Chondro gide

All the surgeries were performed in the same fashion by two experienced surgeons according to a previous report [28 (link)]. Briefly, preliminary arthroscopy was performed through traditional anteromedial and anterolateral portals. Debridement and curettage of the non-viable tissues surrounding the lesion were performed. MFx to a depth of 4 mm were performed using a 65° and 90° pick. In those patients who underwent AMIC, a mini medial parapatellar approach was performed. The perforation of the subchondral bone was performed with a 40° pick or a 1.2/1.4 mm Kischer wire under constant irrigation. An aluminum template was trimmed according to the defect. A type I/III porcine resorbable collagen membrane was used in all procedures (Chondro-Gide, Geistlich Pharma AG, Wolhusen, Switzerland). The membrane was trimmed according to the aluminum template to slightly undersize the defect to avoid displacement. The membrane was hydrated in a saline solution and placed into the lesion and attached with fibrin glue. The stability of the membrane was checked by repeatedly flexing and extending the knee. The rehabilitation process was performed according to our previous study [29 (link)].

The chondrocyte implantation was performed under general or spinal anaesthesia. A tourniquet inflated to 250 mm Hg was applied to the upper thigh to achieve a bloodless field. The lesion was accessed via a mini-open arthrotomy (medial or lateral depending on the location of the lesion) and curetted down to subchondral bone. The surrounding cartilage was debrided to healthy tissue, exposing the lesion to bare bone. Care was taken to avoid bleeding. A template of sterile aluminium foil was used to model the exact shape of the lesion, overcorrecting with 1 to 2 mm. The size of the lesion was carefully recorded. The aluminium template was used to cut out a matching piece of collagen sheet (Chondro-Gide; Geistlich Pharma, Wolhusen, Switzerland), which was used to contain the cells in the defect. The collagen sheet was sutured to the lesion with 6.0 resorbable stitches and sealed with fibrin glue, leaving an opening at the upper part for injection of the cells. The cells were slowly injected using a soft catheter before closing the final opening with a single suture and fibrin glue. The capsule was then closed with subcutaneous resorbable sutures, before closing the skin incision.

The commercial Chondro-Gide^® (Geistlich Pharma AG, Wolhusen, Switzerland) membrane (consists of type I and type III porcine collagens) was purchased from the manufacturer via our orthopedic clinic. Cellulose-based membrane, collagen type I and II membranes, as well as decellularized cartilage, were manufactured at the Department of Modern Biomaterials of the Institute of Regenerative Medicine of the I.M. Sechenov First Moscow State Medical University (Sechenov University) according to the protocols below.

We chose rats for a model of full-thickness osteochondral defect, because of their weak ability for spontaneous regeneration of articular cartilage as in humans. Animals were randomly allocated to experimental groups, with 5 animals in each group. In total, 30 rats were included in the experiment. The full-thickness defect was made in the femur epiphysis fossa of the knee joint [17 ]. The admission was implemented by medial parapatellar incision and abduction of patella aside. A defect was formed in the interstitial fossa with a hand cutter with a diameter of 2.0 mm and a depth until small blood secretions appeared at the bottom of the defect (Figure 6). In the control group, the surgery was performed the same way, but without scaffold implantation. Scaffolds were implanted in the knee joints in the following combinations: (a) articular cartilage defect without scaffold or membrane cover (control) on one knee and membrane I implantation to the other; (b) implantation of the Chondro-Gide^® (Geistlich Pharma AG, Wolhusen, Switzerland) membrane and membrane II; (c) implantation of the cellulose scaffold and decellularized cartilage. The animals were analyzed 2 and 4 months after surgery. Of note, 1 animal from each group was taken for visual macro-analysis and the knee was dissociated for femur and tibia whereas 4 others proceeded for sectioning with an intact knee.

All patients (N = 163) recruited to this study have been investigated as part of an ethically approved project (REACT 09/H1203/90, granted by the West Midlands National Research Ethics Service). Each patient underwent ACI treatment in our center for chondral/osteochondral defects in their knee using a 2-stage procedure as described previously.^{3 (link)} Macroscopically normal cartilage was harvested and processed in our on-site Good Manufacturing Practice–approved laboratory, and isolated chondrocytes were culture-expanded in monolayer for approximately 21 days. These autologous cells were then implanted during an open procedure beneath either a periosteal (ACI-P) or collagen (ACI-C) (Chondro-Gide; Geistlich Pharma) membrane. The location and approximate size of the treated defect(s) were recorded on a specifically designed knee map.²⁶ Patient demographics are shown in Table 1. At approximately 12 months after ACI, patients were offered arthroscopic surgery for a repair tissue biopsy to be performed, as is common practice.