The tibial eminence is also referred to as the tibial spine. The tibia is the name of the shin bone in your lower leg. At the top of this bone is located a protrusion where the anterior cruciate ligament attaches inferiorly. In anatomy, bony protrusions are referred to as ‘spines’ and serve as a landmark to help identify different parts of a bone. Tibial spine fractures are more common in the pediatric population. It is a common result of a sports-related activity. In an adult, a similar injury may cause an ACL tear. However, in a child, when injury occurs that forces the leg into extreme hyperextension, the ACL will usually remain intact and instead of tearing will pull off a piece of bone from its attachment site. That’s what an avulsion fracture is, when a piece of bone is broken off the bone by a ligament. This is because of bones that are not fully developed yet. There are different types of avulsion fractures depending on the severity and if the bone fracture is displaced. The classifications are based on the widely accepted Meyers and McKeever Classification System:

● Type I: nondisplaced or minimally displaced
● Type II: partially displaced, the bone fragment is anteriorly elevated but still attached
● Type III: complete detachment of the bone fragment, which is further broken down according to whether the fragment involves a large or small piece of the tibial spine
● Type IV: the bone fragment is comminuted, meaning that it is splintered or in two or more pieces

An avulsion fracture is the result of the body being forced into an unnatural position, causing a ligament to strain. But, instead of this strain causing the ligament to tear, it instead remains intact and pulls off a piece of bone where it attaches. Avulsion fractures are much more common in children, and rare in adults. In adults, the same injury may cause an ACL tear rather than a tibial spine avulsion fracture. The causes of an avulsion fracture will be a traumatic event, usually forcing the leg into a position hypertension, but interestingly has been found in children to be a result of forced flexion along with internal rotation. The causes of these fractures are nearly always sporting or activity related or may include:

● Car accident or bicycle accident
● Falling from a significant height
● A direct hit to the knee joint or tibia
● Excessive wear and tear on the joint from long term activity/overuse

The symptoms of an avulsion fracture are similar to other acute orthopedic injuries and is the reason that an accurate diagnosis is so important using either an x-ray, CT scan, MRI, or all three. Avulsion fractures are commonly associated with other injuries so a thorough evaluation of the entire knee joint is vital. The symptoms that may be experienced after an avulsion fracture are:

● Severe pain
● Feeling of displacement of a bone
● Swelling and erythema (reddening of skin), and a feeling of warmth of the knee joint
● Numbness and tingling below the site of injury as nerve endings may have been compromised
● Loss of range of motion in the knee joint
● Difficulty walking or placing any weight on the knee

Prompt medical attention is imperative or you risk inadequate healing of the bone or bone healing in an incorrect position.

If You Are Experiencing Symptoms, Schedule an Appointment Dr. Burke Orthopedics Immediately.

Prevention of an avulsion fracture is a matter of prevention of injury, since this condition is caused by traumatic events. However, along with injury prevention, there are steps to take in order to strengthen bones and ligaments so that they are able to withstand greater forces and you lessen the risk of any injury or accident causing devastating damage. These are:

● Wearing appropriate protective gear when participating in sporting events, particularly knee pads and shin guards.
● Properly warming-up before engaging in strenuous physical activity. This will prepare your body both physically and mentally
● Keep the surrounding muscles as flexible as possible through frequent stretching
● Strength training. This will strengthen not only the surrounding musculature but the bones as well.
● Wear proper footwear and promptly replace older, worn out shoes
● Take rest breaks and know your limit with the particular activity that you are participating in