Meniscus injury
What is the meniscus and where is it located?
The meniscus is a crescent-shaped, cartilaginous connective tissue with a triangular cross-section. We have two menisci per knee: one on the inside and one on the outside of the knee joint.
On the one hand, the meniscus serves as a buffer between the upper and lower leg bones and thus protects the corresponding cartilage. On the other hand, the menisci transfer the force from the thigh evenly to the lower leg.
What are the symptoms of a meniscus lesion (meniscus tear)?
A sharp pain in the knee joint during certain movements indicates a problem with the meniscus. Patients usually report an immediate stabbing pain, typically on the inside of the knee joint after a twisting movement of the upper body with the lower leg fixed or when the patient squats. Some patients also describe a blockage, effusion, restricted movement or snapping. The meniscus itself does not hurt because, like the cartilage, it has no nerves. However, a torn meniscus can irritate the joint capsule when the knee joint is rotated and flexed, causing a sharp pain and leading to an effusion. In the worst case scenario, a torn meniscus can cause a knee blockage.
How is a meniscus tear examined and diagnosed?
In most cases, a thorough clinical examination is sufficient to diagnose a meniscus tear. This is when the movement-dependent stabbing pain is triggered. An imaging examination using magnetic resonance imaging (MRI) provides further information about the size, type and localisation of the meniscus tear as well as other consequential damage (cartilage damage) in the knee joint.
How can the meniscus be treated?
A meniscus tear can be treated either conservatively or surgically. Which method is chosen depends on the age and needs of the patient as well as the type (accidental or degenerative), localisation and extent of the meniscus tear. Other concomitant injuries in the knee joint also play a role. These must be discussed in detail with the patient.
Conservative treatment method
You can usually live well with a meniscus tear. However, rotational movements and strong flexion of the knee joint should be avoided.
Scientists from Scandinavia found in a study that the symptoms can often be remedied just as well with targeted physiotherapy as with surgery by means of so-called arthroscopy.
Effective physiotherapy includes exercises to strengthen the muscles and improve stability, mobility and coordination. It is important that the exercises are carried out correctly and that jerky movements are avoided.
We work closely with experienced physiotherapists and put together the right treatment for you.
Surgical treatment methods
Unfortunately, the meniscus does not grow together by itself. Every twisting movement can cause the tear to grow larger, resulting in new stabbing pain. It can go so far that the free meniscus flap turns over, leading to a blockage and severely restricting the quality of life. In certain cases, surgery is therefore still necessary to improve quality of life.
Surgery is usually recommended in the following cases:
- The younger and more athletic the patient
- If there has been no improvement in movement-related pain despite conservative therapies
- If mechanical complaints such as impingement and blockage do not disappear
Meniscus operations can be categorised as follows:
- Meniscus suture
- Removal of the torn part of the meniscus
- Meniscus replacement (in very rare cases)
The procedures are all minimally invasive usingarthroscopy. The video camera and the corresponding instruments are inserted through two small incisions of approx. one centimetre to the right and left of the patellar tendon.
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Meniscus suture
The blood vessels sprout from the joint capsule into the outer meniscus and thus supply the outer third of the meniscus. The rest, i.e. two thirds of the meniscus, is not supplied with blood and is nourished directly by the synovial fluid. The outer meniscus is more mobile than the inner meniscus, which is fused to the joint capsule and the inner knee ligament. The suture attaches the torn meniscus tissue to the healthy part of the meniscus that is supplied with blood and to the joint capsule, so that the torn meniscus tissue is supplied with blood again and can thus heal.
Only a small proportion of meniscus tears can be sutured, e.g. certain longitudinal tears close to the joint capsule. The location, quality and overall care of the knee play a role, as does the age of the patient. The younger the patient, the better the blood supply to the meniscus, the better the healing rate and therefore the higher the success rate.
In most cases, it can only be decided during the arthroscopy whether a meniscus suture is possible and also sensible. The non-healing rate of a meniscus suture (failure rate) is up to approx. 20 per cent. In these cases, a second operation must be performed. The suture and the torn part of the meniscus are then either removed or a new suture is placed if a subsequent tear has occurred. Meniscus sutures in fresh (accident-related) meniscus tears heal better than in older (chronic) meniscus tears. If there are multiple knee injuries (e.g. cruciate ligament rupture), all problems must of course be repaired at the same time.
Removal of the torn meniscus
This is the most common arthroscopic operation in the knee joint. If the meniscus has been torn several times, has undergone degenerative changes or if the torn areas are not supplied with blood, this tear cannot be sutured. This defective part of the meniscus, which no longer has a mechanical function, is removed in the sense of "as little as possible, as much as necessary". We speak of a partial meniscus resection when only the torn pieces of meniscus are removed and of a meniscus resection when the entire meniscus has to be removed. This eliminates the disturbing mechanical complaints and the patient is quickly free of pain.
However, this procedure reduces the load-bearing surface of the residual meniscus, which can lead to it tearing again if it is overloaded again by a twisting movement. In addition, the absence of part of the meniscus buffer can lead to more rapid wear of the joint cartilage in the long term and thus to knee osteoarthritis. For these reasons, the primary treatment is to suture the meniscus.
Meniscus replacement
In very rare cases, the meniscus is not only removed but also replaced. This usually affects younger patients with little or no cartilage damage. If the entire meniscus is affected, it can be replaced by a meniscus transplant using a donor meniscus. It is also possible to bridge the gap with a biological tissue substitute. The meniscus replacement is sutured into the cleaned defect and consists of either collagen or polyurethane, which is gradually replaced by the body's own tissue.
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PD Dr Andreas L. Oberholzer is a recognised expert in knee injuries.
Book your appointment directly online here or call us on +41 44 388 16 16. You are also welcome to come to us for a second opinion.
PD Dr Andreas L. Oberholzer
FMH specialist in orthopaedics and trauma surgery. Areas of specialisation: Knee, hip and foot surgery.