Car accidents are traumatic events that subject the body to extreme forces, which frequently lead to injury. Many people are familiar with whiplash as the most common group of injuries that result from car collisions, but fewer are aware that shoulder injuries represent a significant number of injuries from car accidents.
The shoulder joint is a complex structure that is designed for maximum mobility. The range of motion possible at the shoulder makes the joint inherently unstable, which also makes it susceptible to various types of injuries in the event of a car accident.
How Do Shoulders Get Injured in Car Accidents?
The two most common mechanisms for sustaining shoulder injuries in car accidents is through direct impact, such as when the shoulder hits the door or steering wheel, and indirect trauma, such as when the body is jolted suddenly, causing the shoulder joint to move unnaturally.
When the body is restrained by a seatbelt, the torso is stabilized and movement of the body is restricted, but the arms remain freely movable. A portion of the force from the collision is transferred to the shoulder joint and the structures that provide stability to the shoulder i.e., the rotator cuff and labrum, are overloaded and injured as a result.
What Are the Most Common Shoulder Injuries in Car Accidents?
The most common types of shoulder injuries sustained in car accidents include rotator cuff injuries, acromioclavicular (AC) joint injuries, clavicle fractures, and labral tears.
Rotator Cuff Strains: The rotator cuff is a group of muscles that work together to stabilize the shoulder by holding the head of the humerus in the glenoid fossa of the scapula. The muscles that make up the rotator cuff are the supraspinatus, infraspinatus, teres minor, and subscapularis. Strains occur when the muscles and/or tendons that attach the muscles to bone are torn. The severity of the strain is graded based on the amount of tearing.
Labral Tears: The labrum is a ring of cartilage that surrounds the shoulder socket, providing stability to the joint. Labral tears can occur in car accidents due to the sudden force applied to the shoulder joint. Symptoms of a labral tear can include pain, weakness, instability, and a popping or clicking sound.
A study published in the Journal of Shoulder and Elbow Surgery in 2007 found that among 61 patients who had shoulder injuries from car accidents, 38% had labral tears.1 Another study published in the Journal of Orthopaedic Trauma in 2014 found that among 37 patients who had shoulder injuries from car accidents, 49% had labral tears.2
A physical examination can help identify the specific injuries to the shoulder, but magnetic resonance imaging (MRI) is a commonly used diagnostic tool to evaluate the exact location and extent of the injury. The use of contrast agents, or dye, during MRI can help to enhance the visibility of the labrum and surrounding soft tissue structures.
Studies have investigated the accuracy of MRI with contrast (MR arthrography) compared to regular MRI in diagnosing shoulder labral tears, and they suggest that MR arthrography is more accurate than regular MRI in detecting labral tears. A systematic review and meta-analysis of 19 studies found that MR arthrography had a higher sensitivity (90%) and specificity (92%) than regular MRI (sensitivity 71%, specificity 85%) in detecting labral tears.3 Another study found that MR arthrography detected 15% more labral tears than regular MRI in a cohort of 100 patients with suspected shoulder labral tears.4
How Do You Fix Shoulder Injuries?
There are many factors that influence the treatment of shoulder injuries, but there are ways to manage shoulder injuries conservatively that help the healing process. Many conservative treatment plans for shoulder injuries will include some or all of the following:
Shoulder injuries are a common occurrence in car accidents and can range from mild to severe. Rotator cuff and labral tears can be diagnosed during a physical exam and the diagnosis may be confirmed using MRI. Mild to moderate shoulder injuries tend to respond well to conservative care, like chiropractic treatment.