Anterior Cruciate Ligament Rupture

The anterior cruciate ligament (ACL) is the main stabilizer of the knee joint. Its role is to protect the joint from the anterior displacement of the tibia in relation to the thigh, to control the rotation of the joint and its lateral displacements (stiffness, flexibility).

Its function provides significant stability to the joint during daily activities, running, changing directions and landing by jumping. Rupture of the anterior cruciate ligament involves injury to the ligament in the knee that connects the lower thigh to the upper tibia. It is characteristic that a patient with a rupture of the anterior cruciate ligament complains of instability of his joint but also of episodes where his knee slides anteriorly(παρεμβολη εικονας : anterior cruciate ligament rupture).

Epidemiology
The incidence of anterior cruciate ligament injury in the knee is two to eight times higher in women than in men. In basketball in particular, women are four times more likely to be injured than men. This difference between the sexes is even greater in people attending military academies. Also, people who have had joint ligament repair have a higher risk of rupture in both the (most often) and healthy limb.

The incidence of anterior cruciate ligament injury is high in basketball, hockey, soccer, American football, gymnastics, skiing, and volleyball. Anterior cruciate ligament ruptures are constantly increasing due to the large participation of the population in these sports. Especially in skiing, anterior cruciate ligament injuries cover 25% to 30% of all knee injuries. Professionalism and the high level of sports today reinforce the above phenomenon.

Diagnosis
A good history combined with special tests can make the diagnosis without the need for additional tests. Measuring the relaxation of the ligament with special instruments enhances the clinical examination and provides an objective reference point for future comparisons. The most commonly used articulator is the KT-1000 which uses constant forces to determine the anterior tibial displacement.

Of great importance are the simple radiographs with which fractures of the knee must be ruled out (but also detached fractures in the protrusion of the ligament). Although usually not necessary for diagnosis, magnetic resonance imaging (MRI) is useful as it is more than 95% accurate in diagnosing anterior cruciate ligament rupture. It is also extremely useful in the search for concomitant lesions. Another imaging examination is the knee arthroscopy which, in addition to being diagnostic, also has therapeutic value for the restoration of ligament damage.

Treatment
Combined anterior and posterior cruciate ligament injuries are rare but present with serious complications especially if accompanied by nerve and vascular damage. Although many different views have been recorded on what is the best way to treat these injuries, there are many who argue that the best functional result results from surgical treatment of the anterior and posterior cruciate ligament, rather than conservative treatment. There is also the view that immediate surgery for both ligaments yields a better functional outcome.

In the postoperative rehabilitation of the combined surgical treatment of the two ligaments, the main priority is the early mobilization of the joint, the gradual loading of the limb and secondarily the gradual recovery of the joint flexion. The aim is for the trajectory of the movement to be gradually recovered.

Anterior cruciate ligament rupture is treated with cryotherapy, continuous passive mobilization (CPM), and isokinesis. The methods of cryotherapy are many and include cooling sprays, immersion in cold water, ice cubes with ice cubes, gel pads, crushed ice pads, continuous flow ice water systems (Cryocuff) and cold air generators. Continuous passive mobilization (CPM), in contrast to intermittent passive motion, is motion that remains uninterrupted for long periods of time. It is usually applied by a mechanical device, which moves the desired joint continuously within a controlled range of motion, without the patient’s effort up to 24 hours a day for 7 or more consecutive days. The movement is passive, so that muscle fatigue does not interfere with movement. The machine is used because the person could not apply the controlled movement continuously for a long period of time. Isokinization is a process in which a part of the body accelerates until it reaches a default constant angular velocity against an adjustable resistance. Regardless of the magnitude of the force applied by the patient, the velocity of the segment does not exceed the default angular velocity. As the patient tries to overcome it, the resistance is modified so that it corresponds exactly to the force applied at each point of the range of motion. The force applied by the patient is measured in appropriate units and is represented numerically and graphically to be a reference point for future comparisons.

Restoration of anterior cruciate ligament rupture is a long process (6-8 months) which requires proper planning and full cooperation with the patient to complete with the best possible results.

Ideal Return to Activities and Reduce the Risk of Re-injury.
The decision as to when a patient may be allowed to fully return to activities is, in most cases, empirical because there is little correlation between functional and clinical trials. The use of multiple criteria, including return to range of motion, muscle strength and balance, static and dynamic stability, is necessary to determine the appropriate time for a patient to return to full activity.

Sources
Prentice W.E., & Onate J.A., (2007). Knee Injury Rehabilitation: Sports Injury Rehabilitation Techniques, 4th Edition, (Edited – Translated from English by Athanasopoulos, Katsoulakis), Scientific Publications: Parisianou, Athens