Arthrogenic muscle response induced by an experimental knee joint effusion is mediated by pre- and post-synaptic spinal mechanisms

Effects of Transcutaneous Electrical Nerve Stimulation and Therapeutic Exercise on Quadriceps Activation in People With Tibiofemoral Osteoarthritis

“…Authors of previous studies 10, 21 have suggested that arthrogenic muscle inhibition is a clinical impairment that should be addressed in conjunction with therapeutic exercise. Data from previous studies 10,30 have indicated that quadriceps activation and motor neuron pool excitability increased while TENS was actively administered, and previous reports 10 have suggested that motor neuron pool excitability benefits from TENS were negated when the TENS was removed.…”

“…The inability to optimally activate the quadriceps muscle may be modulated by both cortical 8 and spinal reflex mechanisms. 21,22 While there is some evidence that motor recruitment may be altered cortically in reaction to chronic pain, 18 other models have suggested that spinal reflex circuits may also decrease quadriceps excitability, independent of pain reaction to a joint injury. 10,21,22 Although quadriceps activation deficits are likely a result of a combination of altered mechanisms arising from different areas of the central and peripheral nervous system, there is sufficient evidence that reflexive modulation of the quadriceps motor neuron pool is involved in altering muscle function following a knee injury.…”

“…21,22 While there is some evidence that motor recruitment may be altered cortically in reaction to chronic pain, 18 other models have suggested that spinal reflex circuits may also decrease quadriceps excitability, independent of pain reaction to a joint injury. 10,21,22 Although quadriceps activation deficits are likely a result of a combination of altered mechanisms arising from different areas of the central and peripheral nervous system, there is sufficient evidence that reflexive modulation of the quadriceps motor neuron pool is involved in altering muscle function following a knee injury. 23,21 Arthrogenic muscle inhibition (AMI) is a clinical impairment characterized by a reflexive inhibition of the motor neuron pool in uninjured muscles surrounding an injured joint.…”

“…23,21 Arthrogenic muscle inhibition (AMI) is a clinical impairment characterized by a reflexive inhibition of the motor neuron pool in uninjured muscles surrounding an injured joint. 9,[20][21][22][23] This reflex inhibition, modulated by both presynaptic and postsynaptic spinal mechanisms, 21,22 decreases the ability of the muscle to recruit motor neurons during a contraction, 11,12 T T STUDY DESIGN: Blinded, randomized controlled trial.…”

Intra-articular anesthesia and knee muscle response

“…In testing the Hoffman reflex, joint effusions have been linked to arthrogenic muscle inhibition at the knee (Hopkins et al, 2002, Hopkins et al, 2001, Palmieri et al, 2004. This could be caused by expansion of the capsule, stretching the capsular receptors, which in turn could inhibit the reflex loop.…”