Adductor canal block is an effective analgesic technique for major knee surgery. However, the saphenous nerve block is not sufficient to explain this block's efficiency. It has been shown that adductor canal block can spread to the tibial and fibular nerves through the adductor hiatus. However, this diffusion's frequency has never been measured. The main objective of this study is to assess clinically the frequency of the spread of the adductor canal block to the fibular and tibial nerves.
Adductor canal block is an effective analgesic technique for major knee surgery. The PROSPECT group recommends this block in first intention for locoregional anesthesia in total knee arthroplasty. It has been shown to not be inferior to femoral nerve block in this indication. The adductor canal block targets the saphenous nerve and, through its spread in the adductor canal, the posterior branch of obturator nerve and the vastus medialis nerve. However, these nerves can't fully explain this block's efficiency. It has been shown that local anesthetic can spread in the adductor canal to the tibial and fibular nerves through the adductor hiatus. However, this spread is inconstant, and no study has evaluated the frequency of this spread yet. The main objective of this study is to assess the diffusion's frequency of adductor canal block to fibular and tibial nerves through clinical sensorimotor testing.
Study Type
OBSERVATIONAL
Enrollment
70
Department of Anesthésia, CHU Raymond Poincaré - APHP
Boulogne-Billancourt, France
RECRUITINGFrequency of local anesthetic's spread to tibial and fibular nerve
The primary outcome is the frequency of local anesthetic's spread to tibial and fibular nerve during an adductor canal block, assessed by sensory and motor testing of these nerve territories. Sensorimotor testing will be performed at four hours with loco-regional anaesthesia.
Time frame: at 4 hours
Frequency of reduction of sensitivity to cold or touch or reduction in MRC score
Frequency of reduction of sensitivity to cold or touch or reduction in MRC score in fibular and tibial nerves territories assessed at one and four hours after the adductor canal block has been performed, as well as reduction of sensitivity to cold or touch in saphenous nerve territory assessed at one and four hours after nerve block.
Time frame: at 1 hour and at 4 hours
Spread of the local anesthetic in the popliteal fossa
Qualitative assessment of local anaesthetic spread in the popliteal fossa on ultrasound recording (spread or no spread).
Time frame: at baseline
Evaluation of the positive and negative predictive value
Evaluation of the positive and negative predictive value, sensitivity and specificity, and positive and negative likelihood ratio of ultrasound-visualised diffusion to the tibial and fibular nerves as a predictive test for clinical impairment of the sensitivity and motor function of these nerves at 1 hour or 4 hours
Time frame: at baseline and 1 hour, 4 hours
Clinical alteration assessement
Clinical alteration of sensibility and motricity will be assessed before the adductor canal block is performed and then at H1 and H4. The ultrasound scan of the popliteal fossa will be performed at the same time as the local anaesthetic is administered.
Time frame: at Baseline and at 1 hour and 4 hours
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