Damaged Cartilage and Osteoarthritis of the Knee: Pain Relief and Therapy

Damaged Cartilage and Osteoarthritis of the Knee: Pain Relief and Therapy

Pain when walking down stairs or hills… pain after exercise… pain when getting up after long periods of sitting: Knee pain is a typical symptom of cartilage damage or osteoarthritis of the knee.

In this article, Dr. Gäbler from the SPORTambulatorium Wien summarizes various osteoarthritis therapies and explains why early treatment is so important when there is wear and tear on the joints.

Schmerzen beim Bergabgehen, nach Belastung oder sogenannte Anlaufschmerzen beim Aufstehen nach längerem Sitzen: Knieschmerzen sind typische Symptome für Knorpelschäden oder eine Arthrose im Knie.

Table of Contents

  1. What is osteoarthritis of the knee?
  2. Osteoarthritis of the knee: Diagnosis and therapy
  3. Types of cartilage damage and means of therapy
    1. Chondromalacia patellae (softening and deterioration of kneecap cartilage)
    2. Articular surfaces of the femoral condyles
      1. Microfractures
      2. Mosaicplasty
      3. Knorpeltransplantat (MACT)
      4. AutoCart Knorpeltransplantat (MINCED CARTILAGE)
      5. Cartilage Smoothing
      6. Eigenblut Infiltrationen (ACP)
      7. Stem Cell Therapy
      8. Cingal Gel Spritze – Hochvernetzte Hyaluronsäure
  4. Medication for joint pain and damaged knee cartilage
  5. Other dietary supplements for osteoarthritis therapy
  6. Osteoarthritis of the knee: Reducing pain with early treatment 

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What is osteoarthritis of the knee?

Osteoarthritis of the knee can be very painful. It occurs when the joint cartilage is irreparably damaged.

Cartilage damage can occur due to an acute event or through chronic stress and is a common cause of persistent pain, especially during initial exertion. Cartilage damage often begins with a softening of the cartilage (chondromalacia). Over time, this type of pain is even present after prolonged sitting. When cartilage damage or wear becomes widespread, it is called osteoarthritis. Left untreated, cartilage becomes brittle and can fray or break off. Once cartilage has broken off and the bone surface is exposed, patients usually experience severe pain during knee exertion.

Osteoarthritis of the knee: Diagnosis and therapy

Cartilage damage can occur on the kneecap or on the joint surfaces (femoral condyles, upper extremity of the tibia). Depending on the cause and extent of cartilage damage, there are two basic therapeutic approaches:

1) Eliminate the cause

  • Insoles 
  • Physical therapy
  • Repositioning surgery 

2) Treat the knee joint directly

  • Dietary supplements
  • Platelet-rich plasma (PRP) or hyaluronic acid injections
  • Stem Cell Therapy
  • Microfractures

Types of cartilage damage and means of therapy

1) Chondromalacia patellae (softening and deterioration of kneecap cartilage)

If you often feel pain when walking down stairs or hills, cartilage disease (chondropathy) on the rear of the kneecap (patella) may be the reason. In advanced stages of the illness, even normal use is associated with pain.

Chondromalacia patellae: Therapy

The first step in successfully treating cartilage damage in the knee is figuring out the cause. Malpositioning is a common cause of rapid cartilage damage. Insoles, physical therapy, repositioning surgery, etc. can effectively eliminate the causes.

Alternatively, therapy can address the knee joint directly. However, this usually first requires an arthroscopic examination of the cartilage.

  • Cartilage regeneration treatment
  • Microfractures
  • Pridie drill holes
  • Mosaicplasty
  • Cartilage transplant
  • MPFL reconstruction

The image shows pronounced cartilage damage on the back of the kneecap. By drilling fine holes in the kneecap (Pridie drilling), the sclerosed bone is perforated to allow for the fresh growth of blood vessels. An influx of mesenchymal stem cells stimulates the formation of new cartilage.

