Meniscus Surgery

Meniscus surgery is a therapeutic surgical measure in orthopedics and trauma surgery, which is used to preserve mobility in the event of clinically relevant damage to the menisci (meniscus is the term used to describe a crescent-shaped cartilage in the knee joint). Lesions of the menisci are the most common cause of surgical intervention on the knee joint, as the right medial (located on the inner side) meniscus in particular is unable to withstand the stress as a result of permanent overloading. The cause of damage to the menisci can be either chronic overuse or an acute application of force in a trauma (injury). Degenerative changes are much more likely in older patients than in younger patients. Rupture of the meniscus can take the form of the so-called basket-handle tear. The meniscus in question may also be characterized by a decrease in volume as a degenerative phenomenon, so that the thinning of the meniscus must lead to a tear. The peculiarity of the basket-handle tear is that the rupture runs parallel to the direction of the fibers, which makes diagnostic detection much more difficult. However, a basket handle tear is far less likely to cause pain, so many affected patients do not seek medical attention when the tear is present. Degenerative changes are usually more commonly associated with pain. For the treatment of a clinically relevant meniscal lesion (meniscal damage), there are various therapeutic options in Germany. However, the choice of procedure depends not only on the type and severity of the damage but also on the age and fitness status of the patient. In particular, surgery is necessary for active individuals and especially for athletes, since only surgical intervention can prevent further damage, as the presence of a high load on the knee is likely to increase the rupture of the meniscus. The advancing rupture of the meniscus induced by loading becomes more and more serious in the subsequent period, so that a delay of surgery is by no means indicated. Furthermore, it is important for the therapy that the meniscus consists of the same material as the articular cartilage, from which it can be concluded that the body is not capable of regenerating the damaged area. A meniscus tear is often recognized by the presence of extension deficits, so that the knee can no longer be fully extended. In addition, severe pain in the back and sides of the knee, extending into the shin, often indicates a lesion of the menisci.

Indications (areas of application)

Meniscectomy (surgical removal of the menisci).

  • Symptomatic and nonreconstructible meniscal lesions.
  • Symptomatic disc meniscus (malformation of the meniscus).
  • In the presence of knee instability after surgical intervention after a meniscal lesion.
  • In a meniscus lesions in advanced degenerative joint changes – here it should be noted that age is not decisive for the success of the therapy of a meniscus lesion.

Meniscus replacement

  • To prevent further cartilage damage in young patients, especially athletes, total meniscectomy is performed. It should be noted that the lateral knee joint compartment is associated with a higher risk of hazard.
  • In the case of loss of the anterior cruciate ligament with destroyed or previously removed meniscus, implantation of meniscal replacement in parallel with cartilage protection may also contribute to additional stability.
  • To delay the implantation of an artificial knee joint in elderly patients with existing knee joint osteoarthritis, implantation of the meniscus replacement can be performed.

Contraindications

There are no specific contraindications for the surgical procedures.

The procedures

At the beginning of meniscus surgery, an arthroscopy (knee arthroscopy) is first performed, the benefit of which is that the surgeons performing the procedure can obtain a precise indication of the existing damage to the menisci without causing massive discomfort to the patient. Arthroscopy is necessary because even state-of-the-art diagnostic procedures such as the use of magnetic resonance imaging (MRI) may not allow a reliable diagnosis to be made.Before the endoscope (metal rod with fiber optics for reflection) can be inserted into the knee joint, the knee must first be rinsed in order to be able to make an adequate assessment. Following this, the endoscope with a lens is inserted into the knee so that the structures of the knee joint can be examined and assessed on a monitor. Of utmost importance for the selection of the therapeutic measure in case of an existing meniscus damage is the consideration of the current stability situation of the affected knee joint. The selected therapeutic procedure, such as performing a meniscal suture operation or a meniscal transplantation, must by no means be performed without stabilization measures, since instability is primarily responsible for the symptoms of a meniscal rupture. Conservative treatment options for meniscal damage:

