What is cartilage smoothing?
The cartilage forms a stable supporting tissue on the joint surfaces in the joints. This surface can be damaged by incorrect or excessive load or in the context of arthrosis. Patients often report pain and restricted mobility in the knee. Cartilage smoothing can be used as a therapeutic measure to remove cartilage damage from the surface and avoid any consequences. However, its use has so far been controversial among experts, as it only removes parts of the cartilage but does not restore the cartilage or treat the cause.
How can cartilage be smoothed?
Cartilage smoothing is usually carried out arthroscopically, i.e. small skin incisions are made at the knee joint and a camera and instruments are introduced via these accesses. This procedure is also known as knee arthroscopy. The advantage of such a procedure is that it has fewer complications than open surgery.
As a rule, it is performed under general anaesthesia, in rare cases or at the patient’s request also under regional anaesthesia. In cartilage smoothing, fluid is first injected into the knee joint to obtain a better view of the entire knee joint. This is followed by an assessment of the damaged cartilage surface for superficial and deep damage and loose fragments.
Subsequently, fragments are removed with special electrical or mechanical instruments and the surface is smoothed. The instrument can be thought of roughly like a razor that shaves the rough surface of the cartilage. The joint is then rinsed with water and cleaned to remove any remaining cartilage, the instruments are removed and the skin incisions sutured. In case of heavy bleeding, a drainage is applied, a vessel that collects blood or fluid from the wound or joint through a tube.
What results can be expected?
By smoothing the cartilage, superficial roughening and cartilage residues can be removed. This is important because loose fragments of cartilage block the joints and can lead to pain and restricted movement. An irregular surface of the cartilage leads to less sliding of the knee joint, which also reduces the pressure relief from the body on the knee.
This can lead to arthrosis in the long term. Cartilage smoothing can therefore prevent further damaging developments and consequences of cartilage, but it does not fight the cause. Human cartilage is not supplied with nutrients by blood vessels, which means it has a low regenerative capacity.
Smoothing therefore only removes the damaged cartilage, but does not restore it. Cartilage smoothing can provide temporary relief, but if the cause is not tackled, cartilage damage can soon reoccur. The procedure of cartilage smoothing also only works for superficial damage; in the case of deeper cartilage damage, it can be combined with a so-called abrasio if necessary.
Arthroscopic cartilage smoothing is generally a very low-complication procedure, as it is not an open surgery and therefore the risk of infection or injury is lower. Smoothing the cartilage can provide short-term relief and improve joint function. An advantage of this procedure is the relatively fast time of regeneration after the operation.
Patients are usually able to walk again shortly after the operation, and full loading of the knee can be achieved after 2-4 weeks. However, the chances of recovery are not always ideal if only the cartilage is smoothed. Therefore, depending on the extent of cartilage damage, a combination of microfracturing or bone augmentation is performed.
These procedures create new cartilage, which is often less resistant but stable compared to the original cartilage. Even though cartilage smoothing as an arthroscopic procedure is considered to have very few complications, complications may occur in rare cases, which should always be explained by the doctor before the procedure. The ablation can lead to injuries to deeper layers of the cartilage and to bleeding, which can result in joint effusion and swelling of the knee joint.
It can also lead to infections, wound healing disorders and injuries to the menisci or other components of the knee joint. Scars can form on the cartilage as a result of the ablation, which can also lead to knee problems again later, so that further cartilage smoothing or similar is necessary. In addition, nerve damage and sensitivity disorders may occur.
The risks of general or regional anaesthesia should also be mentioned here. The therapeutic value of cartilage smoothing is still controversial, as only damaged tissue is removed, but no new cartilage is created due to the low regenerative capacity. If the cause of the cartilage damage is not treated, damage can occur again and again, which in turn should make cartilage smoothing necessary.
In the long run, the thickness of the cartilage would be very small, so that it would no longer be able to perform its function of relieving pressure. Experts therefore recommend from the outset using procedures in which new cartilage is formed, for example with stem cells in the context of microfracturing. Find out more about the topic: Causes of osteoarthritis.