2) Articular Surfaces on the Femoral Condyles

In order for the knee joint to glide smoothly and painlessly, the cartilage covering on the femoral condyles and the tibial head must be intact. Here, cartilage damage is mainly found on the inner side of the joint. Depending on the extent of the damage, different therapy methods can be used:


Fine holes are drilled into the bone with a type of awl. The concept is the same as the Pridie technique: the sclerosed bone is pierced, stimulating the blood vessels at the area. The ensuing influx of mesenchymal stem cells stimulates the formation of new cartilage. Research shows a very encouraging success rate for this technique - as high as 80%.

The advantage over Pridie drilling is that microfractures are created using a special awl, whereas the high speed of the drill used in the Pridie procedure can generate considerable heat, burning the bone and blood vessels. With microfracturing, no heat damage is incurred.

Dr. Gäbler achieves excellent outcomes using the microfracture technique; often, cartilage damage is no longer noticeable after just a few months. For this reason, Dr. Gäbler prefers this method of treating relatively minor cartilage damage, rather than a cartilage cell transplant (which is much more complex).

Find out more about knee injuries in sports in this Kurier interview with Dr. Gäbler (available in German only).

This arthroscopic image shows the holes that remain following microfracturing.


Smaller cartilage defects in the weight-bearing areas of the knee can be repaired using a mosaic-like grafting technique that harvests cartilage from parts of the knee where it is less needed (non-weight-bearing areas). These cartilage plugs are then inserted into the defective areas, where they are able to heal into place.

However, this method can leave behind tunnels (lifting defects), which often cause pain—the method is therefore only used in exceptional cases (see below).

What is mosaicplasty best suited for?

Mosaicplasty is a very good method for treating Ahlbäck’s disease (aseptic bone necrosis) and OCD (osteochondrosis dissecans) of the knee and ankle.


Larger defects can be treated using cartilage transplants. To do this, an operation is first carried out to harvest cartilage, which is then cultivated in a cell culture lab under sterile conditions. About six weeks after the initial operation, the newly grown cartilage can be used as a transplant in a second operation. Cartilage transplants are indicated in only a very limited number of cases, as there must be no meniscus damage and cartilage must be intact on at least one of the two joint surfaces.

AutoCart Cartilage (MINCED CARTILAGE)

A simpler method that requires only a single operation is a cartilage graft using the AutoCart procedure (Arthrex). This method is useful for grafting more significant cartilage damage in what is usually a minimally invasive procedure.

Image: The defective cartilage is prepped and a cartilage paste is applied (all rights reserved by Arthrex).

With the AutoCart method, cartilage is shaved from the defective edges and immediately reduced is size (minced). As the edges of the cartilage must be straightened anyway, no further cartilage damage is caused (as is the case, for example, with mosaicplasty), only in rare cases is it necessary to remove cartilage from other non-weight-bearing areas. The cartilage is then mixed with endogenous PRP (ACP) and thrombin, creating a paste that is introduced into the defective area, and coated with thrombin and ACP to create a seal. The ACP contains high doses of growth factors that stimulate cartilage healing. Thrombin is a crucial macromolecule for blood clotting and is taken from the patient’s blood during the operation.

The main advantage of this method is that only substances from the patient’s own body are used, meaning that there can therefore be no rejection and only a single operation is needed.

In most cases, the patient is discharged one or two days after the operation at the most. An orthosis (splint) must be worn for six weeks and mobilization with crutches is likewise required for six weeks to avoid overstressing. Physiotherapy is essential to the healing success.

This procedure is a recognized treatment method with very good therapeutic results. It was decisively improved by the Arthrex company through their development of new instruments and the use of ACP (PRP) and thrombin.


Dr. Gäbler often sees patients with a history of arthroscopy that included cartilage smoothing, or cartilage debridement. In almost all cases, patients felt worse after cartilage smoothing than before.

