuries.

Keywords: KOOS; Knee Injury and Osteoarthritis Outcome Score; MRI; articular cartilage lesion; magnetic resonance imaging.

Figure 1

MRI of the knee joint before and after the MACI operation. Notes: (A) The cartilage defect region before surgery (yellow arrow), and (B) complete filling of the defect area at 6 months after surgery. Abbreviations: MACI, matrix-induced autologous chondrocyte implantation; MRI, magnetic resonance imaging.

Figure 2

Arthroscopic images in two patients before operation and at 6 and 24 months after surgery. Notes: (A) Preoperative image of the articular cartilage defect with a rough surface, (B) at 6 months after surgery, the defect was filled with new repair tissue that had a smooth surface and good integration, (C) the cartilage defect in another patient preoperatively, and (D) image at 24 months after surgery; the color, luster, and hardness of the newly generated repair tissue were comparable to those of healthy cartilage, and the repair tissue was integrated well with the surrounding cartilage.

Figure 3

Histologic examination of the biopsies. Notes: (A) Biopsy of the generated repairing tissue, (B) alcian blue stain (×200), (C) hematoxylin and eosin stain (×40), and (D) hematoxylin and eosin stain (×200) of repairing tissue at 15 months after surgery, which show the predominance of hyaline-like repair tissue. Hyaline cartilage, cartilage lacuna, and infantile chondrocytes are indicated by arrows.