LIPO-AMIC Technique Description: Autologous Matrix Induced-Chondrogenesis With Microfragmented Adipose Tissue Graft

Abstract

Cartilage injuries have historically been challenging to manage, but recent advancements have rapidly expanded treatment options. The incorporation of mesenchymal stem cell sources, such as bone marrow or adipose tissue, has improved repair tissue quality and clinical outcomes. The LIPO-AMIC procedure for full-thickness knee cartilage lesions uses a collagen matrix combined with microfragmented adipose tissue grafts as a source of adipose-derived stem cells, leveraging their chondrogenic differentiation capacity and paracrine activity. This adaptation aims to enhance outcomes and provides a single-stage knee cartilage repair option with biological augmentation.

Fig 1

Representative case involves a 45-year-old male patient. The alignment correction planning using panoramic radiography of the lower limbs reveals a varus alignment of 9.78° in the right knee (A), with the mechanical axis intersecting the medial compartment at 5.7% of the width of the tibial plateau (arrow) (B). The anatomic lateral distal femoral angle (aLDFA) was is 85.89° (C), and the medial proximal tibial angle (MPTA) is 80.93° (D). The center of rotation of angulation is contained within the bone, at 14.92% of the tibial length from the proximal articular surface, characterizing an abnormal varus alignment of the right lower limb primarily due to a metaphyseal varus deformity of the proximal tibia, along with a minor varus deformity of the distal femur. (HKA, hip-knee-ankle angle.)

Fig 2

Accessory surgical table view. The lipoaspirate is processed using the commercially available Lipogems kit (Lipogems; Lipogems International). Three cycles of microfragmentation are performed. The device is shaken, as the mobile metal spheres mechanically act on the fat aspirate, resulting in the appearance shown, with the microfragmented adipose-tissue graft resting in the upper third of the device, to be subsequently collected through the upper filter.

Fig 3

Right knee intraoperative fluoroscopy anteroposterior view. A high tibial osteotomy (HTO) was performed using a medial wedge technique. A 10-mm opening was achieved using a temporary metallic wedge introduced in the most posterior part of the osteotomy site, following a preoperative plan to achieve neutral alignment. (∗) Fixation was performed with a Puddu-type Tibial A/P Sloped Osteotomy Plate (Arthrex). The osteotomy gap was filled with a structured autologous iliac crest graft.

Fig 4

(A) Arthroscopic view of the right knee medial femoral condyle (MFC), medial meniscus (MM), and tibial plateau (TP) trough lateral portal. (B) MFC view through a medial parapatellar mini-arthrotomy and knee flexion, showing the chondral lesion aspect after edge preparation and curettage of the lesion bed (without microfracture).

Fig 5

Accessory surgical table presenting LIPO-AMIC membrane aspect before implantation. The microfragmented adipose tissue graft is carefully applied to the rough Chondro-Gide matrix surface with a syringe and adjusted with delicate spatulas, demonstrating satisfactory adhesion.

Fig 6

Medial parapatellar mini-arthrotomy with knee flexion to approach right knee medial femoral condyle (MFC). Final repair with LIPO-AMIC. Defect filled with microfragmented adipose tissue, scaffold adjusted, and sutured with 6-0 PDS sutures (Ethicon). Care must be taken to avoid excessive suture tension.