Mincing cartilage with commercially available shavers is increasingly used for treating focal cartilage defects. This study aimed to compare the impact of mincing bovine articular cartilage using different shaver blades on chondrocyte viability.

Bovine articular cartilage was harvested using a scalpel or three different shaver blades (2.5 mm, 3.5 mm, or 4.2 mm) from a commercially available shaver. The cartilage obtained with a scalpel was minced into fragments smaller than 1 mm³. All four conditions were cultivated in a culture medium for seven days. After Day 1 and Day 7, metabolic activity, RNA isolation, and gene expression of anabolic (COL2A1, ACAN) and catabolic genes (MMP1, MMP13), Live/Dead staining and visualization using confocal microscopy, and flow cytometric characterization of minced cartilage chondrocytes were measured.

The study found that mincing cartilage with shavers significantly reduced metabolic activity after one and seven days compared to scalpel mincing (p<0.001). Gene expression of anabolic genes was reduced, while catabolic genes were increased after day 7 in all shaver conditions. The MMP13/COL2A1 ratio was also increased in all shaver conditions. Confocal microscopy revealed a thin line of dead cells at the lesion site with viable cells below for the scalpel mincing and a higher number of dead cells diffusely distributed in the shaver conditions. After seven days, there was a significant decrease in viable cells in the shaver conditions compared to scalpel mincing (p<0.05). Flow cytometric characterization revealed fewer intact cells and proportionally more dead cells in all shaver conditions compared to the scalpel mincing.

Mincing bovine articular cartilage with commercially available shavers reduces the viability of chondrocytes compared to scalpel mincing. This indicates that mincing cartilage with a shaver should be considered a matrix rather than a cell therapy. Further experimental and clinical studies are required to standardize the mincing process with a shaver.

Acknowledgements: This study received unrestricted funding from KARL STORZ SE & Co. KG.

Focal chondral defects are thought to contribute to the onset of degenerative changes in cartilage and therefore effective treatments of these lesions are aggressively pursued. A number of options such as bone marrow stimulation, osteochondral autograft transplantation, osteochondral allograft transplantation, and autologous chondrocyte implantation exist. Long-term data regarding efficacy and outcome for some of these approaches seem to suggest that there is still a need for a low-cost, effective treatment that leads to a sustained improvement in symptoms and the formation of hyaline cartilage.

artilage autologous implantation system (CAIS) is a surgical method in which hyaline cartilage fragments from a non-weight bearing area in the knee joint are collected and then precipitated onto an absorbable filter that is subsequently placed in the focal chondral defect. The clinical outcome of CAIS was compared with microfracture (MFX) in a pilot study. In an IRB approved protocol patients (n=29) were screened with the intention to treat, randomised (2:1, CAIS:MFX) and followed over a 24 month period. To be included in the study the patient may have up to 2 contained focal, unipolar lesions (≤ ICRS grade 3d and ≤ ICRS Grade IVa OCD lesions of femoral condyles and trochlea with a size between 1 and 10 cm². There were no differences in the demographics between the two treatment groups. We report 24 month patient-reported outcome (PRO) data using the KOOS-scale. The values (mean±SD) for the Sport&Recreation (S&R) and Quality of Life scales are shown in the figures below. We noted that at 12 months after the intervention CAIS differentiated itself from MFX in that the changes in S&R were different (p<0.05, t-test) at 12, 18, and 24 months. QoL data were different at 18 and 24 months. The other KOOS-subscales in CAIS and MFX were not significantly different at any time point. The data suggest that CAIS led to an improvement in clinical outcomes in the second year post-intervention. It is possible that the improvement of symptoms that we measured may be associated with the formation of hyaline cartilage. Study funded by ATRM and DePuyMITEK.

The Cartilage Autograft Implantation System (CAIS) is being investigated as a potential alternative surgical treatment to provide chondrocyte-based repair in a single procedure for articular cartilage lesion(s) of the knee. CAIS involves preparation and delivery of mechanically morselized, autologous cartilage fragments uniformly dispersed on a 3-dimensional, bio-absorbable scaffold and fixated in the lesion with bio-absorbable staples. CAIS maintains chondrocyte viability and creates increased surface area, which facilitates the outgrowth of embedded chondrocytes onto the scaffold. A proprietary disposable arthroscopic device for harvesting precisely morselized cartilage tissue is used.

