Knee Cartilage Damage and Treatment
If you are experiencing persistent knee pain, damage to the cartilage may be the cause. Left untreated, cartilage damage may progress over time and contribute to the development of osteoarthritis (joint degeneration). This page explains how knee cartilage functions, outlines available treatment options, and describes the role of Matrix-Associated Autologous Chondrocyte Transplantation (MACT), a cell-based procedure designed to support cartilage regeneration.
Understanding Knee Cartilage Defects
Cartilage is the smooth tissue that covers the ends of bones within a joint. It enables smooth joint movement, helps absorb mechanical loads, and supports pain-free mobility. Cartilage can be damaged by injury or prolonged wear and tear. This may lead to symptoms such as pain, swelling, joint effusion, stiffness, or restricted movement.
Because cartilage does not have a direct blood supply, it has only a limited ability to heal on its own. Pain medication and physiotherapy can often provide temporary symptom relief; however, in some cases surgical intervention may be required to reduce pain and improve joint function.
If left untreated, cartilage defects may become larger over time. This increases the risk of developing premature joint degeneration (osteoarthritis). In advanced cases, a knee replacement may eventually become necessary.
Established Treatment Approaches for Cartilage Damage
The German Society for Orthopaedics and Trauma Surgery (DGOU) describes several surgical treatment options for cartilage damage. The most appropriate treatment depends on factors such as the type and size of the cartilage defect, as well as the condition of the affected joint.
Understanding MACT
MACT (Matrix-Associated Autologous Chondrocyte Transplantation) uses a patient's own cartilage cells to help repair damaged cartilage. Two established MACT procedures are available: Scaffold-Based MACT and Injectable MACT. Both procedures begin with the collection of small cartilage-bone biopsies from a non-weight-bearing area of the knee. The harvested cartilage cells are isolated and expanded in the laboratory before being transplanted into the cartilage defect during a second procedure. Rehabilitation follows thereafter.
The choice of procedure is made by a qualified physician based on the characteristics of the cartilage defect and the overall condition of the knee.
Two Established MACT Procedures
Injectable MACT
A cell-based procedure for the treatment of cartilage defects of the knee in which a patient's own cartilage cells are combined with a hydrogel and injected into the cartilage defect using a dual-chamber syringe. The procedure is also referred to as hydrogel-based ACT.
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Scaffold-Based MACT
A cell-based procedure for the treatment of cartilage defects of the knee in which a patient's own cartilage cells are seeded onto a collagen scaffold and subsequently transplanted into the cartilage defect.
Clinical Evidence for MACT
MACT is among the most extensively studied procedures for the treatment of cartilage defects. Its safety and effectiveness have been investigated in clinical studies, some of which include follow-up periods of five years or longer. The scientific literature describes MACT as an established treatment option for appropriate cartilage defects. Because study results are based on patient groups, these studies cannot predict individual treatment outcomes. Your specialist can help you understand what the available clinical evidence may mean for your personal situation.
Find a Treatment Centre
Every cartilage defect is unique. Whether a cell-based cartilage repair procedure may be an option for you can only be determined by your treating physician following a thorough medical evaluation. In cases of advanced joint degeneration (osteoarthritis), these procedures are generally no longer considered appropriate.