What is Tibial Eminence Fractures?
Tibial eminence fractures, although not common, mostly occur in children and teenagers rather than adults. This is due to their subchondral (beneath the cartilage) weakness which can cause the site where the anterior cruciate ligament (ACL), a major knee ligament, attaches to fracture.
This type of fracture, first identified by Poncet in 1875, is seen as an equivalent to an ACL injury in children. It primarily concerns the tibial eminence, a non-joint-related area located between the surfaces of the kneecap plateaus. The ACL is attached to the subchondral plate, about 10 to 14 mm behind the front border of the shin bone. An injury to the tibial eminence can result in the loss of function and stability of the knee.
Since it’s similar to an ACL injury, this condition can also affect nearby ligaments. The front parts of the inner and outer meniscus (knee cartilage) and the ligament between them are in front of the tibial eminence. If the tibial eminence is damaged, these structures can easily get caught up when the fractured piece lifts upwards.
What Causes Tibial Eminence Fractures?
Tibial eminence fractures, which are breaks in a certain part of the tibia, or the shin bone, used to mainly occur in children who fell off their bicycles. However, as more young people play sports, these fractures are now often seen in young athletes who have similar injuries to those of a torn ACL.
Sports collisions are now a common cause of these fractures, but other causes can include car accidents or lower-impact injuries where the knee is bent and the shin bone is twisted inward.
With a tibial eminence injury, the pressure on the bone causes it to break, but leaves the ACL, or a ligament in the knee, untouched. This break occurs in the spongy bone below the hard outer layer of the shin bone.
Past research has suggested that kids’ thighs may be more prone to affecting the tibial eminence than the ligaments attached to it. A study also found that an increased backward slope of the shin bone might make someone more likely to get a tibial eminence fracture.
Risk Factors and Frequency for Tibial Eminence Fractures
Tibial eminence fractures are not very common. They affect 3 per 100,000 children who sustain knee injuries each year. These types of fractures are most frequently seen in patients aged 8 to 14 years. These fractures make up 2% to 5% of knee injuries in children and 14% of ACL (a ligament in the knee) injuries. In addition, up to 40% of tibial eminence fractures are also associated with other injuries, which could involve damage to the meniscus (cartilage in the knee), collateral ligament, capsule (surrounding the knee joint), or to the bone and cartilage itself.
- Tibial eminence fractures affect 3 in every 100,000 children who have knee injuries each year.
- These fractures are mostly found in patients aged 8 to 14 years.
- They represent 2% to 5% of pediatric knee injuries.
- They make up 14% of ACL injuries.
- About 40% of tibial eminence fractures also involve other injuries such as to the meniscus, collateral ligament, capsular, and osteochondral damage.
Signs and Symptoms of Tibial Eminence Fractures
Young individuals may seek medical attention after falling on their knee, for instance from a bicycle accident. The initial symptoms that may be experienced include a swelling of the knee, pain when walking, difficulty in bearing weight and a reduced ability to move the knee.
During the physical examination, it is important to first rule out any immediate threats. This includes checking the skin for signs of an open fracture, as well as performing a thorough neurological and vascular examination to ensure there isn’t a condition called ‘compartment syndrome’ present.
The swelling may not be apparent if there are ligament injuries, since these injuries can allow the fluid to escape from the joint. Pain is usually the cause of a limited range of movement in the knee.
Patients may exhibit looseness when their knee is pushed from the side, suggesting a tear in the lateral collateral ligament (LCL) or medial collateral ligament (MCL). To check the stability of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), doctors can perform tests that involve pushing and pulling the knee. The Lachman test is a specific examination used to identify problems with the ACL.
A positive McMurray test suggests the presence of an additional tear in the meniscus. Tibial eminence fractures, fractures at the top of the shin bone, are often accompanied by meniscus entrapment. Studies have shown that certain types of these fractures are associated with the entrapment of the meniscus or a ligament between the menisci in a significant number of cases. It’s also reported that almost 4% of patients with these injuries also present with a tear in the meniscus.