In an EU pilot clinical study involving 5 countries 25 patients were randomized and treated using a 2:1 schema of CAIS:microfracture (MFX). Subjects returned for follow-up visits at 1 and 3 weeks and then 2, 3, 6, 9, 12, 18 and 24 months and were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS). Outcomes at each time point were analyzed with Students t-test.

This study showed that CAIS is safe to use. During the first year, the clinical outcome data in both groups were similar. However, at 18 and 24 months we noted that selected outcome measures were different. At 18 months the Sports & Recreation values were 50.6 ± 22.70 and 21.3 ± 33.25 (p=0.016) for CAIS and MFX respectively and at 24 months 52.1 ± 27.9 and 26.7 ± 26.2 (p=0.061) for CAIS and MFX respectively. At these same time points the Quality of Life data were 43.0 ± 27.14 and 27.2 ± 29.11 (p=0.2) for CAIS and MFX respectively (18 months) and 45.1 ± 28.07 and 20.5 ± 21.47 (p=0.062) for CAIS and MFX respectively (24 months).

While some of the data are not significantly different in this pilot study, taken together they do provide evidence to support the initiation of a more robust clinical trial to investigate efficacy.

The Cartilage Autograft Implantation System (CAIS) is being developed as a potential alternative surgical treatment providing chondrocyte-based repair in a single procedure for articular cartilage lesion(s) of the knee. Two pilot clinical studies were conducted to assess safety and initial performance of the CAIS system.

CAIS involves preparation and delivery of mechanically morselized, autologous cartilage uniformly dispersed on a 3-dimensional, bio-absorbable scaffold, and fixated in the defect with bio-absorbable staples. The mechanical fragmentation of cartilage tissue both maintains viability of the chondrocytes and creates increased surface area, which facilitates the outgrowth of embedded chondrocytes onto the scaffold. A proprietary disposable, arthroscopic device for precisely harvesting viable, morselized cartilage tissue was used. Two pilot clinical studies conducted in the EU and US were designed to assess safety and initial performance of the CAIS. The studies treated 53 patients at 10 enrolling sites, with microfracture as a control. Subjects returned for follow-up visits up to 3 years. Subjects were clinically evaluated and interviewed for the occurrence of adverse events and asked to complete clinical outcome questionnaires, Knee Injury and Osteoarthritis Outcome Score (KOOS), regarding disability, function, pain and quality of life. In addition, MRIs were completed at baseline, 3 weeks, and 6, 12, 24, and 36 months.

The instrumentation enabled the successful preparation and fixation of morselized autologous cartilage tissue loaded implant in a single intraoperative setting. The CAIS device has demonstrated short-term safety in subjects treated to date. Preliminary data from the US pilot study at 12 months and EU pilot study at 6 months indicate that CAIS is safe and its performance based on KOOS clinical outcomes show improvement over baseline and comparability to microfracture. Additional data must be analyzed regarding long-term safety and performance.

Objective: Meniscus regeneration is limited, moreover, loss of meniscal tissue leads to osteoarthritis. A new biomaterial, consisting of hyaluronic acid and polycaprolactone was applied as a meniscus substitute device in a study in sheep.

Methods: 24 sheep received a total medial meniscal replacement. Group SCF (n=12) was treated with a cell free scaffold, Group SCS (n=12) with a scaffold seeded with autologous chondrocytes harvested from the contralateral joints, which served as sham controls (n=12). Further 12 non-operated and 2 menisectomy controls were included in the study.

The animals were sacrificed after 4 months. The implants and joint surfaces were evaluated on a macroscopic (Implant Gross Assessment Score; Gross Assessment of Joints Score) and histological level.

Results: There was no significant difference of the Implant Gross Assessment score between the SCF and SCS groups. All implants showed excellent capsular ingrowth at the periphery. Dislocation, extrusion and tears occurred in part of the specimen due to biomechanical problems caused by soft tissue quality. The mean Gross Assessment of Joint Changes Score of the groups SCF and SCS was not statistically different. Cartilage damage was significantly more severe in joints with implants than in non-operated joints and sham controls, but less pronounced than in menisectomy controls. Histological evaluation showed residual scaffold with an associated foreign body response in all implants. Fibrous tissue was present in all implants, in contrast small foci of cartilaginous differentiation were more common in the cell-seeded constructs.

Discussion: At 4 months regenerative meniscal tissue was present but immature. The present study showed that strong biomechanical scaffold properties are a required to allow guided tissue regeneration and maturation under loading conditions. Cell seeding of the scaffold encourages cartilaginous differentiation. Modification of the scaffold and the cell-seeding technique will be investigated in further studies.

