Anatomic study of infrapatellar branch of saphenous nerve in male cadavers

Abstract

By enriching the knowledge of these variable anatomical position of the IPBSN, surgeon can try to minimize the risk of nerve damage by avoiding the high risk zones while performing medial knee incision, blind puncture or an arthrotomy thus avoiding the unwanted complications.

Retropatellar Accessory Portals for Improved Access to the Patella; Anatomic Description and Evaluation of Safety

“…While this distance is beyond the suggested guidelines of ''no risk'' described by both Mochida and Kikuchi 24 and Ebraheim and Mekhail, 9 it is well within the gray zone (31-60.7 mm, ''unlikely place to find the nerve'') defined by the latter authors 9 and the low-risk zone described by Kerver et al, 16 extending from the patellar apex medially and cranially. All medial portal-to-IPBSN measurements were also within the most recently reported guidelines of Kalthur et al, 14 who described a safe zone of <4 mm or >10 mm from the midpatella in their study of 32 knees. We believe these studies provide a reliable map of the proposed region we intend for retropatellar portal placement and collectively suggest minimal risk.…”

“…Finding consistency within IPBSN branching has been the aim of many studies since. 2,9,14,16,18,34 Despite our relatively small sample size of 10 cadaveric knees, the relationship between the IPBSN and bony landmarks was no different than those reported in the large seminal study by Mochida and Kikuchi. 24 In their study of 129 knees, these authors reported an insignificant difference in the mean distance from the IPBSN to the midpatella in left (52.2 mm) and right (54.2 mm) knees.…”

“…5,9,15 After piercing the sartorious and deep fascia, it follows a highly variable path curving medially and anteroinferiorly over the knee. 14,15,24 Iatrogenic damage to the IPBSN has been reported after many procedures, including total knee arthroplasty, arthrotomy, anterior cruciate ligament reconstruction, open meniscectomy, resection of the prepatellar bursa, retrograde femoral nailing, tibial nailing, and even arthroscopy using standard portals. 9,14,16 Mochida and Kikuchi 24 recognized the precarious position of the IPBSN during standard knee arthroscopy and were the first to evaluate the risk its variable branching pattern imposed.…”

“…We recognize there is always some risk; risk of IPBSN transection exists even with standard arthroscopy. 9,14,24 Additional precautions can be taken to minimize this risk. Transillumination of the medial knee allows one to observe the veins accompanying the saphenous nerve.…”

“…The comparability of our results with other larger studies does offer some reassurance. 2,9,14,16,18,24,34 Second, the portals were all established on cadaveric limbs in isolation. We do believe, however, that the full joint extension and patellar laxity needed to manipulate the patella and establish the portals is as easy to achieve on a true patient.…”