Importance of anatomically locating the infrapatellar branch of the saphenous nerve in reconstructing the anterior cruciate ligament using flexor tendons

Abstract

ObjectiveTo describe the path of the infrapatellar branch of the saphenous nerve (IBSN) using the medial joint line, anterior tibial tuberosity (ATT), tibial collateral ligament and a horizontal line parallel to the medial joint line that passes over the ATT, as reference points, in order to help surgeons to diminish the likelihood of injuring this nerve branch during reconstruction of the anterior cruciate ligament (ACL) using flexor tendons.MethodsTen frozen knees that originated from amputations were examined. Through anatomical dissection performed with the specimens flexed, we sought to find the IBSN, from its most medial and proximal portion to its most lateral and distal portion. Following this, the anatomical specimens were photographed and, using the ImageJ software, we determined the distance from the IBSN to the medial joint line and to a lower horizontal line going through the ATT and parallel to the first line. We also measured the angle of the direction of the path of the nerve branch in relation to this lower line.ResultsThe mean angle of the path of the nerve branch in relation to the lower horizontal line was 17.50 ± 6.17°. The mean distance from the IBSN to the medial joint line was 2.61 ± 0.59 cm and from the IBSN to the lower horizontal line, 1.44 ± 0.51 cm.ConclusionThe IBSN was found in all the knees studied. In three knees, we found a second branch proximal to the first one. The direction of its path was always from proximal and medial to distal and lateral. The IBSN was always proximal and medial to the ATT and distal to the medial joint line. The medial angle between its direction and a horizontal line going through the ATT was 17.50 ± 6.17°.

Relationship between peri-incisional dysesthesia and the vertical and oblique incisions on the hamstrings harvest in anterior cruciate ligament reconstruction

“…Among them, graft options and techniques used to harvest them are noteworthy 1 . The most used autologous graft options include the central third of the patellar tendon, the flexor tendons (semitendinosus and gracilis), and the quadriceps 2 ; all have been widely used, and their results and complications are well described in the literature 1, 2, 3. The techniques using grafts from the semitendinosus and gracilis tendons require a small incision and have low donor site mobility 3 .…”

“…The most used autologous graft options include the central third of the patellar tendon, the flexor tendons (semitendinosus and gracilis), and the quadriceps 2 ; all have been widely used, and their results and complications are well described in the literature 1, 2, 3. The techniques using grafts from the semitendinosus and gracilis tendons require a small incision and have low donor site mobility 3 . However, due to the particular anatomical location, there is a potential risk of injury to the infrapatellar branch of the saphenous nerve (IPBSN) during harvest, 3 which can lead to complications such as local pain and peri-incisional dysesthesia 4 …”

“…The techniques using grafts from the semitendinosus and gracilis tendons require a small incision and have low donor site mobility 3 . However, due to the particular anatomical location, there is a potential risk of injury to the infrapatellar branch of the saphenous nerve (IPBSN) during harvest, 3 which can lead to complications such as local pain and peri-incisional dysesthesia 4 …”

“…The percentage of peri-incisional dysesthesia in ACL reconstruction with flexor tendons ranges from 14.9% to 77% 3 . Research on the subject addresses preventive measures and comparisons regarding which access would evolve with lower incidence rates of this symptom, which has become a recurring theme in the literature 2, 4, 5, 6, 7, 8, 9…”

“…Several authors recommend the use of oblique and horizontal incisions to expose and harvest the tibial insertion of the flexor tendons in order to reduce damage to IPBSN when compared with vertical incisions; however, there is no consensus to date 3, 6, 7, 8. It is hypothesized that the incisions with greater respect to the anatomy of IPBSN may ensure a lower complication rate.…”