  • Implementation of a therapeutic measure without concomitant surgical intervention is indicated in the rarest cases of an existing meniscal lesion. As conservative therapy options in case of damage to the menisci are the standard measures such as cooling, elevation of the affected joint, administration of non-steroidal anti-inflammatory drugs (NSAIDs; anti-inflammatory painkillers that do not contain cortisone, ie are steroid-free) and the use of a physiotherapeutic exercise treatment or rehabilitation measure to list.
  • As described earlier, using arthroscopy, a precise classification of damage to the menisci into lesions requiring treatment and lesions not requiring treatment can be made. Not requiring treatment or treatable by conservative therapy are all stable and nonsymptomatic forms of rupture. Stable lesions are those in which the damaged portion of the meniscus does not protrude further into the joint or cannot be pulled further in than the inner edge of an intact meniscus. Lesions that do not require surgical intervention (surgery) include a stable incomplete longitudinal tear of the meniscus or a stable complete longitudinal tear that is shorter than one centimeter. Furthermore, radial tears of less than one-third the width of the meniscus and an asymptomatic intact disc meniscus are also among the lesions that do not require surgery. In contrast to stable damage, unstable meniscal damage requires surgical treatment because cartilage damage can be caused by the damaged structures.
  • Symptomatic meniscal tears for which it is foreseeable that they will not heal should preferably be treated with partial meniscal resection rather than reconstruction.
  • Several studies to date have shown that failure to treat a meniscal lesion can cause the same degenerative damage as a complete meniscectomy (removal of the meniscus). Based on this, a treatment recommendation for surgical treatment is always given when therapy is indicated.

The surgical procedures

Meniscectomy (surgical removal of the menisci).

  • Total meniscectomy – the surgical procedure of meniscectomy, in which the meniscus is either removed, can be divided into partial, subtotal or total intervention. Total meniscectomy involves removal of the entire meniscus and the vascular rim (blood vessel supply) necessary to supply it, up to the synovial border (synovium – structure that serves to absorb shock and nourish the articular cartilage). Furthermore, the total removal of the meniscus is characterized by the lack of preservation of the fibrous ring of the menisci.
  • Subtotal meniscectomy – unlike total removal, subtotal meniscectomy does not involve destruction of the fibrous ring. In addition to preservation of the fibrous ring, it is important for the definition of the surgical method that at least 50% of the meniscus is removed.
  • Partial meniscectomy – this surgical method for the treatment of meniscal damage is based on the principle of removing meniscal tissue in the plane of the damaged area. In contrast to the previously presented meniscectomy procedures, partial meniscectomy preserves at least 50% of the meniscal substance and the circular fibrous ring. The advantages of this therapeutic measure include less stress on the patient, less frequent clinically relevant postoperative bleeding, and faster rehabilitation.Furthermore, this procedure preserves the residual meniscus as a functional structure of the knee joint, which subsequently leads to a reduction in the probability of occurrence of degenerative sequelae of the knee joint. However, the risk of load-induced damage to the knee joint depends on both the extent of partial meniscectomy and pre-existing degenerative changes in the cartilage.After partial meniscectomy, a pain-oriented transition to full weight-bearing can occur as early as the day of surgery.

Meniscus refixation (meniscus suture).

  • This method is surgical procedure by which the damaged meniscus is fixed to the bone structure of the knee joint using an absorbable (self-dissolving) suture material. The meniscus refixation represents the gold standard (optimal treatment option) for meniscal damage, however, this therapy of choice can only be used for certain tears or tear at the capsule, because only in this present damage the meniscus can be reattached.
  • Due to the fact that meniscectomies usually result in degenerative joint symptoms, especially in younger patients, a refixation is also aimed at less base-near tears to reduce the risk of subsequent damage. To accelerate the healing process, the blood circulation is stimulated locally by refreshing the tear zone. Subsequently, the sutured meniscus must heal and a long follow-up treatment is necessary. In order to achieve an optimal healing process, it is essential that the movement of the knee joint is restricted in the first phase after the operation. To prevent strain, the patient should wear a stretch splint.

