To evaluate the clinical efficacy and safety of ultrasound-guided hydrodissection combined with percutaneous neurolysis in the treatment of common peroneal nerve entrapment syndrome (CPNES), and to assess changes in ultrasound parameters of the common peroneal nerve.

A retrospective analysis was conducted on 66 patients diagnosed with CPNES and treated at our hospital between June 2023 and March 2025. Patients were allocated into two groups according to treatment modality: the combined treatment group (ultrasound-guided hydrodissection plus percutaneous neurolysis, 36 cases) and the hydrodissection-only group (30 cases). After normality testing, continuous data conforming to a normal distribution are expressed as the mean ± standard deviation, while non-normally distributed data are presented as median (Q₁, Q₃); categorical data are expressed as numbers (percentages). Visual analogue scale (VAS) scores, Kofoed ankle scores, numbness improvement grades, and ultrasound parameters were recorded before treatment and at 1 week, 1 month, 3 months, and 6 months after treatment. Treatment-related complications were also documented. Between-group comparisons of the above parameters at each time point were performed using the independent-samples rank sum test (Mann-Whitney U test) as appropriate, and within-group comparisons across different time points were performed using the Friedman test. A P-value＜0.05 was considered statistically significant.

In both groups, VAS scores, Kofoed scores, numbness symptoms, and the inner diameter at the compressed segment of the common peroneal nerve improved significantly after treatment compared with baseline (all P＜0.05), whereas blood flow signal grading showed no obvious change before or after treatment in either group. At all follow-up time points, the combined treatment group showed significantly lower VAS scores and significantly higher Kofoed scores than the hydrodissection-only group (all P＜0.05). The combined treatment group also exhibited superior numbness improvement compared with the hydrodissection-only group (all P＜0.05). In both groups, the inner diameter at the most compressed segment of the common peroneal nerve increased significantly at 1, 3, and 6 months after treatment compared with baseline (all P＜0.05), whereas no significant change was observed at 1 week (P＞0.05). No serious complications occurred during follow-up. Recurrence was observed in 2 cases in the combined treatment group and 5 cases in the hydrodissection-only group.

Ultrasound-guided hydrodissection combined with percutaneous neurolysis is a safe and effective treatment for CPNES. It significantly increases the inner diameter at the compressed segment of the common peroneal nerve, relieves pain, improves sensory function, and enhances ankle function, offering superior outcomes compared with hydrodissection alone, and demonstrates good clinical value for widespread application.