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Dr. Muneeb Ali
Dr. Muneeb Ali, Intensivist
Category: Neurology
Satisfied Customers: 7385
Experience:  Experience of Neurology of over 4 years, well versed in EEG, NCS and EMG alongwith MRIs and CT scans
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Had a left knee arthroscopic surgery for a meniscus tear in

Customer Question

Had a left knee arthroscopic surgery for a meniscus tear in 2016. Severe instability after surgery. EMG 8 months after surgery shows chronic denervation of the quadricep. EMG 17 months later shows the same chronic denervation of the quadricep. I'm so worse now than before the surgery. Looking for suggestions on what it could be.
JA: What seems to make the symptoms worse or better? Have you noticed any swelling?
Customer: No swelling or pain. Leg constantly buckles. Have to walk with leg in a slightly hyperextended position to prevent buckling
JA: Anything else in your medical history you think the doctor should know?
Customer: No. All of this occurred after the arthroscopic surgery.
Submitted: 1 month ago.
Category: Neurology
Customer: replied 1 month ago.
I'm wondering why I'm having a chronic denervation in the quadricep when the surgery was for a torn knee meniscus.
Expert:  Dr. Muneeb Ali replied 1 month ago.


Welcome to JA and thanks for this question. Im sorry to hear about your symptoms. I just came online to see that you have been waiting for some time so ill quickly answer this question for you. Actually there can be a number of causes for the denervation of the quadriceps muscle. This can be due to focal muscle atrophy which has many neurological and non neurological causes. One cause is that the nerve could have been damaged during the surgery which has led to the denervation which has occurred. Other causes can include,

Peripheral nerve diseases

  • Peripheral nerve injuries - External compression, partial or complete transection
  • Entrapment - Entrapment of the nerve in the thigh
  • Ischemia (vasculitis)
  • Multifocal motor neuropathy with conduction block and high titer of anti-GM1 antibodies

Spinal root lesions

  • Intervertebral disk prolapse
  • Root avulsion
  • Tumors - Meningioma, schwannoma
  • Diabetes mellitus

Diseases involving anterior horn cells

  • Poliolike viruses (eg, neuronopathy following acute hemorrhagic conjunctivitis caused by EV70 virus)
  • PPMA
  • Retroviral infections such as HIV or human T-cell lymphotrophic virus (HTLV)
  • Syndromes mimicking ALS but NOT ALS itself
  • SMA and its variants
  • Monomelic amyotrophy
  • Anterior horn cell degeneration

In short there are several causes for the problem to occur however given that your symptoms appearaed only after the surgery was done, it is very likely that the nerve supplying the quadriceps was damaged even though the denervation is proximal to the site of surgery. Sometimes when the nerve is damaged it can progress in a retrograde fashion and cause this sort of damage to the nerve.

But in your situation i think a MRI should be done nevertheless to rule out the other causes.

Do you have any more questions?

Please leave a POSITIVE rating by clicking on the stars above, until you do i am not compensated for my time. You can continue to ask follow-up questions even after the POSITIVE rating. You can also ask questions from me directly by going on the link below,

Expert:  Dr. Muneeb Ali replied 1 month ago.

Would you like to know anything else? Any clarifications or additional questions that you might have, i would be happy to answer them for you. If done for now, please remember to leave a positive rating as that is the only way we are compensated for our time spent helping you. You can continue to ask follow-up questions even after the rating