Scientific studies now clearly show that cartilage debridement (especially in older patients) not only fails to lead to improvement, but often even causes symptoms to worsen.

As Dr. Gäbler explains, the problem is that the cartilage smoothing process also grinds away good cartilage; this is because the differences between the types of cartilage cannot be distinguished during arthroscopy. 

Some Austrian and German medical associations still recommend cartilage smoothing, but Dr. Gäbler considers the method to be a medical failure and advises his patients against the procedure.

A clear exception is in cases requiring the removal of cartilage scales, which could otherwise loosen and detach, causing pieces to freely float around the joint.


ACP (autologous conditioned plasma) is an autologous blood product. Blood is taken from a vein in the patient’s arm and centrifuged using a specialized technique. This activates the platelets, which in turn release proliferative substances (such as platelet-derived growth factor (PDGF) and morphogenic proteins (transforming growth factor, TGF), which are key to stimulating muscle, tendon, cartilage, and bone healing.

You can find more information about ACP therapy at the SPORTambulatorium Wien here. 


The unprecedented possibilities that have opened up for the use of mesenchymal stem cells, which are derived from fat cells , have led to the development of minimally invasive alternatives to the infiltration therapies and surgical procedures many are familiar with. Recent studies have shown that stem cell therapy significantly alleviates pain and improves quality of life as well as increasing cartilage thickness (see below). The implantation of a prosthetic joint, especially at the knee, can often be significantly delayed and in some cases even avoided by treating with stem cell therapy.
You can find more information about stem cell therapy at the SPORTambulatorium Wien here:


Cingal gel contains cross-linked, stable hyaluronic acid, which has been extensively studied. Hyaluronan, or sodium hyaluronate, is a sugar-like molecule also called a polysaccharide. The molecular structure of hyaluronan, an important component of synovial fluid, is a long chain made up of many identical links. Hyaluronic acid is created by cells in the synovial membrane and released into the joint cavity, where it helps lubricate the surface of the cartilage. The length of the hyaluronan chains affects the lubricating properties (viscoelasticity) of the corresponding medications.


Localized side effects such as pain, heat, redness, and swelling may accompany treatment of the joint. This is a very common side effect of cross-linked hyaluronic acid and, although such reactions are unpleasant, the knee generally calms down within just a few days. In rare cases, hypersensitivity has been observed.


It is not known precisely how hyaluronic acid works, but research has shown that arthritic joints have significantly lower concentrations of hyaluronic acid than healthy joints. Injecting hyaluronic acid into the affected knee joint increases its lubrication. Hyaluron also has an anti-inflammatory effect.

Broad studies have shown that cross-linked hyaluronic acid infiltrations are more effective than injections of simple hyaluronic acid. Additionally, simple hyaluronic acid has the disadvantage of requiring 3-5 injections into the knee, usually one a week, while a single shot of cross-linked hyaluronic acid is often effective for several months.

The gel implantation of cross-linked hyaluronic acid improves natural joint function, extending the joint’s longevity by restoring the mechanical function of the natural synovial fluid (viscoelasticity). In addition, Cingal reduces certain enzymes that cause cartilage deterioration, thus slowing the process. The high stability of Cingal gel means that a single treatment is often effective for 6-9 months.

Cost per infiltration: € 350


Please note that the nutritional supplements and medication listed here may or may not help relieve your symptoms. A good rule is: Try and see. Current research indicates that all of these substances are harmless.

Knorpelpräparat Sportambulatorium

Täglich sehen wir PatientInnen, die an Arthrose bedingten Gelenkbeschwerden leiden. Die betroffenen Gelenke sind in ihrer Beweglichkeit und Belastbarkeit eingeschränkt. Eine Operation ist hier oft nicht erforderlich, denn eine konservative Behandlung kann durchwegs auch zu einer Verbesserung der Schmerzsymptomatik führen. Neben Physiotherapie, einer Ernährungsumstellung und gelenkschonender Aktivität gibt es ernährungsergänzende Präparate, die nachgewiesenerweise Gelenkprobleme deutlich verbessern können.

