The knee is a joint that is made up of 3 bones: the lower part of the femur, the upper part of the tibia, and the patella. The articular surfaces of these bones are covered by a layer of tissue softer than the bone, but marble-like, called CARTILAGE, through which these surfaces slide to give the bending and extension movement of the knee (the bending and stretching movements).
To make congruent the articular surfaces of the femur (spherical surface) and the tibia (flat surface) there are the MENISCUS, in number of 2: The internal meniscus and the external meniscus.
To give stability to the knee joint there are basically 4 LIGAMENTS:
2 lateral: Internal and external, located on both sides of the knee.
2 crossed: Anterior and posterior, located in the central part of the knee.
Preparing for arthroscopy
Prior to the intervention, the surgeon and/or anesthesiologist will have reviewed the so-called pre-operative tests (blood tests, chest X-ray and ECG) in order to rule out any alteration that involves an added risk to the anesthetic and surgical procedure.
Approximately 6 hours before the intervention the patient must be fasting (he will not be able to eat or drink), and will be admitted to the Hospital 2-3 hours before the intervention.
In knee arthroscopies, the most commonly used type of anesthesia is spinal anesthesia (puncture in the lower back), which allows the legs to be asleep during the intervention, but the patient is awake, so that, if you wish, you can follow the intervention by the TV monitor , at the same time that the surgeon explains everything he is doing at that very moment.
Through a first small incision, we introduce a cannula into the joint, and fill it with serum. By a second small incision, we introduce the device called arthroscope, and start the visualization of the joint.
Knee pathologies that can be treated by arthroscopy are:
1- Ruptures of the meniscus:The meniscus are structures of cartilaginous consistency that, in a number of 2, are located between the femur and the tibia, on both sides of the knee. The meniscus is crescent-shaped, and the most frequent location of the breakage is at the level of its back. When there is a break, the broken meniscus fragment causes the joint not to work properly, so, using arthroscopy and the appropriate instruments, it will trim that fragment, leaving the rest of the meniscus healthy in place.
Sometimes the rupture of the meniscus is very close to its insertion area, so in these cases we perform a repair of said injury, using a technique of suturing the meniscal lesion.
2- Ruptures of the cruciate ligaments: By far, the most frequent rupture is that of the anterior cruciate ligament. This is broken with the movement in which the foot remains fixed and the body rotates on the axis of the knee. This movement is very typical in the practice of sports such as skiing, football and basketball.
The rupture of the anterior cruciate ligament implies that the knee initiates a picture of instability, that is, an anomalous and spontaneous movement appears that the patient notices in the form of failures. Once it ruptures, the anterior cruciate ligament has no capacity for repair of its own (healing), so if the injury is not repaired, this anomalous movement ends up affecting the meniscus (which end up breaking), and later affects the cartilage, which initiates a process of degeneration, at which time the injuries are no longer repairable.
Therefore, today it is widely proven that to avoid the start of this degenerative process, the injury of the anterior cruciate ligament must be repaired.: It should be replaced by a structure that is in the same position and does the same function as that of the injured anterior cruciate ligament. That is why the so-called PLASTIAS are used.
Basically we obtain them from the patient himself, and from 2 main locations: From the patellar tendon of the knee (Bone-Tendon-Bone type plasty) or from the tendons of the semitendinous and internal rectum muscles (Hamstring type plasty), located on the back side of the thigh. The use of one or the other plasty depends on the surgeon’s preference and the patient’s demands (for example, depending on the sport he practices).
The plasty is placed through arthroscopy in the same anatomical position as the original anterior cruciate ligament, and is fixed at the level of the femur and tibia with the so-called fixation systems, which are different depending on the type of plasty used. These fixation systems are located inside the bone, and will not have to be removed later, as they will not produce any discomfort.
Rupture of the posterior cruciate ligament is much better tolerated with a correct recovery regimen (there is usually no feeling of failure on the part of the patient). We will only opt for surgical treatment if there is presence of failures, and the same procedure will be done as in the anterior cruciate ligament: Replacement of the original ligament by a plasty.
3- Presence of free articular bodies:They come from cartilage, and their presence may be due to trauma (osteochondral fracture) or degenerative processes.
4- Certain types of fractures:In fractures basically of the tibial surfaces we can help us with arthroscopy to put in place the fragments of the fracture and fix them with osteosynthesis screws.
The RISKS of knee arthroscopy are as follows:
Anesthetic Risks: Allergic reactions to medications used during the anesthetic procedure, respiratory problems, cardiovascular problems may occur. To avoid to a large extent this type of complications, the so-called preoperative tests are requested prior to the intervention (as discussed above).
Circulatory Problems: Phlebitis, thrombosis, … To avoid this, for a few days after arthroscopy, a subcutaneous medication (low molecular weight heparin) is administered, which has the effect of clarifying the blood to a small degree, so that the risk of suffering this type of complication greatly decreases, but it does not disappear completely.
Presence of Joint Stiffness: After arthroscopy, the knee may react causing internal tissues to become inflamed and harden, rapidly decreasing joint mobility. With the techniques that are currently used the mobility of the knee is practically immediate after the intervention, so that the presence of joint rigidity is less and less frequent.
Joint infection: the incidence is less frequent than in open surgery. It appears at 7-10 days after the intervention, and requires surgical cleanings on the knee combined with intravenous antibiotic treatment.
No complete disappearance of symptoms, especially in arthroscopies performed on degenerative knees, that is, signs of wear and tear are present.
For the little complex surgeries (meniscal ruptures, cartilaginous pathologies) at 6 hours of the intervention we already start the mobilization of the knee, and the patient can start ambulation (without any type of immobilization, only a simple bandage to protect the wounds), although in some cases it may require the help of a crutch to reduce the pain. The patient is discharged from the Hospital in the first 24 hours after the intervention, and a few days later can start a practically normal life (except in the performance of sports activity, in which you must wait between 2 and 4 weeks depending on the type of pathology).
In the most complex procedures (ruptures of cruciate ligaments) it is not until 36-48 hours that we start the flexion and extension movements of the knee, and 2 days after the operation the patient is discharged from the Hospital walking, helped by 2 crutches and supporting the operated leg on the floor, but without ANY IMMOBILIZATION in the knee. At 4 weeks the patient walks normally (without crutches), with a movement of flexion and extension of the knee complete, and at 3 months the recovery pattern ends, and the patient can start certain sports activities (continuous running, cycling and swimming). It will not be until the 6 months that you can perform any type of sport (football, basketball, skiing, tennis …).