Photo Credit: Aleksandr Zyablitskiy

The following is a summary of “Advanced 3D anatomical mapping of saphenous and inferior medial genicular nerve branching: enhancing precision in knee joint denervation,” published in the October 2024 issue of Pain by Yu et al. 

Radiofrequency ablation, used as a non-opioid treatment for chronic knee pain, traditionally targeting the inferior medial genicular nerve, but the role of the infrapatellar branch of the saphenous nerve in knee joint capsule innervation remained controversial.   

Researchers conducted a retrospective study to determine the branching pattern frequency of the infrapatellar branch in 3D, assess its spatial relationships with the inferior medial genicular nerve, and to determine if targeting the infrapatellar branch could benefit the existing protocol.   

They serially dissected, digitized, and 3D-modeled the infrapatellar branch and inferior medial genicular nerve in 7 specimens (mean age 57.8 ± 2.0; 2 female/5 male) and documented the relationship, used it to assess the anatomical efficacy of the infrapatellar branch in the protocol.   

The results showed that the infrapatellar branch was most commonly a cutaneous nerve, which exhibited variability, being either unbranched or having 2–3 branches, and was consistently found superficial to the branches of the inferior medial genicular nerve in all specimens. When the infrapatellar branch coursed more distally, the strip lesion would not capture the infrapatellar branch but would consistently capture the inferior medial genicular nerve; when it overlapped with the inferior medial genicular nerve, the strip lesion would capture both nerves.   

They concluded the proposed protocol targeting the infrapatellar branch was likely to consistently capture the inferior medial genicular nerve, irrespective of the anatomical variation of the infrapatellar branch. 

Source: academic.oup.com/painmedicine/advance-article/doi/10.1093/pm/pnae102/7825355