The Nerves of the Adductor Canal and the Innervation of the Knee

Abstract

The results suggest that both the SN and NVM contribute to the innervation of the anteromedial knee joint and are therefore important targets of adductor canal block. Given the site of exit of both nerves in the distal third of the adductor canal, the midportion of the adductor canal is suggested as an optimal site of local anesthetic administration to block both target nerves while minimizing the possibility of proximal spread to the femoral triangle.

Spread of dye injectate in the distal femoral triangle versus the distal adductor canal: a cadaveric study

“…The findings from this small cadaveric study suggest that a distal AC block may miss the NVM and likely result in suboptimal analgesia compared with more proximal injections. This is in keeping with the findings by Burckett-St Laurant et al who recommended an injection in the mid-AC as a means to block both the SN and NVM 6. The converse argument would contend that injectate placed within the distal AC could avoid blocking the NVM as an advantage to prevent VMM weakness while still blocking the SN with its infrapatellar branch and the subsartorial plexus.…”

“…Burckett-St Laurant et al found 100% of the intramuscular NVM branches and 35% of extramuscular branches within the AC 6. In contrast, Horner and Dellon describe the NVM to be within the VMM belly in 90% of subjects throughout the AC 9.…”

“…The NVM has large intramuscular and extramuscular branches that travel obliquely through and round the medial (deep) aspect of the VMM belly 6. These branches are in close proximity to the junction of the medial epicondyle and femoral shaft and terminate distally on the anteromedial knee capsule via the medial retinacular nerve 7.…”

Recent advances in regional anaesthesia

“…The area can be sonographically identified as the midpoint of the proximal and distal ends of the canal. At this site both adductor longus and magnus form medial border of the canal, sartorius forms the roof and the saphenous nerve lies anterolateral to the artery [30].…”

The inter-relationship between clinical outcomes as measured by sagittal plane alignment of implant components, peri-operative kinematics, clinical ratings systems, strength, balance and functional performance assessment in patients post Total Knee Arthroplasty

“…Sensation over the medial aspect of the knee is by the infrapatellar branch of the saphenous nerve [28,36]. Sensation over the areas of knee is by the peripatellar plexus comprising branches of the femoral and lateral femoral cutaneous nerves [28,35].…”