The type of surgery for an external meniscus lesion depends on both the extent of the tear and the age of the patient. Depending on the type of tear, it can either be sutured (meniscus suture), partially removed or completely removed and then replaced by a transplant (artificial meniscus). Regardless of the type of operation, an arthroscopy (knee arthroscopy) is performed.
Knee endoscopy (arthroscopy)
Knee arthroscopy provides surgeons with precise information about the extent of the actual damage, as MRI images often cannot provide an exact picture of the lesion. For arthroscopy, two accesses are usually made to the knee joint gap. One access is used to view the knee joint from the inside.
Accordingly, the rod has a camera, as well as a lamp and the possibility to irrigate the knee joint to maintain visibility. The second access is used for intervention, i.e. microsurgical surgery. Through the camera, the damage can now be closely examined from all sides.
The current stability of the knee joint is particularly important in deciding on the surgical method to be used. Meniscus refixation (meniscal suturing) is the desired method for the operation of the outer meniscus. Here the outer meniscus is fixed with high-quality suture material or meniscus arrows made of absorbable materials.
However, this surgical technique is only possible if the outer meniscus is torn off at the capsule and can be reattached there. Particularly in younger patients, refixation of the meniscus is performed even if the tears are less close to the base. To improve the chances of healing, the tear zone is additionally refreshed.
This increases the blood circulation in the area of the tear. Subsequently, the sutured meniscus must heal. This requires a lot of patience and a long follow-up treatment. View from above of the lower leg (shin / tibia), part of the knee joint: The menisci lie crescent-shaped on the side of the knee and function as shock absorbers. – Outer meniscus
- Inner meniscus
Partial removal of the outer meniscus (partial meniscectomy)
During partial resection of the external meniscus, the torn piece of the meniscus is removed. However, since not too large pieces of the meniscus can be removed, this surgical method (OP) is not always possible. In addition, the sliding function of the outer meniscus in the knee joint can be eliminated after the removal.
This leads to cartilage damage and knee joint arthrosis. For this reason, partial removal is only possible for minor damage. After partial removal, full weight-bearing is possible on the day of surgery, depending on the pain.
Artificial outer meniscus
A meniscus replacement can either be artificial (artificial outer meniscus) or directly from a human donor. It is placed in the place of the removed meniscus, so that in the best case, the body’s own meniscus tissue can regenerate at this point. The donor tissue is usually provided by internationally active tissue banks and was donated by deceased accident victims.
For successful transplantation, the exact size, side and shape of the meniscus must be determined. Rejection reactions as with transplanted internal organs do not occur. Overall, the transplantation of a donor meniscus has good chances of success.
However, waiting times are often long, which is why in more acute cases an artificial transplant (artificial outer meniscus) is often chosen. The artificial meniscus tissue is an implant made of polyurethane or collagen. To date, there are no study results on synthetic meniscus implants (artificial outer meniscus).
However, the biological materials made of bovine (bovine) collagen show good results. It has been shown that within two years in many patients the bovine collagen was broken down and completely replaced by the body’s own material. In contrast to a partial meniscus removal, the follow-up treatment of an artificial outer meniscus takes a very long time. Athletes must expect a break of several months to a year and then a slow build-up of movement.