Testing for Tibial Eminence Fractures
If a person hurts their knee, front-to-back and side-to-side knee x-rays are often taken first to check for broken bones (see Image. Left Knee Tibial Eminence Fracture). These x-rays should show if there are tibial eminence fractures, which are breaks in the bump of bone on the front of your knee. But sometimes, x-rays aren’t enough; they might not clearly show if the broken bone has moved out of place, is lacking cohesion, or if other parts of the knee are damaged.
In these cases, the doctor might suggest other types of scans. Computed tomography (CT) and magnetic resonance imaging (MRI) scans can be more precise. They allow doctors to assess damages to soft tissues or see the presence of broken bone fragments. This is especially important if the tibial spines (small bony projections) haven’t solidified yet (see Image. Tibial Eminence Fracture Magnetic Resonance Imaging).
Two studies showed that some types of tibial eminence fractures are often linked with tears in the meniscus, the “cushion” within your knee joint. They can even result in part of the meniscus getting trapped in the fracture. In fact, one of the studies found that about 7% of such injuries also had associated damages to the cartilage. What’s more, about half of one specific type of fracture came with a trapped meniscus, and 12% had tears in the meniscus.
Treatment Options for Tibial Eminence Fractures
Treatment of a tibial eminence fracture, a type of fracture in the knee that affects the ACL, aims to restore the stability and function of the ACL, get rid of bone fragments affecting movement, and keep the upper surface of the tibia intact. When planning treatment, several things are carefully considered, such as the pattern of the fracture, any injury to the knee’s cushioning or cartilage, and fractures to the upper portion of the tibia.
Treatment method depends on the type of fracture. For type I fractures, the first course of action typically doesn’t involve surgery. The knee is set in a comfortable position using a cast. This position is either slightly bent (at 20°) or fully straight. Holding the knee slightly bent allows the ACL to stretch, while keeping the knee fully straight helps keep the broken pieces in their correct places.
In a study with 14 type I fracture patients, the procedure went as follows: first, excess blood in the knee was aspirated or drained. Then, the knee was kept in hyperextension, or slightly beyond straight, for 3 weeks. This was followed by reapplication of the cast with the knee slightly bent. However, caution is needed with hyperextension since it may cause discomfort, pain, and increase the risk for conditions like compartment syndrome.
To avoid knee stiffness, keep the duration of immobilization as short as possible. Once the fracture is healed enough, as seen in X-rays, mobility and weight-bearing exercises can start. Unfortunately, in some cases, up to one-fourth of the patients also suffer other injuries that require surgical intervention.
For Type II fractures, if the broken pieces can be restored to their alignment without surgery as confirmed by fluoroscopy, a type of imaging technique, non-surgical treatment can be considered. However, if the broken pieces cannot line up properly or if there is injury inside the joint, surgery becomes necessary. In this case, surgeons may open up the knee and fixate the fragments or remove the fragments through an arthroscope, a device with a tiny camera.
As for types III and IV injuries, they were traditionally treated with opening up the knee and internally fixing the fracture. But now, arthroscopic reduction and internal fixation (ARIF), or repairing the knee using an arthroscope, is gaining favor over the open surgery method, as it usually yields better results.
Several surgical options are available for fixing fractures, including using sutures, screws, K-wires, or suture anchors. Suturing is a bit challenging, but doesn’t necessitate hardware removal afterward. If a suture is used, the surgeon may use absorbable sutures, which disappear as the body heals, or metallic ones, which are removed once the fracture is fully healed as seen on X-rays. Alternatively, screws can be used. This can be done in two ways: either inserting the screw from the top of the knee after properly aligning the fracture or inserting it from the front of the tibia and directing it towards the fracture. Patients tend to prefer suture fixation because it irritates the knee less and seldom calls for another surgery to remove the screw. But, whether to use a screw or suture ultimately depends on the specific situation of each patient.
What else can Tibial Eminence Fractures be?
When a doctor is trying to identify whether or not a patient has a tibial eminence fracture, they need to consider other conditions that could potentially cause similar symptoms.
