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Information for physicians
Cartilage damage in the knee joint
Every year around six million patients worldwide – including around 30,000 in Germany– are affected by knee cartilage damage . [1]
Common causes of cartilage defects: include brief, intense abnormal biomechanical loading or twisting of the knee joint in accidents and sports injuries, or as a result of excess biomechanical stress. Fragments of cartilage may come loose from the joint surface; these may vary in size depending on the severity of the damage.
In addition to traumatic defects, the bone condition osteochondrosis dissecans can also lead to damage to the protective cartilage. Likewise, axis misalignments may affect certain areas of cartilage as a result of biomechanical stress.
Joint cartilage has no direct nerve supply or vascular supply, leaving chondrocytes isolated within the cartilage's compact extracellular matrix. As a result, there is either no restoration, or the damaged area is filled with biomechanically inferior replacement tissue.
Treatment recommendations of the German Society for Orthopaedics and Trauma Surgery[2]
Up to 2 cm² defect size
Bone Marrow Stimulation
Small holes are made in the bone beneath the cartilage to stimulate cartilage healing.
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Up to 1.5 cm² defect size
Osteochondral Transplantation
Small cylinders of bone and cartilage are inserted into the defect to repair the damaged area.
1 to 4.5 cm² defect size
Matrix-Augmented Bone Marrow Stimulation
A matrix is inserted into the damaged cartilage to promote healing and stimulate stem cells.
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From 2 cm² defect size
Matrix-Associated Autologous Chondrocyte Transplantation (MACT)
Cartilage cells are harvested, cultured in the lab, and then transplanted back into the cartilage defect.
MACT procedure
MACT for cartilage defects
MACT uses the body’s own cells to trigger the most complete healing of the cartilage damage possible: the implanted cartilage cells gradually repair the defect with biomechanically high-quality cartilage tissue.
The MACT procedure essentially consists of biopsy, processing, and implantation back into the defect area. The first and last step both involve minimally invasive surgery.
MACT has been recommended by the German Society for Orthopaedics and Trauma Surgery (DGOU) as a standard treatment for cartilage defects since 2004.[3]
Biopsy
During diagnostic arthroscopy, small cartilage-bone cylinders are taken from a non-weight-bearing part of the joint.
Cultivation
At TETEC, the chondrocytes from this biopsy are isolated, multiplied in vitro, and applied to a three-dimensional collagen matrix.
Transplantation
The matrix can then be transplanted into the cartilage defect in a second procedure.
Advantages of MACT
MACT has significant advantages over conventional therapies:
01
Suitable for chondral and osteochondral cartilage defects
02
Long-term results demonstrated by evidence studies
03
Avoids rejection reactions by using the patient’s own cells
04
Effective for defects 2 cm2 and larger
05
Implantation of a defined number of vital cells
Clinical outcomes
High success and low failure rates for knee cartilage defects
The results of long-term and prospective randomized clinical trials show: MACT is significantly superior to other methods of treating knee cartilage defects exceeding 4 cm2 in size [1]. Patients with limited degenerative cartilage damage can also benefit from ACI: Initial clinical studies also show good outcomes in such cases [2, 3].
Indications
When can you use our products?
MACT is promising in the case of full-thickness and symptomatic cartilage defects surrounded by healthy cartilage. If, on the other hand, the cartilage is worn over a large area and other areas of the knee are also affected, the patient has osteoarthritis. Patients with advanced osteoarthritis are no longer candidates for biological cartilage reconstruction and require a different treatment, such as an artificial joint replacement.
Individual factors for choosing the right therapy
As with many injuries, illnesses and therapies, individual factors play an important role in choosing MACT. In addition to the cartilage's properties, determining the most suitable therapy will depend on a range of criteria, including the following:
Previous treatments
Weight
Biological age (This is more important than the calendar age. The focus is on the condition of the cartilage surface and the joint as a whole)
The patient's physical and sporting activities
Lifestyle (e.g., smoking, dietary habits)
TETEC: MACT innovation for over 20 years
Around 20 years ago, we launched one of the first matrix-associated chondrocyte products into the German market. Since then, research results from our development team have been awarded prestigious scientific prizes, for example by the Osteoarthritis Research Society International (OARSI), the Association for Orthopaedic Research (AFOR) and the German Society for Orthopaedics and Trauma Surgery (DGOU).
