Introduction
The labrum is a section of rubbery tissue that helps keep the socket of the ball in the ball and socket joint in position. The longest arm bone, also known as the humerus, forms a ball at the shoulder that meets the shoulder blade's socket connected by ligaments.
What Is the Labrum?
Two kinds of cartilage are found in the shoulder.
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The cartilage on the articulating surfaces of the bones is called articular cartilage, which allows gliding movements of the bones on each other. However, this type of cartilage may wear out due to arthritis, causing the joint to become painfully stiff.
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The labrum is fibrous cartilage in the shoulder, which differs from the articular cartilage and is more rigid than the articular cartilage. The cartilage’s presence around the socket makes it unique.
What Are the Functions of the Labrum?
The labrum has the following functions;
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The labrum deepens the joint socket so that the ball remains in place. As a result, the humerus ball is much larger than the flat socket, where ligaments tether bone to bone and hold them together to stabilize the joint.
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The labrum attaches to the structures or tissues around the joint.
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The ball is also kept in place at the socket of the labrum by widening it.
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The labrum essentially forms a bumper at the joint.
What Is a Labrum Tear?
A labrum tear has several forms, and they are.
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The labrum may tear entirely off the bone. The tear is usually associated with an injury by subluxation or dislocation. An individual does not even realize that the shoulder has slid out of the socket.
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A tear may occur within the substance of the labrum and may get torn off, with the edge of the labrum getting frayed so that the border is rough.
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If the labrum tear is in the area where the biceps tendon attaches to the upper end of the socket, it may injure the tendons.
The second type of tearing is quite common and rarely shows signs or symptoms, and is seen frequently in the shoulder as people age. Sometimes a large tear may cause a portion of the labrum to get into the joint, clicking and catching in the socket. Such an occurrence is infrequent, and most labrum tears do not cause these symptoms. This injury is usually to the shoulder and is generally due to trauma. The shoulder can dislocate either toward the front or the back of the shoulder. The torn labrum does not heal back in the right location, and the joint's stability depends on several other factors.
How Does Injury Occur to the Labrum?
Subluxation occurs if the labrum is too small or torn. Injuries to the ball may result in it sliding part of the way out of the socket. A dislocation occurs if it slides out of the socket. The labrum wraps around the socket, and, in most areas, it is firmly attached to the bone of the socket, while in other places, it is loosely attached. The ligaments stabilizing the shoulder joint attach to the labrum in specific locations where an injury tears the ligaments, sometimes pulling the labrum off of the rim of the bone as well due to a subluxation or dislocation.
How is a Labrum Tear Diagnosed?
As the labrum is deep inside the shoulder joint, diagnosing a torn labrum upon physical examination is extremely difficult. Several tests can be performed that may indicate a torn labrum which is sometimes inconclusive and inaccurate.
Medical imaging techniques used make the diagnosis of a labral tear are as follows;
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Magnetic resonance imaging (MRI) scans.
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A CT-arthrogram is a CAT scan preceded by an arthrogram where a contrast dye is injected into the shoulder before X-ray imaging.
What Are the Treatment Modalities for Labrum Tears?
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Treatment modalities depend upon the type of tear in the labrum. Tears due to instability of the shoulder, either subluxation or dislocations, require reattachment.
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A conventional incision made on the front of the shoulder or with an arthroscope can be used with minimal invasions.
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A frayed labrum usually requires no treatment being asymptomatic. However, a large labrum tear requires the affected part to either be repaired or cut out and trimmed.
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Arthroscopic surgery is the best possible method among all other techniques, as reaching the bicep tendons via a conventional surgical approach is challenging. So instead, small incisions the size of a small coin are made to insert thin instruments and the arthroscope. The arthroscope helps view the inner part of the surgical site on a monitor outside, as it has a camera and a light attached to it. The other instruments are used to cut, tear, or grind to perform the surgical procedure, depending on the repair. And the labrum tears can be fixed to the socket by suturing them.
How Is the Postoperative Recovery Phase After Labrum Repair Surgery?
Postoperative recovery depends upon many factors, such as the tear location, severity, and efficiency of surgical repair. The recovery phase takes at least four to six weeks for the labrum to reattach itself to the rim of the bone. An additional four to six-week period is necessary to regain strength. Once healed, the labrum should not be stressed immediately as building up strength occurs gradually.
Conclusion
The labrum is fibrous cartilage tissue among the two kinds of cartilage located on the shoulder. The labrum differs from the articular cartilage and is more rigid than the articular cartilage. This cartilage is only seen around the socket and is treated best with arthroscopic surgery. Though the injury to the labrum does not cause serious or life-threatening conditions, it is best to get evaluated and treated immediately with mild symptoms to prevent complications and improve the living condition of the patient.
