Injury-stricken physical shock absorbers

It is obvious that the function of an intact meniscus is extremely important to preserve the cartilage covering and knee function, i.e. to prevent or to slow down the occurrence of osteoarthritis.

Meniscus injuries are among the most frequent injuries to the knee joint and comprise about 75 percent of the intra-articular knee pathology. They are a consequence of degeneration or trauma, or a combination thereof. A meniscus injury usually occurs by rotation mechanism in a mild flexion. An external rotation mechanism of the lower leg injures the medial meniscus, and an external rotation injures the lateral meniscus. The medial meniscus, especially its posterior horn is four times more frequently injured than the lateral. It is not uncommon that the same mechanism causes knee ligaments injuries, as well as cartilage injuries.

Usually an examination is sufficient to diagnose the injury

A rupture of the meniscus may be transversal, horizontal, longitudinal, inclined, or a combination thereof. In case of a longer longitudinal rupture a free part of the meniscus may “slip” into articulate bodies and block the knee, which, due to that condition, cannot be stretched out. Along with the blockage, other clinical symptoms of a ruptured meniscus are pain at the joint cavity level, slight swelling of the knee joint, and a sense of instability may be present as well.

The diagnosis of a ruptured meniscus is set up by taking of medical history, which is often typical, and a physical examination, which consists of a series of specific, usually not painful, tests. The tests can be supplemented by a magnetic resonance imaging, but only upon examination by an orthopaedist or traumatologist. It is recommended to carry out a native radiographic image of the knee.

Less invasive surgery

The development of arthroscopic techniques and other technical requirements set up the grounds for a minimally invasive treatment of a ruptured meniscus. The first arthroscopic suture was performed by Hiroshi Ikeuchi in 1969. Over time, this method of treatment has become a widely accepted method, so today the treatment of a ruptured meniscus consists of an arthroscopic meniscectomy or a meniscal suture (Figure 2).

This treatment method means that the knee joint is not opened, but an arthroscope (camera) is inserted through a small opening on one side and a specially designed instrument is inserted on the other side, so only the damaged part of the meniscus is removed. If it is in any way possible, the injured part of the meniscus is sutured (Figure 6) thus preserving its integrity, which is favourable for the subsequent function of the knee joint. For many years the only method of treatment was a partial or total meniscectomy, but soon it was realized that the meniscus does not regenerate, it can only be repaired and can grow up to one third of its normal volume, which is not sufficient for a normal function (Figure 3), thus causing early degenerative changes of the knee (Figure 4). All this leads to conclusion that meniscectomy should be avoided whenever possible, and if it needs to be done, it is recommended to be as minimal as possible, i.e. to remove only a part of the ruptured meniscus (Figure 5).

 

Meniscus sutures

Compared to meniscectomy, suturing is a technically more demanding procedure which prolongs surgery and requires the knowledge of several different meniscus suturing techniques, and assumes the availability of operating instruments as a technical prerequisite. Unfortunately, not all meniscus ruptures can be sutured. To suture ruptured meniscus it is necessary to know its blood supply. Since the blood supply is necessary for healing of a ruptured meniscus, the most suitable for suturing is the peripheral meniscus area, which has the best blood supply. When deciding on meniscus suturing it is important to take into account the type of rupture. Suturing is most appropriate for longitudinal ruptures in the vascular rupture zone and the meniscus and cap joint.

This indication is questionable in case of transversal, horizontal ruptures, ruptures in flap shapes, and various degenerative ruptures. The quality of a meniscus is also important, so it must not be torn or degeneratively altered. Younger patients are most suitable for meniscus suturing (younger than 40, and according to some authors, 50) with a fresh meniscus injury (preferably up to two months old), without injury of cruciate ligaments or with the reconstruction of the anterior cruciate ligament, in case of its rupture. The practice has shown that only 10 percent of the damaged menisci meet the above criteria for suturing.

There is a significant difference in rehabilitation process after meniscectomy or meniscal suturing. The rehabilitation process after meniscectomy is quick, typically with minimum of pain, and patients can quickly return to full work and sports activities, usually after three to four weeks. But for a sutured meniscus the patient must be motivated, as the postoperative rehabilitation lasts longer. Due to this prolonged healing many professional athletes do not opt for this treatment. The rehabilitation after meniscus suturing consists of limiting flexion and preventing rotation of the knee. In the first two weeks the movement is limited by orthosis to 0/30°, following with 0/50° range in the third week, and after that 0/90°. After four weeks the full flexion is gradually allowed, but squatting and kneeling are forbidden. Walking is permitted immediately after surgery. Rotations of the knee, such as jumping, landing and running with the directional change are forbidden for three months after the surgery. Running without a change of direction is allowed after three months, and a contact sport with rotation six months after the procedure. If there was the reconstruction of the anterior cruciate ligament performed along with the meniscus suturing, then the rehabilitation process does not differ, with respect to accelerated rehabilitation after the reconstruction of the anterior cruciate ligament and an orthosis is not required.