Introducing the next generation: Gel-based MACT
Our experience and pioneering achievements in the field of matrix-supported ACIs form the basis for the further optimisation of cartilage regeneration using smart biomaterials. The result: a gel-based cartilage cell product that sets new standards in the field of biological cartilage regeneration.
The combination of autologous cartilage cells and a special absorbable hydrogel forms a gel-based matrix-associated chondrocyte product. It has several properties that promote regeneration:
Self-adhesive.
Hydrating
Inhibits unwanted vascularisation
Formed in situ, which prevents cartilage cells from leaking out of the defect
Forms a barrier for inflammatory cells due to its physical properties
Fixes the cartilage cells in the defect area
Together, these qualities promote a high cell survival rate thanks to environmental conditioning.
TETEC quality assurance and product safety
Scientifically proven quality
An independent study [4, 5] of MACT variants available in Europe demonstrated the excellent quality of our biphasic collagen matrix. Similarly convincing properties have also been demonstrated for our in-situ crosslinking hydrogel.
From production to implantation
Our products are manufactured in innovative cleanroom systems – standardized and subject to continuous quality testing. Using state-of-the-art quantitative polymerase chain reaction technology, we check the cell and molecular biology quality of each product before returning it to the user.
For each product, we prepare detailed progress reports on the sterility tests and cell and molecular biology analyses performed. Each user receives a final test report with the product, which, in addition to information on tested sterility, also includes detailed information on cell vitality and the quantitative gene expression analyses performed.
Preventing dedifferentiation
To treat a cartilage defect with MACT, the implanted cells must be capable of producing new, high-quality cartilage tissue. However, the cartilage-specific properties of the collected cartilage cells may be lost when cultured. This process, known as dedifferentiation, is reversed by introducing cartilage cells into our biomaterials.
Allerdings können die knorpelspezifischen Eigenschaften der entnommenen Knorpelzellen bei der Kultivierung verloren gehen. Dieser Prozess, die so genannte Dedifferenzierung, wird durch das Einbringen der Knorpelzellen in unsere Biomaterialien rückgängig gemacht.
In order to check the quality of our individually produced cartilage cell products, we carry out cell and molecular biology quality controls for each product using validated methods. Using this analysis, we ensure that only vital and functional cell products are delivered.
No genetic engineering, antibiotics or antifungals
Our optimised procedures enable the production of high-quality chondrocytes – without the use of controversial genetic engineering methods. Naturally, we do not use antibiotics or antifungals when cultivating the cells. Immunological reactions or transmission of infections of animal or non-animal origin can be ruled out almost completely.
Physician resources
Publications. Videos. Documents.
Explore advancements in knee cartilage repair with MACT. Access over 20 studies, watch repair technique videos, and download clinical and patient resources.
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Connect with TETEC
Conferences
Connect with TETEC at upcoming MACT congresses and events
17.01.2025 - 18.01.2025
Freiburger Knorpeltage 2025
31.01.2024 - 01.02.2025
35th Annual Congress of the BVASK in Duesseldorf
15.02.2025
4th Cartilage Compact Course in Hamburg
21.03.2025 - 22.03.2025
QKG Basic Course in Graz
09.05.2025 - 10.05.2025
12th Berlin Cartilage Symposium 2025
11.09.2025 - 13.09.2025
42th AGA-Congress 2025 in Hamburg
12.12.2025 - 14.12.2025
ICRS-Focus Meeting in Munich
Contact TETEC
Do you need more information about us, our products, the MACT procedure or our user training?
[1] https://www.qkg-ev.de/ueber-uns/was-ist-der-qkg/
[2] Niemeyer P. et al., Empfehlungen der AG Klinische Geweberegeneration zur Behandlung von Knorpelschäden am Kniegelenk. 2023. DOI: 10.1055/a-1663-6807
[3] Angele et. al., Cell-based treatment options facilitate regeneration of cartilage, ligaments and meniscus in demanding conditions of the knee by a whole joint approach. Knee Surg Sports Traumatol Arthrosc. 2021. DOI: 10.1007/s00167-021-06622-8.
[4] Bretschneider et. al., Characterization of primary chondrocytes harvested from hips with femoroacetabular impingement.Osteoarthritis Cartilage. 2016.DOI: 10.1016/j.joca.2016.04.011
[5] Nuernberger et. al., The influence of scaffold architecture on chondrocyte distribution and behavior in matrix-associated chondrocyte transplantation graft.Biomaterials. 2011. DOI: 10.1016/j.biomaterials.2010.08.100