Ligament Sprain: Signs, Grades and Diagnosis

A ligament is a dense band of connective tissue that holds two bones in a joint and limits movement in it. When a joint folds or twists beyond its range of motion, the band is overloaded: the fibers stretch and some of them tear. What is commonly called "pulling a ligament" is called a sprain in medical terms, sometimes a distortion.

What ligaments and ligament sprains are

Ligaments connect bones to each other, tendons connect muscle to bone. These are different tissues: a ligament is stretched, a tendon is torn under overload. In everyday speech both cases are called the same, but for a doctor these are two different pictures.

Strictly speaking, a ligament sprain is always a tear, just of varying extent: in a mild injury it is visible only under a microscope, in a moderate one individual collagen fibers tear, in a severe one the entire ligament tears. Ligaments heal well and in most cases heal on their own, even after a complete tear.

Why a sprain (distortion) occurs

A joint works like a hinge, and a ligament acts as a motion limiter: it prevents the bones from moving apart beyond the normal range. When movement sharply exceeds the normal range of motion — during a fall, a twisted leg, a blow — the load falls on the limiter, and it tears.

The ligaments of the ankle and knee joints, as well as the wrists and thumbs, are most often affected. Muscle fatigue, lack of warm-up and playing sports are triggers.

Signs and symptoms of a ligament sprain

Pain appears immediately and intensifies when trying to turn the joint in the direction in which it was twisted during the injury. It also hurts when pressing on the area of the ligament and at its attachment points to the bones. With a leg injury, it hurts when trying to step on it. Weakness and swelling are added: the swelling increases gradually and sometimes swells the joint to "elephantine" size.

A hematoma, redness and local increase in skin temperature often appear. A bruise often shows up on the second day and below the site of injury. With a moderate injury, joint mobility is limited; with a complete tear the picture is the opposite — the joint becomes excessively mobile and unstable, and this is noticeable when the swelling subsides. With a moderate or severe injury, a pop is heard: this is how a bundle of fibers tears.

Grades of ligament injury

The grade is determined by the depth of the tear. The first — a tear at the microscopic level. The second — a tear of part of the collagen fibers; with a moderate injury, joint mobility is significantly limited. The third — a tear of the entire ligament: the joint becomes excessively mobile and unstable.

Most sprains feel noticeably better after two weeks; severe injuries take months to recover.

How a sprain is diagnosed

The doctor asks how the injury occurred and examines the joint: where it hurts, whether there is swelling and hematoma, whether the person can bear weight on the injured limb.

Without an X-ray, it can be difficult to distinguish a sprain from a fracture: a fracture from indirect force almost always occurs together with a ligament sprain, and without an image they cannot be separated. For soft tissues — ligaments and tendons — MRI and ultrasound examination of the joint are used.

The following are more likely to indicate a fracture:

• pain when pressing on the bone near the site of injury, but not at the ligament attachment points;
• severe aching pain at rest that makes it difficult to sleep;
• impaired sensation on the skin below the injury;
• inability to move the fingers of the injured limb;
• a crunch at the moment of injury — as opposed to a pop when a ligament tears.

When to see a doctor

You should see a doctor if after self-care it gets worse or there is no improvement. An urgent consultation is needed for very severe or increasing pain, large and growing swelling or bruising, inability to step on the leg or walk more than a few steps, or stiffness of the joint. A separate warning sign is a high body temperature, chills, a feeling of heat or cold: this may be a manifestation of infection. If healing is prolonged, physiotherapy is discussed.

A sprain by itself is not a reason to call an ambulance. You should call 103 or 112 if at the moment of injury a crunch was heard, the limb changed shape or is positioned at an unnatural angle, numbness or tingling appeared, or the skin around the injury turned blue or became cold to the touch: these are signs of a possible fracture.

This material is for reference and does not replace consultation with a doctor who will examine your specific joint.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer