After injury or surgery, a patient may find it difficult to contract the quadriceps muscle properly.
Atrophy or inhibition?
It is important to differentiate between quad inhibition, where the muscle itself is not damaged, and muscle atrophy, where the muscle cells have broken down.
Peer-reviewed papersQuote from peer-reviewed paper:
"....Quadriceps dysfunction (QD), defined broadly as a deficit in strength, endurance, and/or muscle coordination of the quadriceps muscle complex, [are] common [sequelae] of knee injuries and both arthroscopic and open knee surgery...."
Citation: Cognetti DJ, Lynch TB, Rich E, Bedi A, Dhawan A, Sheean AJ. Quadriceps Dysfunction Following Joint Preservation Surgery: A Review of the Pathophysiologic Basis and Mitigation Strategies. Curr Rev Musculoskelet Med. 2023 Aug;16(8):338-345. doi: 10.1007/s12178-023-09844-0. Epub 2023 May 27. PMID: 37243966; PMCID: PMC10382434.
Quote from peer-reviewed paper:
"....Arthrogenic muscle inhibition is believed to be an adaptive reflex response from mechanoreceptor signaling, limiting muscle activation in an attempt to protect the joint....[while] muscle atrophy can be defined by loss of total quadriceps volume and/or cross-sectional area versus the contralateral limb or qualitatively as fat infiltration within muscle...."
Citation: Cognetti DJ, Lynch TB, Rich E, Bedi A, Dhawan A, Sheean AJ. Quadriceps Dysfunction Following Joint Preservation Surgery: A Review of the Pathophysiologic Basis and Mitigation Strategies. Curr Rev Musculoskelet Med. 2023 Aug;16(8):338-345. doi: 10.1007/s12178-023-09844-0. Epub 2023 May 27. PMID: 37243966; PMCID: PMC10382434.
What triggers quadriceps inhibition?
Research suggests that quads inhibition is a result of reflexes involving the spinal cord, and are not due to impulses coming from the brain.
Peer-reviewed papersQuote from peer-reviewed paper:
"...findings provide no evidence for a cortical [ie brain] contribution to quadriceps [arthrogenic muscle inhibition] and suggest that ongoing spinal reflex inhibition may be sufficient to explain the marked neural activation deficit that occurs following acute knee injury, knee surgery and in chronic knee joint pathologies."
Citation: Rice DA, McNair PJ, Lewis GN, Dalbeth N. Quadriceps arthrogenic muscle inhibition: the effects of experimental knee joint effusion on motor cortex excitability. Arthritis Res Ther. 2014 Dec 10;16(6):502. doi: 10.1186/s13075-014-0502-4. PMID: 25497133; PMCID: PMC4271337.
Forum discussions
- Re: Caroline's own unicompartmental knee replacement update thread
Part of a long conversation where the causes of quads inhibition are discussed.