Arthroscopic Matrix-Induced Autologous Chondrocyte Implantation

Abstract

Matrix-induced autologous chondrocyte implantation (MACI) is an established technique to treat articular cartilage defects in the knee. Traditionally, the chondral graft is harvested arthroscopically and then implanted via an open or mini-open technique. However, an arthroscopic implantation technique carries with it the potential for reduced pain, improved rehabilitation, and reduced arthrofibrosis. The arthroscopic implantation first involves a standard arthroscopic biopsy followed by cell culture and seeding onto a collagen membrane. The implantation procedure itself is performed 6–8 weeks later. A standard arthroscopy is performed and the defect is debrided to stable vertical walls using curettes and arthroscopic shavers. All irrigation fluid is subsequently evacuated such that the rest of the procedure is performed as a dry arthroscopy. The defect is sized using a graduated probe. If required, a template may be cut out of the supplied membrane. A wide-bore valveless cannula, inserted through the working portal, permits the repeated atraumatic passage of the prepared membrane. The probe is used to position the graft and check for size. A definitive graft is then cut and placed in the knee. Fibrin glue is applied to the base of the defect, the membrane is positioned, and an embolectomy or indwelling catheter balloon is inflated to apply even pressure to the graft while the glue sets. A validated, accelerated rehabilitation program is recommended, with full weight-bearing at 8-week post-procedure. Results using this technique have shown this to be a safe, reliable, and reproducible procedure with good clinical and radiological outcomes at the 5-year follow-up.