- Tears in the anterior cruciate ligament (ACL)
- Tears in the knee’s meniscus
- Strains in the lateral collateral ligament (LCL) or medial collateral ligament (MCL)
- Fracture in the kneecap (or the patella)
- Presence of bone fragments (osteochondral fragments)
- Fracture in the rounded ends of the femur (Femoral condyle)
- Fracture in the top flat area of the shinbone (tibial plateau)
It’s important to note that these conditions can only be eliminated from consideration through a thorough medical examination.
What to expect with Tibial Eminence Fractures
If left untreated, displaced tibial eminence fractures can lead to a high rate of knee instability. A study by Pailhe and his team found that patients who underwent surgery generally had better overall results than those who did not.
Typically, patients who received surgical reduction and internal fixation had good outcomes. On average, they scored 84.6 on the Lysholm scale, an index used to evaluate the recovery of knee injuries, and about 81% of them were happy with the surgery’s results. They were also able to return to playing sports after about 20 weeks.
Interestingly, the study also found no difference in outcomes between two surgical approaches: ARIF (Arthroscopic Reduction and Internal Fixation) and ORIF (Open Reduction and Internal Fixation). Whether the patients were treated with screw fixation or suture fixation also did not affect their recovery.
Possible Complications When Diagnosed with Tibial Eminence Fractures
Tibial eminence fractures can lead to several complications, such as:
- Limited movement
- Improper union of the fracture
- Muscle loss in the quadriceps due to lack of use
- Non-healing of the fracture
- Growth disruptions that can result in deformities or difference in leg length
- Looseness
- Discomfort or interference due to surgical hardware, typically with metal wires and screws
- Mechanical hindrance
- Internal scarring after surgery
- Damage to the cartilage
- Soft tissue getting in the way
In a study conducted by Watts and his team, they found no significant difference in the occurrence of internal scarring after surgery between procedures. However, they did note more risk factors in patients who received arthroscopic fixation, especially regarding the time it took to refer them to pediatric orthopedic surgery and the surgery’s duration. They found a distinct pattern where a longer duration between the time of injury and surgery and surgical times exceeding 120 minutes increased the risk of internal scarring after surgery.
Having soft tissue trapped within the fracture site can interfere with the fracture’s proper adjustment. This could lead to improper union. Certain soft tissues, such as the transverse ligament between the menisci, and the front part of the medial or lateral meniscus, can particularly obstruct proper healing.
Recovery from Tibial Eminence Fractures
If there’s a fracture that hasn’t caused a shift in the bone alignment, it should be kept in one position for six weeks, or until the X-rays show that the bones have knitted back together. To avoid muscle loss, exercises focusing on the hamstring and quadriceps muscles should be started as early as possible in the recovery process.
After surgery, the knee should be kept straight and immobile for two weeks. After that, exercises to gradually increase flexibility and movement can be started. Beginning two weeks after the surgery, the patient can start to put some weight on the leg while using crutches for support. It’s important to start doing exercises for the quadriceps muscles as soon as possible after surgery to avoid muscle loss. It’s important to remember that each person’s recovery plan after surgery will need to be customized to their specific needs.
Preventing Tibial Eminence Fractures
In order to prevent fractures to the tibial eminence, which is a part of the knee, there are several steps that can be taken. These include:
- Exercising to build strength and condition between sports games or events.
- Wearing safety equipment during physical activity.
- Taking plenty of breaks to rest and recover between activities.
- Avoiding pushing oneself too hard.
- Having regular check-ups to identify any potential risk factors for injury.
- Eating balanced meals to help keep your bones, ligaments, and muscles strong.
- Following safety instructions related to your sport.
- Applying the right techniques when playing sports.
In addition to these primary preventative measures, there are also secondary precautions you can take, including:
- Understanding the importance of doing rehabilitation exercises after a surgery.
- Sticking to the prescribed treatment plan and not missing any follow-up appointments.
While these measures can’t guarantee that you won’t ever fracture your tibial eminence or prevent a recurring fracture, they can greatly lower your chances of getting hurt.