Aims: Collagen implants are used for repair of chondral defects. We investigated the behavior of human chondrocytes of either healthy or osteoarthritic joints and ovine chondrocytes and bone marrow stromal cells seeded in a collagen-GAG copolymer matrix comprising collagen type I, II and III. Methods: Cells were seeded on matrices and cultured for 12 hours, 4 days, 1 week, 2, 3, and 4 weeks. We evaluated morphology and biosynthetic activity of the cells by histological analysis, immunhistochemistry, electron microscopy, biochemical assays for glycosaminoglycans and DNA, and expression of collagens by RT-PCR. Results: From 12 h to 3 weeks the histology showed a increasing number of spherical cells, consistent with chondrocytic morphology except in the osteoarthritic-chondrocyte-seeded scaffolds. GAG analysis showed an increasing amount in all cell-types except osteoarthritic ones. Human chondro-cytes from healthy cartilage increased the amount from 0 μg/mg GAG at 12 hours to 0,9 μg/mg at 2 weeks. Ovine bone marrow stromal cells from 0,5 μg/mg GAG at 12 hours to 2,9 μg/mg at 4 weeks. Conclusions: The collagen trilayer matrix may be of value as a vehicle for chondro-cyte implantation harvested from healthy cartilage. This matrix also supports the expression of chondrocytic proteins in ovine bone marrow stromal cells without use of growth factors. However, chondrocytes from osteoarthritic cartilage revealed low bioactivity and can not be recommended for cell transplantation procedures.

Aims: The technique of microfracture for the arthroscopic treatment of articular cartilage (AC) defects has been shown to result in reparative tissue in the defect, however, retrieved tissues have demonstrated þbrocartilagenous material. The objective of this study was to evaluate the tissue types formed in AC defects in an ovine model treated by microfracture with a collagen- GAG-copolymer trilayer matrix consisting of collagen type I, II and III and autologous cultured cells. Methods: Sixteen adult sheep were used in the study following the protocol accepted by the Animal Care Commitee of the University. Two 4.5-mm diameter defects were produced in the medial condyle of the right knee, all AC was removed without penetrating the subchondral bone. In twelve animals microfracture was performed with a curved pick, in four of them without further treatment, in four the defect was covered by the collagen implant alone, and in four by the cell-seeded implant with cultured autologous chondrocytes from the left knee, 4 defects served as controls. After four months the knees were removed, parafþn sections were stained with H & E, Safranin O/fast green, alcian blue, azan, and antibodies to types I and II collagen. Results: All treatment groups showed better þlling of the defects than untreated knees. Histological analysis revealed the biggest amount of hyaline-like tissue in the cell augmented treatment group. Reparative tissue was predominantly þbrocartilage in the other groups. Conclusions: Collagen implants are able to increase the repair of chondral defects in combination with microfracture.

Introduction and Objectives: Autologous chondrocyte suspension implantation (ACSI) has yielded good to excellent results in the treatment of cartilaginous defects of the knee. Thus far, studies on the ankle, analysing fewer subjects, offer promising results. Use of this technique in the ankle joint requires medial malleolar arthrotomy and osteotomy. Matrix-induced chondrocyte implantation (MICI) is a new technique involving the use of a hyaluronic acid-based matrix containing cultured chondrocytes.

Materials and Methods: Eight patients (4 male, 4 female) with an average age of 31 years (21–43) with defects in the talus were treated using ACSI and MICI. Average defect size was 1.9 cm. All patients had previously undergone surgery, and MRI showed Outerbridge grade IV osteochondral lesions on the talus. After clinical and radiological evaluation, arthroscopic surgery was performed to biopsy the articular cartilage of the talus. Later, a second surgery was performed with a mini-arthrotomy and debridement and cleaning of the defect. In ACSI, the defect is covered by suturing a periosteal graft to the cartilage, and the chondrocyte suspension is injected underneath. In MICI, a sheet of hyaluronic acid matrix with autologous chondrocytes of the same size as the defect is placed on the defect site and attached with fibrin glue. Patients were examined 28 months after implantation and evaluated using the Hannover Scoring system for the ankle.

Results: Follow-up results on the 8 patients verified an improvement of joint function and a reduction of pain in all cases. Hannover Scores increased in all patients. The osteotomy of the malleolus healed in all 8 cases. One patient was able to return to active competition in decathlon events.

Discussion and Conclusions: MICI requires a less complex surgical procedure and allows for a smaller incision. This technique therefore represents a broader application of tissue engineering in the treatment of cartilaginous defects of the ankle.