Meniscus replacement

  • Meniscus removal without the use of a meniscus implant leads in many cases to the occurrence of osteoarthritis, because the shock absorption of the knee joint without menisci can not take place sufficiently. However, the disadvantage of this implantation is that the procedure requires a long follow-up, so many athletes refrain from implantation because a possible loss of training of more than a year can be poorly compensated. However, athletes are particularly susceptible to osteoarthritis due to the high load.

Possible complications

  • Injury to the cutaneous nerves with subsequent sensory disturbances.
  • Pressure damage to the non-operable, drooping leg due to incorrect positioning technique.
  • Cartilage damage
  • Permanent swelling of the knee due to accumulation of irrigation fluid in the subcutaneous tissue (under the skin)
  • Anesthesia – the procedure is performed under general anesthesia or after performing spinal anesthesia, which results in various risks. General anesthesia can cause nausea (nausea) and vomiting, dental damage, and possibly cardiac arrhythmias, among other things. Circulatory instability is also a feared complication of general anesthesia. Nevertheless, general anesthesia is considered a procedure with few complications.Spinal anesthesia also has relatively few complications, but complications can occur with this method as well. Injury to tissue, such as nerve fibers, could lead to a long-lasting impairment of quality of life.
  • Risk of severe complications (0, 32%; risk increased by relatively 25% every 10 years of life in older patients); pulmonary embolism in the first 90 days after surgery: one patient per 1,282 patients (0.08%; 0.07-0.09); need for a second operation: one patient per 742 patients (0.14%: 0.13-0.14).

Further notes

  • Therapy of nontraumatic (not injury-related) meniscal lesions:
    • Most patients can be treated without surgery.
    • An undefined subgroup in whom physiotherapy did not achieve the expected success may benefit from arthroscopic meniscal resection. This subgroup may be patients with flap tears that can provoke mechanical symptoms.
  • Meniscectomy after traumatic tear does not appear to be more beneficial for symptoms than in patients with degenerative meniscal changes: Degenerative meniscal tears tended to have a more marked improvement in symptoms than traumatic ruptures.
  • Degenerative meniscal lesions
    • In patients with gonarthrosis (knee joint osteoarthritis; degenerative meniscal lesions), arthroscopic knee surgery with meniscectomy is associated with a threefold increase in the risk of future knee replacement surgery (knee TEP/total knee arthroplasty).
    • In patients with degenerative meniscal tears, partial meniscal resection can no longer be recommended because no benefits were obtained compared with a sham procedure, i.e., this did not have a long-term effect on the progression of (primarily low-grade) osteoarthritis and on pain and function of the knee joint.
  • In a randomized clinical trial of patients with degenerative meniscal damage, a supervised sports program to strengthen the knee muscles (12 weeks of up to three times a week a build-up training) achieved the same good result as arthroscopic surgery.
  • Partial meniscectomy: Three prognostically relevant factors show how promising arthroscopic partial resection of a torn meniscus is:
    1. Radiologically proven gonarthrosis (knee osteoarthritis) there was less improvement in the Lysholm Knee Score/Score for patients with disease or injury in the knee joint (in two of two studies).
    2. Longer duration of symptoms (> 3 or > 12 months): was associated with a worse outcome (in two of two studies).
    3. More extensive meniscal resection (> 50% or meniscal width < 3 mm or absent meniscal rim): was associated with worse patient-relevant outcome (in five of six studies).
  • Within 18 months, progression of cartilage surface damage by magnetic resonance imaging (MRI) in at least two of the 14 regions was observed in 60% of arthroscopic partial meniscectomy (APM) patients and 33% of physical therapy patients.
  • In patients with a nonobstructive meniscal tear, ie, meniscal tear without blockages, diagnosed by magnetic resonance imaging (MRI), patients benefited from 8 weeks of physical therapy to the same extent as from partial arthroscopic meniscectomy (partial meniscectomy).