All-Arthroscopic Nanofractured Autologous Matrix-Induced Chondrogenesis (A-NAMIC) Technique for the Treatment of Focal Chondral Lesions of the Knee

Nanofractured autologous matrix-induced chondrogenesis (NAMIC©) is a 1-step technique that combines nanofracture needling to induce bone marrow stimulation (BMS) and the use of cell-free collagen matrix to optimize cartilage regeneration. In this Technical Note, we describe a modification of the NAMIC procedure using mosaicplasty trephines to prepare the lesion surface and to shape collagen implants in an all-arthroscopic approach (A-NAMIC). This technique is indicated for the treatment of International Cartilage Repair Society grade III to IV knee chondral lesions of ≤4 cm(2). After damaged cartilage is debrided, trephines are used to create a flat, circular lesion surfaces. Subsequently, BMS is performed with nanofracture, eliciting reproducible and stop-controlled subchondral bone perforations of 9-mm depth and 1-mm width. The collagen membrane is then cut to size with the trephine, placed over the prepared defect, and secured with fibrin glue, preventing loss of regenerating cells and growth factors to the joint space. Using trephines allows the rapid and precise creation of smooth defect surfaces with known dimensions, ensuring optimal lesion coverage. Additionally, nanofracture reduces trabecular compaction and allows for a deeper access to subchondral bone in comparison with conventional microfracture, improving lesion filling and production of cartilage with higher hyaline content.