Brain may 'forget' to use healed leg after ACL surgery
NCT ID NCT04837417
First seen Jun 26, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This study looked at 10 people who had ACL knee surgery 6-18 months earlier. Researchers tested whether the brain unconsciously stops fully activating the quadriceps muscle on the injured side, a phenomenon called 'learned non-use.' They used electrical stimulation, balance tests, and brain magnetic stimulation to measure nerve and muscle activity. The goal was to understand why weakness persists even after healing, which could improve return-to-sport decisions.
What this could mean
Our plain-language read of the trial. This is informational only — not medical advice or a prediction.
What this could lead to
If successful, this study could help identify better criteria for when it's safe to return to sports after ACL surgery, and point toward new rehab strategies.
What could go wrong
This is a very small, completed observational study with only 10 participants. Results may not apply to everyone and do not test any treatment.
Disclaimer
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the original study
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Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.
This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
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Locations
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ASST Centro Specialistico Ortopedico Traumatologico Gaetano Pini-CTO, Presidio Ospedaliero Gaetano Pini
Milan, Italy
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Istituto Auxologico Italiano
Milan, MI, 20121, Italy