Abstract
Introduction
Anterior Cruciate ligament reconstruction is a common operation in orthopaedics surgery. A common complication of whilst havesting the hamstring tendon is injury to the infra-patellar branch of the saphenous nerve (IPBSN), resulting in altered sensation to the anterior and lateral aspects of the knee and leg.
Aim
The aim of this study was to further understand the course of this nerve in relation to surgical approach to anterior cruciate ligament reconstruction.
Material and method
The nerve was traced and dissected in 25 knees from 14 different cadavers. Four paths of IPBSN in relation to the Sartorius muscle were identified: (1) a posterior path which ran round the inferior posterior border of the muscle, (2) a transmuscular path that penetrated through the muscle, (3) an anterior path that ran from the anterior border of the muscle and (4) posterior patellar path that ran round the posterior of the muscle at the same level as the patellar.
Dissections were carried out with further 14 knees in a standard manner using both type of incision techniques, vertical incision or horizontal, in ten pair of knees. Using a tendon stripper, the hamstrings tendon were harvested in a standard fashion in different angles of the knee ie full extension and flexion at 90 degrees.
Results
Of these paths the posterior was the most common featuring in 57% of specimens and the nerve was at higher risk of being injured due to the proximity of that pathway and the gracilis and semintendinosus muscle tendons. Horizontal incision has a higher chance of damage to the saphenous nerve and the infra-patellar branch. The saphenous nerve was injured on every occasion by this incision. Vertical incision, 1.5cm from the midline, avoided the infra-patellar branch and the saphenous nerve.
Harvesting of the tendon in full extension was difficult, and it made the incision sites both horizontal and vertical at greater risk injuring the tendons. When the knee was flexed at 90 degrees these problems were overcome.
Conclusions
A vertical incision with a flexed knee gave the best method to harvest the tendon with minimal risk to damaging the infra-patellar branch and the saphenous nerve when using the tendon stripper.