Es gibt zahlreiche Substanzen am Markt. Da wir aber mit dem Angebot nicht vorbehaltlos glücklich sind, bietet das Sportambulatorium ab sofort neu- und weiterentwickelte Knorpelaufbauprodukte und Vitaminpräparate für seine PatientInnen an.

Kollagen Typ II & Natriumhyaluronatsäure & Ascorbinsäure & Kupfergluconat Präparat

Das Kombinationspräparat aus Kollagen Typ II und Natriumhyaluronsäure unterstützt die Regenerierung des Knorpels. Neueste Studien zeigen, dass sich hochdosiertes Kollagen Typ II bei Knorpeldefekten im Knorpel einbaut, es dadurch zu einer Versiegelung des Knorpels kommt und sich eine verbesserte Oberfläche bildet.

Der zweite wichtige Bestandteil in diesem Präparat ist die Hyaluronsäure. Dabei handelt es sich um eine Substanz, die die Gleitfähigkeit der Gelenke verbessert. Meist wird die Hyaluronsäure in das Gelenk gespritzt. Die orale Einnahme ist allerdings eine perfekte Alternative. Obwohl es etwas länger dauert, bis die Wirkung einsetzt, hat man den Vorteil, dass die Hyaluronsäure in allen Gelenken wirkt, nicht nur z.B. in dem infiltrierten Knie. Außerdem vermeidet man mögliche Komplikationen, die im Rahmen einer Infiltration auftreten können.

Glucosaminsulfat & Chondroitinsulfat & MSM Präparat

Bei Glucosaminsulfat und Chondroitinsulfat handelt es sich um Substanzen, die nachgewiesenerweise zur Stabilisierung der Grundsubstanz des Knorpels und zur Knorpelregeneration führen. Die Substanz MSM hilft vor allem bei Patienten mit beginnender, aber auch fortgeschrittener Arthrose ausgezeichnet. MSM hat eine entzündungshemmende Wirkung und kann dadurch fortschreitende Arthrose verlangsamen respektive stoppen. 

Was unterscheidet uns von anderen Produkten am Markt?

Die jahrelange Erfahrung von Prof. Dr. Gäbler, sowie das Einbringen neuester wissenschaftlicher Erkenntnisse, führten zu einer weitaus verbesserten Zusammensetzung unserer Präparate. Unsere Knorpelaufbaupräparate enthalten die wichtigsten Substanzen, die der Knorpel zur Regeneration benötigt, in einer sehr reinen und hochdosierten Form. Da viele Patienten Brauseprodukte weniger gut vertragen, sind all unsere Präparate in Kapselform erhältlich.

Other dietary supplements for osteoarthritis therapy

CONDROSULF (chondroitin sulfate)

In order to ensure an effective protective glide between your bones, cartilage contains many different substances. It consists of cells and a basic matrix produced by the cartilage cells. One of the primary components of the cartilage matrix is chondroitin sulfate, which inhibits the activity of proteins (enzymes) that break down cartilage.

Taking chondroitin sulfate is said to promote the synthesis of a new cartilage matrix, making the cartilage more resistant. Chondroitin sulfate is a natural product and, like hyaluronic acid, is harvested from animal sources, either from fish (Condrosulf®) or poultry (Structum®).

Both supplements are usually taken over a period of about 3 months, once or twice a year. In order for treatment with chondroitin sulfate to be effective, there must be reactive cartilage present. For this reason, these supplements are primarily used in the early stages of osteoarthritis, as well as for growth-related knee pain in adolescents.

As the effects of chondroitin alone are usually minimal, it is important to choose a combination supplement that also contains glucosamine and collagen II.


