# The effect of preoperative ultrasound localization on the incidence of infrapatellar branch of the saphenous nerve injury after hamstring tendon harvesting

## TL;DR

Using ultrasound to locate a nerve before surgery reduces the risk of nerve injury during hamstring tendon harvesting for ACL reconstruction.

## Contribution

This study demonstrates that preoperative ultrasound localization of the IPBSN reduces sensory disturbances without affecting knee function or pain.

## Key findings

- The experimental group had a lower incidence of skin sensory disturbances compared to the control group.
- The average area of sensory disturbance was smaller in the ultrasound-guided group.
- No significant differences in knee scores or pain were found between the groups at 6 months.

## Abstract

The potential of ultrasound-guided labelling of the inferior patellar branch of the saphenous nerve (IPBSN) to reduce IPBSN injury during anterior cruciate ligament reconstruction (ACLR) has not been explored. The primary objective of this retrospective cohort analysis was to assess whether intraoperative hamstring tendon harvesting avoiding the marked IPBSN would be effective in reducing the incidence of postoperative skin sensory disturbances and the mean area of sensory disturbances.

A retrospective cohort study involving 60 patients who underwent autograft ACLR at Yichang Central People’s Hospital from October 2020 to October 2024 was conducted. Patients were divided into two groups on the basis of the use of preoperative ultrasound localization of the IPBSN, including the nonultrasound localization group (control group) and the ultrasound localization group (experimental group), with 30 patients in each group. The control group underwent standard ACLR with a diagonal incision for hamstring tendon harvesting, whereas the experimental group underwent preoperative ultrasound-guided localization of the IPBSN to avoid the nerve during incision. The primary outcome measures include the incidence of skin sensory disturbances and the average sensory disturbance area. The secondary outcomes include the Lysholm score and VAS score at the 6-month postoperative follow-up.

The incidence of skin sensory disturbances in the experimental group was lower than that in the control group, and the average area of sensory disturbance was smaller in the experimental group (P < 0.05). At the 6-month postoperative follow-up, no statistically significant differences in the Lysholm knee scores or visual analogue scale (VAS) pain scores were noted between the two groups (P > 0.05).

Preoperative ultrasound-guided localization of the IPBSN can reduce the risk of nerve injury during ACLR. The ultrasound-guided approach leads to a lower incidence of sensory disturbances and a smaller average area of sensory disturbance. IPBSN injury was not related to anterior knee pain or knee ROM limitations. Patients can choose whether to use ultrasound localization before surgery according to their needs. The study protocol adhered to strict standards of ethical conduct and patient safety. The results of this trial are expected to provide valuable insights into the prevention of injury to the IPBSN during hamstring tendon harvesting.