Ligament injuries: what are they and what problems do they cause?

By Cristiano Antonino On May 31, 2023

Ligaments are strong structures that connect bones together and perform a very important stabilising function

Although they are strong, these structures are not very elastic.

Therefore, if subjected to rapid stretching or excessive loads, they can be injured, from minor to complete rupture.

Find out below everything you need to know about ligaments and what happens in the event of a partial or complete ligament injury, what the symptoms are and what treatments are possible.

What are ligaments and what is their function?

Ligaments are strong fibrous structures that connect two bones or two parts of the same bone by tying them together and performing an important task of stabilising and securing mobile joints.

They should by no means be confused with tendons, which instead have the task of connecting muscles to bones or other insertion structures.

Ligaments serve to guide and limit those movements that could alter the position of the structures to which they are connected, thus preventing trauma and excessive stress from damaging the joints or causing the bones to lose their natural connection.

The ligaments within the human body are positioned to intervene actively only in cases where the degree of movement is extreme, i.e. when the integrity of the joint is seriously threatened.

Therefore, in addition to having an important primary stabilising function, ligaments also have a very important proprioceptive role.

In fact, at ligament level, there are many nerve receptors that, in conjunction with the muscles, tendons and capsules, constantly provide the central nervous system (CNS) with information on the condition of the locomotor apparatus, so that it can actively intervene by regulating muscle tone, correcting posture, balance, coordination and the activity of the muscle groups that come into action depending on the situation.

With each physiological movement, therefore, the muscles that are activated move the bones, which can, however, only perform movements within the limits allowed by the joint and the fixation means that have the task of preserving the different anatomical structures not only mechanically, but also thanks to the support of the central nervous system.

Why are ligaments prone to injury?

Like all other structures of our locomotor system, skeletal ligaments also have their own characteristics of resistance to trauma and stress and can only resist applied forces within a certain limit.

Their fibrous structure makes them extraordinarily strong but very inelastic and therefore not very susceptible to deformation under the action of high loads.

Like tendons, ligaments consist of approximately 70%-80% type I collagen fibres, which are particularly resistant to stretching.

The percentage of elastic fibres that are very stretchable but not very resistant, on the other hand, is particularly small.

The elasticity of the ligaments can, however, be increased, even up to 150%, by specific stretching exercises, which involve a particularly low load; however, at high loads, these fibres can suddenly rupture.

The extraordinary degree of joint mobility that can be achieved through stretching is truly impressive, but such a degree of elasticity is nevertheless to be considered dangerous at the same level as excessive stiffness, as it greatly increases the degree of instability and joint laxity.

When the forces applied to the ligaments exceed the maximum tensile strength of their fibres, so-called ligament injuries occur.

The ligament fibres tend to stretch at first, then tear until complete rupture occurs.

The faster force is applied to the ligaments, the more susceptible they are to injury.

In cases of particularly slow trauma, the resistance of the ligaments is such that a small part of the bone to which they are connected becomes detached, resulting in bone avulsion.

Degrees of injury and most frequent ligament injuries

When a ligament injury occurs, its extent is proportional to the trauma and can be classified into four different degrees of severity:

Grade 0: when there is a joint trauma in which, however, no anatomical damage to the ligaments is observed.

Grade 1: when there is a minor trauma that causes a very small injury to the fibres within the ligament; these injuries are really microscopic and, in most cases, do not interfere in any way with the normal stability of the joint involved.

Grade 2: when there is a medium-sized trauma that causes a partial rupture of the ligament; in cases where the torn fibres are less than 50% of the total we speak of a grade II minor injury, whereas if the number of broken fibres exceeds half, this is a grade II major injury. Obviously, as the number of injured collagen fibres increases, the degree of instability of the joint will also increase.

Grade 3: when there is a severe trauma in which there is a complete rupture of the ligament that can affect both the central area and the ligamentous insertion in the bone.

Usually it is sprains and dislocations, traumas in which the joint is stressed beyond its normal limit of motion or makes abnormal movements, that cause ligament injuries.

In the knee joint, for example, the most injured ligament is the anterior cruciate ligament, which is often sprained, especially in sports participants.

The most frequent mechanism of injury is the involuntary movement of external valgus-rotation while the foot remains locked to the ground.

Ankle sprain is also one of the most frequent ligament injuries.

Usually the ligament that is most affected by sprain injury is the anterior peroneal-astragalic ligament, located in the lateral compartment.

All it takes is to place the foot incorrectly in a position where the ankle is abruptly moved away from the heel, to have a strong impact with the ground after a jump, or to change direction quickly, for the ankle to undergo a strong inversion trauma and cause an injury to the ligament.

Symptoms of a ligament injury

The symptoms and their severity obviously vary depending on the degree of the ligament injury.

In the case of a medium to severe distortion-type injury, where the number of torn fibres is very high or even complete, the most predominant symptom will be pain, which may be accentuated by palpation or particular movements.

Subsequently, the joint will swell due to haemorrhaging in the joint space and ecchymosis may appear in the area affected by the trauma.

If the injury is complete, a feeling of laxity and instability will be perceptible.

If it was a dislocation that caused a ligament injury, the limb will assume a kind of defensive posture, making it almost impossible to perform any kind of movement, either active or passive.

How is a ligament injury diagnosed?

Sometimes a careful anamnesis and an objective examination, with specific tests and investigations of the injury mechanism, are more than sufficient to make the diagnosis of a ligament injury.

Often, however, the specialist also chooses to make use of instrumental diagnostic techniques such as X-rays, which are useful to exclude the presence of possible fractures or alterations of normal joint relationships.

In more serious cases, the doctor may also prescribe a magnetic resonance imaging (MRI) or a computed tomography (CT) scan to confirm the clinical diagnosis.

What are the treatments?

In the most acute phase of the injury, the patient will be advised to apply the famous RICE protocol:

Rest: remain at rest.

Ice: make ice packs of 20 to 30 minutes every hour for at least 4 hours after the trauma.

Compression: compress the affected area with a bandage for at least 24-48 hours after the injury.

Elevation: elevate the area affected by the inflammation, possibly above the level of the heart in order to promote venous return and avoid further blood pooling.

In most cases, ligament injuries are treated conservatively.

This is due to the fact that ligaments are quite vascularised and therefore possess a fair reparative capacity.

Only in a few special cases, and always after a careful analysis of the patient’s lifestyle, is a surgical intervention resorted to.

This is the case, for example, with injuries to the anterior cruciate ligament, since this ligament never heals spontaneously, but tends to accumulate injuries until it ruptures completely.

The recovery time from a ligament injury is quite long, ranging from a period of 3-4 weeks for moderate injuries to 6 or more months in more severe cases and complete ruptures.

In order to regain mobility and stability, rehabilitation is extremely important, but it should not interfere in any way with the patient’s healing process.

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