Healthy cartilage needs a dense network of collagen fibers for internal stabilization and nutrient transport as well as a dense matrix, which is mainly composed of glucosamines. Athletes, people in professions with high joint stress, and patients undergoing rehabilitation and regrowth all have an increased need for collagen.

Dietary collagen supplements should provide the body with the amino acids needed to build up collagen. In animal experiments, a study using radioactively marked hydrolyzed collagen found that collagen fragments were indeed actually incorporated into the cartilage.

Other studies found that patients with mild osteoarthritis who were treated with hydrolyzed collagen reported improved joint mobility and pain relief after about 4-6 weeks. However, these effects have not been scientifically proven in double-blind studies.

Dietary supplements with hydrolyzed collagen are available in drugstores and pharmacies in pill and powder form.


Glucosamine is an essential component of proteoglycans (glucosaminoglycans), proteins that bind water in cartilage tissue to ensure that impacts are minimized.

An important component of synovial fluid, glucosaminoglycans ensure viscosity, maintain the joints’ gliding ability, support the supply of nutrients to joint tissue, and thus play an essential role in maintaining and regenerating cartilage tissue. Glucosaminoglycans also support the growth and structure of our connective tissue.

Glucosamine is taken in the form of glucosamine sulfate. There are now a number of combination supplements on the market that contain chondroitin sulfate and glucosamine sulfate, meaning that you only have to take one pill. Glucosamine can also be taken as green-lipped mussel extract instead of in pill form. (Young dogs are often given green-lipped mussel extract to build up their cartilage, but it is also highly valued by runners.)


How green-lipped mussel extract works: In addition to vitamins, minerals, and trace elements, green-lipped mussels also contain many amino acids and a high level of sugar-like substances called glucosaminoglycans (see above for more about their effects). In addition to maintaining and building up synovial fluid and connective tissue, there is another relevant aspect to the treatment of rheumatic diseases: the anti-inflammatory effects of the extract. This is attributed to the fact that green-lipped mussel extract contains omega-3 fatty acids, which inhibit the synthesis of prostaglandins from arachidonic acid, thus counteracting the inflammatory processes.

Many runners swear by green-lipped mussel extract for nonspecific joint pain and diffuse cartilage damage. However, these effects have not been scientifically proven in double-blind studies.


The abundant silica contained in this supplement supports both the body’s own production of collagen and also matrix production (encouraging glucosamine formation). The combination of horsetail concentrate together with hydrolyzed collagen is said to be particularly successful. Here, too, effects have not been verified by double-blind studies.


Since it is not possible to regenerate damaged knee cartilage, osteoarthritis is always only symptomatic. Osteoarthritis therapies that preserve the joint, such as stem cell therapy, ACP injections, or medical therapy through dietary supplements are effective means of maintaining and improving knee function and minimizing knee pain.

If your knee osteoarthritis requires surgical treatment, your doctor will recommend the most suitable method for your specific case (cartilage regeneration, microfractures, Pridie drilling, mosaicplasty, cartilage transplantation, or MPFL reconstruction) following a personal discussion.

The knee specialists at the SPORTambulatorium Wien, directed by experienced knee surgeon Dr. Gäbler, look forward to meeting you during your appointment, which can be scheduled online or by phone at 01 4021000.

More information on knee osteoarthritis

>> Interview with Dr. Gäbler on osteoarthritis | vielgesundheit.at (German only)

>> Dr. Gäbler on the topic of knee injuries in sports | Kurier article 08/2010 (German only)

More questions?

Our experts are happy to help you

Just give us a call!

Please note that medical indications and therapies are constantly changing and evolving. Sometimes these changes occur more rapidly than Dr. Gäbler is able to update the homepage. Detailed information about the dosage, administration, and composition of medications may have changed since the last update. Reading a website is never a substitute for visiting your doctor. An examination by and discussion with your doctor can provide significant additional information for you based on your personal diagnosis and the latest scientific findings. Please note that surgeries and outpatient procedures are not performed on the premises of the Sportambulatorium Wien.