the Risks of Displaced Patellar Screws After Knee Surgery

Patellar screw migration

Hello Dr.
Li,
In April of this year, I was involved in a car accident that resulted in a fracture of my right patella.
After surgery, two steel pins and a figure-eight wire were implanted for stabilization.
On June 6, during a follow-up appointment, the doctor informed me that my patellar bone had fully healed and that I could begin rehabilitation exercises such as squats and running.
However, an X-ray revealed that one of the steel pins has slightly migrated (this pin was inserted from directly above the patella).
The doctor assessed that this may have been caused by my previous rehabilitation exercises and did not provide specific precautions, only mentioning that if I experience discomfort, I could have the pin removed early.
I am currently still performing knee flexion rehabilitation exercises (I can achieve 110 degrees of flexion at this time).

I would like to ask you, Dr.
Li, whether the migrated pin could potentially shift further out in the future, or could it possibly come out completely? I am scheduled to enlist in the military in October, and I would like to understand the severity of the situation regarding the migration of this pin.
Thank you.

Guo Xiansheng, 20~29 year old female. Ask Date: 2016/06/10

Dr. Li Yongheng reply Orthopedics

Smooth bone screws may shift due to rehabilitation activities.
If there is pain or irritation to the skin during movement, consideration should be given to removing the protruding bone screw.
It is recommended that you return to your original treating physician for a follow-up appointment.
If you have any further questions, feel free to reach out again.
Thank you for your inquiry.

Reply Date: 2016/06/10

More Info

After a knee surgery involving the fixation of a fractured patella with screws and wires, it is understandable to have concerns about the implications of a displaced screw. In your case, where one of the screws has slightly migrated out of its original position, there are several factors to consider regarding the risks and potential consequences of this situation.

Firstly, it is important to recognize that the healing process of the patella can vary significantly among individuals. The fact that your patella has healed according to your physician's assessment is a positive sign. However, the displacement of the screw could indicate that the fixation is not as stable as it should be. This could potentially lead to complications if not monitored closely.

1. Risk of Further Displacement: A screw that has already begun to migrate may continue to do so, especially if subjected to stress from activities such as deep squats or running. The risk of complete displacement increases if the screw is not adequately anchored in the bone. If the screw were to slide out completely, it could lead to instability in the patella, which may result in pain, further injury, or complications in the healing of the surrounding tissues.

2. Symptoms to Monitor: It is crucial to be vigilant about any changes in symptoms. If you experience increased pain, swelling, or instability in the knee, these could be signs that the screw is causing issues. Additionally, if you notice any unusual sensations or if the knee feels less stable during movement, it would be advisable to consult your orthopedic surgeon promptly.

3. Impact on Rehabilitation: Engaging in rehabilitation exercises is essential for regaining strength and mobility in the knee. However, if the screw is not stable, certain movements may exacerbate the issue. It is advisable to communicate with your physical therapist about the screw's condition and adjust your rehabilitation program accordingly to avoid putting undue stress on the knee.

4. Surgical Considerations: If the screw continues to migrate or if it causes significant discomfort or instability, your physician may recommend its removal. This is typically a straightforward procedure, but it is essential to weigh the benefits against the risks of undergoing another surgery.

5. Military Considerations: As you prepare for your upcoming military service, it is crucial to ensure that your knee is in optimal condition. The physical demands of military training can be significant, and any instability in your knee could hinder your performance or lead to further injury. It would be wise to discuss your concerns with your orthopedic surgeon and possibly seek a second opinion if you feel uncertain about the current management plan.

In conclusion, while the displacement of a screw can pose risks, careful monitoring and communication with your healthcare providers are key to managing the situation effectively. Ensure that you follow up with your orthopedic surgeon for regular assessments and discuss any concerns you have about your rehabilitation and upcoming military service. Your health and safety should always come first, and addressing these issues proactively will help you achieve the best possible outcome.

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