Trochleoplasty

What is Trochleoplasty?

A trochleoplasty is a surgery to correct a specific area of a bone in the leg, called the femur, when it has developed abnormally. Usually, the kneecap – called the patella – glides along a groove in the femur. That groove is known as the trochlea.

Sometimes the trochlea is shallow, flat or bumped up, instead of having a well-developed groove, and when that happens, the condition is called trochlear dysplasia. When that happens, the kneecap can easily and frequently dislocate. A trochleoplasty procedure, indicated when there is high grade dysplasia (flat or convex/bumped up), fixes this problem by creating a new trochlear groove, thus enabling patients with their best chance to return to sports and activities.

What are the benefits of Trochleoplasty?

A trochleoplasty surgery creates a new, more normal, trochlear groove. By creating a proper groove, the procedure allows the kneecap to move normally without instability and gives the patient the best possible chance to prevent future dislocations. Ligaments that have been damaged by kneecap dislocations are also fixed at the same time. Numerous published studies have shown the efficacy, patient satisfaction and safety profile of trochleoplasty. The risk of have a future knee cap dislocation after a trochleoplasty is less than 1%.

What are the possible risks and side effects of Trochleoplasty?

Stiffness in the knee is the most common post operative risk that would require repeat surgery. Fortunately, this risk is only 5-10% and is generally avoidable with early rehabilitation. Any surgical scar will have a numb patch next to it and trochleoplasty is no exception.  Fortunately, the numb patch is on the far outside aspect of the knee and is of little to no bother to most, if not all, patients. Most patients will have pre-existing cartilage damage at the time of surgery. While the trochleoplasty fixed the problem that caused the cartilage damage, cartilage has no self-healing capacity so it is appropriate to counsel patients that a small cartilage defect could get bigger in the future and require treatment.  A long term goal of a trochleoplasty is to slow down any the progression of any pre-existing cartilage damage as much as possible. There is a chance of cartilage damage during surgery in the form of a crack or fissure.  This is a rare occurrence and it has not been demonstrated to impact short or long term outcomes.

What are Children's Health's outcome metrics for Trochleoplasty?

The Children’s Health team uses the Banff Patellar Instability Instrument (BPII), the Kujala knee pain score and the International Knee Documentation Committee (IKDC) score to help determine a patient’s improvement after surgery.

What to expect with Trochleoplasty

The trochleoplasty procedure is an outpatient surgery, and patients are generally released to go home within a couple of hours after they wake up. There are no knee range of motion restrictions and patients can weight bear as tolerated afterwards.  Crutches are typically needed for walking assistance for 2-4 weeks after surgery.  Physical therapy will start roughly one week after surgery. A rather noticeable amount of knee swelling is expected for at least 6-8 weeks after surgery and is not a cause for alarm unless there are other symptoms that accompany the swelling.  Most patients are back to some level of sporting activities with 4-6 months.

What to expect before Trochleoplasty

Before surgery, patients will meet with their surgeon for an assessment. The doctor will likely ask for X-rays, an MRI and, occasionally, a CT scan. These imaging tests allow your doctor to look inside the patient’s knee, understand the problem and plan the surgery.

On the weekday day before your surgery, the care team will reach out to you about when you should arrive at the surgery center or hospital. The care team (your surgeon, nurses, and other specialists) will review the surgery plan with you and welcome any questions you have.

The care team will also talk to you about what to expect after the procedure and what you can do to ensure the best possible recovery.

Patients are put to sleep using general anesthesia. The operation takes about two hours.

What to expect during Trochleoplasty

In the operating room, the surgeon will make two incisions on the knee. The new trochlear groove is created by elevating the cartilage of the trochlea and removing bone to shape a new groove. The cartilage is molded into the new groove and secured.

For most patients, ligaments on either side of the kneecap that have been damaged because of previous dislocations. These ligaments are reset using a donor's tendon to augment and strengthen the ligaments on the inner aspect of the kneecap.

What to expect after Trochleoplasty

Patients are generally released to go home within a couple of hours after surgery. For the first couple of days, your knee will feel painful and stiff. Your doctor will give you a prescription for pain medication. However, most patients don't need to take it for more than a week. Cold therapy is strongly encouraged as well.

Your knee will get better faster if you flex, bend and move it soon after surgery. Patients are also encouraged to put as much weight on their knee as they can tolerate. Depending on how their knee feels, the patient will need to use crutches for two to four weeks after their procedures.

What do recovery and long-term rehabilitation look like?

Your surgical care team will connect you with a physical therapy team to plan an evaluation within one to two weeks after surgery. One benefit of coming to the Children’s Health Andrews Institute is that our physical therapists specialize in treating athletic conditions and are fully integrated into our surgical care program. This means they work closely with your surgeon, to understand what your needs are and create a tailored physical therapy plan.

Our physical therapists will work with you to design immediate and long-term goals for your health, safety and participation in activities. We aim to have patients fully rehabilitated and cleared to resume sports within four to six months.

How do I prepare for the Trochleoplasty procedure?

If you are young and healthy, there is not typically any bloodwork or extra physician visits needed. If you have pre-existing medical conditions, or are above the age of 40, then there will be the need for bloodwork and pre-surgical clearance from either your primary doctor or a specialist.

Patients will not be able to eat or drink anything after midnight the night before surgery. If you have a prescription medication that you need to take in the morning, this is typically fine to do with a sip of water but it’s important to share those medications with the nurse who calls you the day before surgery.

What questions should I ask my provider about Trochleoplasty?

• What other procedures correct trochlear dysplasia?
• How many trochleoplasties have you done?
• What are your trochleoplasty success rates?
• How long will it take to recover?
• What kind of physical therapy or rehabilitation support will I need to do?
• Are there any risks or complications that I should know about?
• Is there anything I should watch out for during recovery that might be abnormal?
• What level of pain is typical during the days and weeks after surgery?
• When will I be cleared for full activity after surgery?